Oil Pressure dropping - Help!

[apstguy]

A couple days ago, I noticed the oil pressure lower than it normally is. I checked the level and sure enough it was low. I added some oil and was on my way. Today, it is lower than normal and the oil level is FULL. I bet this means my oil pump is giving out. Would this be the case? Is it hard to change on a 2wd?

[1FaastC10]

when was the last tim eyour oil was changed? could be that the oil is just thinning out, which it does after being used for a while.as for changing out your oil pump, it MAY fix it if the oil is not the problem. most of the time when you get low oil pressure it means the entire engine is shot.

[Jason Spears]

I'm in the same boat you are. Last week my low oil pressure light came on just as I was pulling into work. To start diagnosing the problem I installed a mechanical oil pressure gage and the sender for the idiot light. Since I did this I haven't had the light come on again but I haven't taken the truck on a long drive yet to get the engine hot. (The pressure will be higher when the oil is colder and more viscous.) Hopefully it was just a fouled sensor. The end of the sender had some gunk on it and the electrical connection was really dirty. Try the easy things first!

An air leak in the pump pick-up tube can cause low pressure. The other thing is the pump is worn out. The pump is a positive displacement gear type pump. If the clearances increase it will not make as much pressure. The question to ask is what made the pump wear out? There must have been something in the oil to make it wear. (Timing gear teeth, piece of timing chaing, dirt, etc.? Check the bottom of the pan to try to find the reason. Oil pumps for these trucks are pretty inexpensive. I priced a fedral mogul one for $ 30 (cdn).

The worst possible case is if the bearing clearances in the engine have increased. If this happened the bearings will offer less resistance to the oil flow and the pump will in turn make less pressure. I hope this isn't the case.

As for taking the pan off, I don't have any problem but I have a 4x4. I've heard other people on this board that it is also very easy on a 2wd.

Hope this info helps a bit. Good luck.

[apstguy]

I changed my oil two weeks ago. It best be not the whole engine or I'll shoot myself. I know the sender is a bit off, but the contacts are clean and the gauge move quite a bit. The engine has 134,000 miles on it so . . . It could be just the pump's time or the motor. I hope not the motor or I will be without a truck.

[79BIG10]

How about the smell of the oil? Reason I say this in another post someone mentioned that with a leaky fuel pump it can wash out the oil on the bearings. I would smell the oil for fuel. If not that get another gauge to verify for sure.

[WheelsUpRacing]

Oil pumps do not wear out, nor do bearings at a rate you can see the change in Oil pressure in a day or week....(Outside of Catastrofic (sp) failure) Do not trust the elec guage....go buy a mechanical.....a round or 2 of elec tape to temp stick it to your colum, and hook it up in place of the sending unit...this will tell you the Truth... but don't be suprised when it drops down to about 10 PSI at a idle when warm.... Just hope you have the classic 10 psi per 1000 RPM.. or close to it...can get away with a bit less if you drive like Grama..err...bad example in my case...but you get the point.. Good luck

[rockman20]

Did you change the oil yourself? Did you notice any noticeable metal shavings in the oil? From my experience, a drastic drop in pressure has always been bearing failure. Depending on how the truck was used, 134,000 is getting up there on the engine. Especially if it has towed or hauled a lot.

I would still double check the accuracy of the gauge, but I am going to say it sounds like the bearings are going out. You'll have to drop the pan anyways to get at the oil pump so you can check then.

[apstguy]

Oil doesn't smell like gas at all, but you can smell burning oil after you have ran the truck for a while (45 min. + )

I do change the oil myself and there has never been any metal shavings in the used oil. The truck has towed very little. Is there any other signs of bearing failure?

I suppose if the pressure drops to 0, than the choke light will come on and tell me no pressure. The sender I have in there now is iffy - it is a new one, but never showed more than 20 psi. It does move quite a bit though. I'll have to tear into it next week and hope it isn't the bearings.

It is cheap for a new oil pump, so it is worth a try right? I need to see how worn the engine is anyways, so what the heck.

BTW: I don't drive like a grandma.

[Zilverado]

My old '77 had a 305 with very low oil pressure. Almost 0 at idle, once the oil warmed up and thinned out.

The main bearings were so bad, I could easily hear the crank bouncing around. I doubt your bearings would be that bad, or you'ld hear the noticable "knocking" sound.

I agree with "wheels" when he says the bearings don't wear that quickly. Mine got progressively worse over a couple of years (I was planning to replace the truck anyway). As far as oil pumps are concerned - no experience here.

Hope you figure it out.

[apstguy]

Thanks for all your help. I think the combination of the messed up sender and the oil being thinned out b/c it was on the freeway for about an hour made the oil VERY thin. I'm going to mess with the sender when the weather clears up and going to replace the oil pump just in case. I need to have a look at the bearings anyways. I'll need a seal for the pan. What was the one seal everybody was raving about? Some one piece seal? Where was that from? I need to see if I can get this oil leak under control if I can. Thanks for the help again!

[Jason Spears]

The one piece gasket would be a fel-pro. They're awesome. They come with clips to hold the gasket in place so you can install the pan and bolt it on without needing three hands! Good luck.

[rage'nrat638]

just a thought......
did you buy the cheapest oil filter???????could be bad!!!!!!!

unscrew the filter and blow out the bypass valve....it may be stuck open.....lets hope

[apstguy]

I buy good filters. I always get fram filters. Fel-pro! That's it! I'm going to see if the local Kragens can order it for me.

[79BIG10]

Originally posted by apstguy
I buy good filters. I always get fram filters.

I thought the same thign about Fram filters. Then I saw this and changed to Wix. http://www.frankhunt.com/FRANK/corve...lterstudy.html Scary thought on Fram and others quality.

[apstguy]

Whow! I'm not using another Fram filter! That is scary!

[MSL]

Dang im not using fram again either. so it looks like the wix filters and the napa ones are the same and seem to be one that is better recommended. So now that where on filters what about oil is there something we could read on that.

[TIMSPEED]

Hey Tyler...don't think your bearing can go out? Thing Again! I didn't think my bearing was out either..it just sounded like a SMALL exhaust leak...then one day, it died, and I had to have it towed home, and when I started it back up.., CLANG CLANG CLANG! No power loss or oil pressure loss either! (I have a mechanical guage) It was real crazy..Me and all my friends couldn't believe it...so I took my oil pan off, and show nuff #8 rod bearing's were GONE! Not even a 40 over bearing would hold. The crank was TOAST!

[old Rusty C10]

twice i used fram fileters where they screwed up id never buy another lately im sticking with the factory filter for the vehicle

[swervin ervin]

Here's a page on oil I found a long time ago.

http://www.vtr.org/maintain/oil-overview.html

[Jason Spears]

Most of my lubrication experience is around industrial machinery but here is a good source of info that sometimes has automotive info:

http://www.oilanalysis.com/

Jason