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I have a 1999 996 C2 with 69,000 miles and the temperature warning light started to flash yesterday. According to the owner manual this indicates that the coolant level is low. I checked to coolant level and found it to be about ½ gallon low. I refilled the coolant to the correct level. Today the light started to flash again. It was low again so I thought I must have a leak somewhere but I couldn’t find any leak. I decided to check the dipstick and found the level very high and the oil light brown in color. I figured that someway the coolant got in the engine.

I’m afraid to ask but how serious a problem is this? I found references to porous engine in early 996, could this be my problem? Could this be an oil/water heat exchanger problem or a head gasket? If so how can I tell? Will I need to have my engine replace? If so any ideas on how much it will cost?

Thanks,

Lee

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Well as an Ex-mechanic and with a father with a lifetime of Mechanic experience... I can tell you that means your head gasket is bad. not good at all, also another possible reason for water in the oil is a cracked head... maybe even a cracked block depending on location of the water passeges on teh block and heads.

Edited by CJ_Boxster
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I have a 1999 996 C2 with 69,000 miles and the temperature warning light started to flash yesterday. According to the owner manual this indicates that the coolant level is low. I checked to coolant level and found it to be about ½ gallon low. I refilled the coolant to the correct level. Today the light started to flash again. It was low again so I thought I must have a leak somewhere but I couldn’t find any leak. I decided to check the dipstick and found the level very high and the oil light brown in color. I figured that someway the coolant got in the engine.

I’m afraid to ask but how serious a problem is this? I found references to porous engine in early 996, could this be my problem? Could this be an oil/water heat exchanger problem or a head gasket? If so how can I tell? Will I need to have my engine replace? If so any ideas on how much it will cost?

Thanks,

Lee

I’ve owned the car for about two years and haven’t had any major engine issue. I had the starter replace just a few weeks ago and the coolant reservoir but that was over a year ago and the oil fill tube. I had the 60,000 mile service completed a few months back with no reports of any engine issues.

The Porsche service manager said it was likely the oil separator. I plan to have it towed there Tuesday.

If anyone else had this part go bad please reply or send me a PM.

Thanks,

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The problem with the idea of it being the oil separator is that the only function of the oil separator is to keep oil from intake, has nothing todo with water... Just oil and vaccum, no water goes in, or out.

and if its a head gasket, they isnt anyother way of telling unless you remove the head and see the breach in the gasket. Whatever you do, DONT put radiator stop-leak to cure the leak, not sure if porsches like stopleak leaking into the block and clogging oil gallys.

Edited by CJ_Boxster
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I think it would be prudent to drain the oil and actually see whether there is water there or not. The fact that the oil is "elevated" might not mean much.

Usually when water gets into oil you gonna see it first by clouds of white smoke from your exhaust. Also, it is usually the oil that gets into the water since it is under higher pressure and you see it floating on top of the radiator. Also, your hot engine oil will have "milky white" appearance due to vapor bubles.

I bet you just have a minor leak where water just hits something hot and evaporates!

Edited by PeterK
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Also, it is usually the oil that gets into the water since it is under higher pressure and you see it floating on top of the radiator.

So, is this the sign of a blown head gasket? It could pertain to another vehicle I have...

It could be it, esp if it is a GM car. Or a cracked block. Either way it is not a good sign.

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The problem with the idea of it being the oil separator is that the only function of the oil separator is to keep oil from intake, has nothing todo with water... Just oil and vaccum, no water goes in, or out.

It wasn’t the Oil Separator that the Service Manager said was the likely problem but the oil/water heat exchanger. :oops: I have read that there have been numerous incidences of the diaphragm failing causing coolant to mix with the oil. Judging from how much coolant that I’ve added I figure that close to a gallon has been mixed with the oil. Has anyone had this happen to their car?

I’m hoping this is the case instead of the head gasket because it’s my understanding that if it’s the head gasket that the engine will need to be totally rebuilt and that there are only a few individuals that has the expertise and because of this Porsche opts to replace the engine.

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I had the same problem and had to put in a new engine. The dealer said that head gaskets do not fail usually. They suspected a cracked cylinder sleeve due to overheating at some point. I mentioned the pourous engine casting and they denied any knowledge of this problem in a 996 engine. The good news is that the new engine comes with a 2 year unlimited miles warranty from porsche and is shipped with all new components (a/c, intake, hoses, oil cooler,etc). Cost should be around 10k installed with core exchange if you work them on the price... Good luck.

Edited by Loren
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  • 2 weeks later...

Yeah, I paid my mechanic about $600 to remove and test the oil/water heat exchanger. It was fine. No problem with the gaskets or RMS either. Funny, no obvious sign of water in oil, only oil in coolant. Losing oil quickly somewhere. They say a new motor is only choice. Gearing up for that fun thing. Just a matter of time, I guess.

The problem with the idea of it being the oil separator is that the only function of the oil separator is to keep oil from intake, has nothing todo with water... Just oil and vaccum, no water goes in, or out.

