Major oil leak surprise

Driving down highway at a good clip, suddenly awful oil smell permeated the cabin so pulled over and discovered stream, yes STREAM of fresh GTX 20-50 at the high side of the cam cover right at the back corner. Checked the oil level, was down a bit but OK so headed over to the shop.

When I pulled the cam cover, found a 3/4" gap in the gasket. At first I wondered how a piece of the gasket could gave gone missing but later realized that the gasket must have got brittle and cracked/shrunk.

Have new gasket arriving tomorrow but as a temporary fix I cut a piece of gasket material to fit and siliconed it in the gap. Seems to work ok and at least no more leak or stink.

Hey Larry!
And it’s so easy to replace the cam cover gasket. What brand did you buy? When I replaced mine like 10 years ago (or maybe more) the gasket was too short and I had to stretch it by hand a bit. Still holding up.

Hey Joe - went with BECK/ARNLEY 0361606 from Rockauto.
Three choices there but other two out of stock. it was probably about 10 years (or more) ago when I changed mine out too.

A highlight from the last changeout was after deciding to replace the PO’s chewed up Philips head bolts, I called the UK Jag heritage parts dept asking for the 13 bolts and the parts guy refused to sell me them insisting that the cover only used seven or something. :roll_eyes: …so I decided to source Allen head bolts combining them with half stainless/rubber washers which as it turned out was a far better choice!

Let us know about the fitment.
I thought that parts guy was thinking the series III cam cover but it has 11 bolts so I don’t know which Jag uses seven bolts.

92’s and earlier maybe even 93’s

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Your engine is rejecting Castrol GTX 20W/50. :wink:

You may find a thinner oil actually causes fewer leaks as instead of pooling in the engine, it returns to the sump more quickly.

I learn something on here almost every time I visit :grinning: My 93 has only 7 cross head bolts, I always assumed all XJ40’s were the same except the 2.9

Nonsense. I hope you are joking!

I guess it’s only the 94’s that have the lucky number then!

Strange Larry, I’m sure my 94 Sovereign only had the seven bolts too, that’s why I assumed they were the same for all years. Is the rubber gasket and ‘D’ section seals the same on all years ?
I also use Castrol GTX 20W 50, have done since 2003, I think it’s a great oil for this engine :+1:

Perhaps it goes by VIN? Joe and I both have 94’s with the 13 bolt cam cover - maybe Mike can tell us how many his 94 has?

I think the gasket kit fits all the cars - (well I sure hope so as Fedex just delivered mine and I’ll be attempting to install it in a day or two :slightly_smiling_face:)

Lucky 13 for me. Hard to tell from this picture as some on the right side are hidden by spark plug wires, and there are three on the aft end that are out of view.

Years ago I changed out the cross-head bolts for recessed hex (Allen) head bolts and initially tried the metal with rubber washers but later went back to copper washers.

Not at all.

Obviously if the engine has torn gaskets and worn out seals it won’t help, but a healthy engine might suffer more leaks due to the pooling effect the more viscous oil has.
Rotating parts oil seals usually have a small oil well inboard. Using a more viscous oil increases the depth of oil, likewise the oil sitting in the valve train well will be deeper.

The AJ6 is a slant engine and this particular cam cover gasket had split on the high side so no pooling there, just oil leaking due to cams splashing about.

GTX 20-50 is the recommended oil for the AJ6 engine and this particular engine is in fine fettle btw.

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You mean it is the most viscous of the recommended oils for that engine, not the median for general use.
The range Jaguar recommended spans from 10 to 50, with 40 weight being the median for temperate climates.
20W/50 is for high ambient temperatures, over a constant 40 centigrade, which Jaguar calls tropical.
Bear in mind a synthetic oil has a significantly higher heat tolerance and a mineral oil needs to be a higher viscosity to provide the same hot protection, so if using a modern synthetic oil, go thinner for quicker circulation.

That pic explains a lot, I was wondering where the ‘extra’ 6 bolts would fit. My 94 Sovereign (with 7 bolts) didn’t have the oil filler cap in the cam cover either, it was like my 93 - a separate oil filler tube with the cap on top. Maybe the 13 bolt versions are only on the covers with the integral filler cap ? I also replaced the washers on mine with copper ones, the original ones were made from very brittle metal and most of them broke into two or more pieces.

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I’ll be sure to tell the XJ40 handbook publisher that they made a typo recommending Castrol GTX 20-50. Thanks!

Can you please post an image of that recommendation, as to date no-one has been able to provide that information.

See thread Oil change info - XJ-S - Jag-lovers Forums

Different engine and thats that posters decision.

No issue with that, I’m curious about Jaguars recommendation being to use Castrol GTX 20w/50.
The V12 and I6 use the same oil according to oil suppliers.