wacky oil pressure

[rfalkner]

92 V6. Recent oil change (5w30w), wife driving and notices "clicking" and no oil pressure-- shuts down engine. Tow in--put on mechanical gauge that shows 55lb at idle or at 3000 rpm and some "lifter noise" (not bad for ford). Change oil to 20w50w which takes care of "tick" (lifter noise) and replace sending unit. Dash gauge reads fine. Take for test drive and oil pressure drops and fluctuates before finally going to zero. Put cheap mechanical gauge in ****pit and this is what I see: 50 lbs at idle or revved up while sitting still. When road tested, pressure drops to 20 lbs and stays there. Can shut off and when restarted will give 35-50 lbs, but when revved up will fall back to 20. No abnormal noise from engine. Ideas? Mine would be pump or pickup. Could a blown chain tensioner cause this or anything else post bottom end? I have a hard time beliving the crank/rod bearings are problem since the pressure is fine except when underway. Finally, can I pull pan and oil pump without pulling the engine?

 

[SteveVB]

clogged pickup?

I would guess that the pickup may be clogged. Since the pressure drops when the volume needs to increase. Hard to say though.
Unfortunately you can NOTpull the pan or the pump without removing the engine. There are some systems around that may be able to use a back flush of cleaner through the oil filter passages to clean out the pan and the pick up. I cant remember the source but I think I saw it on this site, or maybe the singleton site.

When I took my 160k mile engine apart with no pressure the pickup was clogged. Bearing clearances were fine, the upper end of the engine was where the wear occured. The bypass hole in the pick up seemed to provide enough oil for the bottom end even though the pressure was 6-10 psi.

Good luck.

 

[JDraper]

My mother-in law just had this happen in her '91 XLT. Blew up her motor 'cause they couldn't find the problem. Turns out there is a general problem with the older 4.0 oil pump springs. The spring that holds the return ball in the pump (i.e. keeps the pressure up) either breaks or gets really weak. Sometimes it shows pressure when you take it to the garage, and sometimes it doesn't. My wife's uncle has a repair station, and he has seen quite a few of these recently. Both in Explorer's and Bronco II's. Best bet is to take out the pump and check it (pain in the a**! gotta pull the pan!) or just replace it to be safe.

 

[fordkrazy]

go to the dealer and have that engine clean out service done. its like 60-80 bucks but its cheaper than pulling the engine to put in a new oil pump(or engine).im sure this will solve your problems. also try using a synthetic blend. i use quaker state 4x4 oil 10w30.