‘98 V90 here! And hello again!

I replaced the PCV system and the front cam seals about a half year ago. Ever since, I’ve been running with the dipstick popped for fear that the seals would blow. As far as I knew, the old seals were original. I still get smoke out the dipstick, but oil is starting to blow out of it causing a mess.

My thing is this: if I’m still getting smoke out the dipstick hole when the stick it out, would putting it back in cause the engine to over pressure and pop the cam seals? I’d really rather not do them again (easy but time consuming) and I also don’t want an oil soaked engine.

Any thoughts? Thanks in advance!

In case anyone was wondering, I took a couple nice, long rides with the dipstick reinserted. No blown seals or anything else (so far!).

Thank you all for your help! What a lovely forum.

Shove the dipstick down. Warm up the engine and do a glove test.

When you replaced the PCV, did you also replace the small plastic screen? If so, remove the screen and throw it in the garbage. The screen does nothing except cause a clog after a short life span.

If the glove test inflates the glove, did you clean out the holes behind the separator that go through the block? Some times they get full of deposits from conventional oil.

It is quite normal for vapors to come out of the dipstick hole after engine shut down. It is not normal when the engine is in idle mode, as the vacuum pressure at idle should route the vapors through the PCV.
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Keeping it running is better than buying new

They don’t come out after shutdown - just during running. I cleaned out all those plug holes on the block. I’ll double check about the white screen in the flame trap. I think I left it out based on similar advice I read.

I’ve tried the glove test a couple of times, but it inflated. Will I have to undo the whole thing and re-clean those block holes?

The o-ring at the dipstick top and how the tube bends, bending the dipstick when in-place, both serve to retain the engine oil level dipstick in place. If excess crankcase pressure, the oil level dipstick in the tube would pop-up exposing the o-ring so excess crank pressure can escape. An old o-ring has shrunk, and may not help seal / retain the dipstick in place.

A new o-ring can help maintain the oil level check dipstick in place with normal crankcase pressure.

The engine oil seals are pressed into place and are secured more tightly into the engine oil seal bores. Is oil leaking from the engine oil seals you replaced?

Securing the engine oil dipstick into place won't cause the engine oil seals to pop out with normal crankcase pressure and proper PCV system.

As oil heats to near and above water boiling temps, combustion byproducts including moisture in the oil boil out. The PCV as you know scavenges this crankcase vapor in a push - pull action. Push from the sump vapors boiling out of the oil, some very slight combustion passing the piston rings, and pull as engine vacuum pulls the vapors through the PCV and into the air intake.

The white block engines employ very tight tolerance in design. Combustion product passing the piston rings happens, yet is very slight.

You used Volvo or OEM quality parts when replacing the PCV assembly on the 2.9 L B6304 I6 in your 1998 S90? And I'll guess you used seal presses for oil seal installation?

The B6304 PCV crank case ventilation uses no moving parts, contains no valve or moving parts. Merely the flame arresting sieve in the flame arrestor assembly. Two vacuum connections draw crank case pressure into the engine through the air intake port manifold, one for idle and the larger PCV vapor hose when throttle is open.


Some vapor will escape from the running engine through the PCV and, if unsealed by a not in-place oil level check dipstick tube, the oil level check dipstick tube.

Link to the Volvo Parts Webstore B6304 Crankcase Ventilation Assembly. Opens in new browser tab or window:

Crankcase ventilation 6-Cylinder. Fits Volvo 960 (1994-1997); Volvo S90 (1997-1998); Volvo V90 (1997-1998).

Link URL
https://www.volvopartswebstore.com/showAssembly.aspx?ukey_assembly=238482

If the engine is cold, and you start the engine, and vapor begins to immediately escape the unsealed dipstick tube, suspect engine combustion (detonation) escaping into the engine oil sump or crankcase. Either passing the piston rings or through a combustion pressure leak into an engine oil drain passage in the form of a cylinder head gasket failure.

So far as you know, the B6304 engine timing belt has not ever broken during the engine lifetime?

You have verified that the oil trap, or oil breather separator box mounted to the engine block is in no way clogged. Vapors escape yet oil vapor condensate drains back into the engine?

One way to check for proper PCV action is to perform the unsecured engine oil fill cap. With oil fill cap unsecured, yet set in place, with engine started, cold engine is best, the combination of running engine intake vacuum stays the unsecured cap in place. The other method is the glove test, yet the B6304 does not offer a rise on the valve cover to secure a glove to as with say, redblock four cylinder.

You use synthetic or mineral oil?

Another way to test with cold engine off, remove the large PCV pipe at the intake, pinch or stuff closed the smaller PCV vapor at the intake end, wipe the large PCV vapor end and blow into it. With oil fill cap off, easy to displace air through the engine sump space and out through the uncovered engine oil fill hole. With oil cap in-place, about impossible to blow through.

You've checked compression or performed an engine leakdown test?

Sorry for the armchair speculation. Been a long time I've had my ham-handed-hands on the B6304. Would love one in an S/V90 with M90L behind it. All about torque. No need for Turbo.

I'm sure Spook and other brickboard 900-series owners with recent or current direct experience can better help you.

Hope that halps.

Questions??!?!

