This is a 1991 Volvo 240 with 141,000 miles.
In the process of doing some front engine work due to an oil leak, I plan to change out the water pump, the accessory bushings, the timing belt and seals, and the gasket on the plate surrounding the crankshaft. After viewing a couple of You Tube videos, several questions come to mind.
1. On the water pump, when applying some sort of gasket sealer, is it applied only on the pump side of the gasket? Is there a recommended gasket sealer? RTV, silicone sealer?
2. There are two black sort of O-rings, one on the top side and one where the metal water pipe enters the pump from the rear. One video recommended applying Vaseline petroleum jelly for each. I am concerned about a possible leak in those areas. Is there something more substantial/durable that would help ensure no leakage in those areas?
3. When pressing in the new accessory bushings, what choices do I have for lubricating those bushings. Would something like liquid hand soap be sufficient?
4. On the passenger side of the engine just forward of the oil filter there is a device (temperature sender?) screwed into the engine block with a wire attached that comes out of the engine harness at the same place as the alternator wires. What is that item? Any need to consider replacing that when the area is open and easy to get to?
5. When replacing the gasket and cover plate that is screwed onto the block around the crankshaft, same question. Is gasket sealer applied only to the cover plate side of the gasket?

To answer your questions with what has worked for me (not everyone agrees with all solutions).
1. I use either red high temp silicone sealer or just plain wheel bearing grease on the gasket. NOT A BEAD -just a smear to make a very light coating spread out between my thumb and forefinger on both sides. This isn't for sealing purposes - the gasket does that - but to ensure the gasket will slide as the pump is lifted into place.
2. I use just WB grease to lube the O-rings so they slide into place - just a light coating--not a "glob". It's the squashed O-ring that does the sealing.
3. Yes, liquid soap, a spritz of silicone spray or a little grease will help the bushings slide into place.
4. That's the oil pressure sending unit. Examine the wire insulation for cracks or missing sections of insulation. If that wire gets grounded it will cause the oil light to go on.
5. This is the trickiest question because if you remove the crankshaft seal housing it's likely the the oil pan gasket will tear in the process where the two parts meet. I loosen a couple of oil pan bolts back from the seal housing and slide a thin blade between the oil pan gasket and seal housing to try and get them separated. If the oil pan gasket doesn't shred, the area where it tore from the seal housing can be repaired by cleaning thoroughly and applying red silicone sealer. If it's really shredded a new piece of oil pan gasket may need to be cut. I would remove the crankshaft seal housing only if it is definitely leaking from the gasket area- otherwise just replace the seals with the housing in place. A little grease on the rubbing surface "lips" of the seal will help it slide into place. Great care must be taken to ensure the sealing "lips" don't fold under as it slides over the crankshaft. I load the back side of the seal with grease to keep the spring from popping out while installing. Like the water pump gasket I use only a very thin (both sides) coating of sealer if the housing does get removed. Good luck with your project. -- Dave

Thanks Dave and Nahtanha for the helpful information.
Dave,
1. when you suggest wheel bearing grease for the water pump gasket, are you distinguishing that from what used to be called "cup grease" which is just an ordinary grease? My experience with WB grease indicates it is a fibrous grease that is hard to wipe off one's hands which I presume means it is a more durable grease. Would either one do? I have both. This suggestion appeals to me in that I would not have to buy a tube of silicone sealer. On the other hand I might buy the silicone sealer just to be on the safe side.
4. Thanks for identifying the oil pressure sending unit.
5. I went under the car to examine the area where the front of the oil pan meets the seal housing. Both the pan and the gasket extend forward until they are right below the seal housing. In fact two of the oil pan bolts are threaded into the seal housing. Obviously they would have to be removed to get the seal housing out. Okay, now I understand what you are saying. I will take your advice and not take that housing off unless I see evidence that the seal gasket is leaking.
You wrote "Great care must be taken to ensure the sealing "lips" don't fold under as it slides over the crankshaft. I load the back side of the seal with grease to keep the spring from popping out while installing." Are you saying to pack grease in the circular cavity where the spring resides? I can see where that and greasing the shaft would help prevent the lip from folding in.
Again, thanks for your comments.

