Oil Leak - crankshaft rear oil seal

[jfbale939]

Having just recently wandered into the wonderful world of Mk2 Jaguars, I’m afraid I’m a bit of a novice, so forgive the vagueness of what follows!

I bought an early Mk2 late last year. Living in Jersey, I need to import it here, and it needs to go through our notoriously finicky DVS (UK equivalent probably a cross between the worst MOT centre you’ve ever heard of, and DVLC).

My mechanic is doing some work, including replacing the exhaust system in toto, and has spotted what looks like a regular drip of oil from the rear crank oil seal - my service manual describes it on page B.s-2 (around the p.120/121 mark). The engine is an LC- in a 1960 body/chassis.

The question I’ve got is whether someone has a smart fix for this .. because I’m being told that it’s an engine out, crank off, seriously expensive job, to replace that seal .. ? Is there, perhaps, a clever (at least short term, so it won’t drop for a day or so to get it through the check (our DVS is notorious for failing any oil smuts or drips)) fix that anyone’s aware of? We don’t think the seal is shot completely, otherwise I wouldn’t hesitate, and take it back to England for a specialist to do the replacement, but it may have be that the seal’s simply older and brittle or stiff. The car’s been overfilled with oil and that’s done something (we had to drain down an overfilled oil reservoir), perhaps, but we’re not sure.

Thoughts / ideas / suggestions gratefully received for me to pass on to my mechanic.

Thanks

JB

[piman]

Hello JB,

the older scroll seal engines would leak when parked on a hill that raised the oil level, but I don't think an overfull sump will cause any harm to the rope seal.

How regular is the drip? You have little to lose in running the car to see if it reduces in frequency in case the seal has been saturated. If the drip is unacceptable to your testing authority then it is an engine out job to cure. Material cost is almost nil, it is all labour.

It may be worth looking to see if the lower back plate can be removed and silicone sealer applied to prevent any obvious drips just for the duration of the test, obviously.

Alec

[jfbale939]

Thanks, Alec. Further investigation is ongoing, and it looks like the culprit may, in fact, be the sump gasket .. there's evidence that someone's had the sump off at some point, and it looks like they've not had the correct gasket and used silicone sealant . . which may have failed . . so we're going to have it off, and replace the gaskets and see where we go from there.

In the meantime, via the club's technical section, I contacted Peter Bell, who'se response I set out below, in case this helps anyone else later:

"It’s worth noting that as a 1960 car, your Mk2 might not actually have a rear main seal installed. Early cars simply had an oil thrower and Acme thread on the crank which isn’t terribly effective... Jaguar folklore has it that the 2-piece wick seal used from 1961 onward was an answer to complaints of oil leaks that occurred on cars parked on the relatively steep street gradients of San Francisco.

The rear of the engine can be a bit prone to leakage, particularly when the rear main seal gets old, but leaks can also occur from the sump gasket, camshaft oil feed pipe and cam covers. These ‘ancillary’ leaks tend to converge at the rear of the sump and can make things look worse so it might be worth checking they aren’t contributing.

There isn’t a quick fix for a leaking rear main, but using a modern multi-grade oil that’s a bit too thin will make matters worse. Either a good quality 20-50 (don’t use the really cheap stuff - the stated viscosity isn’t necessarily correct..) or a fixed 30 grade is recommended for these engines.

Overfilling them with oil is very common, and it’s also not unusual to find that a dipstick hasn’t been correctly marked, or has been substituted with one from a different engine. An early Mk2 engine with a tin sump should hold 11 pints, and it might be worth draining and refilling yours to see if it’s reading correctly. For the sake of the DVS test, it might be prudent to temporarily fill the engine to the minimum mark."

I'll update if we do identify the issue.

JB

[piman]

Hello JB,

just a point as you say the engine is an LC series, i.e. younger than the car and I think I'm right in saying should have a rope seal. My car built late 1961 has a scroll seal, LB series engine.

Alec

[jfbale939]

So, the update .. we got through the tests, and all is done .. and the car is cleared for registration in Jersey. Yay!

Taking Peter Bell’s advice, we took apart a number of components (sump, cams etc), and lo and behold, we found a lot of sealant, and vey little gasket .. ! In short, no gaskets at all on cams or sump. We changed out the rear seal on the sump, put in a full set of new gaskets (if it needed a gasket, and it was in the engine bay, it got a new one), cleaned her down and watched. No leaks, still a very very slight weep, but nothing really noticeable.

Street legal, and happy!

Now for all the other issues .. !

Happy post-lockdown motoring.

JB

[peterheywood52573]

Assuming my 1965 car will have the rope seal. Does anyone know if the club has the sizing tool, shown in the manuals?
Peter Heywood.

[alec2824]

I borrowed the sizing tool many, many moons ago, so it should be available. Talk to the head office.

[peterheywood52573]

Hi Alec 2824,
Who is "head office" ?

[JimMann]

Hi Peter, 'head office' is the main office of the JEC and is located in Bristol. Contact details are in the magazine. In addition, within the magazine you will find information on the stock of specialist tools that are available for members to hire, but these are no longer held by 'head office' but by Ken Jenkins, one of the Club's technical experts. Ken's business has a full page advert in the Club magazine every month on the inside back cover.
Trust this helps.
Jim Mann

[peterheywood52573]

Thanks Jim,
I find the Ken Jenkins article the best part of the magazine. It was in a recent one that he recommended use of this tool. In case he reads this, it would be nice to have a list of tools available for hire, their cost and any provision to reserve them.
I am just interested and like to plan. I hate finding out too late, how I should have done it.
Peter

[JimMann]

Hi Peter, there is a list of the hire tools available on Ken Jenkins website, see https://www.ukjag.co.uk/store/ but it is simpler to either drop Ken an email or give him a call. Refer to the magazine for Ken's contact details.
Also on the website there is a series of tools than can be purchased.
Good luck with your plans.
Jim Mann

[peterheywood52573]

Is this normal? There is a spiral groove on the crankshaft sealing surface (rear). It seems a hopeful thing to do. The groove might transport oil back into the engine when running but could be an additional leakage path when the engine isn't.

[piman]

Hello Peter,

older XK engines (like mine) do not have a rope seal just the scroll on the crank. It does work as long a syou dpon't park facing uphill on a steep slope. It helps to clean the groove of any muck to help it along.

Alec

[peterheywood52573]

Hi,
I wish I had now tried harder to find the sources of the leaks. I was convinced it would be the rope seal but now I am not sure. There was oil all over the place.

.
I am pretty sure the front crankshaft seal leaked but that is all I am sure about. I wish I had tried replacing the gaskets on the cranckcase vent. I had tried tightening the sump screws but not the timing chain housing. A lot of screws were loose.
All I can do now is replace all gaskets. The gaskets had been dressed with black silicone. In the case of the sump the silicone had not stuck very well to the iron block. It is easy to see how flakes of it could end up in the pick-up pipe.
Anyone have good advice on what to use? On paper and cork gaskets, I like the idea of Wellseal because it soaks in a bit. Probably Hylomar blue for the water pump and I guess silicone everywhere else. I would hate to end up with a more leaky engine!
Peter

[peterheywood52573]