Rear main oil seal
I have a 1987 Jaguar XJS-C V12 which I bought for a project car.
Has anyone changed the rear main oil seal using the sneaky Pete Remover/Installer Tool?
If so, how well did it work? How did you do it, (procedures)? Did it solve your oil leak problem?
I have two major oil leaks, the rear main oil seal and the cam cover half-moon seals.
This is my first time to attempt this, I am an entry level (starter) mechanic.
The cam cover half-moon seals also look like a major project.
Thank you for your advice.
Danny

 

Half moons are bad leakers once they harden up but the rear main is more often than not due to a problem with the breather set up rather than the seal itself. I suggest you check and clean all the breather system first.

 

Also, what you think is the rear seal leaking may well be oil running down from the half moons. Also it is worthwhile renewing the oil pressure sender and warning light sender while you are doing this area, as they leak notoriously and it is hard to spot. Even if they are not leaking, they will be! Support the ally casting they are screwed to against the torque when you undo the senders though, as it will fracture if not.
Your chances of replacing the rear rope seal so it does not leak without removing the engine from the car, the gearbox from the engine, and the crankshaft from the engine, and then properly sizing the rope seal with the correct tool, are ZERO.
Greg

 

Danny,

Like yourself I'm an amateur (at best) mechanic. I did the half moon seals and cam cover gaskets last year. For me, it was a challenging project, not difficult but time consuming and worth every minute. I learned a lot about the car and feel much more comfortable around it. While I had access, I was able to clean out 20+ years of junk in the V, replace the water rails, new plugs, plug wires, coils, distributor cap, rotor and repaint the cam cover itself.
As you are already finding out, there are several excellent, knowledgeable and helpful people here, ready to help with any question you may have.

So, to answer your question regarding the cam cover, it is a big project, but very doable.

Just label everything you take apart, and take plenty of pictures and don't be afaid to ask for help.

 

danny; the half-moons are a simple project, compared to the rear main seal!
and nobody i have ever heard of can make the early rope seal engines leak proof!

i did mine(taking very careful time and effort), and it did not leak for about 2000 miles, then slowly at 1st started leaking, and got progressivley worse as time went on!

the Group44 race guys did all types of fixes, finally used a 2 piece Chevy neo seal,but had to machine the rear of the block amd custom a make a plate to bolt to the block, worked fairly well for awhile, but it proved to be a headache area.

in the end, Ford cast a new block(altho using some tech from TWR racing),
it also requierd a different crankshaft, an expensive change at best.

and someone mentioned the crankcase breather system,YES very important to be sure its working properly , i increased the case vacumm by changing PVC valve,so as to try to keep case pressures negative,HOPING to hold oil in, my engine now has 0 leaks ,except for the rear seal!





anyhow my 1978 XJS V12 leaks oil from the rear seal, been 20+yrs, and i just put a catch plate under the car, and say to hell with it!

 

Hi Danny the half moon camshaft oil seal is mentioned in TSB 12-51.

The recommendation is to use Hyosil RTV (room temperature vulcanising) sealant

 

I'm not sure if Ron Kelnhofer is still making the aluminum (aluminium) half moons anymore, but it may be worth a try getting in touch.

XJ-SC Modifications

 

I thank everyone for your advice. The half moon cam cover seal is fixed. I still have other oil leaks, I think the rear main seal. Not sure what to do next.

 

So much depends on how bad the leaks are and, of course, the amount of labor needed to correct them. Some fixes are fairly easy. Some leaks are fairly tolerable.

I've never done a rear main seal on a V12 but it doesn't sound easy....which would make a minor leak quite tolerable

Cheers
DD

 

Rear main seal is incorporated into the crank main. If any wear is suspected on the block everything has to be machine to fit newer seal. Pan has to be dropped and tranny pulled, never seen this done in car. Not an easy fix. Look at oil sender on top also for leaks, as it comes down the back with everything else.

 

Mine banjos fittings on the heads leak and look like a rear main leak a lot of the time. Jagfixer, what are you talking about machining? The rear of my V12 sitting in the yard looks like any typical rear main seal. Are you saying machine the block for a new rear main seal? That sounds bonkers lol.

Sounds like the worst of this project is getting the bellhousing bolts out.

 

Yes, it is a typical seal. They usually start leaking when the main bearings are at a stage of wear, that the crank starts moving around forcing a leak at the now oblong seal. Block would have to be line bored, costly, and the seal re-centered and set. Therefore, block would need machining. Seal can be replaced, but, if leaks again, there lies the hidden problem. Had to do this on quite a few blocks years ago and now, with the lack of used blocks (as they are not manufactured any more) machining and renewing an old block is expensive.

 

.

the 6.0L crankshaft is different than the 5.3L crank, at the rear seal area.

that is why Ford cast a different block, Jag knew about it ,but had no money to put it into production.

Grp 44 went about it completly different, using Chevy neoprene seal (58 onward), with an aluminum plate, machining the block face and plate, so to use an early 5.3 shaft!

no matter the later 6.0 block has other small improvments also, much improved engine!

and later 6.0 had cast cranks, no matter can still handle 700hp( i dont think anybody here is gonna do that),maybe!

 

Hello, i have problem with oil leaking on my XJS V12 1983. Is this rear main seal fault?

Oil leaking

 

i have never in 25yrs seen an 1989 and earlier Jag V12 not leak oil from rear seal area!

as said i was very carefull when rebuilding V12 , and it did not leak for about 2000mile.

then slowly but surely it kept getting worse, TWR suggested run engine oil level down about 1L, or about a Quart!

make sure PVC system is in proper order!

i still put a drip tray under car after a run, let go over night, is about the best we can do without R&R engine & transmission!

i'm told Ford/JAG v12s dont leak rear seal .

 

Well an 89 cam't leak as it has the rubber seal... Mine has it and mine is a matching numbers engine. It was introduced with the Marelli ignition.

Engine 66783 was the first with the real oil seal. Mine is something like 69xxx amd mine is an 89.So around 1988 for the 1988.5 model...

The rework was done prior to the Ford purchase of Jaguar.

 

good reason for ford to buy jaguar.

like negotiating , you fix that problem and we will buy it ,10% on the pound.

maybe i should have worded it , "any V12 with rope crankshaft seal will leak oil"

 

My original engine number is 65430 in 1989 xjrs and was rope type so it was definately into 1989 before change was made.

 

I had an XJ12C with a similar rear main leak. Went to the local Jag dealer to buy a seal. The service manager was there and he asked me how I planned to put the seal in. I told him I was going to drop the pan and use a Chinese finger. He said that was not possible and that I would have to pull the motor. I said how much if you do it? He said $1500 plus $2.50 for the seal. But he said, since we will have the motor out and it has 60,000 mile on it we might as well do an engine job on it. I said how much is that? he said $6000 plus $1500 to pull the engine and $2.50 for the seal. I ask him if there was any alternative procedure? He said yes go to your local grocer, by a can of tomato paste. Dump the paste and wire the can to the leak and drain it weekly. When I sold the car, I was still doing weekly draining's. This was back in 1985! This is a true story and it occurred in San Diego Ca.
By the way, Constantino tomato paste make excellent cans!

 

Then it was in the 89 year, but before Ford purchase... Mine was built before the Ford "invasion". But is also an 89. Of course, 1989 was, with 1988, the most successful year for the XJ-S so there is of course a good chance it was somewhere early/mid 1989... Engine number has been stated