I just use whatever WB grease I have at the time or the red hi-temp silicone. I just put a dab on each side and use my fingers (thumb and forefinger) to rub it into the gasket leaving just a very thin film with either material. My purpose is to provide a "sliding" surface so the gasket doesn't bind.
The oil seals actually have two sealing surfaces - one facing into the motor and the other to the front. The inside lip keeps the oil in - the outer one other matter (water for instance) out. The inside one splays out with its edge toward the rear. That's the one that can fold under allowing oil to slip past. I use a rather thin but blunt pick tool to guide the lip around the shaft as the seal gets installed over the shaft. The outer lip will naturally (usually) be facing the correct way. I usually rotate the seal as I install it until it meets the housing, then press it into place.
Yes, I fill the void with grease to help lock the spring in place and a very light coating of grease on the shaft is an aid. -- Dave

Thanks again Dave for the clarification.

If the block face where the water pump mounts is free of corrosion and pitting, I use silicon grease like SuperLube NLGI 2 grease (Do-It Best and Ace may continue to sell it).

There is the action after you place the gasket and seals where you have the water pump loosely secured through the oblong holes. You lever up the water pump upward to compress the top seal to that seal between the cylinder head underside and the water pump top. As sustain the lever upward action, you then secure the water to the block hardware to torque. I use a star pattern and apply torque in three torque stages.

I also apply silicone grease to the seals where the coolant return metal pipe that routes under the exhaust manifold secures into the water pump.

If the block face is pitted near or at where the water pump and gasket set during the install lifetime, some may use some manner of exceptionally fine abrasive action to smooth the pitting edges, if possible.

Please read here (copy and paste URL in new browser tab or window):
https://www.brickboard.com/FAQ/700-900/Cooling.htm

If the block face is pitted near or at where the water pump and gasket set during the install lifetime, quality RTV with a long working time to accommodate the lever up action and torque the water pump to block face toque time and may be best. Permatex and other sealant brands offer a range of sealants. Se Art's comments on pitted blockface.

Use Volvo seals and gasket. I like HEPU wasserpumpens.

Use distilled water when making up two gallons or so of 50/50 antifreeze and tap water to make coolant. I merely pour both antifreeze and DISTILLED water (1$ at Wally World) into the expansion tank. Or pour 1 and fill with water.

Consider replacement of the two large hoses. Sometimes the two small diameter at the back of the engine that serve as connection to the heater core. Leave the heater control turned to hot during the coolant drain and fill. Recycle the old stuff.

Questions?

Hope that halps.

Nihil Boyeeee.
--

Thanks KittysGrey for the suggestions. I have a pretty smooth engine block where it meets the water pump. Your comments prompt me to ask if I should consider draining the engine from what appears to be a plug on either the side of the engine or the front, down low. This is the time, given that the front of the engine is mostly open after removing the crank pulley and that black cover. However, I don't want to blindly do this without some input from experienced folk. FYI I am just now getting to the point of installing the new alternator bushings. I threw out a question to the BB guys about that. Next will be the water pump. Again, thanks for sharing your insights.

Yes, as Art Benstein shows you in his response.

Please choose both model and year in the MODEL/YEAR drop-down menu choices. The choise persists in subsequent posts. (Forgot to choose this in my response to you.) The heat control valve changes from 1991 and all prior years to a thermal ABS plastic design.

Have a hose section ready to drain in a stainless or plastic container. Doubtful you'll re-use the coolant mix.

Use a 13 mm spanner at the drain with barbs at the end, and, if I recall, a 15 mm wrench on the drain section secured in the block as counterhold. The two yellow metal sections (bronze / brass) of the block drain can sometimes unscrew together using a sole spanner to open the drain.

+++++1 to a stiff wire section as Art indicates, like coat hanger, to unplug the sediment that may plug this lowest section of the coolant system. Also, with the cabin temp control turned to hot to complete the drain.

If you encounter a lot of hard sediment in the drained coolant, inspect the radiator through the large bottom cooled coolant return port. See the end of horizontal coolant tubes clogged or no?

