Hi all,

I've got a 760 Turbo that seems to be approaching its last leg at 220k miles.

It runs okay, but yesterday, when I checked the oil while getting gas, the oil was thin and frothy—water in the oil, which means either a cracked head or a blown head gasket. Either way, it's not going to be running for much longer.

As I understand it, there's no way to tell which is the problem without taking the engine apart to look, correct?

So my question is this: would it be worth it to source a new engine? This one is leaky and old and requires a bit more work than just replacing a head gasket/head (whichever is required).

I would love to replace the worn parts and put another 200k miles on the engine, but I don't have the time to devote to it, so replacing the engine with a junker seems like the more practical option.

IF replacing the engine with a newer one makes sense to you all, are there any specific years/models that I should look for? Is the 87 auto tranny compatible with later-model (perhaps early 90s?) 4-cylinder turbos?

Thanks for any and all advice.

if you decide to break it down and replace the head gasket, make sure you give the head to a machine shop that can pressure test the head and be sure it's not cracked. you wanna know before the head goes back on. good luck, chuck.

And that's just the question I'm asking--is it worth it to take the thing apart, only to have to get a new engine, considering the wear and tear already on the existing one?

I suggest you do some more assessment of the engine you have before deciding, and before pulling it apart. I would at least run a wet and dry compression test on it. Does it burn oil, or does it leak so much you don't know?

Pulling a head is pretty easy, and after it's off it can be checked for cracks/warpage.

If you get a used engine, you would (should) be putting new oil seals, timing belt, etc. on it anyway. So it's no more work to do that to the one you already have.

If you found a nice low mileage replacement, that would be good, but I bet it's a hard find.

I would not buy and install a used engine if all I needed was a head gasket, valve job, and oil seals on the existing one.

Charley

I'll try and get over to my father's this weekend to do a compression test.

It doesn't burn oil, but there's far too much blow-by (the source of which definitely isn't blocked-up PCV, as I clean that little joint and associated hoses and connections almost every time I'm under the hood, and the oil separator is recently cleaned), and a pretty severe oil leak that I haven't been able to locate.

I just found a head on ebay that was recently pressure-tested; it comes with a cam and recently-done valves, as well as the cam seals and valve stem seals, which I was planning on replacing anyway. It might be worth my while to just get the head and save myself some time. It's pretty cheap, at the moment.

You're right about the work involved in replacing the engine--but the only thing is, I'm concerned about the wear-and-tear on the current engine due to the oil loss. I try to keep it topped up but occasionally I'll get the flashing light...not to mention the water in the oil that I found before. It runs decently enough, but I'm concerned about internal wear.

You do have a legit concern about any damage from the water in the oil. But, you can minimize that by parking the car now and not using it until you can get the head and gasket replaced. Edit to add: If you can, also drain the oil prior to parking it, change the filter, and fill it with clean oil. Don't run it after that, until the new head is on. This oil is just to protect the innards from the water in the old oil. You will change it again before you start it up after the head work.

Changing a cylinder head on these engines is pretty easy. I've done it twice, once three and a half years ago for a blown head gasket, and a second time (just finished yesterday) because a mechanic screwed it up back in July. Just to put you at ease, the second gasket change was not needed as a matter of course, but because I procrastinated about changing the heater control valve, which then split and blew out the coolant, overheating the engine and warping the head. Shop I took it to screwed it up, so I just redid it my self. If you want something done right . . .

Anyway, the first time you tackle head work in these engines you might feel overwhemed, but believe me, it is far easier than you think/fear. Since it is fresh in my mind now, let me know if you are going to do it, and I'll write up some details that are not in the FAQ, and which might help you a little. Biggest advice: study what you are going to have to do, think about it and visualize over and over again, then tackle it with patience and persistance. Buy top quality parts (Elring or Victor Reinz, if not Genuine Volvo), and work very clean and carefully. The most difficult part on the turbo engines is access to some of the nuts: the ones that hold the turbo to the exh. manifold, and several others on that side are very slow to get on and off. Probably so even if you have stubby or stubby/ratcheting combination wrenches (I don't). Patience and persistance are the keys.

