My 82 F250 has low oil pressure. When hot, I have about 30 lbs at speed, and it drops to near 0 lbs at idle. The truck otherwise runs great. Decent power, no noises, only 1 minor fluid leak...the rear main seal, which is how I found out the crank bearings are worn. The truck is rock solid, and is in otherwise excellent mechanical condition as well. Tires, brakes, hoses, belts, battery, etc. are all new or in like-new condition. It needs zero maintenance items. Every light, switch, gauge, dual tanks, etc. works perfectly. Clutch has 35k on it. AC is inop, but I don't know why, and don't care. The paint sucks. The door panels are shot, but the rest of the interior is pretty nice. I only drive it about 2,000 miles/year. I've had it on several hour+ freeway trips like this without any problems. No problems driving around town, either. I've got about $4,400 in the truck as it sits, including what I paid for it.

I've got 3 options:
A) have the existing 400 rebuilt
B) swap in a reman 400
C) drive it and hope it doesn't blow up, and if it does, either sell it, or revert to one of the first 2 options.

No interest in changing to a different engine, so a 460 is out.

A is likely the most expensive, which would rule it out. I'm inclined to go with C and hope for the best. If I do end up doing A or B at some point, I would swap in a straight-up timing set to get a little more power. The factory setup is retarded 4 degrees. I've read that this change alone makes a nice low-end difference.

WWYD?

Option C.

Just a suggestion but another option is to keep an eye out for a similar truck, but rusted, with the same 400 but better oil pressure than yours.

Another idea, as I'm typing, would a high volume oil pump solve your problem?

Mike.

400M? I didn't realize they put them in that late. I thought 78-79 was it. It does look nice.. I sure if it was an old mopar money wouldn't matter, lol. Kevin

How about a Coyote swap?

D] Roll a set of bearings in it along with a new oil pump and drive it.

75% 20-50 oil, 25% gear oil for an oil change. May not help that much, but sure can't hurt it.

Thought about that, but the engine has 189k on it. I'm concerned I'd be throwing good money after bad if I did that.

First, verify the gauge and sending unit are telling you the truth about the oil pressure. Then option C but run a thicker viscosity oil to see if pressure improves.

While that is always a gamble, in my opinion it would be a good gamble. Rock auto rods, mains, oil pump and pan gasket less than 200.00 with good parts. Cheaper less. If it bothers you to do so go with C and heavier oil which might help some.

I'll give that some more thought.

It is a nice truck. Pull a crown vic motor out of a police car and swap it in.

I love the truck. It would be perfect with a 5 speed (creeper low, OD high). It's currently a 4 speed with a creeper 1st gear, and with the 4:10s, it's a little steep on the freeway.

I would do what I would have done in 1980 with the exception of it being PAW that the parts came from. I assume Summit has them the same way.
Get the Ring/Bearing/Oil/Pump/ Gasket Rebuild Kit/ Ball Hone that Sucker and add in a new Summit Cam & Lifters "Drive the Wheels Off It"
Maybe send the heads out just so I never had to mess with it again

This^! Or just yank it out, throw a crank kit,oil pump and gaskets at it and jamb it back in. Did LOTS of Ford crank kits back in the day. Pull them, put it on a stand, flip it over, pull t-cover and oil pan. Yo-yo crank,t-chain and oil pump. Back together and back in the same day. All of them ate the mains causing low oil pressure. Few hundred bucks and you're good to go!

Is that a 4x4 model?

I'd start with verifying the gauge isn't lying about the oil pressure being low. Use a real mechanical gauge. If it really is low, I'd probably try thicker oil and see what that did for it. The next step would be a compression test, and maybe a leak down test. I guess I'd really want to know what condition the motor is in. If the compression and leak down tell you the motor is pretty sound, I'd roll in the rod & main bearings, new oil pump, and a pan gasket, and maybe that timing chain and gears.

If it fails muster on the real oil pressure test and fails on the compression test, save your money for a reman motor, and then drive this one until it retires itself. I've seen low oil pressure Ford motors run a long time without issues. Gene

What viscosity oil is in there now ?
I'd verify with a mech gauge first.
Then, depending on how long you're keeping the truck:
20W-50
or higher-pressure pump
or plug in a good used or quality rebuilt engine.
Bonus if you find a good used deal with an OD trans.
You can kill some gear ratio with, say, a 33-inch or taller tire...

I'd start with verifying the gauge isn't lying about the oil pressure being low. Use a real mechanical gauge.

