hello, got a 1989 f250 with the 7.5L 460 and i was driving home from a 60 mile camping trip and noticed my oil pressure gauge went to low when i came to a stop, the oil light did not come on, is there a sign of a major problem or just a sensor?

 

You have a oem oil light and oil gauge or a aftermarket oil gauge with a light?

If aftermarket gauge it could be your light doesn't come on till its below what your gauge was reading.

 

First welcome to the forum.


I take it you checked the oil level?
How many miles on the motor?
How hot is it where you are and the weight of the oil used in the motor?
What oil filter are you using hope not the orange can of death?


If all above is good, mileage low then the motor may have bearing issues as that is the only thing I know to kill oil psi.
Dave ----

 

89 truck has the fake factory gauge if that is what he is looking at. Not a real gauge, no pressure sending unit on those models.

 

thanks! Yes, oil level is good, its got about 170,000 miles, its been in the low 90s here and the oil i use is 10w-30 and the oil filter is a fram ultra synthetic. it has the factory oil pressure gauge and i turned the key to on and i didnt see an oem light of the oil can like other vehicles do.

 

if Franklin2 is correct then theres really no point in looking at that gauge then right?

 

It's an idiot gauge, same as a light so still watch it. How ever you could use a true pressure gauge just to be safe. When the factory gauge drops it means your oil pressure is below the factory set safe limit. Probably 4-7psi. To start I'd add a true pressure gauge. It's 90deg there, swap the 10w30 for 20/50. If it drops again I'd consider looking for a good used engine to swap so you can go thru that one. Sounds like mains or cams are getn old.

 

ya once i learn how ot manually check oil pressure i plan to do so and see what its running at. previous owner definitely did not take good care of this truck so i knew it was going to need maintenance but if the engine is just flat wore out i will probably look into replacing it.

 

Check out this video on YouTube:

 

Thanks for the video! Looks like an easy job. Been looking up where that oil pressure sensor is and its behind the engine,is it even possible to check it?

 

It's hard to see back there, but usually you can get to it on most engines. If you went to all that trouble I would not bother with the stock setup. I would get a aftermarket setup from the store with the tubing and hook up a real gauge. I have always used the plastic tubing that comes with the gauge with no problems, but some people like the metal line. You can get a copper line kit at the store also.

If you are really having problems, when the gauge drops you may hear some ticking or a very faint low frequency thumping sound coming from the engine.

 

Yes it's possible, may look worse then it is especially if you're fuel injected. Top of the block at the bell housing behind the intake. If you can spring for it, buy a brass tee to put in it & an aftermarket gauge to mount under the dash. That way your factory gauge will still work plus you will have a true gauge full time. Some say it's not needed but I always use thread tape on those threads. Never had one leak & they always come apart easy.

And remember a big block in 90* weather needs more then 10w30.

 

I apologize for all the late replys, i get busy during the day. Gonna check the oil pressure sometime this week. Franklin2, when the gauge went to L i didnt here any ticking or thumping sound. im thinking that since im using 10w-30 and it was a hot day if the oil pressure dropped from the engine oil being hot and i just need to add a thicker oil like OneLostCowboy said?