xj8 3.2 1998 engine trouble

[Diavel]

Ive recently bought my first jag only to discover after chasing low coolant for a couple of weeks the head gasket has been the trouble something the previous owner decided not to mention. I will be tackling the job myself as the repair work out ways the value of the car any advice regards to timing vvt special tools etc would be very helpful.

[PaulGover]

Bad luck.

Before embarking on this it's worth pondering Nikasil. If it's a high mileage engine consuming oil, and it's not had steel liners fitted already, a better course might be to source a replacement (I presume second hand) engine which has got steel liners. My 1997 XJ8 has a Nikasil engine and started burning oil at about 160,000 miles, and died just short of 200,000 miles.

You can find out how to check if the engine's been fitted with liners in several articles in the JEC magazine, and I expect there are entries in these forums too. If you do decide to replace the engine, you'll need to find a friendly Jaguar dealer to reset the engine management system, as it won't allow changes like this as an anti-theft precaution.

If you do decide to overhaul the engine, you should also check the timing chain tensioners, and replace if they're not the latest version, as the old versions are a known weakness causing catastrophic damage if they fail. Again, see back articles in the JEC magazine.

My guess is your engine's done a bit over 140,000 miles, as that's when the cooling pump impeller starts shedding its vanes, causing the engine to overheat and leading to the head gasket failure. So plan to replace that too.

[Diavel]

Hi thanks for the reply the engine has only done 83k with fsh its not burning any oil but it does have signs of a backfire cracked airbox etc.Would this be a possible cause of the head gasket failure?