Coolant still leaking into oil after rebuild :(
11-26-2002, 11:25 PM
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Coolant still leaking into oil after rebuild :(
Hi Guys:
A brief recap of my situation is that I noticed coolant in the oil of my '86 951 a few weeks after I bought it (May). Not lots - but enough that inside of the oil filler cap would be seriously wet after each drive ... and some oil was noted in the water bottle.
So I assumed either its the cylinder head gasket, or the heat exchanger seals - right?
Since it had 140K on it and had one broken exhaust stud, I decided to pull the head, rebuild it & change the head gasket, replace the rod bearings etc. I also replaced the seals in the heat exchanger.
The bad news is the oil still looks exactly the same as before the rebuild - same quantity of water noted on the inside of the oil cap after running the engine.
The old cylinder head gasket did not show signs of being blown when I removed it, but the seal in the heat exchanger practically disintegrated when I removed it. So, I assumed I had found the problem.... but it appears not.
So, the only other thing I can think of it that the turbo is fed with both oil & coolant - is it possible (or previously reported) that the fluids can mix at the turbo? This was the one component that I did not remove/replace/rebuild.
As a test, I'm contemplating clamping off the coolant supply hose to the turbo (and driving around slowly, of course) to see if that resolves the problem. I'd then know that the water was leaking into the oil at the turbo.
Does this sound reasonable - how dangerous would this be (as a temporary, test measure)?
Any other suggestions appreciated - after 6 months of ownership and hundreds of hours of labour, I'm beginning to lose heart.
Cheers,
Michael
1986 Porsche 944 Turbo
1985 Alfa Romeo GTV6 3.0
A brief recap of my situation is that I noticed coolant in the oil of my '86 951 a few weeks after I bought it (May). Not lots - but enough that inside of the oil filler cap would be seriously wet after each drive ... and some oil was noted in the water bottle.
So I assumed either its the cylinder head gasket, or the heat exchanger seals - right?
Since it had 140K on it and had one broken exhaust stud, I decided to pull the head, rebuild it & change the head gasket, replace the rod bearings etc. I also replaced the seals in the heat exchanger.
The bad news is the oil still looks exactly the same as before the rebuild - same quantity of water noted on the inside of the oil cap after running the engine.
The old cylinder head gasket did not show signs of being blown when I removed it, but the seal in the heat exchanger practically disintegrated when I removed it. So, I assumed I had found the problem.... but it appears not.
So, the only other thing I can think of it that the turbo is fed with both oil & coolant - is it possible (or previously reported) that the fluids can mix at the turbo? This was the one component that I did not remove/replace/rebuild.
As a test, I'm contemplating clamping off the coolant supply hose to the turbo (and driving around slowly, of course) to see if that resolves the problem. I'd then know that the water was leaking into the oil at the turbo.
Does this sound reasonable - how dangerous would this be (as a temporary, test measure)?
Any other suggestions appreciated - after 6 months of ownership and hundreds of hours of labour, I'm beginning to lose heart.
Cheers,
Michael
1986 Porsche 944 Turbo
1985 Alfa Romeo GTV6 3.0
11-27-2002, 05:28 PM
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Michael:
Do a leak down test on each cylinder to rule out the seal of the head gasket/block/head connection. If this is the problem, it will become very obvious. Were the head and deck checked for flatness during the rebuild?
Next, pressurize the cooling system to about 7 psi and see if it shows up. Listen for air at the oil filler tube. Unless the block/head are cracked, this would tell me the oil cooler seals need attention again.
Is oil getting into the coolant, or is it just in the oil? Some condensation is usually present at the oil filler cap.
Do a leak down test on each cylinder to rule out the seal of the head gasket/block/head connection. If this is the problem, it will become very obvious. Were the head and deck checked for flatness during the rebuild?
Next, pressurize the cooling system to about 7 psi and see if it shows up. Listen for air at the oil filler tube. Unless the block/head are cracked, this would tell me the oil cooler seals need attention again.
Is oil getting into the coolant, or is it just in the oil? Some condensation is usually present at the oil filler cap.
11-27-2002, 05:49 PM
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I assume the cooling sytem was flushed multiple times before you ran the car again? It can be a real bitch to get all the oil out of it after an oil cooler gasket incident.
Personally, I have never seen a failure of a KKK water cooled turbo cause a mix.
I am thinking an oil cooler seal was damaged on install (easy to do). There are not many places that cause this condition.
Personally, I have never seen a failure of a KKK water cooled turbo cause a mix.
I am thinking an oil cooler seal was damaged on install (easy to do). There are not many places that cause this condition.