Should take a first-timer about two to three days of comfortable, not-rushed, work. The biggest hang-up will probably be the machine shop, they can be miserably slow at times, and you don't want to rush them.
--
Scott Cook - 1991 745T, 1985 RX-7 GSL-SE, 1986 Toyota Tercel (Don't laugh, it is reliable, faithful AND gets 41 mpg!)

Hmm. I'd definitely appreciate any info you can send because I think I'm going to do it. I found a head that the guy is selling with cam and recently machined valves so if I get that a lot of work that I'd have needed to do (or have a machine shop do) will be done.

For that matter, while the engine's apart, I'll likely replace rings and bearings. The RMS probably needs to go as well, because it's 220k miles old, and that can't be good.

While we're there...who knows when the motor mounts were replaced. And the transmission mounts, for that matter.

Anyway--thanks ahead of time for any info you send. vinniethefro at gmail dot com, if you please.

Will do. Are you in a rush, or do I have a couple of days to organize and write it up?

First thing I suggest is that you take a good look at Charlie's (Kentucky's) advice and decide how far you want to go with your engine. Heads are easy, I've done a few recently. It has been a very long time since I have done the lower-end and pistons/rings on an engine (a Chrysler/Plymouth 440), but it was not anything even close to easy. Unless really trashed, the bottom-end of a Volvo should run nearly forever. Maybe not as smoothly as when it was new, but reliably and long.
--
Scott Cook - 1991 745T, 1985 RX-7 GSL-SE, 1986 Toyota Tercel (Don't laugh, it is reliable, faithful AND gets 41 mpg!)

I've got a few days. Thank you again for your help.

Volfro,

Well, it looks like you have your self all primed up to let this project snowball on you. If that's what you want, go for it. You could end up with a very well rebuilt engine as a result.

However, I haven't seen any indication in your posts that you have evaluated what you have now. Once you pull the head, you have lost much of what is required to evaluate what you have. There is evaluation that is done before you start taking things off, and evaluation that is done during and after disassembly. You need to do them in the proper order unless you decide from the get go that you want to do a full rebuild.

On these boards, it is hard to assess what someone else knows without seeing a lot of their posts. I've not seen many of your posts because I was active a few years ago, but only recently bought another Volvo and became active here again. Now it's like I'm new to the board. In other words, you may have rebuilt many more engines than I have, and I wouldn't know it. So, if it seems like I'm talking down to you, please forgive me.

I get the sense that you are thinking, "as long as I have the head off, I might as well replace the rings". If you can get a head that is ready to go, as you have indicated you might, swapping that out can be done in an evening after work. Replacing rings and bearings is a whole different kettle of fish.

At this point, I don’t' see that you have done anything to assess the rings you have in the engine now. If they are working well with the amount of cylinder wear you have, they may be fine for quite some time. New rings may not like your old cylinder walls, and at your mileage, measuring may indicate boring and oversized pistons are needed. Who knows what you will find in the bottom end. It could be lots of work and big money. If that’s the way you want to go, you can have a good engine in the end, but don’t count on this being an “as long as the head is off” kind of job.

It could be that putting another head on it, or having yours reworked, is not enough to fix it. But, doing the head is so little work compared to rebuilding the engine that I think it might be worth the risk of wasting a head gasket set and a few hours to find out before you tear down the whole engine.

And again I will say, don't take the head off before you assess everything you can while the head is still on.

Charley

I'll be honest: although I'm not afraid to tackle a project like a head gasket, I've never actually done it before. I've owned older Volvos since I could drive, so I know the '84-'87 4cyl engines pretty well, but I've never had to do work more extensive than replacing some gaskets above the head and replacing accessories/belts/etc.. I've just never had the necessity to go further than that, so with bigger projects, I tend to rely on my father, who is an experienced mechanic.

You're right though--I was thinking of the rings as an "as long the head is off" project, and I'm glad you told me it's not.

What sort of evaluation do you recommend before I remove the head? (Besides compression tests mentioned above.)

