Salozar

Hey everyone,

I just picked up an '86 944 with 107k on the clock. It was advertised as having a bad head gasket and I bought it with the intention of replacing it. However the more I read the more I have begun to wonder if the oil cooler seal may be my issue. Here are the symptoms.

The car runs/idles/starts fine. I took it out for a short drive when I looked at it and it ran great, it idles well and makes no weird noises. The oil is completely white in the dipstick and the coolant tank is empty but both the oil cap and coolant tank have this odd brown powder like substance in them. There is a bit of white smoke but it's not overwhelming.

I read that if it's the oil cooler, then oil will go into the coolant tank but the coolant won't go into the oil for a while. The PO states that he discovered the issue and the car basically sat for the last 3 years which I believe could explain why the coolant is also in the oil, because it had enough time to get in there while the car was sitting.

Another thing I have noticed is everything near the oil cooler is very obviously being leaked on by something, (View picture below). There is also a cam cover leak but I think this is unrelated.

Please note some of the wetness could be from excess pb blaster used on the bolts in preparation for the head removal.

My plan of action is to do the cooler seal hopefully next week and flush the oil/coolant a couple times. Once I do this I will also do a compression test to see if any cylinders are out of spec.

My question is, with all this said, does it seem likely that my problem is the oil cooler seal and not the head gasket? I'm not sure the car would run perfectly with a bad head gasket?






And here is where the car leaks it out while parked. I should also add that it's also made a puddle of white oil in the belly pan between where the sway bar and ps pump are.

951Dreams

That leak looks more washer fluid than coolant. Right place too. But could be the pic.

I went through the same thing. Decided since I had both mixed, I'd just do it all.

One thing to keep in mind, really.. REALLY should do rod bearings if you have water in the oil. No matter the cause. I'm using it as an excuse to throw in 88 high CR pistons. To give myself a 15 HP bump.

If you spin a bearing, it's likely new block time. Better safe than broke, toyless, and sorry. Do the rod bearings, do them when you do the oil cooler. Just do it. If you don't kittens will die, and world drought will ensure.

Kidding aside, I really think you might want to consider doing them. Good chance to do engine mounts while your at it, if yours are bad.

If it's been 3 years, need to do the belts too. Not if, not maybe. Not later. Now, with the oil cooler seals and rod bearings. Oh, and rollers too, probably the water pump.

Isn't 944 ownership fun?

Don't make me break out the memes about this.

951Dreams

It's 2am, and I had to!







And after the belts, the rubber gas lines are next! Or:







OK, I'm done

SloMo228

The oil cooler seals are easy enough to change out, and they don't cost that much IIRC. At the age of these cars, replacing any rubber you can afford to is almost never a bad idea anyway, so even if it doesn't solve your problem it's at least preventative maintenance.

Edit: I'd bet $5 your lower balance shaft housing is leaking from the rear seal, too. An easy temporary fix is to clean the area really well (I just sprayed a bunch of brake cleaner up there) and spread some RTV around the cap. It'll stop the leak until you have the chance to remove the housing and replace the seal properly. Since getting that lower housing off is kind of a PITA, it's something I decided to leave until I pull the engine for a rebuild.

Datkinsj

Last fall I completed a HG change along with TB, BB and associated bearing, this spring after a short shake out from sitting all winter, a puff of white smoke. Well, after a compression check, all cylinders at 165-168, I changed the O rings on my Air Oil separator, and in the process of an oil cooler gasket replacement, now I kick myself for not doing all this last year! My 944 was awaken after sitting for 8 years with a blown HG....

Salozar

Thanks for the replies. I think I am going to proceed with the oil cooler job, put new oil in, do a compression test and see where I'm at. Hopefully running it a bit after that job to do a compression test won't eat the bearings immediatley as I'm going to try to diagnose if it's a head gasket or not before I do the rod bearings.

I know the plugs will look steam cleaned if the HG is bad so I pulled them to look and they don't seem steam cleaned to me. Any thoughts? (Note I didn't get a picture of 1 of the plugs but it was no better than any of these)

joes

Sorry you don't really have an option. If there is water in the oil especially in an unknown engine you must change the rod bearings. Do yourself a favor save your crank change the bearings.

V2Rocket

At best, the 88 pistons are worth 5hp, provided you have the matching DME chip...hope you didn't pay too much.
1987 944 had 9.5:1 and 147hp, runs on 87 octane...1988 had 10.2:1, different chip, and got 152...and needed premium gas.

Block is untouched if a rod bearing goes...but the crank may be wiped.

Re: leaking...oil in the coolant would make me suspect the oil cooler...a matter of pressure differences. Oil is at 3-5+ bar when engine is running...coolant is at ~1. Only way I can think of a reverse exchange here, is if there's a leak and the coolant is still under pressure when the car is shut off, hot (0 oil pressure).

bonus12

I am expecting my oil cooler seals to arrive today from pelican. (Tip: buy the kit as individual pieces to save a lot of money.)

The reason I am doing the job is because, starting very recently, I have noticed a very thin film of sludge in the expansion tank. I am pretty sure this is a new thing. There is absolutely no coolant at all in the oil, thankfully.

