Help a newbie out

[nate_o23]

OK I have a 88 Grand Wagoneer with the all too common low oil oressure problem. At start up its OK but once it gets warm it goes way down. When its warm and at idle its at zero. What I would like to know is, whats the easiest way to fix this?? There is no ticking or knocking coming from the engine and I would like to keep it that way! What I had figured on doing was pull the TC cover and rebuilding the pump and changing the chain and water pump while I have it apart. Does this sound right? Is the Edelbrock timing chain any good?? Any other advice? Thanks!

[Littlewolf]

Sounds to me like you got a bad sending unit change it first . i had the same trouble on my 77 cherokee . try that first alot cheaper to start with.

[Goose]

Hey Nate Welcome.. Do try the sending unit first, But If that isnt it.. You can go back over some of the msgs on this topic "amc oiling" and find a lot of good info. I went through this same scenario a couple months ago and found the bearings were just flat worn out..

[nate_o23]

OK I bought a mech oil press gage today to verify my oil press. Where is the best place to hook this up?

[Goose]

Pull your oil pressure sending unit and put it in there.. (under the alternator (it's actually easier to do if you flop the alt out of the way))
But take this bit of advice.. Disconnect the battery cable first! ask me how I know this and I'll show you the burn marks on my wrench and my wedding ring..

[nate_o23]

Thanks for the help Goose! I put the mech oil press gage on today. I got 35 psi ,warmed up at 1/2 throttle and 8 psi at idle. Its better then what my stock gage was saying but still not great. Is this good enough pressure to keep driving? Or is it rebuild time? Thanks

[fuzz401]

it could be the pil pump or the frount cam bearing has opened up to let to much oil pass through it

[Goose]

I can only offer an opinion, so here it is.. When I went through this a few months ago My oil pressure numbers were similar. My engine had a lot of miles on it but ran good other than oil pressure. I tried putting a new pump in it and it made little to no difference I then pulled the pan and a a main and rod bearing, They were just flat worn out. I would recommend pulling the pan and having a look. If you think about it what would wear an oil pump or the aluminum housing out is going to do worse to the bearings. and unless it is something simple like a sending unit . Rings and bearings are a small price to pay now rather than a new crank or worse later. Now the discalimer.. I have seen a lot of engines (amc ) live a long time with pressures this low, but for me I would be continually worrying when it was going to shell out on me..

[tufcj]

When my CJ developed a low hot oil pressure, it turned out to be the #4 cam bearing. All the coating had just flaked off. I've seen that problem on more than one AMC V-8 I've rebuilt. It resulted in about a 20 PSI drop across all RPM ranges when hot, and almost 0 at idle. Bad news is the parts went thru the motor, and scored the main and rod bearings. Probably time for a look and a rebuild. Any bearing parts should be easy to see in the bottom of the pan.

Bob
tufcj

[73hornut]

How much pressure do people think an engine needs at hot IDLE? Where not talking high rpm here. If the pressure is over 0 and consistent, no problem.
When the pressure changes dramaticly in a short amount of time, then I would check into it. Have you tried running thicker oil? Have you checked the oil level?