928S2 - Overheating oil in water
08-20-2002, 08:25 PM
#16
Racer
Just for the Record, S4 auto cars had both motor and trans coolers in the rad. through 1990 or 91. Somewhere in 1990 or 91 they removed the motor oil cooler from the rad and mounted it externaly.
08-21-2002, 01:37 AM
#17
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1. I don't think it is a good idea to remove the oil cooler.
2. If your oil looks like cafe au lait...then you probably have more than a bad heat exchanger!
-In a previous life, I kept a VW Corrado VR6 in my garage. I noticed that the oil temperature crept upwards of 250 F during hard driving in traffic in Orlando. I added a huge external oil cooler, and the difference was dramatic- 215-220 was now the max oil temp observed, but more importantly...the engine gained quite a bit of driveability and always seemed a little stronger. This was not a cheap kit- it even had a thermostat. I wish I knew what my 928S2's oil temperature is...I'd love to add an additional oil cooler. I'm certain that a high-compression motor like an S2's would benefit from nice cool oil.
-Think about this: The cap on your coolant reservoir is set to open and relieve pressure when 13 psi is sensed. Your oil pressure is at least 3 bar- about 45 psi. If your oil looks like coffee...it is most likely that you have a serious problem that needs to be addressed! Though I suppose it is POSSIBLE that coolant is making its way into the oil, but most likely there is a blown head gasket or cracked block.
Hope that it works out for you-
Normy!
'85 S2 5 speed
2. If your oil looks like cafe au lait...then you probably have more than a bad heat exchanger!
-In a previous life, I kept a VW Corrado VR6 in my garage. I noticed that the oil temperature crept upwards of 250 F during hard driving in traffic in Orlando. I added a huge external oil cooler, and the difference was dramatic- 215-220 was now the max oil temp observed, but more importantly...the engine gained quite a bit of driveability and always seemed a little stronger. This was not a cheap kit- it even had a thermostat. I wish I knew what my 928S2's oil temperature is...I'd love to add an additional oil cooler. I'm certain that a high-compression motor like an S2's would benefit from nice cool oil.
-Think about this: The cap on your coolant reservoir is set to open and relieve pressure when 13 psi is sensed. Your oil pressure is at least 3 bar- about 45 psi. If your oil looks like coffee...it is most likely that you have a serious problem that needs to be addressed! Though I suppose it is POSSIBLE that coolant is making its way into the oil, but most likely there is a blown head gasket or cracked block.
Hope that it works out for you-
Normy!
'85 S2 5 speed
08-21-2002, 06:42 PM
#18
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Hi all,
For your extra information:
The rad is now with a specialist who will remove the end cover, replace the oil cooler, and put it all back together again. After steam cleaning and pressure test I'll be for the road soon :-)
Normy - I hear what you are saying but here is my explanation of how my oil and water have mixed both in the engine and water system. The oil cooler has cracked and I can make it leak into the radiator by simply blowing in the port with my mouth. When the engine was running I had high oil pressure in the oil cooler and forced oil into the water. The water quickly became unable to absorb heat and the engine starts to overheat. i stopped the car when the red temp light came on and there followed a huge cloud of smelly steam from the expansion tank. At this point the engine is off so no oil pressure but huge pressure in the water system and all the muck gets pushed out through the expansion tank and/or into the oil system. Make sense !?
I have run two gallons of oil through the engine now and done a compression test 182-190psi on all cyclinders. Head gaskets etc. all OK = big sigh of relief and happy feeling.
I'll keep you informed of progress and when it's running again.
Thanks again for all the suggestions - so valuable!
For your extra information:
The rad is now with a specialist who will remove the end cover, replace the oil cooler, and put it all back together again. After steam cleaning and pressure test I'll be for the road soon :-)
Normy - I hear what you are saying but here is my explanation of how my oil and water have mixed both in the engine and water system. The oil cooler has cracked and I can make it leak into the radiator by simply blowing in the port with my mouth. When the engine was running I had high oil pressure in the oil cooler and forced oil into the water. The water quickly became unable to absorb heat and the engine starts to overheat. i stopped the car when the red temp light came on and there followed a huge cloud of smelly steam from the expansion tank. At this point the engine is off so no oil pressure but huge pressure in the water system and all the muck gets pushed out through the expansion tank and/or into the oil system. Make sense !?
I have run two gallons of oil through the engine now and done a compression test 182-190psi on all cyclinders. Head gaskets etc. all OK = big sigh of relief and happy feeling.
I'll keep you informed of progress and when it's running again.
Thanks again for all the suggestions - so valuable!
08-24-2002, 06:10 PM
#19
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Paul
seriously do not bother having your rad reconditioned either fit external coolers or buy a new rad. my rad has been reconditioned 3 times due to coolers leaking and you will not know they have leaked till it is too late
must be an s2 thing
cheers Tim
seriously do not bother having your rad reconditioned either fit external coolers or buy a new rad. my rad has been reconditioned 3 times due to coolers leaking and you will not know they have leaked till it is too late
must be an s2 thing
cheers Tim
08-24-2002, 09:20 PM
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I'll second that-
When I bought my car, it had a minor leak from the end of the radiator. Having had this problem on several Volkswagens in the past [also equiped with Behr radiators. Behr should stick to paint, in my opinion...], I decided to not mess around this time. I sprung for a Devek radiator, and haven't had a problem since.
-My temperature gauge runs exactly in the middle- even with the a/c cranking in 90 degree heat in Orlando's horrid traffic. Don't just replace the heat exchanger or the end tank. If you do, you'll just wind up having to do the job again later.
Normy!
'85 S2 5 speed
When I bought my car, it had a minor leak from the end of the radiator. Having had this problem on several Volkswagens in the past [also equiped with Behr radiators. Behr should stick to paint, in my opinion...], I decided to not mess around this time. I sprung for a Devek radiator, and haven't had a problem since.
-My temperature gauge runs exactly in the middle- even with the a/c cranking in 90 degree heat in Orlando's horrid traffic. Don't just replace the heat exchanger or the end tank. If you do, you'll just wind up having to do the job again later.
Normy!
'85 S2 5 speed
