Afternoon,

I was driving my car ( '98 XK8 Coupe ) this afternoon and got an engine coolant level warning, so I pulled over and filled it up.

I noticed that the colour of the coolant was off-white, with some gunk in the lid. I've called my local garage and they said it sounded like it was probably a head gasket failure, but didn't want to take the work on themselves.

They suggested trying to get the oil, coolant and filters changed, on the off chance that it was caused by condensation or something like that. Any thoughts on that?

Also if it is a head gasket, is that the sort of thing you take to any old garage, or would I be best trying to find somebody who specialises ( either in oldish Jags, or general head gasket replacement, or something else ). I'm in Blackpool, on the off chance that somebody can recommend somebody locally.

They suggested I post on a forum asking if anybody knows of problems with the heads splitting or anything like that.

Also, last ( of many ) questions, how much am I looking at for replacing the head gaskets?

-edit: I forgot to mention, the off-white liquid is splattered all over the inside of the engine bay - could this indicate a radiator leak or something equally cheap? Could the off white colour be explained by the previous owner putting water in the engine coolant ?

 

Take it to a Jag mechanic- they will need the cam timing tools to do the job.

I also would recommend changing the coolant and oil to see if there is a difference, although the spray under the hood indicates that there was probably an overheat and/or a bad hose that burst/leaked. You *could* do it your self if it is needed, as there is plenty of help and how to's here on the forum.

 

Sounds like a simple leak, Have the cooling system pressure tested. Some auto parts stores will loan a pressure tester for free. I've had to replace most of the hoses on mine due to small leaks in several places. The white gunk could be mixed coolant or like mine the previous owner dumped stop leak (a lovely off white paste) into the system. if it's all over the engine compartment it's probably not the head gasket.

 

The aluminum engines on these cars are VERY sensitive to heat, so be very careful if you start it or try to drive it. The OEM temperature gauge is almost useless as it will not show a hot motor until it is nearly too late, so please do not rely on it as your means of telling if everything is OK.

So, some questions for you to help us help you diagnose: You said you stopped and filled it up. Have you driven or started it since? Is it still losing coolant? Did the temp gauge say the engine was overheating? What does your oil look like?

The bad news is a foamy look to coolant on/in the expansion tank does point to overheating and possibly head gaskets.

p.s. fulton makes a good point that coolant sprayed all over the engine bay may point to a leak vs. something worse.

 

+1

Take this advice very seriously.

Expensive damage can occur extremely quickly to the Jaguar V8 with overheating.

Graham

 

I drove it two miles home, and the level didn't drop in that time. I drove it for a couple of miles this evening but it's still warm so no point checking the levels again until the morning.

Did the temp gauge say the engine was overheating? No

The oil still looks like oil, with no gloop on the filler cap or the dipstick.

Am I safe to drive it as long as I watch the coolant level?

 

You really can't watch the level while you're driving. As everyone mentions, the engine is very sensitive to overheating, one result of which could be a head gasket failure. By the time you get a low level alarm you might have lost enough coolant to be in trouble.

It would be far wiser to get hold of a pressure test kit, or drive to a garage that has one if they are very close.

 

Probably, as it is sounding more like a leak. However, are you willing to bet your engine on it?

I would look for the cause of the leak before I ventured too far. The consequences are dire if you guess wrong or the leaking component gives way while you're on the road.

 

A quick check for a gasket leak is to have or do a compression test you will have to remove the coils and plugs but it will take the guess work out of and tell the state of your valves etc. Though the other members are probaley right and you have a small hose leak.

 

It's in the garage now, they say it sounds like just a leak but they're going to do a pressure test to be sure.

Fingers crossed.

 

The garage phoned back, there was both a leak and a failed head gasket.

Apparently they had to do a rev test to get it to register the failure, so it's a minor one. They're going to try some K-Seal and re-test. I'll get it tested in a few months and see how that goes.

Thank for your help gents.

 

Sorry to hear that.

For many years, Jaguar used and recommended a leak sealant product called Bars Leaks. The World was divided into those who swore by it and those who swore at it! (I detested the stuff) Jaguar have long since dropped this product.

K-Seal appears to be a similar leak sealant.

If there's a cooling system leak, then the only satisfactory solution is to fix the source - be it a hose, a hose clip or one of the plastic components in the system.

If the cylinder head gasket is blown, it is wildly optimistic to think leak sealant will fix this.

Graham

 

Sorry it was a head gasket, I'm not a fan of stop leak products, the previous owner of my Jag used it to stop leaks before I bought the car. It only lasted about 500 miles and now I'm cleaning up the mess. I've spent most of the winter changing hoses and cleaning the gunk out of the pipes heater core, etc. In my case it caused far more problems then it solved.

 

I've decided I'm going to get the head gasket replaced in a couple of weeks, along with the tensioners and anything else that needs doing.