Hello everybody. I have a 2011 Jaguar xjl with a 5.0 L non supercharged engine. I had somebody do the head gaskets for me about a year ago. It was fine for about 1 month and I took for a long drive through the Hills to go on a vacation. The car lost some coolant so I pulled off to top it off and completed my drive. I then drove all the way home and everything was fine no loss of coolant. I've been struggling for the past year to try to figure out what is causing loss of coolant. I replaced almost all of the cooling system parts to try to identify leaks and cannot find any external leaks. Brought it back to the mechanic right after my long drive through Hills and vacation. Was about 250 Mile Drive. I do not get any misfires to trigger check engine light but I do have very rough startups and smoking out the tail pipes. It clears up and goes away. Took it to two shops and they both told me blown head gasket. One mechanic let it sit overnight after driving it and pulled the plugs in the morning and stuck a borescope in two of the cylinders and they had coolant in there. So there are my rough startups. When I did a compression test all cylinders were 195 PSI to 205 PSI. I also did a coolant test to see if exhaust gases were in the coolant and I am not getting a positive reading so pretty sure no exhaust gas getting into coolant but yet coolant is getting into cylinders. I finally got the mechanic to return calls and talk to him and he is going to redo the head gaskets. If there is small deviations in the flatness of the block is there a possibility to put a thicker head gasket and if so where can I buy one from? I do not want to take the block out and redo. I may decide to get used engine. I thought by redoing head gaskets wood be better to have new top end instead of getting used engine. I'd like to know what thoughts anybody might have that can help me get this going without having to resurface the block. But I do not know for sure if the block is Warped or not. The car runs really good and does not show any misfires that trigger the check engine light but when I do hook scanner up to it it shows that there are Catalyst damage judgments but it does not trigger check engine light. Any recommendations or tricks of the trade to do that I could let my mechanic know.?

 

I would think that there is possibly some minor warpage of either the engine block, or the cylinder heads, that the head gaskets cannot overcome. Do you happen to know if the mechanic who performed the first head gasket replacement, had the surface of the heads machined before he reinstalled them? Also, a good question would be as to what caused the gaskets to need replacing, in the first place.....

 

Block and heads will need to be decked to fix this problem properly. You can't just slap a thicker headgasket in this engine; it isn't a 350 Chevy with a closed deck iron block.

I am surprised the mechanic was willing to warranty his own work from a year ago. That shows good character and I'd definitely continue taking my cars to him.

 

Why were the head gaskets changed in the first place?

It's not common and is a GIANT red flag that the engine was severely over heated causing head gasket failure. If that is the case then yes it has been reported that both the heads and the block can warp because of over heating. When that happens you can't just replace the head gasket.
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Thank you for the responses. As far as I know the mechanic did have the heads resurfaced. As far as the block I'm not sure if he checked for flatness. I asked him after the fact and he said yes he did all that. So my thoughts are if he did all that and put it back together that he might have lied to me about something or skipped a step. Possibly could have missed something. I asked him to see about the head gasket failing one month after he repaired it and he argued with me that it is not the head gasket that there is a leak externally somewhere. That still did not give me an answer why the rough startups and smoke. So going back and forth with him for months I finally took it to two different mechanic shops and they both gave me same answer as far as blown head gasket. I wonder if he really did do both gaskets because on one side the heads looked like they had some Caked Up dirt and sludge and the other one looked a little cleaner. My thoughts if the heads were checked out fully and reconditioned that it would be a lot cleaner than what I was able to see.

 

It is remotely possible that the shop didn't clean the parts when they did the job but not likely. And if so, there's pretty much no chance that the heads would have been resurfaced without being cleaned.
If the shop that did the job had to be forced into acknowledging the problem with findings by two other mechanics and you have no other reason to trust them, it is possible they just tried to apply some head gasket sealant or something and hope that fixed it.
I'd think it would be tough to trust that same shop if they did that the first time.
"Fool me once, shame on you. Fool me twice shame on me."

 

I agree.

And I'd also be leery of the job, if only one cylinder head was removed, and had 0.002" skimmed off of it's surface, and the other was left in place, with regards to things lining up properly, when reassembled.

 

Yes but why were the head gaskets changed? We still need to know that.
You have to understand these are all Aluminum engines and when they are over heated massive damage is done to ALL the components. Sometimes it's just the heads and those can be surfaced but other times the block is also warped.

There is a reason the head gaskets failed again. No thicker gaskets are not the solution. You need to find what is out of spec that is causing this.

Again was the engine over heated?
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That would require removal and complete disassembly of the engine. A lot of time, effort, and money.

Just sayin'...................