Hello folks,


I purchased a 1985 Series 3 4.2 Sovereign last year while my 1983 Vanden Plas took a rest in the garage as it needed some major work.


Previous owner of the Sovereign had the engine rebuilt in 2012, receipts and photos of the professional rebuild came with the vehicle on purchase. All was good until last week when I noticed huge plumes of water vapour/steam coming from the exhausts. This took about 10 kilometres to disappear, on a wildly hot day here in Adelaide, Australia.


The car has been losing coolant, but not a huge amount and with no obvious external signs. Unfortunately, there is now definitely an odour suggesting my worse fears of head gasket, cracked head or block allowing coolant into the cylinders.


On investigating this last week, I also noticed oil 'splatter' around the dipstick and leaks around the oil filler cap on the rocker cover. It looks like there is a pressure problem, as in too much pressure forcing the oil out.


Neither oil nor coolant appear to be contaminated, coolant remains bright green and the oil looks nice and fresh, not burnt or milky.


To make matters worse the starter motor has packed up so I cannot even turn the motor over to test anything. Before I start dismantling to get the head off, does anybody have any idea as to if the problems are related and where I might start looking for the culprit in the system?


I have since resurrected the Vanden Plas, always pays to have a spare few cars around when relying on old Jaguars for daily transport - but I wouldn't have it any other way.


Any advise would be greatly appreciated.


Cheers.

 

Try removing the spark plugs and then try the starter. If coolant has filled a cylinder, the engine will not turn over, the starter may be alright, the engine may be hydrolocked.

Better yet, turn the engine over by hand, with the spark plugs removed.

 

just curious,

1) were the huge plumes of water vapour/steam coming out of the exhaust pipes at the rear of the car?

2) or was water coming out and falling on top of the exhaust pipes in the engine compartment? (which would explain smoke and odor too).

 

Get a cooling system pressure tester, pressurise the coolant and watch to see if the pressure drops over a while, if so its indicative of a leak somewhere, and if you cannot visually see the leak, its usually a headgasket leaking into oil or a combustion chamber.


If it was into the oil, you'd more than likely see a milkshake in the oil system, but if its in the combustion chamber it'll just burn off the coolant with plumes of steam out the back, if its bad enough, it will also make the car run rough initially after start up.


Another quick test to see if there's coolant in the oil, is to undo the sump plug, if coolant comes out first then you know there is an issue, if oil, there's no coolant in the oiling system.

 

Plumes of steam coming from both exhausts, which has me more worried.

 

Good idea, I did not think of that. Too busy worrying about dollar signs.

 

Thanks, I shall get myself a tester.

 

hopefully it will not be the headgasket, but I have a feeling it is.

regardless, you got 4 excellent troubleshooting tests to do.

 

You got some good advice here. I would also do
1. Compression test and compare numbers.
2. Cylinder leakage test.

If your compression is low in 1 or two cylinders, the cylinder leakage test will tell you were the lost compression is going

 

Based on your description of the events, it seems the engine ran hot for some time. This can also be caused by a blocked radiator as Jaguar recommended the addition of sealant when these vehicles were in for service.

As others recommended, a compression test is probably a good indicator. Do you smell combustion gasses in the coolant recovery tank with the engine running or notice any bubbles in the coolant?

The XK engine does not tolerate being overheated as the tappet sleeves can become loose and rise out of the cylinder head. If this happens, the tappet sleeves can break as the cam lobe strikes them thus causing catastrophic engine failure.

Did the overhaul of the engine by the previous owner include securing the tappet sleeves?

 

White "smoke" out of the pipes in an early morning is mere condensation being 'burned' off. Not an issue at all. I kinda like it. But, if it continues and the weather is warm, not good. Hot exhaust gases into a cold day will "smoke". OK, not an issue.


But, the other tests mentioned are far more meaningful as to whether all is well or not so good.


Carl