I guess even though I am changing the seals I can't help but wonder if such a thin film of sludge in the expansion tank can be caused by the oil cooler seals. It must be a very minor and/or early leak. And, the coolant itself is perfectly clean and I don't really see a rainbow layer on top of the coolant. But I am changing the seals regardless because it's the cheapest and easiest first step and they probably need to be changed anyway. And I'm doing it ASAP because of fears outlined above.

SloMo228

When the oil cooler seals go, they will let oil into the coolant first, and generally only when they get really bad does the coolant make its way into the oil. White on the dipstick could just be condensation from sitting, if you didn't drive it long enough to bring it up to operating temperature and boil off any condensation in the block.

I would pay close attention to the oil when you do the oil cooler seals. If there's been coolant mixing into the oil, you'll be able to tell when you drain it. If it's the case that the oil cooler seals failed and the oil/coolant mixing only went one way (into the cooling system), then you'll probably be fine to run it without replacing the rod bearings.

On the other hand, if there is any evidence of coolant in the oil, you will definitely want to change out those rod bearings.

maj75

"No coolant in the tank and a white dipstick says you almost certainly have water in the oil. If you try to shortcut the repair, you will end up paying a lot more later...

951Dreams

All the Sources I've seen show 158 or 160 for 88's? So really it's 10 I guess. I always think 15 from an 83 with 142 to a 88 with 158. That was before I found sources showing the 5 HP increase for 85.2+ cars.

And maybe these are different, but in all my V8's, and the F-body club I raced with in their V8's, if we spun a rod bearing we threw a rod too (mostly). Sometimes into the head, sometimes through the oil pan, but always mangled the block. I've read a few stories on here about racers doing that with these too. Is that not normal? Do these not throw the rods if the bearing spins very often?

Either way, a crank is bad enough. And these are prone enough to spinning the rod bearings I personally wouldn't take a chance. From all my reading, there are two big things you want to make sure of. ALWAYS change your timing belt after 3 years (even if not used) or 30k miles, and change the rod bearings if you ever see water in the oil.

Normally with a head gasket, I'd expect some smoke (vapor), steam cleaned plugs, and/or exhaust in the coolant. But it does depend on where they failed. Normal failure is of course around the compression area, but I've seen a gasket fail in other ways too. It's more rare, but you can have failure around the oil channels, that allow oil to be forced into the coolant. And if it's bad enough you'll get coolant in the oil, like explained above, for the same reason. I find those failures are more related to a bad job installing the gasket in a previous HG replacement, some kind of human error. Or once I was sure it was a faulty gasket.

So, when I pulled my head, my gasket looked pretty good. I couldn't for the life of me see where my fluids were mixing. I would say oil cooler was my problem, except I had a overheating/exhaust in the coolant issue. I had looked at my oil just days before the overheat event, and no milkshake. Even had my AOS off, to do the seals, and it was clean as could be. Few days later, I start overheating on a 12 F day. Get it home, oil is milkshake, AOS is full of milkshake. So it was a sudden event, not gradual.

My upper hose was cold, the T-stat had stopped opening. However my coolant was super pressurized. I can't prove it, but I'm pretty sure what happened is my HG gave, fluids mixed, got exhaust in the coolant and air got trapped behind the T-stat, so it stopped opening.

From the moment my temp started to rise, till I shut it off was 1.5 miles. It has never overheated (for me) before, has always ran perfectly solid right where it was supposed to. No up and down, no movement at all once up to temp.

Ran perfect with no smoking right up till I shut it off.

I guess it could have been the oil cooler cracked or something. I'm going to pull it soon and find out, but all my symptoms (aside from no smoke) said head gasket.

If I knew then, what I know now, I'd do what your thinking. I KNOW I didn't have coolant in the oil just days before, so I know it was a super recent event. I'd have drained the oil and coolant right then, refilled with oil. Ran it for like a minute (to flush the coolant out of the bearings), drained it again. Changed the oil cooler seals and pressure tested the cooler itself (for leaks/cracks), refilled the oil again and refilled with coolant. Then watched it like a hawk.

And assumed my overheating was unrelated, and just a stuck stat.

However, since the car is new to you, and you don't know how long it's been like this..... I'd highly suggest doing the rod bearings just to be safe.

EDIT: I would have flushed the bearings, not because I would think that would somehow "save" them, if damage was already done, nothing to do. I would have just flushed them so the coolant wouldn't be sitting there between my bearings and crank while it sat waiting on getting the oil cooler done. Steve at 944online told me he ruined a crank by letting it sit with water in the oil too long. Course then I hear of people who blew a HG and parked theirs and let it sit years and years... so meh. What I would have done.

mel_t_vin

Re: no up/down, no movement...are you referring to indicated water temp? If so, this is not normal operation for any 944/968.

Maybe, in winter, at a constant 40*F ambient, the water temp may settle around ~180*F. But for the other 8 or 9 months of the year, water temp/gauge will fluctuate around ~190*F and vary from ~185*F to ~195*F, continuously, as fans kick on and off.

951Dreams

I never got to drive mine in warm weather. It blew... whatever it was it blew, In January. It had been pretty cold it's entire life with me. So I have no idea how it should be in warmer weather. But mine would rise, hit a certain level, and stay there. not moving, from then on out.

Till the one day it didn't. Then it didn't stop rising till it hit the red just as I shut it off..

mel_t_vin

Sorry to hear that. This is a recent issue/problem?