Head Gasket Failure
07-08-2013, 05:30 AM
#1
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Head Gasket Failure
Anyone have a head gasket failure? 2006 A8 with 104,000 miles. Experiencing engine misfire on #2 cylinder on start up. Started using small amount of coolant and now get flashing check engine light at start up with a engine miss. Vagcom showed #2 misfire.
Removed plug and coil pack from #2 and switched with #1 cylinder no change.
Plugs looked fine with no difference or scaling.
Now water pump is dripping coolant a few hours after engine shut off. (only 30K on pump) I think there is too much presure in system and may have damaged water pump seal! I Loosen coolant cap and let presure out but still leaks overnight.
Suggestions? Considering a couple of head gasket seal treatments where you drain and treat coolant system.
Removed plug and coil pack from #2 and switched with #1 cylinder no change.
Plugs looked fine with no difference or scaling.
Now water pump is dripping coolant a few hours after engine shut off. (only 30K on pump) I think there is too much presure in system and may have damaged water pump seal! I Loosen coolant cap and let presure out but still leaks overnight.
Suggestions? Considering a couple of head gasket seal treatments where you drain and treat coolant system.
07-08-2013, 07:01 AM
#2
AudiWorld Super User
If your head gasket is broken you would have coolant in your oil which would make oil white (oil/water emulsion), or you will have major coolant leak, even blown hoses.
I think that pump and misfiring issues are coincidental. If swapping coil packs didn't make any difference you should check that injector. Injector cleaner treatment may help. If not than check compression on all cylinders. Low compression could cause misfiring on start up.
Pump wise, which one it is? I would replace it with OEM one.
I think that pump and misfiring issues are coincidental. If swapping coil packs didn't make any difference you should check that injector. Injector cleaner treatment may help. If not than check compression on all cylinders. Low compression could cause misfiring on start up.
Pump wise, which one it is? I would replace it with OEM one.
07-08-2013, 07:10 AM
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I would be highly surprised if you have a bad head gasket. The first thing to look for would be cross contamination between engine oil and coolant. If you find that you do have this, then look at the spark plugs for the cylinders on the bad head side- they will be cleaner than the other bank.
My guess is that this is all just coincidental.
My guess is that this is all just coincidental.
07-08-2013, 08:42 AM
#5
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Hello All,
A blown head gasket will not always send coolant into the motor oil making it milky, it could just leak air and fuel mixture into the cooling system on the compression stroke, I have seen it before, check your coolant reservoir for bubbles as you give the throttle some gooses, if you can, remove the reservoir cap when cool enough and it is not over filled if you have added some coolant, then start the engine and look for bubbles and smell for gas vapor, usually when you apply even throttle the coolant level will drop in the reservoir slightly, if you apply throttle and it bubbles and spit coolant out like old faithful you have a problem.
I hope you see no bubbles....
A blown head gasket will not always send coolant into the motor oil making it milky, it could just leak air and fuel mixture into the cooling system on the compression stroke, I have seen it before, check your coolant reservoir for bubbles as you give the throttle some gooses, if you can, remove the reservoir cap when cool enough and it is not over filled if you have added some coolant, then start the engine and look for bubbles and smell for gas vapor, usually when you apply even throttle the coolant level will drop in the reservoir slightly, if you apply throttle and it bubbles and spit coolant out like old faithful you have a problem.
I hope you see no bubbles....
And right about bubbles too.
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07-08-2013, 03:06 PM
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Head Gasket
Water pump was done at dealer so assume Audi part. Oil not milky and I just changed it. No bubble in coolant but will check again. System holds preasure and even overnight will still have some. DO get white smoke/vapor from tail pipes at start up and a odd smell. Suspect very small leak in cylinder 2 with coolant into cats. Spark plugs were fine with no difference between #1 and #2. I did do fuel injector cleaner when tank was 1/4 fuel and saw no change also. It runs perfect after the first minute.
Last edited by parkrog2; 07-08-2013 at 03:09 PM.
07-08-2013, 07:31 PM
#10
AudiWorld Super User
Some next step ideas:
Monitor coolant level exactly over several days. Mark it cold on the reservoir with a Sharpie. If no drop, no leak and no head gasket issue either. If any drop, could be either.
In general, head gasket issues on the 4.2 seem very rare, so I certainly would look all over for a leak first if you end up finding a slow drop. For example, my W12 apparently had a slow drop when near new per the paperwork, but they found nothing. Years later as I approached end of 4/50 warranty, I found the radiator core was just a bit wet on the bottom edge; typically it just burned off with engine heat. Sure enough, they confirmed and replaced radiator, and nothing ever hit the ground or really even ran onto the belly pan. Just recently, I spotted the classic pinkish deposit indicative of antifreeze being cooked off and then traced it upward to a cracked overflow bottle plastic line. Again, no coolant on ground or belly pan, and I had just noticed a slight drop in the coolant a few days before by chance during an oil change and check, but it hadn't registered until I saw that antifreeze residue.
Some white smoke/vapor at start up can just be condensation in the exhaust that then vaporizes again as the exhaust heats up further forward. If rotten eggs smell, that of course is converter related, but not too worrisome if so CEL's or codes. Can also be valve stem seals, where you get a bit of oil leakage down stems after shut down and just a bit of smoke on first start. At 100K miles on an Audi, could be--I've seen and owned lots of Audis over the years where it happens as the motor ages. That of course would be more of an oil burning initial smell.
In general, head gasket issues on the 4.2 seem very rare, so I certainly would look all over for a leak first if you end up finding a slow drop. For example, my W12 apparently had a slow drop when near new per the paperwork, but they found nothing. Years later as I approached end of 4/50 warranty, I found the radiator core was just a bit wet on the bottom edge; typically it just burned off with engine heat. Sure enough, they confirmed and replaced radiator, and nothing ever hit the ground or really even ran onto the belly pan. Just recently, I spotted the classic pinkish deposit indicative of antifreeze being cooked off and then traced it upward to a cracked overflow bottle plastic line. Again, no coolant on ground or belly pan, and I had just noticed a slight drop in the coolant a few days before by chance during an oil change and check, but it hadn't registered until I saw that antifreeze residue.
Some white smoke/vapor at start up can just be condensation in the exhaust that then vaporizes again as the exhaust heats up further forward. If rotten eggs smell, that of course is converter related, but not too worrisome if so CEL's or codes. Can also be valve stem seals, where you get a bit of oil leakage down stems after shut down and just a bit of smoke on first start. At 100K miles on an Audi, could be--I've seen and owned lots of Audis over the years where it happens as the motor ages. That of course would be more of an oil burning initial smell.