Uh Oh, low oil pressure!

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Feb 7, 2004
Pittsburgh, PA
I have been running my 72 Ford pickup for about a year with the stock gauges and noticed that the pressure gauge was always on the lower end but never worried about it. Today I installed all new custom gauges and was pleased to see that it idled at 50 PSi when cold... I drove it around the block and noticed that it was at about 25 PSi in gear, which is OK since it idles rather low. I kept driving and it went to almost zero. It would move when revved up to about 25-30, but mostly close to zero.

Anyway, it's a bummer. The motor is still powerful and has actually seen some engine work at one point as it's very clean inside. It uses some oil, maybe a 1/2 quart a week. I have been running Rotella 15W-40. I'd like the engine to last awhile at least until I have a 460 ready to drop in (currently has a 400M).

Would be acceptable to run a straight 50 WT oil in it until I can find the time to put in a HVHP oil pump? It's a daily driver and only in the summer.

Seems like the oil pump is OK it can push 50 psi cold. More like excessive clearances....

So hot, at what RPM is 25-30 psi?

I would try another oil. Maybe not a straight 50, though.

Originally posted by hirohatamerc:
It uses some oil, maybe a 1/2 quart a week.

Geeezzz, that's one heck of an understand, don't you think? Unless you drive a good deal of miles every week, that's a pretty good level of consumption that warrants, at least IMHO, switching to a different oil if repairs are out of the question.

If this were my own vehicle experiencing this problem, here's what I'd use:

Pennzoil High-Mileage 20w-50
Motorcraft Filter

Both available at Wal-Mart.
Yeah, I drive about 150 miles a week so it is excessive. The confusing part is that the engine seems to run fine, doesn't leak and is more or less quiet, as no knocking or ticking. At higher RPMS you can hear some valvetrain noise but not like it wants to "BLOW UP" or anything.
I've been through the same thing with several of my old ford trucks with 400M/351Ms. They aren't very good motors from the factory but they make good builders. What I had good luck with on the two I've had with 150K+ was to pull the pan and replace the rear main seal and main bearings. Install a new HVHP oil pump and put on a straight up timing chain. This cost about $150 and takes about one good saturday. Pressure was never less than ~30psi at idle afterwards (40wt). I would only do this if the compression is good and everything else on the top end is ok. If it is actually burning a qt in 150mi then its not worth it. If your going to put on an oil pump do the bearings also(only $20), otherwise dump some 20W-50 in it and run it till it dies.
I thought ford put FEs in the trucks untill 1975-76?
I have experience with an old Ford 72 351W. When the car got old and the oil consumption got high, I would sometimes get caught off guard with the low oil level. The engine would have valve clatter from the low oil pressure, especially at idle.

What I'm saying is that if you don't have valve clatter at idle your low oil pressure may not be serious enough to damage the engine.

Originally posted by hirohatamerc:
I think I might run it until it kicks the bucket. Thanks for the help.

Well, ok, but what oil are you gonnna use?
I opted for 5 quarts of Valvoline Max-Life 20W50 as it was given to me, along with a FL-1A. The oil pressure went up a little, it's slighly above zero now when at a warm idle, and about 25 psi when cruising. I'd really like to get it up to 25 or 30 at idle but that's probably not possible w/o some engine work. Has anyone ever run an engine on gear oil before?
Jelly: "If this were my own vehicle experiencing this problem, here's what I'd use:

- Pennzoil High-Mileage 20w-50
- Motorcraft Filter

Both available at Wal-Mart."

Sounds good, Big J, but I didn't think they made that stuff in 20W50??

I thought 10W40 was the highest it went?

--- Bror Jace
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