Jaguar V12 Oil Leaks - Going through the common leaks on Jaguar V12 engines

[@davidpalidwor3229]

Adam. I worked on many of these when they were new. Oil leaks were a huge issue once they got a little older and there are 2 Jaguar products which can make these virtually leak free for a much longer time than just reusing gaskets. Hylomar and Hylosil will seal these up. Always allow the Hyolosil to cure at least overnite before refilling the engine with oil. Hylomar has no curing time. You talk about the copper washers on the oil feed pipes. A light smear of Hylomar on the new washers helps a ton. Same on the oil filter housing gasket. Before I mention Hylosil again - DO NOT EVER use it where there is pressure! Besides the leaks you mention, the most common on these is the rubber plugs on the timing cover and the rubber 1/2 moons on the valve covers. And you didn't even mention them. When doing the sandwich plate / oil pan / valve covers spend the time to clean these 100% Soak up the oil in the troughs surrounding the cam followers with paper towels and while the towels are still in there carefully use a rotary Scotch Brite disc and remove any old gasket. When you think you are done then wash it off with some brake cleaner and get the pieces you missed. NO SCRAPERS OR SHARP BLADES. Spending a little extra time making sure EVERY surface is 100% clean is much better than putting up with leaks later on or having to pull it apart again. Put a light coat of Hylosil on the 1/2 moons and a SMALL bead of same on the valve covers using NO gaskets. This will cure the leak(s) from there permanently. While the valve covers are off push out the rubber plugs from the timing cover and coat the plugs on the sealing surface with a light coat of Hylosil and push 'em in. The sandwich plate gasket should be replaced with a bead of Hylosil as well. There is a small casting near to the filter area on the inner edge of the sandwich plate that must be ground away before refitting it! Use Hylomar on the pan gasket on both sides. If you are doing ANY work on the top of these engines make sure you put a rag in any openings such as the distributor or intakes and always replace the small oil pressure switch. Pressure washing these is a learned art and can be done without any damage but I will agree with you that it is a practice that should be avoided if you do not know what you are doing.

[@LivingWithAClassic]

Thank you for all the great advice! I use those products and especially love Hylomar Blue! I also belive it's the way to get these engines leak free. Thanks again for the great comment!

[@dixiedog7840]

Can we get some content with vacuum lines on a 1997 xjs v12

[@thegearknob7161]

Another spot where they like to leak is the front timing cover. It has a blanking plug for accessing the chain tensioner that is notorious for leaking oil. Mine is coated with oil all down the front, I suspect this may be the cause, although I'm sure the rocker covers are contributing as well.

[@BoudeM]

Thanks for yet another good video. I had most of the leaks you mentioned and fixed them. I also had the steering rack leaking quite bad and had it sent over to England.

[@LivingWithAClassic]

You're welcome! Hope you get your steering rack back soon. Where was it leaking from?

[@chasermalloy7406]

Do yourselves a favor and use Dirko on cam covers, both sump flanges etc. Use on every flange type join. Don't put gaskets on the cam covers or anything on any car with two mating alloy surfaces and a thin gasket. Dirko bonds very strongly as well as sealing and is permanent on most things, specially V12 and 6 cylinder cam covers. lt's Expensive but superior to everything. Just be prepared for a fight if you have tp get it back off ! One more thing, you can have a leak between the cam blocks and heads on V12s too. It's a much bigger job to clean and seal those surfaces too with removal of cams required of course but it's horrible to get it all back together and see oil weeping. Clean and check for leaks there before dismantling. Better to do it anyway and have a nice dry V12 top end forever.

[@morkthebuilder9943]

Great great video. Some great advice from someone who clearly knows their stuff.

[@WilliamKennedy-e5j]

If deleting the fan and replacing with a electric fan , where can you get power to the fan since the battery is in the trunk ? Of course I asm keeping the smaller electric fan already there . I have a 1990 Jaguar XJS V12 coupe base model .

[@LivingWithAClassic]

Alternator feed with a relay would work

[@lobour2000]

An oil leak I recently fixed where the tubes coming from the automatic transmission. I saw some ATF on the floor underneath the car. It appeared that these tubes, where they are connected with a clamp to rubber hoses that go to the radiator ATF, were leaking. Through this way transmission oil is cooled down. Tightening the clamps solved the problem.

[@LivingWithAClassic]

If they start leaking there I would replace the hoses since it would be bad if they sprung a big leak while driving. They can be replaced with normal fuel hoses that can stand oil and heat.

[@klwthe3rd]

I'm really into the 1993-1994 XJ81 cars with the V12 engines. Are a lot of these tips and information relevant to that engine as well? I know the older V12's were a 5.3 and the later are a 6.0. Thanks

[@LivingWithAClassic]

Yes, the engines are very similar in their basic design. The XJ81 is fantastic! I have a friend with a nice one that I will try to feature on the channel in the spring.

[@williambradley3826]

I have a 1984 xjs .I think the valve stuck and busted a piston .would I be better off pulling the engine and fixing what is broken , buying a engine and using what it takes to fix mine ,or buying another xjs and using mine for parts ? PS , I love the xjs And I am going to do one or the other !!!

[@LivingWithAClassic]

If your XJS is om good shape otherwise I'd try and find an known good used engine. These engines do cost quite a bit to rebuild. Thanks for watching!

[@maxallan4007]

@@LivingWithAClassic I think you will find a valve seat insert came loose, which the piston then hit shattering insert into small pieces. Any knocking noise is likely to be bits of insert imbedded in the piston hitting the head. Piston should be OK, but repair will require replacement head. Take care to thoroughly clean intake manifold to ensure its clear of any residual bits of insert.

