Replacing an oil pump, questions - Diesel Forum

Peter C · 03-22-2005, 02:04 AM

I picked up a project truck ('88 F250) in addition to my main transportation to play with. I figured if one is so much fun, why not double the fun and get another!

Anyway, my question is, on this truck I've got a bad oil pump and I'm trying to figure out whether to try to source one used or go new. And if I get one used, from where? (I'm currently in Oregon) Also, how long (miles/age?) should you expect an oil pump to last? And, are there any secret tidbits that you should know before tackling it? I've got the factory manual and it looks like it describes the process pretty completely.

Thanks for your help!

Peter

argve · 03-22-2005, 02:18 AM

Never heard of one going bad. How did you come to this conclusion? Not throwing stones just never heard of one going south for the winter before. (now oil pressure switch/idiot gauge yes, but pump no... )

ltl_jrw · 03-22-2005, 06:58 AM

The oil pump will last the life of the engine, they are a positive displacement pump with a relief valve. I too would like to know how they came up with a bad pump.......... Jim

perryg114 · 03-22-2005, 07:44 AM

I have seen one bad oil pump and it ate a sliver of metal or something and was not pumping well at all. The rotor had a big groove in it. The crank was in pretty good shape. I take that back I had the shaft wring off of a VW oil pump one time cause of the soft taiwan metal that was not hardened properly. Most of the time low oil pressure is loose bearings.

Perry

Peter C · 03-22-2005, 08:55 AM

The truck lost oil pressure suddenly when the previous owner was driving it. He shut it down immediately to try to avoid causing engine damage. I picked it up from him assuming that the engine was bad. If you start it (which I've only done briefly twice to hear what it sounds like), it makes a loud knocking noise which I originally thought was from damage caused by the short time it ran with no oil pressure. But I had the oil analyzed by Blackstone and their report showed there to be nothing out of the ordinary (no extra iron deposits from advanced bearing wear or anything else unusual). So I was thinking about it more trying to figure out what the noise might be. I thought that it may end up just being the oil pump that had a sudden failure, because the sound is somewhat similar to what my other truck (the one that actually runs) sounds like right after you start it up before it gains oil pressure. So, I'm looking to replace the oil pump and see if that solves it. If not, I'm not really out much (other than the cost of the pump) because I bought it with the anticipation of needing to get an engine for it anyway. Just thought I'd try this first. From what it looks like, the oil pump installation will take a lot of time (just a few more steps and you'd be able to pull the engine all together), but I don't mind putting some time into it if there's a possibility of getting it going for now without dumping a bunch of cash into a new engine. So, what do you guys think? And do you have any thoughts on my original question about where to source a used one? If they generally last forever I don't mind using a used one if the price is right. I've got more time than money right now so I don't mind troubleshooting it in depth to see if there's a less expensive way to get it going.
Thanks!
Peter

ENUSYELLSAW · 03-22-2005, 09:47 AM

I would say, put a pressure gauge on it first and get an accurate reading of the oil pressure [img]/ubbthreads/images/graemlins/shrug.gif[/img]. You could get an aftermarket gauge or use one of those temporary gauges machanics use. I have learned that there are a lot of things that can cause these engines to have a knock(bad injector...ect). But if it really has no oil pressure, then the lifters not pumping up could cause all kinds of noises!----MUCH LUCK!!!---ENUS

Peter C · 03-22-2005, 10:17 AM

I'll try that this weekend and see what I get. Any other ideas of things to check while I'm at it?

perryg114 · 03-22-2005, 10:46 AM

It would be best not to run it at all if there is no oil pressure. The more you run it the more damage you are doing. I have not had one of these engines apart so I don't know if you can remove the pan without pulling the engine. You could also remove the oil sender and see if it is working by applying air to it. Make sure you have the body grounded to complete the circuit. If it works with air you can assume that you really don't have any oil pressure. Do you have any external leaks. I have heard of oil gallery plugs coming out and all your oil leaves the engine pretty quick at that point. Make sure you turn down the air regulator to below 50 psi so you don't blow the sender.

Perry

Peter C · 03-22-2005, 11:05 AM

I haven't run it since I first purchased it and fired it up to hear for a few seconds.

No external leaks.

I have tested the oil sender and it works. So I guess that it'd be redundant to check pressure with another gauge this weekend like I was going to. According to the instructions in the manual, you almost have to pull the engine to pull the pan. It's an involved process for sure.

Any other ideas aside from the oil pump? And sources for a pump if its going to be replaced?

perryg114 · 03-22-2005, 12:06 PM

I think you are going to have to pull the pan to do much with it. Look for missing or clogged pickup tube. If that is not it pull the pump and inspect the drive mechanism and see if it is turning the pump gears. Pull the pump rotor cover and pop out the rotor to see if it is scored or damaged. There should also be an oil pressure regulator that might have failed. It is a ball and spring thing. Might just be sludge has clogged the pickup. If the engine has not gotten warm enough you could have sludge in the pan from condensation. I say this cause I noticed you were in Alaska.

Perry

Peter C · 03-22-2005, 12:22 PM

Thanks for the advice. Now I have some specific things to look for when I get into it. I guess now I just need to see what it looks like and go from there. Thanks!
Peter

d9d · 03-22-2005, 01:32 PM

Tundra,

There's a good pick-n-pull just north of Eugene Oregon, on hwy 99 (which runs north/south like I-5, but is just west of I5). It's on the right side when going north on 99.

I don't know that you'll find a pump already out; because used engines get sold 'as is'. Nobody pulls the pan to remove things like that.

My friend Mike (sw Oregon, near Grants Pass) has half a dozen engines...he -might- want to sell a used pump for 50 bucks or something, but I'd have to ask him. You can reach me at 541-944-9746.

If the truck 'suddenly' lost oil pressure, and lost it completely; then it doesn't sound like a pump to me. Maybe the relief stuck open or the spring broke, or the pickup fell off, as the other guys suggested.

I believe you can pressurize the oil system -externally- on these....via the filter-mount if nothing else. So you might want to try pumping oil into it to 15-20psi and running it. Something like a power-steering pump on an electric gearmotor should do it.

If you've still got your loud banging noise when running it with oil-pressure, then obviously something more serious is wrong...

Peter C · 03-22-2005, 03:09 PM

D9D,

Thanks for the additional insight. I would be interested to find out if your friend is interested in selling a pump in the event that that is the problem. It'll be a fun weekend getting this all figured out. I'll let you know what I find.

cdnsarguy · 03-22-2005, 09:29 PM

Tundra
My advise would be to pull the oil filter and check out the filter head, there should be a washer staked in a hole with a fibre disc behind it, see if it is there or missing.

93turbo'd_animal · 03-23-2005, 02:24 PM

I think if I was going to all the work to put in a new oil pump I would put in a NEW pump [img]/ubbthreads/images/graemlins/shrug.gif[/img] [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]