It wasn’t the Oil Separator that the Service Manager said was the likely problem but the oil/water heat exchanger. :oops: I have read that there have been numerous incidences of the diaphragm failing causing coolant to mix with the oil. Judging from how much coolant that I’ve added I figure that close to a gallon has been mixed with the oil. Has anyone had this happen to their car?

I’m hoping this is the case instead of the head gasket because it’s my understanding that if it’s the head gasket that the engine will need to be totally rebuilt and that there are only a few individuals that has the expertise and because of this Porsche opts to replace the engine.

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hi mate,

saw your post, thought my input my help you out.

Have you had the oil cooler checked for oil and water mixing?

To diagnose possible head gasket failure's on cars, I use a cumbustion chamber leak detector from SNAP-ON.

It's basically a chemical which, when mixed with coolant from your car, changes colour if combustion fumes are detected.

If the chemical changes colour then I'm afraid it's not good news...some where combustion fumes are entering the cooling system which means it's either:

blown headgasket

crack in the cylinder block

The snap-on part number is GDCT16. I've been using this for a while and has always been accurate. It should retail for around $100, which may be cheaper than paying a mechanic.

hope this helps.

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hi mate,

saw your post, thought my input my help you out.

Have you had the oil cooler checked for oil and water mixing?

To diagnose possible head gasket failure's on cars, I use a cumbustion chamber leak detector from SNAP-ON.

It's basically a chemical which, when mixed with coolant from your car, changes colour if combustion fumes are detected.

If the chemical changes colour then I'm afraid it's not good news...some where combustion fumes are entering the cooling system which means it's either:

blown headgasket

crack in the cylinder block

The snap-on part number is GDCT16. I've been using this for a while and has always been accurate. It should retail for around $100, which may be cheaper than paying a mechanic.

hope this helps.

Check out my post Another Engine Failure here http://www.renntech.org/forums/index.php?showtopic=12096 I just got my car back this afternoon. I need to take a few long drives (what a chore) to break the engine in.

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  • 8 years later...

Is there any way to test if the oil cooler / heat exchanger is bad in the car? My just bought 2004 C4S with 60k miles has low coolant levels and high oil levels, and I am suspicious. I replaced the engine oil and did not see any oil in the coolant. It was hard to tell if there was any coolant in the oil, but there was no mayonnaise in the oil filler neck.

 

I ordered the combustion leak detection kit that Kanin suggested, but it hasn't arrived yet.

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I highly doubt you will miss the intermix. Coolant will show up as froth in the oil and oil will make milkshake in the coolant. Sounds like you have neither. You could just top up the coolant to the level between min and max when engine is cold and keep an eye on it.

Make sure you have the latest coolant cap. If you are losing coolant and it's not in the oil, you need to pressure test the cooling system to locate the leak.

Mayo in oil filler tube is only condensation from driving in cold and humid weather and the engine is not hot enough (e.g., long freeway driving) to burn off the water vapor. Nothing to do with intermix.

Edited by Ahsai
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  • 10 months later...

Ok, I have spent countless hours studying this issue on multiple web sites and books trying to figure out my new coolant in oil problem.  Yes, I understand it is probably my worst fear, but this occurred in such odd circumstances.  1999 C2 -87,000 mile - oil changes every 3000-4000 with Joe Gibbs oil (since 45,000 mile purchase) - I pull the oil sump off every other oil change and look around (IMS fears), inspect the filter in detail every change - always  perfectly clean - almost too clean!

 

I had the vehicle up on jacks doing other work, completed an oil/filter change - ran it on the jacks for 3-5 minutes, topped the oil off and then left the vehicle there for about 2 months while I was out of town.  Came back, started car, moderate miss in one cylinder and smoke out the pipe, but it was quickly clearing up (smoke and miss) as it started to warm.  Shut off, pulled vehicle off of jacks, checked oil - noticed an 1/8" high to what I know was an exact fill (jacks and ground level)  Thinking I must have screwed up on fill 2 months back, I reset the mis code and restarted.  Mis and smoke very light and almost gone, it did pull a mis code- let it warm up for 5 minutes - mis and smoke gone now and shut down.  Checked oil - 1/2" or more high, checked coolant - yes - low and also got the coolant low light. Obviously expecting the worse case scenario, even though the vehicle was only run a very short time without load on both occasions.   Performed vacuum leak check on coolant tank, it leaked so bad/fast, I could not get any location indications.  Drained fresh, but now chocolate milk oil and pulled sump to look around.   Drained coolant and NO evidence of oil mix!  I had to leave car for a month, but got back and performed a leakdown test.  1 and 6 had a 25% leakage (still in green), but clearly one was exhaust and one intake.  2,3,4,5 were tight, virtually no leakdown.  Engine was cold, so not the best test.

 

I am totally confused.  This engine dumped one to two quarts of coolant in oil in those three short 3-5 minute no load runs and yet my leakdown test seems to show no cracked head, D chunking, etc.  (unless the crack did not reopen with the cold engine).  Before I tear into things, is it possible that the oil cooler could do this one way leak?  I understand the oil vs. coolant pressure difference.  Or in all my reading, I still cannot determine if there are coolant lines on the top AOS where a diaphram might let go on this model.

