Getting ready to do a set of head gaskets this week. Not looking forward to it at all. Car is consuming coolant, but not a lot. It takes about 2,200miles for the low coolant light to come on. Never found the leak into the cylinders, NO EXTERNAL leaks what so ever. Not leaking into the Trans, I know that for sure. Not leaking into the block, I know that for sure too. The only other place is the cylinders. No misfires because the leak is very small. The weird thing is that there are no signs in the cylinders that coolant is leaking. I was advised by Jag is replace the head gaskets. Like I said I'm not looking forward to it.

 

Sorry to hear about this, Jaglover922. Is this a warranty repair? How many miles on the odometer?

 

You probably already did this...but did the compression and/or cylinder leak down test support the conclusion? Can you post the test results for future troubleshooting/reference?

 

Like mentioned, compression test it before you dig into it. Generally you'd see smoke out the tail pipe if it was getting in there. If it was a small leak you might notice it more on start up after the car sat for a long period. Also, the spark plug in the leaking cylinder would probably look different than the rest helping you narrow it down.

This is under warranty correct? If so let the dealer figure it out.

 

Is the car equipped with a vent to atmosphere coolant tank? I'd be inclined to check there first for the 'lost' coolant, and replace the header tank cap.

Head gaskets on a less than 12 month old engine is super extreme.

 

You probably won't see that much if any smoke at all. Depending on the size of the leak. A compression test really isn't going to tell you anything with such a small leak. You would.almost have to have a crack between cylinders to get crappy compression readings. There would also be misfires too, which I don't have. LEFT][/LEFT]y

 

It got a brand new tank in april, because I thought the same thing. Tank was empty pretty much 2,000 miles later with no external leaks. This car has been in 4 times for the same issue in 8,000 miles. That's a problem.

 

European cars use a sealed and pressurized cooling system. There is no vent to atmosphere. Overpressure results in air and then coolant escaping the expansion tank cap. Underpressure after cool down is dealt with by a suction operated valve in the cap.

If coolant is disappearing and the system was not overfilled then combustion gas is entering the cooling system and pushing coolant out or coolant is being drawn into the combustion chambers. This assumes no coolant in the engine or transmission oil nor on the ground.

 

I'd still run the test. The spark plug in the cylinder where it's happening is bound to be different than the rest. Have you drained the oil and checked for coolant in the oil? The oil would look like chocolate milk with coolant in there and you should be able to see small amounts in there if you let it sit for a bit to separate.

 

Jaglover,

Is your 2011 still under warranty? You haven't responded to that question. I guess I'm not understanding why you would want to take on this job yourself if the car is still under warranty.

 

I'm a jag tech. I'm fixing the car under warranty.


Is your 2011 still under warranty? You haven't responded to that question. I guess I'm not understanding why you would want to take on this job yourself if the car is still under warranty.[/QUOTE]

 

The repair was a success so far. Took about three days. Huge pain in the butt. I dropped the motor and trans out as a unit. Much easier to do it that way.

 

What would be the cost of something like this on 5.0 supercharged?

 

Was the head gasket the problem?

I would love to see a picture of it.
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Interesting topic.

 

If the head gasket was leaking, you can see evidence of it upon inspection of the gasket. Hopefully, this is the problem.

 

No coolant showed up in the oil? Are you getting the heads checked for squarness or cracks? Sure would be a pisser to get it all back together to have to do it again.

 

ALOT!..lol

 

SO this can be a tricky one, my guys were trying to trace down an obvious coolant loss but where having such a damned time of it. Sometimes on start up the xf would have some white smoke for a few seconds out of one bank, left in this case, there was no coolant under, or on the engine, oil was fine, no smoke after warm up, pressure remained steady on pressure test.
We finally found it. You had to drive the car for about an hour on a warm day 80F +. then the coolant system would reach enough pressure that it would force the coolant into the cylinders and combustion gas would make it into the coolant. This would cause a misfire on the 4/6 cylinders that the leak is between.
Stop the car to let the pressure bleed off, or bleed from the overflow tank cap and the car would purr like a kitten until the pressure built up again.
They are starting the tear down now.

 

My 2011 NA had a crossover pipe failure. System did not report overheating but it seems gasket has blown. No coolant in oil what so ever. I did a chemical test. But there is gas in coolant. I am going to have to tackle the job. I have gone over my Service Manual and it details head removal and installation sequence but nothing about how to remove timing chains. Here is an interesting video of the work done on a V6. Wish I had this for the 5.0 V8. Guidance from a Jag Tech would be appreciated.