My engine oil analysis
03-13-2018, 01:59 PM
#1
My engine oil analysis
Hello all,
I sent some oil to Black Stone Labs to see how my '07 was doing internally, results said I have coolant in my oil and should change oil every 2k - 3k until fixed. I knew I was loosing coolant but previously had no idea where it was going. It takes a few months for my overflow jug to go from full to just above the minimum mark. My overflow container shows no signs of oil and no signs of milkshake at the oil cap.
I've read that head gaskets rarely fail on the 4.2 and I'm hoping this stands true in my case! Now I haven't had a chance to examine further, but I'm guessing a pressure test might not reveal the source of an internal leak. And if my spark plugs look good, where else can coolant enter the oil, oil cooler only?
I sent some oil to Black Stone Labs to see how my '07 was doing internally, results said I have coolant in my oil and should change oil every 2k - 3k until fixed. I knew I was loosing coolant but previously had no idea where it was going. It takes a few months for my overflow jug to go from full to just above the minimum mark. My overflow container shows no signs of oil and no signs of milkshake at the oil cap.
I've read that head gaskets rarely fail on the 4.2 and I'm hoping this stands true in my case! Now I haven't had a chance to examine further, but I'm guessing a pressure test might not reveal the source of an internal leak. And if my spark plugs look good, where else can coolant enter the oil, oil cooler only?
03-14-2018, 04:47 PM
#2
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Same same here
Hello all,
I sent some oil to Black Stone Labs to see how my '07 was doing internally, results said I have coolant in my oil and should change oil every 2k - 3k until fixed. I knew I was loosing coolant but previously had no idea where it was going. It takes a few months for my overflow jug to go from full to just above the minimum mark. My overflow container shows no signs of oil and no signs of milkshake at the oil cap.
I've read that head gaskets rarely fail on the 4.2 and I'm hoping this stands true in my case! Now I haven't had a chance to examine further, but I'm guessing a pressure test might not reveal the source of an internal leak. And if my spark plugs look good, where else can coolant enter the oil, oil cooler only?
I sent some oil to Black Stone Labs to see how my '07 was doing internally, results said I have coolant in my oil and should change oil every 2k - 3k until fixed. I knew I was loosing coolant but previously had no idea where it was going. It takes a few months for my overflow jug to go from full to just above the minimum mark. My overflow container shows no signs of oil and no signs of milkshake at the oil cap.
I've read that head gaskets rarely fail on the 4.2 and I'm hoping this stands true in my case! Now I haven't had a chance to examine further, but I'm guessing a pressure test might not reveal the source of an internal leak. And if my spark plugs look good, where else can coolant enter the oil, oil cooler only?
03-16-2018, 04:17 AM
#3
same story here. Had coolant in the oil they said change and test again at 3k. I ordered an oil cooler and the two o rings from jim Ellis audi in atlanta. Cheapest price for the part, for the S8 it’s a $300 part. Should be delivered by the end of the week or next week. Now my concern is the trans cooler. That’s a real pricey part. Yikes. I have some test strips for the trans fluid that detects coolant, so I’ll give those a shot when I do the oil cooler to test for any issues. Hate to trash the trans.
03-16-2018, 06:52 AM
#4
AudiWorld Super User
I would look at the coolant and oil diagrams to see which gaskets have these 2 fluids next to each other. Oil cooler seems to be one, but there are quite a few unsolved problem here. One had to sell the car because the mixed existed after oil cooler pipe replacement . Hope someone finds this problem.
Cheers,
Louis
Cheers,
Louis
03-16-2018, 12:55 PM
#5
I would look at the coolant and oil diagrams to see which gaskets have these 2 fluids next to each other. Oil cooler seems to be one, but there are quite a few unsolved problem here. One had to sell the car because the mixed existed after oil cooler pipe replacement . Hope someone finds this problem.
Cheers,
Louis
Cheers,
Louis
03-19-2018, 06:27 AM
#6
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How many miles on your S8 and do you have reason to suspect the trans cooler? I'm at 134k! So the oil cooler is the most likely suspect in our case, with coolant being in the oil? I hate to just throw parts at it but how else can you find an internal leak if its not a head gasket? I was thinking of changing my water pump and thermostat at the same time, since the system will be drained.
cooler is to blame. As for the trans, I don’t have any reason to suspect anything other than it seems my particular car has a bad case of leaky seals, at least the engine oil seals. I’ve replaced the oil filter housing o rings and well as the valve cover gaskets, all were leaking. I noticed a good amount of oil at the oil pan, but it looked like it was coming from higher up. I’m hoping the oil cooler is to blame for that leak, and that I don’t have to reseal the oil pan gasket. So going in stages and since the coolant in the oil prompted me to replace the oil cooler, I’ll wait and see how that replacement goes for the oil leak I have left. I think this car sat for long periods of time, hence the lower miles and leaky seals. Cars don’t take kindly to sitting a lot and not being driven. No worries though. I figured I’d have some issues like this going in, so I’m not too surprised. But I’m super glad I did the Blackstone testing. I’m going to adding that to my other vehicles regime as well.
03-19-2018, 06:29 AM
#7
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I would look at the coolant and oil diagrams to see which gaskets have these 2 fluids next to each other. Oil cooler seems to be one, but there are quite a few unsolved problem here. One had to sell the car because the mixed existed after oil cooler pipe replacement . Hope someone finds this problem.
Cheers,
Louis
Cheers,
Louis
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03-19-2018, 05:47 PM
#8
57k miles on mine. I’m going to replace the oil cooler now and see if that solves the issue. Cheaper than headgaskets, and should be the most likely spot where the two fluids would mix. Head gasket issues should cause other problems as well, I would think, so I’m pretty sure the oil
cooler is to blame. As for the trans, I don’t have any reason to suspect anything other than it seems my particular car has a bad case of leaky seals, at least the engine oil seals. I’ve replaced the oil filter housing o rings and well as the valve cover gaskets, all were leaking. I noticed a good amount of oil at the oil pan, but it looked like it was coming from higher up. I’m hoping the oil cooler is to blame for that leak, and that I don’t have to reseal the oil pan gasket. So going in stages and since the coolant in the oil prompted me to replace the oil cooler, I’ll wait and see how that replacement goes for the oil leak I have left. I think this car sat for long periods of time, hence the lower miles and leaky seals. Cars don’t take kindly to sitting a lot and not being driven. No worries though. I figured I’d have some issues like this going in, so I’m not too surprised. But I’m super glad I did the Blackstone testing. I’m going to adding that to my other vehicles regime as well.
03-21-2018, 05:11 PM
#9
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I agree that cars don't like to sit too long without being driven, operation is good better! This was my first oil analysis and I think it was money well spent, I'll probably use their service regularly from this point on. Oh, the other reason I don't suspect the head gaskets is because I have no 'white' smoke from the exhaust and no bubbles in the coolant reservoir. I'll order my oil cooler in a few days and prepare to flush the system, then change oil and test again.
03-21-2018, 05:12 PM
#10
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I agree that cars don't like to sit too long without being driven, operation is good better! This was my first oil analysis and I think it was money well spent, I'll probably use their service regularly from this point on. Oh, the other reason I don't suspect the head gaskets is because I have no 'white' smoke from the exhaust and no bubbles in the coolant reservoir. I'll order my oil cooler in a few days and prepare to flush the system, then change oil and test again.