Find a manufacturer and date mark on the radiator. Usually at the top or on the plastic side tanks. The ABS thermal plastic material embrittles. With bad motor / transmission mount, engine moves about and also sags rearwards towards the bulkhead / firewall. Pulling on the top hot coolant hose from the thermostat housing to the top radiator large hot coolant in port. The top large hot coolant radiator port can brake away from the side plastic tank.

Your 1991 240 should have a coolant temp switch on the radiator near the top above the large cooled coolant return, that controls the on / off of the front pusher fan. Replacement radiators do not include this coolant sensor. So reuse it. The replacement radiator maker stuffs a grommet in the sensor hole that can fail (leak at least or blow out under coolant system pressure). So stuff a propr plug or move the sensor from the old raidator to new. More than likely, the pusher fan that mounts in from of the A/C condenser is bereft of sintered metal bushing / bearing lubricant and is resistance to turning when power or by hand. Now hard to clean and relube the assembly if the motor has not electrically failed. A continuity test of this pusher fan motor at the connector proved continuity and a chance for restoration. If you plane to restore A/C, can help. There is a relay for the fan. The fan is also controlled by the A/C pressure switch at the A/C evaporator / drier.

At the age / miles, please consider replacement of the low pressure rubber fuel line return to the steel line secured to the firewall. The high pressure fuel line (black nylon hard line with outer rubber hose sleeve) and the low pressure fuel line are usually sheathed togther. I make mention as this low pressure fuel line section, 'downstream' of the fuel pressure regulator (FPR) has endured far past the duty cycle since factory install. I forget the fuel line specification designation for this low pressure line section. Art Benstein knows.

Questions?

Hope that helps.

Selling Silver Dollars at the Numismatist Store for Volvo fuel food and my food.

My occasional daily quote:
Never leave Spokane. The lesser of evils for this targeted individual or contract. Saint Louis MO is a malodorous dump under the arches thing. A massive hateful pia fascist toilet.
--
Jonathan Harshman Winters III: The Mightiest, Greatest, & Most Powerful North American Comedian & Comedic Actor in Perpetuity

Hi,

I don’t quite under stand the part about there being plugs that you are seeing with the front of the engine naked of any engine accessories.
Any plugs that have anything to do with draining the coolant are where Art is showing in his post.
All other accesses to the cooling jacket areas would be through the large freeze plugs on the sides of the block. Those are pressed in and not a serviceable intended item.
If there are any plugs up higher in the cooling jacket area might be there for only future sensors.

The biggest hole you have to work with is there in the front under the water pump.
If you wanted to, you could flush water in and out of there that might stir up a muck of rust, if the cooling system was abused by not using a rust inhibiting soluble oil solution or an antifreeze for cold climates.
In the USA, the use of antifreezes are considered the norm but there are always exceptions for a few owners that use straight water for not knowing better. When they don’t care, they are the beaters of cars, that create the beater cars supply chain.

Pressure hose water, will most likely contain hard water or dissolved rocks in it, so use compressed air to help in expelling that water afterwards.
Compressed air works for a heater core service by inspecting or replacing those hoses on the back of the engine. Most people kiss off that job detail as long as possible. I’m one that shouldn’t do that, but have.
Make sure that the hoses clear of the sides of the dipstick as they can get a rubbed-in hole! Bend the dipstick tube over, with a length of pipe, just a wee bit.

On those threaded plugs, that’s exactly what they are!
You should not play with those unless you are rebuilding an engine.
They are strictly plugs used for giving access for cleaning purposes. Otherwise, don’t mess with them just because they screw in.
These holes are drilled into the block for, “engine oil passages,” to reach other parts of the engine.
The pressurized ones are called “oil supply galleries” and can run even at angles.
Other holes can be a simple “cross drilled hole.” Some make up a system of oil drainage passages, from the top of the engines head on down through to an open space above the pan.

Holes can go those short distances while others can run the length of the whole block, especially, down low along the line of the crankshaft.
It can have a plug on both ends to shorten the lengths of twist drills.

