Oil Pressure Drop

[bluerocket]

I run mobile 10w40 with stp addative.

My jeep used to run 40lbs idle and 55-60lbs when under way.

Now its running about 20lbs idle, 40-45lbs when under way. This happened about a month ago.

I'm wondering if this could be a failing oil pump, or maybe a seal (rear main) is just leaking more than before. I do leak oil out of what appears to be the rear main seal. Its always leaked since I got it.

I havent had a lot of experiance with oil pressure changes like this. But I do assume change is bad. Has anyone seen this? I just dont want to waste 80$ on a new oil pump, if thats not the problem.

[creeperjeep]

The rear main wont make oil pressure drop like that.
Put some 15w40 in the beast and shell come right back up to pressure.
Also I used to leak an a** load of oil from the rear main, I cleaned the PCV and drilled all the fittings and ran a bigger vacuum line and it doesnt leak more than a drop or 2 a nite.

[bluerocket]

I'll try the 15w40 this weekend when I have a chance to change the oil.

[creeperjeep]

15w40 is what I run, I dont think its recomended for it especially in winter, but I still run it, Ive heard of a bunch of guys running 15w40 in 4.0s.
I also have a block heater($30) that I use on the sub zero nites.

[christj97]

I get something wierd like that too, mine will drop to 0 then the dummy tone dings and it shoots back up to 40 lbs. Only does this in idle or low speed and has only happened about 2 times.