What People Say About Engines.....

The more people you talk to about jaguars, the more conflicting opinions you get. These opinions seem to fall into two general catagories:

1. "At that mileage it's just run in" - regardless of mileage
2, "Shhhh, that sounds expensive - I reckon that head/block/diff ets's scrap"

Well I've been taking advice about our oil leak and the funny ticking sound that we get when the engine's cold and on Friday a mate was talking to a Jaguar Specialist in Peterborough:

The oil leak from the head gasket just above the distributor (just like yours) is extremely common on the 4 ltr engine. Apparently there is an O ring in the head gasket that seals around one of the pressurised oil passages. This O ring moves slightly and allows the oil to leak. He has seen many of these at a variety of mileages. His suggestion was to leave it alone unless it is leaking a lot of oil or is too annoying to live with. His reason? He reckoned that replacing the head gasket is not a difficult job, but tends to be one that turns into a much bigger job than planned. Expect several of the exhaust manifold studs to shear off in the head, also do not be too surprised if a head bolt shears off during removal. Once the head is off, having done 170,000 miles expect to be shocked at the state of the valves (burnt) and the amount of wear on the cam shafts. Bingo! Unless you are sufficiently strong willed to put the head back without further attention, a simple head gasket replacement just turned into a top end rebuild! Could you put a worn out head back on?

The ticking noise was a bit of a surprise (well it surprised me). All I told him was it happened when the engine was cold but under a hard load, and it sounded 'tappety'. "That'll be the exhaust", Clive says without a moment's hesitation. "Oh?", says I, "what bit?".
"The manifold. Either it'll be cracked or, more likely, the gasket between it and the head has failed or one of the studs has come loose or sheared off. Take the stainless steel cover off and have a feel around for a blow when the engine is cold. If it's just a loose stud you can sometimes just carefully tighten it up a bit.

The thing is that we can't really have it dropping oil all over the place so I think taking the head off it is inevitable - I really wonder how knackered it can be. The mileage is very high but it has been on the back of an auto box for all that time and by most accounts the AJ6 engine is capable of 250,000 miles before an overhaul.

We may well see....

Simon

Small faults fixed ... major fault discovered

I had to cruise down to the south coast in the green beast this weekend so I felt it was time to rectify a couple of small faults. The rear windscreen has been making quite a racket at motorway speeds and a bit of investigation (i.e. pulling the seal off) showed that this was because it was the least-bonded bonded-windscreen around and was liable to be sucked out at any minute. As glass is structural and not to be messed with, I rang the local auto-glass company and they sent one of their 12 year olds round in a van to re-bond it.

We also decided - as we know a friendly young chap at the local garage who does this sort of thing for pocket money - that it was time to get the rear offside directional tyre pointing in the right direction, on the off-chance that we might coax an extra mile-an-hour (or, even better, mile-per-gallon) out of the barge.

While we were there, we asked a sympathetic mechanic for his view on the oil leak that has been troubling us and he confirmed our suspicions - the head gasket needs replacing before Staples to Naples or we will wind up stranded somewhere half-way up the Alps. A can of Wynn's Leak-Stop has staunched the flow for now but, since the choice is replace it ourselves or pay £850 for a garage to do it (there is nothing more expensive than a cheap Jaguar), we will be commencing a major engine overhaul just as soon as the weather catches up with the time of year. Great.

Matt

That oil leak... And another thing!

The strange thing about the oil leak is that although oil was dropping out of the car, the level wasn't dropping on the dipstick. Also, our engine oil is mucky, sludgy stuff whereas the oil collecting on the subframe was beautiful clean golden virgin oil. Turns out that the PAS system on the XJ-40 is filled with HMSO oil rather than the stuff that is deemed to be good enough for all other cars on the road - hence the golden hue.

Anyway, being as it's not gushing out I couldn't see where it's coming from until I cleaned the engine block, which is what I did today. Spent an hour of so with a paint brush, engine de-greaser and a high-pressure hose underneath the block and also from the top, into the engine bay. It's all clean now so I'm waiting until tomorrow to see where the oil is coming from. There was a slight brown-trouser 'oh-no' second when it wouldn't start after the cleaning but a brief drying of the coil and distributor solved that problem. And I haven't broken any of the electrics today. Not a warning light to be seen anywhere.


I also took the Daimler on a bit of a jaunt out into Suffolk today, just for the hell of it and have found another little problemette: at speeds of anything over about 60mph, there is a wind-whistling sound from the rear windscreen which gets worse and worse with speed. I investigated the window and was surprised to be able to pull the seal off with my fingers. Hmmm, loooks like there's nothing holding our rear screen in place! I think I'll be gluing it in before it gets sucked out by air pressure.


Simon