Ham-Handed-Hand Boyeeeeeeeeeeeeeee!!!!!
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Jonathan Harshman Winters III: The Mightiest, Greatest, & Most Powerful North American Comedian & Comedic Actor in Perpetuity!

I ended up trying the cold start oil cap suction test. There was no suction. In addition, smoke seeped out from around the dipstick after a minute. I’m guessing the compression is toast due to some worn out piston rings?

Did you put in a new oil trap/ breaker box when you did the PCV? I think you still might have a clog in your PCV.

Try the blow test. If it passes, at that point it might make sense to move on to doing a leak down test and compression test. Probably a good idea anyway. Unless the car has been seriously neglected I doubt you’ll find a problem with the compression or rings. The white block engines have bottom ends that are typically bulletproof. Usually what happens with them is with very high mileage (200k+) the valve seats start to leak some oil. That happened to my 95 850 at around 230kish.

Do you use any oil? How much? An old school test for the rings is to warm the engine thoroughly then lock into second gear on a downhill, rev the engine to 4000rpm+, hold it for a minute then release. After releasing the accelerator, look out your rear view mirror for oil smoke clouds.

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Will I buy another Volvo??? We'll see....

I wouldn’t be surprised if this car was neglected. I feel like there’s still a clog, but I cleaned out those ports on the block. I can try cleaning out the one that’s on the underside by the oil pan again. That’s the only one I can think of.

On my next big drive, I’ll try that oil usage test. This car leaked a lot, but I don’t think it used oil like that.

Thank you so much for your post! Super helpful!

How do Kit!!

Hi Herr!
Kit is absolutely on the money. As long as the dipstick o-ring rubber is in good shape the dipstick should pop out first before the seals if there is high crankcase pressure. If it pops out after full insertion then you definitely still have high crankcase pressure.

Have you already tried the oil cap test?

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Will I buy another Volvo??? We'll see....

Heck yeah this board rocks. I love both responses!! Definitely cleared up my worries. I’ll give the oil cap test and the blowing test a try.

I used original parts in both replacements. I don’t know if the belt has ever broken. The car was pretty beat when I bought it. Granted, it only had 128K on the clock.

For what it’s worth, I use synthetic. I have no other known oil leaks. The main leak was the front cam seals, but I replaced those which stopped the leak.

I’m just happy I can put the stick back in!

Hiya Mr. Walker! Hope all's aces and eights and you, yours, your colleagues, and everyone and everything are in the finest of fettles this and everyday!!!

Hi HerrGruyere,

Oooch! Verify the timing belt change! I'm unsure the mileage. Something like 70k or 100k miles or less for a B6304 belt change. Also, the timing belt tensioner is hydraulic on the whiteblock engines. (Unlike the spring tension to set t-belt tension and then apply retainer nut torque on them over head cam redblock engines in 240 and newer.)

I'm unsure, yet feeble memory, yet now verified by an i-net search, indicates you replace the B6304 t-belt tensioner with each new B6304 timing belt in 960, S&V90 up to 1998. Also, you replace the tensioner idler pulley and some other bits. The Volvo 700-900 Series is sort of lax on 960, S&V 90 (up to 1998) info. Maybe I missed the info? Here is on of several pages in the FAQ on 960, S&V 90 (up to 1998). Found the page. Link opens in browser tab or window:

960-90 Series Information: Volvo Maintenance FAQ for 7xx/9xx/90 Cars

URL (Copy and Paste)
https://www.brickboard.com/FAQ/700-900/960_90Info.htm


960 Timing Belt Change in B6300 Series Engines.

URL:
https://www.brickboard.com/FAQ/700-900/EngineSealsBeltsVent.htm#960TimingBeltChange

Yet as you write, you think it through, so I bet you replaced the belt, tensioner, and pulleys, and other bits?

FCP Euro has a kit for 1997-1998 S&V 90, yet dunno if OEM quality and / or OEM bits. Maybe want to service the serpentine belt and idle pulleys also. Engine oil is deleterious to any of these belts. Yet the timing belt is of the utmost concern!

https://www.fcpeuro.com/products/volvo-timing-belt-kit-and-water-pump-kit-comprehensive-tbkit270wp-1



I'll guess Continental is OEM for the t-belt? I've seen t-belt made of kevlar somewhere for red and white block engines. I know INA brand is now OEM for redblock overhead cam. Dunno about white block. Yet best to get OEM as Volvo blue box or get the OEM from the OEM manufacturer!

Really want an S&V 90, yet not ever going to happen. One without neglect and abuse with an M90L 5-speed would be swell. I like the torque yet worry the S&V 90 is a little touchy. I guess needs a very expanded tool set to care for them properly. Like rear IRS suspension bushing replacement! I'd go for urethane and lot of silicon grease (SuperLube NLGI 2)! Wish you could use something other than them Nivomats. A stiffer less plush ride would be swell. Then ply the rotten roads of the midwest! Ugh!

Sorry to go on so.

Mr. Walker and others like Uncle Spook will have useful guidance. That Earl Grey tea I have daily makes for a keyboard gadfly!

Earl Grey Tea with hunny and milk Boyeeeeeeeeee!!!!!!
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Jonathan Harshman Winters III: The Mightiest, Greatest, & Most Powerful North American Comedian & Comedic Actor in Perpetuity!