I don't remember if the suggestion to do a compression test included doing it first dry and then wet, but it should be done both ways to give some indication of ring wear vs. valve leakage. If you have a blown head gasket, it may be hard to assess the rings/valves with a compression test.

If you can get your hands on one, a cylinder leakage test would be nice. Any aircraft mechanic will have one, as will most shops. If you don't have one of those, you can still pressurize the cylinder with an adapter and an air compressor or air tank. With either the tester or just the air hose, listen for how fast the air leaks, and from where it leaks to locate problems. You might hear it from the exhaust, intake, or by removing the oil cap, or in your case it may bubble out of the cooling system. The valves have to be closed on the cylinder tested and it can be tough to keep the engine from spinning because of the pressure, but it can be done.

I would install a mechanical oil pressure gauge and see what the oil pressure is like on a warmed up engine. This would give some indication of bearing condition.

A cooling system pressure test may give some clue about the coolant in the oil. This test may give different results if done on a cold engine vs. a warm one, so try it both ways.

Checking crankcase pressure or quantity of air discharged can give some idea of ring condition because worn rings allow more blow by. I suppose you could get some idea by blocking the PVC system and running with the oil cap off.

After it has been sitting for a while, like days, pull the oil drain plug, but hold it against the drain hole and see if you have free standing water or coolant that runs out. If you do, drain until the water is gone and you are left with the oil that was floating on top of the water.

If you only have a little bit of water in the crankcase, or if you can bleed the water as mentioned above, I would warm it up, change the oil, and see if the new oil gets contaminated. It could have been a freak thing, or possibly someone put water in it. If you get water out of the crankcase, and you have antifreeze in the cooling system, that would be quite suspicious eh?

If your oil is really nasty, you may just have to change oil once with out warming it up, and again to flush it before you can have clean enough oil to see if the problem returns.

I'm sure others will come up with more suggestions of things to check before tearing it down.

Charley

As I am sure many after me will point out, 220k is barely midddle age for the b230ft. It definitley sounds like a "simple" blown head gasket. Personnally I would just do the headgasket, water pump and all belts. UNLESS I suspected issues with the turbo or the rear main is pissing like a hobo. But if you are gonna swap then you would be well served to search out a 93-95 b230ft(L Block). Longer piston skirts and the addition of piston cooling "oil squirters" seems to add longevity and makes the engine much quieter(no piston slap).
Matt

Yes, I know it's still young yet. It does have a pretty serious oil leak, but I don't think it's the RMS. It's more likely the turbo's oil return line, but I haven't been able to find the exact source.

Replaced the water pump a few months ago, still gotta do the belts. I was planning on replacing all seals from the head up--but if the head is cracked, it might not be worth it.

That's the conundrum: there's no way for me to know if it's a cracked head till I've taken it apart, and I'm wondering if it would be worth it to just source a new engine, considering the original engine's existing problems. Just wanted to know what you folks thought I should do.

I had similar issues trying to keep my 88 765T running. The engine only had 147,000 miles on it, but had been severely mistreated. After a head gasket change and removal of the turbo plumbing to try and reduce the internal clanking, I replaced it with a lower mileage B230F out of an 86 244. That was about 15,000 miles ago and the "new" old engine works fine.

Regards,
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles, 88 780 246K miles, 93 Buick LaSabre 119,000 miles

Yeah, if I can't get parts for cheap then I'll likely source an engine, but I think I'm going to go the repair route. It'll be cheaper, I think, though it'll take longer.

Your 780 is awesome, btw! I've only seen one of those in real life, in Chattanooga. I wish Bertone still did cars for Volvo.

That 780 is still very much of a project, but it will certainly be awesome when it is finished. We are still undecided about the engine, but it will be backed with a T-5 Tranny and road gearing. Right now I am working on the interior which looks like pigs wallowed in it.

Used motors are cheaper than rebuilding yours, although, if you do go into yours to the point of rings and bearings, I would recommend spending the money on getting it balanced also. The ones that I have torn down are several grams out and could spin a lot better with the tolerances closer.

Regards,
--
Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com, www.dallasprecision.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles, 88 780 246K miles, 93 Buick LaSabre 119,000 miles