I got the first one listed here from RockAuto, I was assuming there was no difference between them all, should I try a slightly more expensive one next? Wonder how much they are from Advanced.

 

Well if your motor has a lot of "slop" oil pressure will drop at idle. Basically it cant push out enough to build pressure. Could be a bad sender but sounds like it's not because the original did the same thing. You need to put on a mechanical gauge before anything and find out what you have.

 

Not what I wanted to see but I got the mechanical gauge hooked up. Its a bit over 40 under load, around 25 normal driving, but goes to zero at idle.

What should I do next?

 

You could try going to a slightly heavier oil, and see if that helps, but, that's just a stop-gap measure. Time to start saving your pennies for a rebuild......

Now, conceivably..... If you have a 4x4, you could drop the pan, and replace the rod/main bearings, and you *might* get some more life out of that motor.... but, if the journals are out of round, even that won't help.

 

So this could have nothing to do with a blockage? Motor runs extremely well currently, anything else I can do before it goes to that extreme? What would cause them to get out of round?

I snapped a picture of the oil cap and inside, and just fired it up cold and this is the reading it held.

 

Let it sit and warm up while you watch the gauge. What you are interested in, is if the gauge slowly drops to zero, or, if it goes all at once. It may not hurt to drop the pan, and have a look. Might have something floating around in the pan that eventually blocks the pickup. (like a rag......)

 

Took the highway to work so I would get lots of stop and go and some high speed. Here is all that happened.

At operating temperature the pressure was at 30-40 while I was normally driving, when I would coast the pressure would drop to around 10, however, only when I came to a complete stop, the pressure would slowly drop from 10 to 0.

Tonight I am going to put some 5W-40 in it and see how it acts, then maybe a warm weekend drop the pan, possibly change the pump?

 

If you elect to change the pump, get a high volume variety. It will help make up for some of the excessive bearing clearance you apparently have.

 

I think I may start there, it makes me a bit nervous to put extremely thick oil in just in case we get a cold week in Wisconsin. Is there a certain brand of pump that I should be looking for other than high volume?

Once again, thanks for all the help!

 

Melling is good..... also get the pick up tube. The opening on the aftermarket pumps is much larger than the stock unit.