11-27-2002, 05:56 PM
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Michael, I know exactly what you are going through since I have been going through it for the past 2 years of finding out where my oil and water are mixing at after my engine over-heated due to a blown out coolent tube. I have heard the same thing from everybody on doing a leakdown, compression check, this and that and nothing seemed to work. Finally, (since I was already at the point of losing heart on these 951s)I took out the whole engine and drove it down to John Anderson (Anderson Motorworks) who is now testing it for the source of the leak and rebuilding it back together. I would give him a call on this situation, he gave me a great price since my enigne has already been rebuilt in hopes of fixing this problem, sadly after replacing seals, bearings, and the rings the thing is still mixing. I would suspect that you have the same issue that I do,...the mysterious mixing place!!!
All the best,...Gabe 831-239-6216
All the best,...Gabe 831-239-6216
11-27-2002, 08:33 PM
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Thanks for the replies.
Gabe, I've been following your saga in the "Mixing Oil and Water after rebuild" thread - exactly the same issue as mine.
The head was decked slightly to ensure it was flat and to create a good seal. The block was not checked though - it stayed in the car.
I could do a compression/leakdown test - however, would this show up a leak somewhere between the coolant/oil jackets?
Surely this would only show if air was leaking past the rings or valves (or possibly, through the head gasket into the oil/water jacket). But this is not the problem - there is no pressurization of the oil/coolant jackets when the engine is running.
I'll try the pressurization of the cooling system - I presume this is done with the coolant removed? (Else all it would do is inject the coolant into the oil without the engine running).
I’ll have done lots more research into this by tomorrow evening!
Cheers,
Michael
Gabe, I've been following your saga in the "Mixing Oil and Water after rebuild" thread - exactly the same issue as mine.
The head was decked slightly to ensure it was flat and to create a good seal. The block was not checked though - it stayed in the car.
I could do a compression/leakdown test - however, would this show up a leak somewhere between the coolant/oil jackets?
Surely this would only show if air was leaking past the rings or valves (or possibly, through the head gasket into the oil/water jacket). But this is not the problem - there is no pressurization of the oil/coolant jackets when the engine is running.
I'll try the pressurization of the cooling system - I presume this is done with the coolant removed? (Else all it would do is inject the coolant into the oil without the engine running).
I’ll have done lots more research into this by tomorrow evening!
Cheers,
Michael
11-27-2002, 10:44 PM
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I found the thread I had been reading months ago - regarding the oil & water mixing at the turbo...
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=15&t=000119" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=15&t=000119</a>
Check the post by webberman ....
"If you have been mixing for any length of time some say you should definitly replace your rod bearings. I had a nasty leak due to a turbo failure. Water was coming innto the pan through the turbo oil return line, how I haven't got a clue but it was. I replaced the turbo ran an oil system cleaner through it and changed the oil. I drove it gingerly for a couple days then went to Limerock for a DE where it spun a rod bearing on my first run."
So it has been reported before - I guess I can try and remove the water hoses to the turbo, and blow compressed air in them, see if anything comes out the oil lines?
Cheers,
Michael
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=15&t=000119" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=15&t=000119</a>
Check the post by webberman ....
"If you have been mixing for any length of time some say you should definitly replace your rod bearings. I had a nasty leak due to a turbo failure. Water was coming innto the pan through the turbo oil return line, how I haven't got a clue but it was. I replaced the turbo ran an oil system cleaner through it and changed the oil. I drove it gingerly for a couple days then went to Limerock for a DE where it spun a rod bearing on my first run."
So it has been reported before - I guess I can try and remove the water hoses to the turbo, and blow compressed air in them, see if anything comes out the oil lines?
Cheers,
Michael
11-27-2002, 11:48 PM
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Wow.. that is the 1st one I heard of. You learn something new every day.
You can block or pinch off the water lines to the turbo and run it without harm. I would not hot rod it and get the turbo real hot, but for a short period (a few days if needed), you should not see any ill effects.
Give it a try. I am still baffled on the mixing in the turbo though. I am even more baffled that I did not remember, after reading and even replying to that post!
God I am getting old!
You can block or pinch off the water lines to the turbo and run it without harm. I would not hot rod it and get the turbo real hot, but for a short period (a few days if needed), you should not see any ill effects.
Give it a try. I am still baffled on the mixing in the turbo though. I am even more baffled that I did not remember, after reading and even replying to that post!
God I am getting old!
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11-28-2002, 03:47 PM
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It was almost 18 months ago 
I emailed 'webberman' to try and get information, but the email bounced. Anyway, I'll try to clamp off the coolant feed line for the turbo.
