Around a year ago the old Jag suffered from HGF, my local Jag specialist did the work for me on both heads, skimmed and all put it back together again.


Ever since its been using coolant, I can also smell burnt coolant everything now and again.
I have taken it back to them 3 times for them to investigate, they tell me they cannot find a leak nor smell any coolant. They have also pressure tested the system and tell me it doesn't loose any pressure at all.


I couple of weeks ago I bought a new header tank cap as I once noticed a small amount of steam coming out of it, the problem solved I thought.


Went for a 30mile round trip yesterday, checked level from cold again this morning and its used 1cm of coolant in the header tank (now less then half full).


If what the Jag people are saying is true where else can the bloody coolant be going?

 

As you have taken it back to have it checked with no result...I'm beginning to wonder if they are trying to fob you off.
You have replaced the pressure cap, good move.

Have you had a good look around the engine with a bright torch to check for leaks or weeping?

The correct level for the coolant at dead cold is at the base of the filler neck no more because it just gets burped into the catch tank.

There are no leaks coming from the thermo tower, header pipe or associated hoses?

For piece of mind i would be having an independant pressure check done and a 'sniffer' test for coolant in the combustion chambers or vice versa.
1cm is only 10mm

 

I'm beginning to wonder the same thing as well, though they know I'm well onto the fact that something isn't right even if they don't fancy doing the job again they cannot lie if it loosing pressure surely.


I have had another garage check for leaks from the top and underneath and he couldn't find anything either.


Its a bizarre one, I went out about a week ago driving the car really hard for 30mins, checked the next day and the level was bang on where is should be. Went out for a gentle drive yesterday and its used a load.


All hoses have been checked and when I had the HGF I also got them to replace the pipes under the supercharger for piece of mind. There hasn't been anything overlooked. There is no white smoke coming out the exhaust.

 

What's the story with your water pump and thermostat....have they been replaced of late?
Have you checked to see that your bleeder tubes are connected correctly to expansion tank and haven't been crossed over.

I would still have a 'sniffer' test done independantly and if it at all confirms any exhaust in the coolant or vice versa, I would be putting the screws on the guys who performed the work.
A super charged engine is a complex device and not to be screwed around with.

 

It has a later (not original) water pump which was inspected when having the work done for the HGF and seemed to be working fine. I had to replace a faulty thermostat 3 weeks ago due to making the engine run colder, still loosing coolant after this time.

 

My wifes '02 XJR uses coolant. I couldn't find the leak until I went and purchased a pressure test kit. I now know the problem is from the hose fittings under the supercharger. Now just need the time and money to get the parts and do the work.