Hello all,

I'm new to the Forum, and a couple of people have kindly suggested that I post my question here on the XK8 board, so here goes, and thanks in advance of any help or advice you can offer.

After 46 years dreaming of Jaguar ownership, I finally scrape together enough to purchase a 1998 XK8. 30 minutes into the journey home the coolant low light comes on, and having topped up with 4.5 litres of water, I finally get home. My local garage then informs me that the head gasket has gone.

My love affair is almost over as soon as it's begun, so 2 questions to the forum as a newbie:
1) Is it possible that a head gasket could have let go so quickly without the prior knowledge of the previous owner?
2) Can anyone recommend a Jaguar engineer in the Bristol (UK) area who could tackle the job.

All advice warmly received. Thanks in advance, Andy

 

I don't think they are catastrophic like that. Is there residue on the side of the block?

 

Hello

I cannot answer your question about the head gasket.
Even if this was a private sale you still have rights, if you can prove the seller was aware of this condition.

Although several UK members frequent this site, there is also a .co.uk forum you can try as well. Who will be able to advise on UK engineers to try.

 

First off you should get another opinion to verify the diagnosis.

Was that 4.5 liters added all at once or in several fills?

If that was all at once, your coolant could have been so low as to cause an overheating situation and cause the head gasket to fail during your drive. When the coolant is very low, it's level could be below the coolant temperature sensor and may never even give you an overheating warning.

 

If it was that low would it not have given a low coolant warning?

Also this car has serious problems. See other posts by this member.

 

The low coolant sensor is in the overflow tank, so a just few ounces low would register a warning.

The coolant temp sensor near the top of the radiator level....if the coolant is very low (liters low) the temp sensor will be sitting in air, not coolant, because it could be too low to pump.

Low coolant warnings need to be checked on promptly. Most of the time it is a slow leak and no big deal...but it is a very fast leak you can have an overheat and not even know it.

I learned this the hard way on my wife's S-type. She called me and said she had a low coolant message. I told her not too worry, it was probably just a slow leak, as I had seen before. I told her to pull over if it even begins to overheat. Fifty miles later the engine was toast, and there was never any indication of overheating, except no coolant left in the car when it was finally towed home.

 

The XK8 is a low volume, high flow rate cooling system. With a total capacity of 9.5 litres, the reported addition of 4.5 litres represents a catastrophic loss. As WhiteXKR says, coolant loss needs to be investigated immediately as damage can occur very quickly.

More information is needed about how the loss occurred, over what period of time and mileage to be able to comment on possible cause or consequences. Blown head gasket(s) is one possiblity. How have the local garage arrived at the conclusion it's gasket?

Graham

 

Shouldn't the car/system go into "restricted performance" mode when the coolant sensor on the water pump housing goes dry?

 

No, restricted performance is only set with electrical or electromechanical failures in the ignition or fuel systems. So issues like overheating, low oil level or pressure do not trigger restricted performance.

 

This car has to go back to where it was bought!

See other post ref gearbox judder fault etc!

 

Yeahhhhh.....sounds like a genuine well-squeezed lemon.

 

I wonder about relocating the coolant temp sensor to the hole for the engine block heater?

 

Thanks so much for the helpful replies. Just to explain what happened, the engine coolant low light came on after about 30 minutes - i.e. 30 minutes after I bought the car! It probably 10 minutes later that I got to a garage to top up. I let it cool for 10 minutes before unscrewing the cap with a big sweatshirt - and there was a fair bit of pressure behind the coolant. I put about 1.5 litres in at this point.

The remaining journey was around 150 miles, during which the coolant liight came on a further 4 times forcing me to repeat the process and using the best part of a further 3 litres. Beacuse I was (by now) carrying water I was always able to stop within 5-10 minutes of the coolant low light coming on and kept a close eye on the temprature gauge throuhout but it never went above normal.

I thought it would have been a loose / leaking hose, but it was only when I took it to my local garage that he gave me the bad news having completed a block test. It looks like I'm looking at a big old bill to get it back on the road.

Stumpy, and Old Jag lover - thanks too for your comments. You're right that this is the car with gearbox judder too. I won't mention the ABS, traction control or stability control lights that came on during the trip home!

I have been well and truly mugged with an absolute lemon! Beware the perils of the smiling seller and the 10 minute test drive.......!

Cheers

 

Sounds to me that you wisely kept enough fluid in the system, and if it is bad head gasket, it was a pre-existng conditon.

I hope you can return the car, and if not, befriend a good independent Jag specialist.

 

Not a bad idea to investigate.

What is really maddening to me is that there is an oil temperature sensor, and according to JTIS, if the engine oil temperature reads too high the ECM substitutes the engine coolant temperature sensor!

 

We need to find a workaround for this.