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Oil pressure sending unit leak

Renegade

NAXJA Forum User
Location
Denver
'96 XJ My 4.0 is leaking oil on the hex shaped adapter that the oil pressure sending unit attaches to the engine block. Is there a gasket between the hex adapter and the engine block? The sending unit itself is not leaking, or the o rings for the oil filter adapter. Hope this makes sense...

Josh
 
hose the whole area down with degreaser, then remove the pressure sending unit, then the adapter. Clean the threads on the adapter off well, if you can do it without dropping gunk and grit into the engine, clean those threads off too. Coat the adapter liberally with PTFE thread sealer compound (or whatever you prefer) and reinstall it. Make sure you point the pressure sending unit port in the right direction before the sealant cures.
 
There is one other thing that likes to leak in that area--the distributor. There is a mounting gasket:

FEL-PRO Part # 70051
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1 11/32" OD
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Awesome thanks so much for the replies. I don't think the distributer is leaking, but now know which gasket to use...
 
Joe, thanks for pointing that out. I thought it was weird that the used 92 engine I bought from the "salvage yard" and my old 88 4.0 had no distributor gasket. Gonna get me one.
 
A bit of RTV around the dizzy base will seal it as well.

For the oil pressure sensor, I'll use some RTV copper smeared on the threads - not anything else. I've been about 50/50 using other sorts of RTV or PTFE paste with the sensor not "self-grounding," and the copper-bearing RTV seems to have solved that problem.

Since I don't like doing jobs twice, I'll only use RTV copper on one-wire sensors...

Although, I think the OP wasn't talking about the threads on the sensor proper, but a leak at the base of the hex adapter - the bit that remains when you've pulled the sensor. The hex shape leads me to believe that you can back it out with a wrench, but I've not yet had occasion to try...

Oh - and make sure it's not a "spurt up" from the oil filter adapter that is presenting as an oil pressure sensor adapter leak.

- Clean the area thoroughly.
- Let dry.
- Start engine.
- Idle for about ten minutes while you watch the suspect area(s). Stop when you've found the leak (which usually takes a good deal less than ten minutes.)
- Service or replace parts PRN, return vehicle to service.
 
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