As I posted in the thread about removing the stuck, or tight, oil pressure sendor unit, I have an oil leak after installing the oil pressure sendor and running the engine - the leak does not look like it is coming from the oil pressure sendor mounting position - what is the down side to removing the air balance pipe, that is between the intake manifolds, running across the back of the engine - figured removal of this will give me more room to get further down to the area that has oil all over it - I am presently soaking up the oil that is collected on the rear of the engine, just in the area of where the engine number is before I run the engine again to try to see better where the leak is - I was only able to see the oil dripping down from the cam feed pipe, on the left but still not sure the origin of the leak - Tex.
I have not had to do this, so I am thinking out loud- if you plugged both intake manifolds where the balance pipe crosses over, and then made a vacuum connection to supply the ECU with a vac. signal, then I think you would be safe. Not sure where the idle speed would end up, though.
FWIW: There is the sender for the gauge, the sender for the idiot light, and a banjo bolt that secures the hard lines to the “tree.” Any could be the culprit in that area.
To Dave - thanks for the suggestion - I was thinking only of remove the balance pipe to gain access to clean up the area from the oil leak, then replace it to test - I guess I could try to run the engine for just a little bit with it off, to avoid removing and replacing multiple times, as you have suggested - Tex.
To Bob - does not look like the leak is from where I replaced the oil pressure sendor and the oil pressure switch sensor, but not 100 percent sure yet - I did not undo the three banjo fittings but I realize they might be leaking as to what you state, so I will check them - this is why I am trying to gain better access to the area but just do not want to cause more problems by removing something - Tex.
Easy to bump them whilst swapping out the sender, if you do remove them, remember to use new copper (annealed) washers when replacing everything as it’s not a job I’d want to do twice!!
OK. I got the idea from the first post that you planned on running the engine again. You could do that, then you’d be sure.
Tight quarters working those oil pipe banjos at the rear of the engine.
Recommend running a long length of dental floss through the stack-up of a washer, oil pipe circle, washer to keep together whilst inserting the bolt and maneuvering the assembly into place…and once the bolt is starting successfully to be threaded into the engine pull the floss out and then finish torqueing.
Helps retain the washers in place until secured by the bolt being successfully engaged. Otherwise have some spare washers readily on hand for when one or two get loose and drop into the Bermuda triangle at the rear of that engine.
I am back working on this oil leak problem - has been over a year of not being able to work on it - yesterday I removed the two coils, and the throttle tower, to gain viewing and working access to the area of the oil pressure switch unit, for the purpose of identitying the leak - today I had my wife start the car, letting it run for about 30 seconds, then shut it off - I still could not determine the exact point of the leak - I dried up the area again, then placed a shop paper towel under the oil pressure switch mounting nut area and over the banjo bolt connection, and had my son restart the car for about 15 seconds - iI pulled out the shop towel and it seeme like it is not leaking from the oil pressure switch, but from the banjo pipe connection from the “A” bank (LHD passenger side) just wanting clarification of my nexrt steps -I am thingking that I will have to remove the oil pressure sendor, then the oil pressure switch, so that I will have better access to the leaking spot - for repair - as an added note, I did run jumper cables, from each coil mounting bracket, to a engine ground, so as to have the coils work correctly, and I have been leaving the battery negative cable disconnected while doing my work, for safety, and only reconnecting the battery to turn over the engine - I have reread all through the archives again, concerning any steps on working on this oil leak, so now jsut asking for reassurance on the repair steps on this 1991 XJSA V12 - thanks, Tex.
If the leak is back of cam cover, it could be banjo bolt washer, cam cover half moon seal, or cam cover gasket. Or all three, because they are common failures.
Pulling cam covers is warranted.
I just did all of the above for my winter project. So far all good, no more leaks.
Wasn’t a difficult project, but it took time and patience.
Thanks Greg - so far it does not look like any leaks are at the cam cover areas - one thing I am pondering, is there any reason that I would not be able to remove the oil pressure sender unit, then place a bolt, with the same thread specs, wrapped with teflon tape, back in to the mounting hole for the oil pressure sender - I am thinking that tis would then give me a better viewing of the leak area so that I can make the repair - I am figuring that I will have to remove the oil pressure sender anyway to remove the oil pressure switch, if that proves to be the failed unit - Tex.
I usually take a Kleenex type tissue and place it at bottom of pressure sender. No fresh oil? Then do the same at the pressure switch, then banjo bolts, etc working downwards. Sometimes mechanical fingers extension helpful.
Not familiar with the term “mechanical fingers” - is it a tool of flexible extended tweezers - Tex.
Kinda sorta, Tex… useful for retrieving those pesky dropped nuts and bolts that land where you can see them, but can’t put you hand on 'em
Confess to making up the term
Ok Jim - sure wish there was some sort of tool like that - trying now to have one last go at wiping the area and looking for the leak, with everything still in place - if no luck, then I will remove the oil pressure sensor, plug the mounting hole, and look again - what my goal is, is to definitely find the leak, not just assume it is a bad leaking new oil pressure switch - Tex.
They go by manh names, but this is one:
They are available in various lengths, and can be lighted or no light.
Yes, Jerry - that one is what I have used many times before, with great success, but guess I was thinking more along the lines of something that would go around, under, or over obstacles - Tex.
Yeah Jerry. Like mine but mine is shorter (did I really say that :- ) Mine is more like 24 inches.
Anyway, I put a small piece of paper towel or tissue in the gripper and use it swab under suspected leak points that I can not reach
With my tongue in cheek " I say You might be thinking of a coat hanger"
Yeah, bendable and snakeable ,like doctors use for endoscopic, would be nice. And costly
Tex, foggy memory, but years ago I bought “improved” oil banjo bolts from Ron Kelnhofer (he has since passed, but JohnJohn sells same thing now). Seems that I installed without removing pressure switch and sender. Only throttle tower and air pipe. Just did one at a time. Tight fit but got it done
Well Jim, I was thinking about that method - I have a unit, shaped like the modulator on the side of an automatic transmission, that is installed in the middle of the air pipe rear cross section, mounted using two pieces of hoses, with clamps, - this unit is almost touching the oil pressure sendor housing - I am thinking that removal of this unit, might give me the access to get to the banjo fittings - I do have the throttle tower pedestal, and the two coils, unmounted - Tex.