302 Oil Pressure Problem - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Fritz The Cat · 04-27-2003, 14:47

I have an 86 302 with an oil pressure problem, I hope someone here has an idea as to whats wrong. Engine has 160 K miles on it. After driving about 10 miles, the oil pressure at idle will drop. I can rev the engine up to about 1500 rpm and hold it there, and the pressure will build back up. If I shut it off, wait about a half hour, restart and go, the pressure is good till about 10 miles again. Oil and filter change with 10W30 has no effect on problem, but oil and filter change with 20W50 solves the problem for about 100 miles, then pressure starts to drop again. Note: I do not hear lifter clatter when the pressure drops. Any one have an idea of whats going on? Thanks in advance!

xacoupe · 04-27-2003, 15:14

could just be a worn motor. Oil requires certain clearances from things like the bearing to crank shaft to maintain pressure. Oil pressure is lower at idle anyway, the sweet spot for cleveland oil pressure is about 2000-2500 rpm.
This brings me to my next question.. being from the US, wont your 302 be a windsor???

TyreToaster · 04-27-2003, 17:24

bottom end bearings are completley stuffed, running that water thin oil wont help fix much. either pull it apart and rebuild it or start running some 40w-70 oil that will help keep pressure up a bit even at idle until you got the cash for a new one.

Fritz The Cat · 04-27-2003, 18:19

Would dropping the pan, pulling the caps, and sliding in new standard size bearings help? No one in my area sells 40W70 oil.

ebxr8240 · 04-27-2003, 23:02

Check oil pressure with a known mechanical guage.
So you know where to start. Checked your old oil for brass fillings?
Bottom of oil pan in good nick? Like not dented up onto oil inlet pipe to pump..

smciner1 · 04-28-2003, 03:29

As someone else said, check it first with an external mechanical Pressure Gauge to see that you are actually getting a true reading. If the miles are reasonably high, the bearing clearances may be excessice and a thicker grade of oil may help.

big1 · 04-28-2003, 10:57

This is a common problem on older 302's. The advice given is dead on, but if your strapped for cash, just install a new high pressure oil pump, this will carry you for quite sometime. Please remember that it is an older engine and don't abuse it.

TyreToaster · 04-28-2003, 17:36

i have slid in standard bearings in the past and it can fix the problem temporalily, providing the crank isnt pitted heavily so at the end of the day you are wasting your cash on a temp fix. If ya just want to keep it running put in the thick stuff and you will get more time out of it.

TTNOS8 · 05-02-2003, 19:32

As posted, bearings are stuffed. Try a mechanical gauge to confirm if oil pressure is at a dangerous level.

Has engine been apart before? Is crank std grind? As tyretoaster said, I have had to because of budget limit, checked crank surfaces (both big end and main) and slid in std bearings. this is only a temporary fix usually, and depending on crank cond, may be only a very short fix as a buggered crank will only stuff the new bearings as well.

HalfAF · 05-05-2003, 13:25

Oil pressure which behaves like that is telling you the bearings are worn. I had a rebuilt engine fire up like that, and I could hear the noisy bigend. The installer told me it was OK and wouldn't budge, but its not and I'm down $3000+ for a stuffed engine.

Valvoline make a 30/60 oil and STP make a 35/70 (lower figures maybe slightly off but higher figs are right) You could by the STP stuff in 5 litre containers in BigW for about $17. This helpd a little, but you have to keep in mind oil flow problems in cold weather, so if its below 10C in the mornings where you live, consider using 20/50 untill summer.

Jason