Clean oil pickup screen?

Is there any way to clean the oil pickup screen in a 4.0 without dropping the pan? The dang thing overheated last week and the oil pressure has since suffered slightly. Reading approx. 30 at idle and drops to just under 30 on the highway. 210K on the beast and it's starting to make some noise. I don't think the oil pressure sensor has ever been replaced so I'll probably do that as well. I'm going to do an oil change and use 15W-50 or 20W-50 to try and keep it alive a while longer.

Thanks.

Brian

The only physical access is by dropping the pan. You might try pulling the filter and blowing solvent back down the hole. I'd have to review the oil circuit diagram in the FSM to tell you which orifice to push solvent through. After doing that you would have to be very careful to drain the pan and get all the solvent and crud out.

I'd change the sender first. If that doesn't do it, I think you would be better off to drop the pan, inspect the oil pickup, de-sludge the pan, and maybe replace the rod bearings while it's open.

rod bearings

so if someone is going to do as you suggest do you just get OE bearings or do you get oversize? Do you have a link for the "how to" on the procedure? I can't imagine it's that hard but it would be nice to get inside info from someone who has done it.
TIA

yeah i would'nt think that cleaning the oil pump screen would do much for your oil pressure considering you said you've have low pressure since you overheated the motor, that has nothign to do with the screen getting dirtier than normal. I'd say bye bye to your bearings it sounds like, replace the rods and mains and it should give ya more life outta the motor. As for the bearings i'd mic the crank to figure that one out, see how much wear it actually has on it. You can replace all bearings though without even pulling the crank or pistons/rods, just push pistons up in the cylinders.

eric

Sorry guys but I guess I should have worded things a bit differently. The drop in oil pressure has been present for 15K or so. I don't think it's directly related to the overheating. Actually, sometimes it reads 20 at idle, 30 at speed and other times 30 at idle and 40 at speed and still other times as described above. Kind of erratic. I bought a new oil pressure sender on my lunch break and I will see what happens. The temp gauge only got slightly into the red zone due to a cracked coolant overflow bottle (now fixed).

I'm not ruling out the fact that bearings may need to be replaced, but I just don't want to dive into that unless it's absolutely necessary (I'm considering unloading the XJ for something a bit newer...but then again, I just put two new liftgate supports on it today as well and need time to enjoy them ).

Thanks. I will post my results of the sender replacement.

Brian

I would be hesitant to backflush the screen - that would involve pushing solvent thru the pump in reverse, and you'd have to make sure to reprime the pump after you are done (remove and pack with grease, or remove distributor and run with drill until you get pressure.)

The screen is usually coarse enough that sludge is a minimal problem - it is really there to keep your oil pump from turning into a "trash pump" - like what is used to clean sunken basements and the like. If anything breaks, the screen catches it. Anything that will go thru the screen will also go thru the pump, and get caught in the filter can.

If I suspected that the pickup was that dirty, I'd replace it anyhow - I think crud in the tube would be more likely to be a problem than crud on the screen, and I'm already in there if I see it anyhow. While I'm in there, yeah, I'd mike the crank and replace the bearings - I've come this far.

5-90

Well, I change the sender last night. I wish every repair was that easy.

However, I did not have a chance to check the oil pressure w/ a mechanical gauge. With the new sender installed and engine cold, the dash gauge reads 50 psi at idle and 60 at highway speed. Once she gets nice and warm, the gauge reads about 22 at idle and 48 at highway speed.

The noise I'm still experiencing has me puzzled though. The more I think about it, it doesn't sound like bearings going bad (granted I've never had an engine where they did, but I heard my brother's Saturn before it blew). When the engine gets nice and warm, it sounds a bit like a diesel. When it idles for a long time, it really sounds like a diesel.

What do you guys think? The noise goes completely away when I get on the throttle. Currently running 10W-40 oil if that makes a difference.

I'm not going to try and do anything w/ the pickup screen at this time. Seems like I could cause more problems than I would fix. I may go ahead and do the bearings sometime soon.

Thanks for your tips and suggestions.

Brian