I am currently experienceing what I believe is an oil pump problem with an '88 Bronco, 302 v8 with 122k miles.

I just bought the vehicle from an auction, it's in pretty bad condition, but it's almost back to a good running state (replaced several things from an ECT sensor to a cracked manifold). After those and some other repairs, the vehicle is running a lot better, but still not running all that great.

The following problems are most evident right now:

-It gets REALLY hot REALLY fast. After starting it, not even a mintue later the exhaust manifold is too hot to touch
-At idle (right now its idling at about 600 RPM when warmed up), the oil pressure gague (this is the dash gague, I haven't checked it with a shop gauge) goes to zero and the "Engine" light comes on, but then returns to normal presssure when RPM is over 2000 and the light goes off.
-Once the engine is hot, if you let it sit at idle for a few mintues it will start to smoke out the exhaust manifolds and buck like it has no oil (when it has a full oil level)
-It's running a little rough and failing emissions with high HC (possibly because it's so hot i'm getting a pre-ignition?)

...okay, so it obviously is having some kind of oil problem. It would be really nice if all I had to do was do a flush out the engine and then replace the oil pump and screen, etc...

However, when I changed the oil it was blacker than night, and the filter felt like it had a brick in it. I'm afraid that the engine has been run in this condition for a long amount of time by the previous owner, and that an engine rebuild may be in order.

Any thoughts about this would help, specifically I'm looking to see how probable it is that the engine is seriously damanged and needing a rebuild, and any recommendations for getting the oil pressure back to normal.

Also, if someone knows how to check the pressure with a shop gauge that would be grealy appreciated.

Thanks,
Robert

 

Well, you probably know this, but the exhaust manifold gets real hot real fast on a healthy engine also. If it's starving for oil, it'll get hotter faster, but exhaust is always the hottest part of the engine. No doubt though - an oil-starved engine gets hotter than normal, faster than normal.

Low oil flow. I don't trust the idiot OEM gauge either, but this time I think it's giving you good, usable info.

Lots of miles, some oil getting past rings, added heat from just idling, and of course, low oil flow probably. I don't understand your term "bucking," though. You mean bucking in an "ignition miss" way, or what? One question - when you observe the bucking, are you hearing a lot of unnatural valve clatter also? Usually, when an engine is starved, the lifter assembly lets you know with a sound not unlike shaking a dozen spoons in a metal bucket.

I'd be willing to bet you a soda pop that if you opened up the bottom end of this engine, you'd find big time sludge. Sludge like you see in oil filter ads. Sludge sufficient to plug screen, pump, filter, galleys - basically the entire lubrication system. Bad news, I know, and I feel for ya.

Honestly, I don't think you have much to lose, so maybe in this instance I'd suggest an engine flush. (ducking) I'll warn you - chunks of crud may break loose and block oil system completely, finishing the job of low pressure, but like I say, it seems to me you got little to lose. If this were my engine as described, and I intended to rebuild, it would be done *only* after a complete and thorough vatting by a reputable company. Otherwise, throwing good money after bad.

Remove sending unit, thread gauge into that hole on your's, I think. Simple.


I'd probably go ahead and get an idea of used/rebuilt engines prices, especially if you expect this to be your daily driver.

Good luck Robert. I hope problem turns out to be less fatal than I think.


Best -


Joe Horn
'93 EB 302

 

Wow! Lot's of information, thank you for all the input.

You are right about the lifters, they do clatter when it's hot and at idle. The "bucking" i'm talking about it the engine acting like it's about to overheat and stall out.

Either this weekend or next I'm going to be pulling the oil pan to take a look at what's going on down there, so I'll let you know how that goes.

Thanks,
Robert