On the exhaust side of the early nineties engine blocks, you will notice “casting bumps” showing up on the outside of the engine. They are right over the main oil galley that runs over from the oil filter area. The oil pressure switch port is in a galley hole. It’s technically a fancy plug! (:)
This modification is where extra material was placed for the purpose of installing “threaded-in” oil squirters that place oil up under the pistons on some turbo model engines.
It is my belief, as I have not seen them, that the 1993 engines and slightly earlier ones, may have these oil squirters as “standard equipment” on both style engines.
I have read, only, that they are the same as used on the BMW’s around the same era.

I hope this answered some of questions.

Phil

Hi,

I have the felt the way many of us feel when using fiber paper gaskets dry or the need to use a holding compound to help place the gasket correctly.
I can’t say that SuperLube would do anything to help seal fibers, but the elastomer type of seal are very compatible to the stuff, according to their specifications sheets.

The purpose of the fibrous gasket materials are meant to have their fibers to be cross laid on top of each other in a random configuration. This way, when compressed in joints, they will impede the migration of molecules of gases or fluids through it.
The cross lay disrupts “channel paths” outside the fibers form, let alone with the internal molecules of the gaskets substances. Finding or definitely making Gasket materials is an applied science to meet many many variables.

On today’s gasket materials the term cold forming is used. This idea has “ slipped in” (:-), with newer materials that are working more closely at the molecular level of thinking?
With all of those, you are required “not” to use any kind of other sealant.

I too, have wondered about that very first layer on each side of the material to work or wiggle into place all the time its being compressed. This is an area of contention within the gasket industry should of it be left dry or not? Marketing more products is always good for business.

The finish that’s made on the sides or surfaces of any joint will have microscopic grooves from “any” material removal machining process no matter how fine a media used.
These grooves are straight lined or circular and in combinations on surfaces.
Whether this is a mechanical method or chemically one, it takes motion to be part of the removal process.
Cutting is done with either pressure or motion singularly or any combination of those two, within a controlled procedure or process to reach a dimension and finish tolerance.

With that said, I have used some products to help contend with both worlds a compromise to fill those voids.
In some cases I have used this product.
http://hylomarsealant.com/

One has to read about their thinking, as it is not so much in the silicone school of thought nowadays!
Anaerobic sealants are looking to be the newest rage in techniques and of not even having a separate gasket material in the joint.
It is used as a go between or to be a get around of the faults of solvent (drying) driven sealants or those silicones for many years.
Hylomar was a thinner lighter product back then and that has gotten me by for many years.

It helped keep me away from those ”Loctite” products that go bad right inside their containers before the next project!
With Loctite products I have try to line up many projects in a row so I can use up at least a half a tube and trust me that hasn’t worked out either, as I run out of space nowadays! (:)

Prematex products are expensive enough without that built-in feature of not getting it sealed back up!
Shows me they still don’t know much about sealing a joint of even their cap device.
I have seen more and more products get repackaged in a smaller units to “hang on the wall” within their product line.
Anti-seize and dielectric pastes are some that have gripe me over the years.
The product get priced upwards and the dumb public follows the charades of marketing, thinking it must be preciously good stuff!
You can tell, at times I disdain their marketing tactics, now used, when the company has to work to gain an honorable reputation.
Their nothing like 3M, that makes the products and has grown up to be
an industry standard in many many other fields.
Both have been around just as long in my life!

I hope this shed some light of the purposes for gaskets.

Phil

I'll throw my 2 cents in -- it's worth about 1/2 a cent!

There are, quite generally, several common types of gasket materials or situations where we need to seal against fluids ending up somewhere they shouldn't.

1) Paper gaskets -- these abound. They are designed to provide a proper seal installed dry. This of course assumes that both mating surfaces are clean and true/flat. Trying to make up for a lack of cleanliness or for surfaces that aren't true or are warped with the ubiquitous "RTV" sometimes works, sometimes doesn't, sometimes works at first and then begins to "doesn't" with the passage of time. I prefer to coat paper gaskets with Hylomar Blue -- it's a gasket dressing that primarily aids with dis-assembly. In terms of getting the gasket to stay where it's supposed to stay - many use adhesives of one type or another. Not my preference.