Cheers
Michael
I emailed 'webberman' to try and get information, but the email bounced. Anyway, I'll try to clamp off the coolant feed line for the turbo.
Cheers
Michael
11-28-2002, 07:10 PM
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Michael,
To test your system easier I would recommend the following: Drain your oil, place a pressure pump-gauge to your coolant resevoir, and leave out your oil-pan plug to see if water starts to come out of it. If so, then you know that you need to check your coolant system instead of your oil system. John Anderson told me this info., but I already had my motor pulled before I could try it. I've been told by Derrik @ Huntley Racing that it is impossible for his hybrid turbo to be a mixing point for oil and water due to the fact that there is a metal plate inbetween the two passages,...I'm not sure if that is true though. Michael, if you still havent had a chance to call John Anderson I would still recommend it since he has had my engine now for two weeks and probably has new info on the mixing issue. I'll keep you posted on his results,....
All the best, Gabe
To test your system easier I would recommend the following: Drain your oil, place a pressure pump-gauge to your coolant resevoir, and leave out your oil-pan plug to see if water starts to come out of it. If so, then you know that you need to check your coolant system instead of your oil system. John Anderson told me this info., but I already had my motor pulled before I could try it. I've been told by Derrik @ Huntley Racing that it is impossible for his hybrid turbo to be a mixing point for oil and water due to the fact that there is a metal plate inbetween the two passages,...I'm not sure if that is true though. Michael, if you still havent had a chance to call John Anderson I would still recommend it since he has had my engine now for two weeks and probably has new info on the mixing issue. I'll keep you posted on his results,....
All the best, Gabe
11-28-2002, 07:54 PM
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Thanks Gabe:
I'll try that test.
By the way, I subscribed to Alldata.com as I wanted to see a TSB for this subject too. I'll email you the page so you can see the pictures...
Is this something you have checked?
Cheers,
Michael
--------------------------------------------------
Engine - Oil In the Cooling System
91porsche01
May 17, 1991
Models Affected: 944 Turbo, 944 S2
Concern: Engine oil in the cooling system.
General Information: The VIN number /model year range in Technical Bulletin Group 1, Number 9001 no longer applies. This bulletin applies to all 944 Turbos and 944 S2's.
Service Information: Whenever the oil cooler thermostat housing is removed from the engine, whether for oil in the coolant or other repair, the depth of the connector pipe bore in the crankcase (arrow Figure 1) and the connector pipe itself (arrow Figure 2) must be measured.
Repair Information: 1. Measure the depth of the connector pipe bore in the crankcase.
Correct depth is 14.2 mm-0.4 mm
If the bore depth exceeds 14.2 mm, install spacing washer, Part Number 928 107 166 00, in the crankcase bore with Loctite 638.
Note: Clean washer and bore thoroughly to ensure proper cure of the Loctite.
Repair Information (cont.): 2. Measure the connector pipe. Two versions of the connector pipe
were used in production. The version illustrated below, Part Number 951 107 152 03, can be identified by careful measurement. When repairing, use only the connecting pipe having the dimensions given in Figure 3.
Caution: Part numbers given in this bulletin are for reference only. Always check with your Parts Department for the latest information.
Warranty Information: R & R Thermostat HousingDamage Code: 1737500002
Labor Operation: 17371900
Time Units: 430
Measure crankcase per Technical Bulletin Group 1, Number 9105.Labor Operation: 17370150
Time Units: 20
------------------------------------------------
I'll try that test.
By the way, I subscribed to Alldata.com as I wanted to see a TSB for this subject too. I'll email you the page so you can see the pictures...
Is this something you have checked?
Cheers,
Michael
--------------------------------------------------
Engine - Oil In the Cooling System
91porsche01
May 17, 1991
Models Affected: 944 Turbo, 944 S2
Concern: Engine oil in the cooling system.
General Information: The VIN number /model year range in Technical Bulletin Group 1, Number 9001 no longer applies. This bulletin applies to all 944 Turbos and 944 S2's.
Service Information: Whenever the oil cooler thermostat housing is removed from the engine, whether for oil in the coolant or other repair, the depth of the connector pipe bore in the crankcase (arrow Figure 1) and the connector pipe itself (arrow Figure 2) must be measured.
Repair Information: 1. Measure the depth of the connector pipe bore in the crankcase.
Correct depth is 14.2 mm-0.4 mm
If the bore depth exceeds 14.2 mm, install spacing washer, Part Number 928 107 166 00, in the crankcase bore with Loctite 638.
Note: Clean washer and bore thoroughly to ensure proper cure of the Loctite.