 

Could I be that lucky?  I doubt it, but what am I missing here guys?  Any experienced thoughts?  My next call will be to Raby I guess.

 

Thanks,  Jim

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AOS is what comes to mind....there is a diaphragm in there separating the coolant from the crankcase side.  If the diaphragm leaks or is totally blown, or the AOS cracks internally, coolant has direct access to the crankcase. Since the crankcase is under vacuum and the coolant is under pressure, it would rapidly dump coolant into the crankcase.  Worth a check.  Sound like you have checked everything else.  Hope it works out!

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Ok, I have spent countless hours studying this issue on multiple web sites and books trying to figure out my new coolant in oil problem.  Yes, I understand it is probably my worst fear, but this occurred in such odd circumstances.  1999 C2 -87,000 mile - oil changes every 3000-4000 with Joe Gibbs oil (since 45,000 mile purchase) - I pull the oil sump off every other oil change and look around (IMS fears), inspect the filter in detail every change - always  perfectly clean - almost too clean!

 

I had the vehicle up on jacks doing other work, completed an oil/filter change - ran it on the jacks for 3-5 minutes, topped the oil off and then left the vehicle there for about 2 months while I was out of town.  Came back, started car, moderate miss in one cylinder and smoke out the pipe, but it was quickly clearing up (smoke and miss) as it started to warm.  Shut off, pulled vehicle off of jacks, checked oil - noticed an 1/8" high to what I know was an exact fill (jacks and ground level)  Thinking I must have screwed up on fill 2 months back, I reset the mis code and restarted.  Mis and smoke very light and almost gone, it did pull a mis code- let it warm up for 5 minutes - mis and smoke gone now and shut down.  Checked oil - 1/2" or more high, checked coolant - yes - low and also got the coolant low light. Obviously expecting the worse case scenario, even though the vehicle was only run a very short time without load on both occasions.   Performed vacuum leak check on coolant tank, it leaked so bad/fast, I could not get any location indications.  Drained fresh, but now chocolate milk oil and pulled sump to look around.   Drained coolant and NO evidence of oil mix!  I had to leave car for a month, but got back and performed a leakdown test.  1 and 6 had a 25% leakage (still in green), but clearly one was exhaust and one intake.  2,3,4,5 were tight, virtually no leakdown.  Engine was cold, so not the best test.

 

I am totally confused.  This engine dumped one to two quarts of coolant in oil in those three short 3-5 minute no load runs and yet my leakdown test seems to show no cracked head, D chunking, etc.  (unless the crack did not reopen with the cold engine).  Before I tear into things, is it possible that the oil cooler could do this one way leak?  I understand the oil vs. coolant pressure difference.  Or in all my reading, I still cannot determine if there are coolant lines on the top AOS where a diaphram might let go on this model.

 

Could I be that lucky?  I doubt it, but what am I missing here guys?  Any experienced thoughts?  My next call will be to Raby I guess.

 

Thanks,  Jim

 

You have three possible ways to get coolant into the oil: 1. A crack somewhere in the cylinder heads or engine case; which you appear to have eliminated with your leak down.  2.  Your oil cooler may have failed (it is an oil to coolant heat exchanger), which can be tested by pulling it and running a vacuum test on it (if it is good, both channels should hold high vacuum).  3. Your AOS.

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DBJoe996 and JFP in PA

 

Thank you very much for the quick replies!  This has been driving me nuts and very glad to confirm my AOS thoughts especially due to the volume of coolant and no opposing pressure.  I was ruling out the cooler as I always thought it would create an oil in coolant or a combination with the pressure differential.   I am pretty sure the AOS is original - at 17 years old, this should be a time replacement item - not for the potential AO separation failure, but for this coolant issue!  Very lucky it failed where I caught it in the shop.  Imagine if it slowly dumped coolant in on a long trip where it might not get noticed - water in oil for 1000 miles?

 

I will report back with results - I will be changing out water pump, a cooler thermostat, a few choice coolant hoses, fresh coolant etc. while I am in there and flushing system with fresh oil for a short run and then fresh oil change.

 

Thanks again!

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In general, your thoughts about a failing cooler leading to oil in the coolant are correct, but when you shut the car off, there is no oil pressure but there is about 18 PSIG of coolant pressure so it can also go the other way, albeit slower.

 

As for the AOS, you can pressurize the coolant system to 18 PSIG and pull both hoses off the AOS, and you should hear or feel a leak.

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  • 2 weeks later...

The AOS replacement will be a slow process with limited time, but I guess this photo inside the plenum after throttle body removal confirms the AOS dumped coolant instead of a cracked head or bad head gasket (along with the previous leakdown test).     In the future with a potential AOS failure or coolant in the oil, this would be one of the first easy things I look for: pop open the throttle body and look for coolant in the plenum.

 

So the AOS not only dumps lots of coolant into the crankcase, but also sucks it into the engine plenum.  Sure would like to eliminate this from happening in the future.  What problems would occur by not allowing the coolant flow through the AOS

 

Not a fun thing to see......

post-70804-0-68036300-1455988479_thumb.j

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