I bought my Super V8 2 months ago with a disclosed head gasket issue (the price was right), and until tonight I thought I had gotten lucky, that I had simply been dealing with old hoses and a tired cooling system. This conclusion was based on an inconclusive block test (fluid went green, not yellow), spark plug examination and endoscope review of each cylinder. Tonight for the first time I took it on the freeway after having replaced all the hoses (save for that 'no long available 270 degree hose from the heat exchanger to the intercooler pump) and all 3 water pumps. I returned home to coolant sputtering out of the pressure cap... so 14 psi was exceeded and that can only be from compression gases escaping into the coolant system (my reasoned conclusion).

I want to do the work myself, but have to decide between an engine swap and replacing the head gaskets. I am leaning towards replacing the head gaskets, because it's just me that will be working on it and while I have experience wrestling 200 lb. Subaru H4 blocks into place, a 500 lb. longblock V8 is a different animal. I'm also intimidated by step 1 of the engine removal process: 1. remove transmission.

Any advice regarding the head gasket replacement in the supercharged 4.2 would be appreciated. I have the factory manual and all necessary tools (including the timing chain tools, the crank bolt wrench and remover/installer). I have access to an automotive machine shop with good pricing for head resurfacing and valve work.

From my review of the forums and the single X350 (NA V8) video on youtube I have found, the head gaskets can be replaced with the engine in place. Confirmation / denial of this would be appreciated. The hardest part seems to be removal of the power steering pump and AC brackets.

Felt good to have the car on the open road. Turns out I have a bit farther to go before enjoying the Jaguar. Oh well, at least when it's done I'll have full confidence in the car.

Thanks again for any thoughts / advice.

- scooter

 

A quickie, when I had overheating causing a leak at the pressure cap, it was caused by a failed thermostat?

Just a thought!

 

All thoughts appreciated, I had the OBDII scanner on live data for ECT temps and I never exceeded 196 degrees F. A compression or leak down test would tell me for sure, but I'm convinced there is a gasket failure under load.