That said as before Mike just run it if it blows then deal with it i ran a 351 with a rist pin knock and low oil pressure for 40,000 miles and if you need I have a 460 here

I'd think you should be able to find a good 400M out of some granny car for peanuts, car included. Truck is clean and solid, I'd try that, find a late 70's land yacht being given away.

Carsten

And what Kevin said too:



I replace my oil pressure sending unit every time I start getting low oil pressure gauge readings and it immediately jumps back up into the mid to high range on the gauge. I have an '85 E350 with a 6.9 liter (420) diesel that I have driven since new in '85 with over 400K miles. Just changed the fuel injectors, fuel return lines, fuel filter, oil, oil filter, and going to change the oil pressure sending unit just for that reason even though the pressure gauge is reading within normal range but gets so much better (looking on the gauge that it makes me feel good I don't know if it's because of the diesel oil condition from soot (?) that the sending unit starts to read lower as time goes by but it sure makes a difference with a new unit??

Agree with checking the oil pressure (and replacing the oil pressure sending unit) first before I did anything else.

Mike if you need any body sheet metal check out Mill Supply they are near by and some of the sheet metal is still being stamped out in Cleveland near you

MileR


NICE OLD TRUCK THERE Mike I really like it ...........................even though it's a FORD.....

Thanks everyone.

Oil pressure was checked with a mechanical gauge and confirmed low. Assumption was it was the oil pump, so the plan was to replace the pump when doing the rear main seal. Disassembly found that the bearings are worn.

It currently has 10W-30 in it, so making a change there might help me a little.

And Kevin, I'd love to drop a 460 in it, but my understanding is that it's not a direct bolt-in.

Not shocked, Your diagnosis was my immediate thought. Lower end rebuild. Get crank turned, rods resized, new bearings and might as well do new oil pump.

Fix it up and drive it Mike! Then you know exactly what you have! Good trucks are hard to come by that are reasonably priced and not beat to death!

I have done this several times with good results every time. Squaring up the cam timing at the same time is also a good idea.

Pull it, new bearings, new timing chain, enjoy.

Crank kit. Old school farmers way.

Since you already said you can get the oil pan off new bearings and a pump sounds like it would be a good option.

If its not burning oil.. new bearings pump and chain right in the truck.

Not to pee in everyone's cheerios but,

Its unlikely that the rod and main bearings are going to fix it. These engines were known for iffy cam bearings and that in my experience is the most common source of low oil pressure. The lower end wear is a symptom not a cause.

Still, if it were mine id gamble on the bearings and high volume pump, and thicker oil. Then run it till the valvetrain starts to rattle.

More work, but I'd be tempted to build a Clevor engine.

reman start fri. night drive it sunday

I vote reman too. Wait for a sale on a long block with a warranty. Sounds like a good truck to keep.

I've seen remanufactured engine that had issues as well as being weak on power.

I know a guy who bough a remanufactured chevy 350 crate engine and it spun the crank bearing about a year later. When they took it apart it was a hodgepodge of used parts and poor machine work. If time isn't an issue just rebuild what you have.

You should have just rolled in a set of bearings when you had the pan off it.

If it's a 400M, it should be pretty close to bolt in. A 460 was available in a 250 so if the mounts are different on a 400M, the correct ones should be readily available.

Kevin

The pan is still off.

No brainer then. Roll in new bearings, seals, oil pump and a timing set. Enjoy.

This ^

Back in 2003 my father was in a Florida campground for the month. He was in his 5th wheel camper. His 89 chevy pickup he pulled it with lost oil pressure. Another retiree buddy in the camp ground who was a handy guy dropped the pan and did the bearings seals and oil pump on the grass/dirt ground. Truck ran great and he sold it in 2005 still running great.

Mike
What shop has the truck /? are the good and can just put bearings in it like said if so that's what we did back then and only the mains and seal

10w30 has no place in an old worn engine unless you can confirm the oilpressure is still good.
20w50 oil should have been put in it a long time ago.

Since you have the pan of anyway, now is the time to change the bearings, as long as the journals don't have deep grooves in them.
A timing kit and a HV-oilpump will bring many more years in an engine.

I'd fix it, that's a good looking truck.

I don't understand your answer, bearing replacement is your cheapest out.
How many miles per year do you drive this truck?
How much longer do you hope to drive it?
What is the primary use of the trunk?

Would you do rebuild yourself? I didn't see it if you mentioned it.

If you are doing it yourself, I'd do a complete rebuild too, other than sending out for machine work. You know it'll be assembled right, save money, and won't leave you stranded. The truck is solid. If you're not doing the work yourself, I might just drive it until it dies.