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89 F250, 351 Windsor 5 speed manual transmission

My 89 F250 runs like a champ but when the engine is fully heated to operating temperature, the oil pressure gage drops to 0. I put a wet gage on it and at operating temp at idle I have 5 pounds of oil pressure, with some rpms I have 20. The odometer shows 98,000 miles but I bought this truck about a year ago so I imagine that’s a turnover reading. The seat, steering wheel, gear shifter and pedals all have very little wear so the 98,000 might be accurate. I installed a new oil pump and am running 20W40 motor oil.

If not pushed too hard the engine might last many more thousands of miles but what you describe indicates an engine in its last days. How is the truck used?

It’s pretty much of a daily driver. I don’t go over 65mph and don’t put too many RPMs (I shift to a higher gear whenever possible). Is this common with the 351 Windsor or is it just a case of too many miles and the need for a newer engine?

We had a 1976 Ford with that engine. We sold the car in 1988 with108,000 miles on it and the engine used virtually no oil. It’s a rugged unit and I suspect it was used hard or had little maintenance. It could also be on it’s 198.000 mile point in its life. Just the same, this engine should use almost no oil if well maintained.

Odds are the crankshaft bearings are worn out of it; possibly due to prior neglect.

Replacing an oil pump for this kind of problem is generally an exercise in futility. If neglect is bad enough to wear out the oil pump (which is the first thing to see oil inside the engine) then it follows that everything after it will be worn out also.

With the pan off what should have been done is to remove the rear 2 main bearing caps and have a look at the bearings. Chances are there’s nothing but copper showing; meaning worn out.

And you didn’t notice any white bits of plastic in the oil/oil pan?


No white bits of plastic or any other foreign material in the oil pan. Replacing the oil pump was, indeed, an exercise in futility; made no difference in oil pressure. Changing the pump with the engine in the truck was really a hassle. I’m considering going to a friend’s place and removing the engine and replacing the connecting rod and main bearings. Someone also tole me that this could be caused by worn camshaft bearings.

The truck runs fine and is pretty strong but every time I come to a stop, the needle drops rapidly and it drives me nuts. I know the gauge is bad because when I jumped across the terminals, the needle only went about 2/3 of the way up.

The engine oil system is like a tube tapped along the length to a bunch of slightly leaky balloons, each balloon in the analogy being a bearing of some kind or another. If any of the balloons pop, the tube pressure will drop like a rock. But it is hard to say which balloon popped just based on the pressure reading. Maybe they all are just leaking a bit more. So your problem could be main crankshaft bearings, rod bearings, camshaft bearings, or all of them, etc. Oil pumps rarely fail because they are in the perfect environment, bathed in oil all the time. No harm to double check though. Often this can be done by a visual inspection, just making sure there are no broken oil pump parts laying about.

If you are certain of your pressure readings, I guess the best option is just go about your business. Maybe avoid long trips away from home b/c eventually you will start to notice some ominous noises. Best to have that occur close to home. If you have any doubt about the pressure readings, this would be a good time to ask yourmechanic to hook up his own oil pressure gauge at the sender and see what it reads. You may be looking at an engine rebuild. No worries, nothing lasts forever. And the good thing about car engines is that pretty much anything out of sorts can be fixed. Best of luck.

I have another question: My daughter has a 1997 Taurus SHO and it’s been running pretty well until this morning when a turn of the key failed to start the engine. The battery is fully charged but when she turns the key, we get the click from several places under the hood, including the starter relay. I’m pretty sure it’s the starter relay, it’s inside of the fuse box, is identified as “starter” on the guide printed inside of the cover and is black plastic about 1.5 inches square. The windows, radio, horn and all of the other accessories work, but no reaction to the key. Has anyone got any ideas? Thanks.

Many years ago I had a 71 pick-up with the 302. I had the same oil pressure problems you have. Almost nothing at idle and maybe 20psi at about 3000 rpm. I knew a buddy who loved to tinker with engines so he dropped the pan and found the main and rod bearing tolerances were way out of spec… I went out and bought a new set of rod and main bearings and he installed them, also cleaning the oil pump screen which was not too bad…Also you have to make sure the cranshaft is not scored.

He got it all together and started her up…After the engine got up to operating temp had 25 psi at idle ( normal on a Ford 302 ) and 45 PSI at about 2000 RPM. I ran this old work truck for years after the repair and finally sold it…The guy that bought it had it on the road a few years after that, then I moved out of state so don’t know how long he had it after that.

My buddy only charged 300.00 labor. I looked at the bearings and you could see a few were down to the copper layer. I would throw a new set of bearing in it and hopefully you will be good to go. This truck had over 200k on it and only blew a quick puff of smoke on start up…The idea is to do the repair now before more severe damage is done as it will get worse and you will start getting lifter clatter.

My Corolla has a starter relay inside the passenger compartment too. This is used to switch-on the battery current to the starter solenoid on the starter when the key is placed in START. It should click when in START. It could fail to deliver the full current it should, but unlikely. If it isn’t cranking, and you hear another click under the hood, that’s probably the starter solenoid attempting to power up the starter motor. The most common cause of this problem is a marginal battery or corroded battery connections. That is the first place to start. After that, measuring the voltages at the starter motor during attempted cranking would be next. Since it didn’t happen in the summer, and is occurring now that it is colder, my guess is a bad battery or corroded connections. Next in line would be starter solenoid contacts on the fritz.

The small wire at the starter solenoid needs to be checked for voltage when the key is turned to the START position.If power is reaching the solenoid and the solenoid is clicking then the problem is likely going to be either a faulty starter or bad battery cable connection; assuming the battery is good.

If the starter relay in the underhood panel is clicking with the key in the START position then everythng should be fine in other areas of the circuit; or at least going by the schematic.

Serpent64 should start another thread on this different problem…trying to answer 2 different threads in a single post can get confusing to some …just a suggestion to make things easier. Have a happy Veterans Day and remember our troops…US Army 30 years Retired here.

Serpent64 here: I tried to start another thread but couldn’t quite figure out how to do it. Sorry, if you could point me in the right direction, I would appreciate it. Happy Veteran’s day…US Army Special Forces, 21 years retired. DOL

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