I prefer to buy a couple of extra bolts of the same size at the local hardware store, cut the heads off, and slot them for a flat blade screw driver. I can put these into 2 or 3 locations to act as temporary dowels to hold the gasket in place, start a couple of the OEM fasteners, and then remove the 'dowels' and replace with the proper bolts. Gasket held in place and no adhesives used. And yes -- I have little baggies marked accordingly (header dowels Ford 5.0L, lower intake dowels Ford 5.0L, header dowels LS3, etc.) This counsel applies to all the other gasket types listed below - use a temp dowel to hold the gasket in alignment whenever you can.

The one exception I'll make with regard to RTV/paper gaskets is if I have a configuration where 3 surfaces come together in different planes -- best on I can think of is where the lower intake, the head and the timing cover converge on a 5.0L Ford. In an area like that, I'll add a small dab of RTV in that type of "corner" to help the gaskets do their job.

2) Rubber, viton, buna-N, o-rings, etc -- these should be installed onto clean, true/flat surfaces with a bit of something to lubricate them so they don't bind when you start tightening things. Some use vaseline, some use a bit of oil. I prefer my trusty tube of white grease or engine assembly lube. Doesn't take much - you just want them to be able to slide rather than bind. This also applies to metal/rubber composites where there's a metal substrate coated with a rubber-like material.

3) Graphite/composite gaskets -- more and more common, especially on exhaust manifolds. These should be installed clean and dry. The graphite IS the lube it requires to not bind. When these seal coolant passages as well as other passages simultaneously (as in the lower intake manifold of a 5.0L Ford) if you just can't help yourself you can put the lightest smear of RTV on both sides of the gasket around the openings that seal coolant passages. But I don't do that and have never had a problem with them leaking.

4) Cork -- I HATE cork gaskets. I've tried just about everything to get them to seal reliably over the long term. I guess it depends on how one defines "long term"..... The approach that seems to work the best, for me anyway, is to smear a light coating of grease (I use wheel bearing grease) all over the cork gasket before putting it into place. This lets it move a bit, helps tremendously with dis-assembly. And in my experience, if you have no other choice but to use a cork gasket, you'll be disassembling it at some point to replace the leaking cork gasket.

5) Threads -- Sometimes threads penetrate into coolant passages and the like. I use Permatex or ARP Thread Sealer. They're designed to not ever harden or leave debris behind when you remove the fastener in the future. I would NEVER use RTV to seal threads. It's not designed for that -- and clean up after disassembly becomes a real pain.

6) Bushings -- I usually lube these with Armor All if they're rubber (sway bar links, shock bushings, accessory bushings or shifter bushings, etc), and water resistant grease formulated for poly bushings.

Lastly - pet peeve - almost every non-cast, aftermarket exhaust manifold/header I've tried over the years has a head flange that isn't true. They're usually warped a bit from the welding. And I've watched lots of folks struggle with stripped threads (lucky if it's the bolt/stud, unlucky if it's the threads in the head) and bolts that keep backing out on their own -- all because they're trying to pull a warped manifold flange flat against the head with the header bolts. Check the header flange with a proper straight edge. It's it's not flat/true - spend a few bucks at the local machine shop and have them mill it flat and perpendicular to the fastener surfaces. It will bolt up perfectly, it'll seal, and the fasteners will stay tight.