Repair Information (cont.): 2. Measure the connector pipe. Two versions of the connector pipe
were used in production. The version illustrated below, Part Number 951 107 152 03, can be identified by careful measurement. When repairing, use only the connecting pipe having the dimensions given in Figure 3.
Caution: Part numbers given in this bulletin are for reference only. Always check with your Parts Department for the latest information.
Warranty Information: R & R Thermostat HousingDamage Code: 1737500002
Labor Operation: 17371900
Time Units: 430
Measure crankcase per Technical Bulletin Group 1, Number 9105.Labor Operation: 17370150
Time Units: 20
------------------------------------------------
12-02-2002, 12:18 PM
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Hey Blurry,
Any word on your mixing problem yet? I went out and bought a coolant pressure tester. I still have not diagnosed my mixing problem yet either. I looked at your instructions that John gave you and thought I would try it. Unfortunately I did not have time to drain the oil but I did charge my cooling system to 15 psi and it held for about 10 minutes until I released it. Are you suppose to do this with a warm engine (because of the open thermostat) or does it matter?
Also Oil cooler assembly, is it part of the coolant system or the oil system? If coolant comes out of the oil drain hole, what does this tell you? What is the leaky part? How does one diagnose these mixing issues without tearing parts apart and hoping you got the right one?
-R.B.
Any word on your mixing problem yet? I went out and bought a coolant pressure tester. I still have not diagnosed my mixing problem yet either. I looked at your instructions that John gave you and thought I would try it. Unfortunately I did not have time to drain the oil but I did charge my cooling system to 15 psi and it held for about 10 minutes until I released it. Are you suppose to do this with a warm engine (because of the open thermostat) or does it matter?
Also Oil cooler assembly, is it part of the coolant system or the oil system? If coolant comes out of the oil drain hole, what does this tell you? What is the leaky part? How does one diagnose these mixing issues without tearing parts apart and hoping you got the right one?
-R.B.
12-02-2002, 03:18 PM
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The oil cooler assembly is basically only vestigial in that it is not functional in the 944 Turbo.
All it is there for is to carry the oil from the block to the oil cooler radiator.
Instead of the heat exchanger assembly inside the housing, all the turbo has is an oil pipe from the block to the threaded fittings on the outside of the oil cooler housing. (This pipe is bathed in coolant since it is in the water jacket).
So, a leak at one of the seals in this area will cause coolant/oil mixing. I'm betting that the TSB (19105) referenced above might explain what’s going on in my car.
However, I have not had time to run further tests - I have larger fish to fry currently <img src="graemlins/crying.gif" border="0" alt="[crying]" /> …
( see <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=003128)" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=003128)</a>
Cheers,
Michael
All it is there for is to carry the oil from the block to the oil cooler radiator.
Instead of the heat exchanger assembly inside the housing, all the turbo has is an oil pipe from the block to the threaded fittings on the outside of the oil cooler housing. (This pipe is bathed in coolant since it is in the water jacket).
So, a leak at one of the seals in this area will cause coolant/oil mixing. I'm betting that the TSB (19105) referenced above might explain what’s going on in my car.
However, I have not had time to run further tests - I have larger fish to fry currently <img src="graemlins/crying.gif" border="0" alt="[crying]" /> …
( see <a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=003128)" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=18&t=003128)</a>
Cheers,
Michael
12-02-2002, 08:43 PM
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Water leaking into the oil in the oil cooler is a problem on the 944 turbo. There two O-rings inside that become hard as plastic. Holbert Porsche in Warrington PA will tell you that it is a comon problem.
12-15-2002, 10:38 PM
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Hi:
Got the 'heat exchanger' out again this afternoon (as regards access for service, this car has to be designed by a complete sadist! <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" /> ).
One thing that never looked quite right were these 2 green o ring seals. They look way too skinny considering the width of the groove in the connector pipe. This is the short aluminium pipe which connects the block to the heat exchanger housing.
Check this pic:
Are these supposed to be a tight fit in the groove?
The TSB indicates 2 possible parts - I think I have 'wrong' one and will need to buy 951 107 152 03 - the green o-rings will hopefully fit better in that connector pipe
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
Michael
Got the 'heat exchanger' out again this afternoon (as regards access for service, this car has to be designed by a complete sadist! <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" /> ).
One thing that never looked quite right were these 2 green o ring seals. They look way too skinny considering the width of the groove in the connector pipe. This is the short aluminium pipe which connects the block to the heat exchanger housing.
Check this pic:
Are these supposed to be a tight fit in the groove?
The TSB indicates 2 possible parts - I think I have 'wrong' one and will need to buy 951 107 152 03 - the green o-rings will hopefully fit better in that connector pipe
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
Michael