Help!!! Coolant in Oil on 944

[Fatboy]

dern said:

When the engine is warm and the rad is cold are the pipes from bottom left of the rad (as you look at it from the front) to the pump (near the oil filter) and from the top of the engine to the top right of the rad cold or warm? Mark

The top right pipe is warm at the engine end and gets progresively colder as it approaches the rad, as does the big fat pipe at the bottom left...

[silverback mike]

I think that sounds like an airlock in the rad....Have you given the pipes a damn good squeeze? Mine did a similar thing when I refitted it, Leave the expansion tank screw lid off whilst squeezing, eventually it will rise to the top and bubble out.

[numbnuts]

Buster44 said:

I had very similar symptoms (apart from the mayo) and it was the waterpump - the impellor had come off!

Good advice

[dern]

Fatboy said:

The top right pipe is warm at the engine end and gets progresively colder as it approaches the rad, as does the big fat pipe at the bottom left...

Ah, I'd assumed when I mentioned this earlier the pipes were hot but the rad was cold. In that case it looks like you aren't getting water circulated through the system in which case either the rad may be blocked as you believe although I'd be surprised if this was the case as the rad would slowly lose efficiency over time rather than suddenly start overheating, the thermostat is stuck shut as you also suggested or possibly the pump has failed.

I guess you need to flush the rad to see if it is blocked and test the thermostat (or try running without it to see if the rad gets warm which would be pretty conclusive) and finally, if the rad is clear and the thermostat works ok, suspect the pump I guess.

The thermostat begins to open at 83 degrees and is fully open at 90 degrees according to the workshop manual.

The fan sensor switch looks like it's in the radiator according to the manual by the way which would explain why that isn't coming on.

Mark

>> Edited by dern on Saturday 15th January 21:16

[Fatboy]

Cheers for that guys - how do I go about running without the thermostat? Never done that before?

I have been giving the pipes a good squeeze while bleeding the system, but it hasn't made any difference to the overheating...

[dern]

Fatboy said:

Cheers for that guys - how do I go about running without the thermostat? Never done that before?

You can run it without the thermostat (assuming it'll physically go back together without it) to prove the pump works but I wouldn't run it to work and back if you have a choice as it won't let the car get up to temperature this time of year I wouldn't have thought.

Didn't you have coolant leaking from the bottom of the rad though, did you find the cause of that?

Mark

[Fatboy]

So I'd just pull the thermostant out then re-assemble without it if it works?

I couldn't find the source of the leak - wanted to get the overheating/lack of water circulation sorted first.

I'll try flushing the rad first, then see if I can get hold of a thermometer and test the thermostat in a saucepan if I can't re-assemble the hosing without it in place...

[dern]

Fatboy said:

So I'd just pull the thermostant out then re-assemble without it if it works?

The only reason to reassemble without the thermostat is to prove if the problem is the thermostat jamming shut. If you can prove that in a pan with a thermometer then you'll have proved that anyway.

If I couldn't get hold of the thermostat and I'd flushed the rad as you plan to (I'd flush the block while you're doing this, just in case... you'll have to remove the thermostat to do that though I guess) and then if that hadn't worked then I figure the only two things left is the thermostat and the pump. If you reassemble without the thermostat and run the engine and the engine gets slowly warm including full length of pipes and eventually the rad then the thermostat is at fault. If, however, the engine gets warm without the thermostat but the pipes stay as they have been, warm only at the engine end and cool at the rad end and the rad stays cold then it's the pump as there's no other small restrictions in the system assuming you've flushed the rad and the block.

Again, I'm pretty much guessing being unable to see the car but this is the procedure I'd do.

I'd be happier handing out advice if someone else could confirm that it's a reasonable way forward but hopefully this helps you find the problem.

Regards,

Mark

[Fatboy]

I'll try it that way then - I appreciate the advice, it all seems logical and it's good to get someone else who knows more than I helping out, but I know how difficult it is to diagnose without seeing the situation, and am grateful for any pointers

Cheers,

Fatboy

[diver944]

If you are going to remove the thermostat to test it then I would say just buy a new thermostat. They are only around a tenner and to be honest circlips on the old one will be such a pig to get out that it is easier to just shove a screwdriver through it and destructively remove it

[Fatboy]

Good news everyone!

After mornings swearing etc I got the thermostat out, tested it and lo and behold the thermostat was well and truly ed

One new thermostat (8 quid from hellfrauds), some new hose clamps, a lot of bleeding and job done, gets up to temp quickly, and stays at a sensible temp with no hassle.

Cheers for all the help guys - beers coming your way when we meet at Pistonfest or wherever

All I've got to do now is see if there was a leak in the system, and fix the heater motor which only runs on full blast, whilst the heater only give out hot air

[dern]

Fatboy said:

Good news everyone!

Nice one, glad you got it sorted

Mark

[busa_rush]

If your thermostat doesn't have a little valve in it it's worth drilling a small 3mm hole in it to allow some water to circuate at all times.

This does several things, firstly it makes the thermostat more responsive as it's got water on both sides of it. Secondly it reduces the influx of cold water to the engine when the thermostat opens as some water always circulates. It won't extend the warm up period very much at all, maybe an extra minute at most.

[silverback mike]

Good man, well done Fatboy

[Fatboy]

ninemeister said:

99% of oil-in-water scenarios in the 2.5/2.7 944 engine are to do with the oil to water heat exchanger (oil cooler to you and me) located in the housing that mounts the oil filter. It will probably be one of the o-ring seals that go on the in/out stubs of the matrix, but in rare cases the matrix fails normally as a result of being frozen at some time. The gaskets are around £50, the job takes an afternoon of swearing.

I've unfortuneately got to ressurect this thread as, after a run to blackpool this weekend I noticed that the car was running a bit warmer than usual (just below the upper white mark instead of half way between the two) and on checking the oil noticed it was low (the car uses very little oil indeed).

So I though 'Oh Bugger' and (after it has cooled) took the cap off the expansion tank, and there's mayo on the underside of the cap... Also I noticed in the oil filler neck that there was an awful lot of mayo (might just be that I don't use the car much and this was simply condensation, but I thought better not to assume).

So is this likely to be just the oil seals in the oil cooler, or a head gasket? (I REALLY hope it's just the seals...)

Cheers,

Fatboy

[basil brush]

If it's getting hotter during fast constant driving and there's a lot of mayo on filler cap/dip stick then it does sound like head gasket may be leaking. I think oil cooler seals result in oil in the water, not the other way round.

[Fatboy]

That's what I was worried about - I really can't afford a new head gasket right now (well, the labour I can't afford, the parts shouldn't be a problem ).

I'll see if there's any mayo on the dipstick bottom now it's been sat for a bit, and if not, I'll just put on some new seals and see if it works.

If it doesn't work, and a new head gasket is needed, can anyone recommend a good specialist near Warwick?

Cheers,

Fatboy

[verysideways]

Clean the mayo off and go for a drive - give it a good half hour run around unless it seems to be getting hot, in which case shut it down or go home quick!

If after that half hour it's not seemed over warm, and there's no mayo, then it could just be that you've collected some condensation in the recent wet weather and haven't gotten the car hot enough regularly enough to burn it out.

Good luck!

[Fatboy]

Worth a try - but there's definately oil in the coolant, as I can see a (small) amount of mayo on the expansion tank cap?