Thanks Phil for the detailed explanation of engine plugs.
And thanks Phil and Michael for the interesting and informative discussion of gaskets and sealants.
Given your extensive knowledge of this aspect of automotive work, I want to tap your expertise about a specific application. Here is the situation. To determine the source of an oil leak dripping down in the front when the engine is running, I removed the timing belt covers, water pump, timing belt sprockets, crank pulley, and plastic backing plate. After installing a new water pump and new bushings on the alternator, and putting the timing belt back on, I re-attached the water pump pulley (no fan) and put on a fan belt to run the water pump and alternator. Now with pretty good visibility in the area, I started up the engine to observe for leaks. The camshaft seal had a slight leak, and the crankshaft seal housing was leaking. It was unclear as to whether the two lower seals were leaking, but it was clear that the seal housing cover plate was leaking at least at the top. I checked the attaching bolts and found that they were tight except for two or three along the top of the plate. After tightening the loose ones across the top and running the engine briefly I observed that the oil leakage was substantially reduced. Now the plan is to remove that cover plate and attach a new gasket. I understand this will be difficult because the oil pan gasket is attached to the underside of this plate, and by removing the plate I will likely damage the front of the pan gasket. In the first response to this thread, "Volvo by Heck" wrote:
(Beginning of quote) "This is the trickiest question because if you remove the crankshaft seal housing it's likely the oil pan gasket will tear in the process where the two parts meet. I loosen a couple of oil pan bolts back from the seal housing and slide a thin blade between the oil pan gasket and seal housing to try and get them separated. If the oil pan gasket doesn't shred, the area where it tore from the seal housing can be repaired by cleaning thoroughly and applying red silicone sealer. If it's really shredded a new piece of oil pan gasket may need to be cut. I would remove the crankshaft seal housing only if it is definitely leaking from the gasket area- otherwise just replace the seals with the housing in place." (End of quote).
Well, it is tempting to just accept a small leak and not have to deal with the intricacies of sealing up this area. My question is what might you recommend for sealing up this area if I proceed? What material might that original factory oil pan gasket be made of? If that section of the oil pan gasket is not destroyed, will tightening up the loosened oil pan bolts seal it back up? From a practical point of view, I cannot imagine how I would go about thoroughly cleaning the area before applying some gasket sealer.

The last time I actually worked on a Volvo engine was sometime around 1998....my daughter's 760 Turbo wagon needed a timing belt and I could not get the pulley off the bottom. So I hacksawed the plastic timing belt cover about 3/4 of the way down -- and installed the new belt and the top 3/4 of the cover - and just left the bottom portion exposed. Just so you know the level of mechanical incompetence that my counsel is coming from....

Having said that, the situation you're facing is very similar to what happens when the timing cover of a 5.0L Ford motor is removed. The oil pan gasket extends under the bottom of the cover. Further complicated by a dowel on each side of the pan that locate the bottom of the cover. What we would do is actually cut the portion of the oil pan gasket that was exposed -- as cleanly as possible flush with the block. Buy a new oil pan gasket and cut off the front piece to match the new exposed pan rail. Liberally "dollop" (it's a verb too) some RTV right at that interface between cover, pan, block and where the two ends of the old/new oil pan gasket come together -- and bolt it all back up. I never had any problems with that approach.

As to whether to tolerate a small leak -- in my experience - small leaks become larger over time. I'd try and fix it as long as you're in there and as long as you're planning to keep the car until the sun burns out. If you know what I mean....

What fluid do you want to drain? If coolant, the block drain is on the exhaust side of the engine at the rear.



Don't be put off by the oxygen sensor in the foreground of this pic. I've already forgotten what year car your thread is about, but this photo is very old and probably from a B23-powered '83 240. Regardless, you have the same drain petcock in your car. You may have to remove the valve stem completely and use a wire to dislodge a pile of debris before you get a decent flow. Once you clean it out, the valve works quite nicely. Connect a hose to it.


--
Art Benstein near Baltimore

“Dance like no one is watching; email like it may one day be read aloud in a deposition.”

Thanks Art for that clear picture of the petcock for draining coolant from the engine block.
Here's one for you.
A mechanic who worked out of his home had a dog named Mace. Mace had a bad habit of eating all the grass on the mechanic's lawn, so the mechanic had to keep Mace inside. The grass eventually became overgrown. One day the mechanic was working on a car in the backyard and dropped his wrench, losing it in the tall grass. He couldn't find it for the life of him, so he decided to call it a day. That night, Mace escaped from the house and ate all the grass in the backyard. The next morning the mechanic went outside and saw his wrench glinting in the sunlight. Realizing what had happened he looked toward the heavens and proclaimed, "A grazing Mace, how sweet the hound, that saved a wrench for me!

Allow sealant to set up before installing gasket. It has to skin over to work properly. Both sides of the gasket, smearing with your finger and thumb for the thinnest amount of sealant. I've seen too many gooped up wet applications. Silicon plumbers grease for the rubber seals.