Oil pressure drop 4.0

[muddeprived]

So it's doing it again. I had this problem before and replaced the oil pressure sending unit with a factory mopar replacement. That did not work and it turned out the head gasket blew so that was replaced along with the crack-prone head. Everything was peachy all these days until recently when I decided to gun it and race a camaro for fun and the oil pressure dropped to zero. It eventually woke up and went back to normal pressure after a few stop n goes. It's been fine since until today when it dropped to zero again. Jeep runs fine, oil is clear, coolant is clear, and no leaking anywhere. There was white smoke coming out of the exhaust but it dropped to the mid 40's today so I guess that explains that.

Any ideas?


2001 4.0 with 115k (12k since head gasket/head/sending unit replacement).

My thoughts are the oil pump but not sure.

[Deadman 94 xj]

Is it showing any of the symptoms it was showing the first time?

If not, I'd replace the sending unit again since they always suck. If that doesn't work drive it until it dies?

ha

[muddeprived]

Is it showing any of the symptoms it was showing the first time?

If not, I'd replace the sending unit again since they always suck. If that doesn't work drive it until it dies?

ha

Nah, none of the original symptoms are there. I got the sending unit from the dealership so I figured that was still ok since it's like a year old but who knows, maybe it's faulty. I need a mechanical gauge.

[joshs1ofakindxj]

I ended up putting a mechanical gauge on my cherokee. The connection for the sensor on my Renix motor was 1/8" NPT so it was no big deal to add a "T" and run the factory sending unit and a mechanical gauge.

[muddeprived]

I ended up putting a mechanical gauge on my cherokee. The connection for the sensor on my Renix motor was 1/8" NPT so it was no big deal to add a "T" and run the factory sending unit and a mechanical gauge.

Is that possible on the 01?

[joshs1ofakindxj]

Looking at the sensor on rock auto, it looks like it could be. Go buy one, go to Lowe's, see if it threads into a 1/8" NPT brass pipe "T" to check it.

[muddeprived]

Thanks. I will try that.

[Azzy]

And there is a mech oil pressure gauge in the sales forum for $5 right now ;)