[@charlieadams9460]

Max makes a great point, it you have not done already, use a bore scope to got a good look at what is going on.

[@ElHuaso89]

Do you have a video on why the Jaguar xjs isn’t reversing?and wow your engine looks beautiful!! And where do you find parts for the car? Jagbits, partsgeeks , junk yards and eBay have been my go to but any suggestions for other sites would be awesome.

[@dimitrilensflareabrams2893]

Hi! Great video! Very detailed. I was wondering how long these leak fixes will last. For example, after how many miles would they be necessary again?

[@louisjones2653]

Another very common leak on the V12 comes from the timing chain tensioner rubber plug on the front of the engine.

[@donx03]

Can you do a video of putting ABS on an older XJ also replacing the brake booster.

[@drewframson7495]

What's your opinion of a quality additive ((Stop Leak) in the V12?

[@lapalmax59]

Great video again thanks

[@LivingWithAClassic]

You're welcome!

[@jabraan1360]

Hey I just got done fixing an oil leak in one of the transmission lines that almost put my car on fire but afterwards I went to start the car and there was a grinding noise while the car was running/just started. I shut it off immediately to prevent damage. Any ideas on what it could be? It’s a 94 xj12 xj81

[@LivingWithAClassic]

Is the grinding coming from the transmission? Was it run low on fluid?

[@V12motorsports]

Are there any gaskets you can buy that are rubber or silicone so they won't have to be replaced as often?

[@brianrobson5208]

Yes for the rocker covers. Jaguar make some far better quality ones aprox £35 each instead of the crap paper ones for £9 each. Also you can buy alloy half moon inserts to replace the rubber ones. Well worth the money on these engines. 👍

[@V12motorsports]

@@brianrobson5208 does sng barratt sell them?

[@brianrobson5208]

@@V12motorsports Yes had a quick look on their site and £29 each. Also aluminium half moon seals on ebay £56 .

[@LivingWithAClassic]

Yes you can get those that are a better quality and I would if I were you. I replaced all the gaskets on the XJ12 with the newer ones and haven't had any issues since.

[@V12motorsports]

@@LivingWithAClassic where did you order your gaskets from and what is it made of?

[@hardit359]

Hi Adam, I started our '84 V12 after hibernation and i have quite a bit of oil leaking out of what looks like the oil pressure relief valve; next to the oil filter. The oil and filter were changed only a few hundred miles ago (but 3 years ago), i can't find a good guide on how to investigate this - do the 'o' rings fail? I can't drive the car far because of this leak. I can send you pics if you have an email address, Cheers - Tim

[@LivingWithAClassic]

Yes those O-rings do fail. It happened out of nowhere on my 1977 XJ12. Feel free to send me a picture at [e-mail]

[@hardit359]

@@LivingWithAClassic I sent you an email, many thanks, Tim

[@COLORBOOKANTICS]

@@hardit359I’m having almost this exact same problem, I know this is a really old comment but could you tell me if you ended up being able to get this done?

[@hardit359]

@@COLORBOOKANTICS Hi, if you let me know your email address i can send you the letter i wrote for the xjs club.

[@joeykeysade986]

Hey I have jaguar vanden plas 1996 and check out the engine bay today and I saw so many leaking down there what can I do and it’s v6

[@LivingWithAClassic]

Is it oil leaks or what? Do you mean a straight 6? The V6 was not produced until 1999 for the S-type

[@seanm8030]

Haven't yet seen the video. Never had an XJS or V12 E-Type. However, I'm going to guess that the most common leak point on a Jaguar V12 engine is the Jaguar V12 Engine.

[@jongodsell88]

Another item you need to keep maintained is the breather filter or fire trap on the front of the left hand bank. I took mine out and found it was solid with gunk. If you allow this to become blocked fumes from the sump will be unable to drawn off in to the air cleaner casing and burnt in the engine. This will result in pressure in the sump to building up and force oil out from wherever it can escape from causing a tremendous mess. I had this problem on an 850 Volvo as well, which gave the impression that it several piston rings broken I have also, amongst other things, changed the valve/camshaft cover gaskets and rubber thing at the back. Oil was obviously getting past these making the mess even worse. I have yet to start the engine, so I don’t know yet whether the problems have been solved, I hope to find out in the next week or two though.

[@LivingWithAClassic]

You managed to guess this weeks video topic! I should start to have a price for that :) I've had a similar issue on my Volvo V70 which is basically the same car. Those rubber half moon seals often leak too. If you replaced all of that it should be leak free now

[@jongodsell88]

Oh! Sorry Adam, I need to talk to you about something other I'm a bit stuck on, I'll email you later if I may.

[@thegearknob7161]

Mine was like that when I bought it. Degreaser wouldn't touch it, so I ended up soaking it in petrol which worked well.

[@MrXlskywolf]

How you recommen to clean the engine, I'm thinking squirt trigger bottles

[@LivingWithAClassic]

I've used engine dehreaser and then rags.

[@rossilake218]

@@LivingWithAClassic Same here and a vacuum. Your friends!

[@mglamarmd1]

Is there nothing that will keep these engines dry?

[@LivingWithAClassic]

Mine are dry. You just need to fix the leaks if it has any

[@mglamarmd1]

Maybe I should send my car ro you for the job! @@LivingWithAClassic

[@mglamarmd1]

@@LivingWithAClassic Which gasket kit, seals, sealants in tubes do you recommend?