Possible head gasket failure

[jookul100431]

Hi Guys

Looking for your opinion...I have attached two pics and kind of hard to see but you can see the start of an orange scum in the top of the water bottle and the pic of my finger shows some evidence of a scum type substance when I rubbed my finger on the inside of the bottle....to me looks like possible head gasket. What do u think....

Other possible symptoms...I still have some water loss in the bottle and I noticed this weekend in the cloder weather the car was very slow to get to full temp...I drove nearly 25 miles in fog at about 30mph before the car was fully warm...not sure if related

Yet another problem to slice and no doubt a very costly one..

[ptjs1]

Charlie,

I think it could be premature at this point to infer head gasket problems. The header tank will inevitably become the repository for any corrosion of any element of the cooling system, whether, block, rad or hoses. Previous owners may have used plain hard water etc to top up which can cause scaling, scum etc. My very initial suspects of head gasket failure are huge coolant loss, steam through exhaust pipes, oil trace in coolant etc.

I would be minded to remove and thoroughly clean the header tank, thoroughly flush the system through as best you can, refill with good quality coolant, run the car for a few weeks and see how you're doing.

Cheers

Paul

[BrianG]

I agree with Paul, clean the header tank out first and run it again before deciding. The slow warm up problem is probably separate and caused by a duff thermostat.

My old X308 4 litre V8 blew a head gasket at 95K miles; it was still running fine and the only symptoms were the "coolant low" light on and actual rapid loss of coolant. I was on holiday at the time and had no alternative but to keep topping up with water until I got the car home. At low speeds it lost hardly any coolant but if I went above 40mph it would lose about 2 litres in 10 miles. I had to carry lots of 2 litre pop bottles full of water for the trip home! If the head gasket is blown it depends on where abouts, as this could alter the symptoms. Mine must have had a blow so that the coolant went straight out the exhaust pipe (the garage binned the dead gasket, so I don't know for definite). There was definitely no "emulsion" in the oil even after a few hundred miles, just lots of rapid water loss.

If it is a blown gasket you may be able to identify which bank by doing a compression test on all cylinders, but that's not guaranteed depending on where the leak is. If you do narrow it down to one bank I would lift both heads and change both gaskets; it's false economy to change just the one if the mileage is fairly high.

[J44EAG]

I agree fully with the opinions and actions suggested by both Paul and Brian. Both are experienced V8 X350 guys with an eye for diagnosis, understanding and an eventual fix.

If coolant hasn`t been regularly changed or tap water has been used in place of de-ironised water, then you certainly could see this manifest as scum and sludge. As suggested, a flush and refill with a quality premium grade OAT anti-freeze would be a good starting point. If you do have a head gasket failure scenario developing, you might (dependent upon the position of the gasket failure) see coolant escaping from the exhaust tail pipes or evidence of oil in the coolant or coolant in the oil. You might also get a "sniff test" done by a competent garage which would detect the presence of combustion gas within the coolant system. Presence of that gas would also tend to pressurise the coolant system which you would easily be able to detect. This may or may not lead to boil up scenario situations.

It is vital to diagnose accurately before wading into expensive, complex, perhaps unnecessary engine tear downs. Informed diagnosis is all....One step at a time! If in doubt, consult an expert at a local Jaguar Independent specialist garage.

Mike K

[jookul100431]

Thanks guys for the replies. For now at least my fears are laid to rest. And I have to come clean I have been topping up with normal tap water for the last few weeks while we are trying to chase down this water leak....so I'm hoping this is nothing more than a hard water reaction...

My car is diesel but I assume all the same logic applies.

I hope to get the car to my mechanic next week to see if he can track down this water leak. Between the two of us we have found 4 leaks so far