I have an oil leak in my 1991 xjs v-12. I’m planning to use Lucas stop leak to see if that will help. But I’m always hesitant about adding additives etc. Anyone use Lucas or other stop leak for similar issue.
Chaz
If you’re sure it’s just the pan leaking, heck, just replace the gasket. Probably the easiest repair you’ll ever do on a V12.
Cheers
DD
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Agree, if it’s the pan it’s an easy fix. However, you might perform a TSB while you’re at it and remove the bolts that hold the oil baffle to the sandwich plate, clean the bolt threads and the threads in the aluminum block, and apply some sealant (NOT threadlocker!) to the bolt threads and reinstall them. Any bolt whose head is inside the sump while the threaded hole leads outside the sump needs to be sealed in this manner. Really easy, and puts a stop to one source of oil on the outside of the engine.
While the pan is off, I recommend holding the ball end of a ball pein hammer against one bolt hole and hit the face of the ball pein hammer with another hammer to dish that hole the other way. Repeat for the other 20 or so holes in that sheet metal pan. This will help the new gasket seal properly on reassembly.
If the pan is held on with the OEM bolts that have a triangulated thread, I recommend spending the $10 or so to replace all those bolts with new Grade 5. Those triangulated threads are garbage.
I don’t think you can get to any O-rings by simply removing the pan; getting at those involves getting the sandwich plate off which is much more involved. If my memory is bad and you can get at any O-rings, though, be sure to replace them with Viton O-rings. I’m convinced that the use of nitrile O-rings in that oil pick-up plumbing is a large part of why these engines tend to have low oil pressure when warm.
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Just a caveat on hitting the hammer, use a copper hammer rather than another steel hammer.
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Why? Do you think you’re gonna hurt the hammer?
It could be the pan gasket, the drain plug, or…it could coming from higher and dripping onto the pan making it appear that it the source. I’d clean everything well and pin point it before taking it apart. I’d never use an additive to stop an oil leak, coolant sure, but not oil.
Never a good idea to hit hardened steel against hardened steel, thats what I was taught when I did my toolmaking apprenticeship, too much of a chance of chipping a head and getting a sliver in the eye (yes it will find its way into your eye, ask me how I know)
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TRUe words: how I flattened pan/timing cover flanges was—as so many were—a brilliant idea of my Dad’s.
He took the paddle end of a VW halfshaft, cut it off, so you can hold it in a vise, paddle pointing up.
The paddle is the perfect size to fit in the flange, and gentle tapping with a lead hammer, opposite of the paddle, flattens out the flanges perfectly.
I do that on a regular basis with a hammer and chisel.
Sounds like really sound advice. Much appreciated!!
Chaz
What do the striking faces of your chisels look like? Mine are mushroomed. That is because the cutting end of the chisel is fully hardened (tempered to blue/straw), but the striking end is softer. I grind the mushroomed end back to form every now and then.
I was taught that you never hit a hammer (or any other hardened steel surface) with another steel hammer. This was considered to be a worse offense than leaving the chuck key in the lathe chuck (Punishable by weeks of stern looks and derogatory comments).
Perhaps generally true, but you’re not hitting the ball pein hammer very hard. Certainly not hard enough to chip it.
That sounds good, but it’s my contention that flat isn’t the ideal condition of the flange. It’s better than convex, which is the condition it’s likely to be in when removed, with each bolt head pulling a dimple in the surface. I contend that it’s better to dish it the other way, the area surrounding each bolt hole dished downward toward the bolt head. This will help spread the compression more uniformly over the area of the pan gasket.
softer on striking end makes sense. yes, they mushroom rather quickly and usually replace after loosing an inch our two. have seen some that lost 5" but not mine! use to be I would grind them every few monthes but on the newer ones, chunks just fall off.