• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Oil Pick-up tube/screen...clean or replace?

Dave138

NAXJA Forum User
Location
Phoenix, Arizona
Hello. First time posting. I apologize if this has already been discussed on the forum, I did a search and couldn't find anything. I have a lot of questions that I hope some of you will be able to answer. Anyway...

97 XJ
4.0 I6
150,XXX

I picked up a used XJ about a month ago which has been having a low oil pressure issue (cold start 40psi, hot 1600rpm 21psi, hot idle 8ish psi) that I think may be related to sludge in the oil pick-up screen. This may be wishful thinking on my part because I am not currently financially prepared to have bearings replaced, engine rebuilt or replaced. What I'm planning on doing is pulling the oil pan and checking it all out, but I'm a huge noob and could use a little guidance.
Here goes it.
1. If the screen is caked with sludge what is the recommended method for cleaning it? I've read that if you remove the tube you need a special tool to get it back in and should replace the gasket in the oil pump, if that's the case would it be best just to purchase a new tube?
2. If there is significant sludge in the pick-up tube, should I clean or swap out the oil pump? I've heard that replacing the oil pump is rarely necessary, but would a repair kit from NAPA be worth while?
3. While I'm in there I've also read that I should plastigage. Any recommendations for doing this from underneath the engine? To do this I'll need to buy a Haynes manual so I know the right clearances and I'll also need to buy some tools.

Thanks for any advice you're able to give.
 
It's not to likely a sludge issue, best bet would be a new HV pump!
 
Purple cleaner, power, whatever name it may go by is one of the best degreasers. I cleaned a gunked up pickup tube with a 50/50 purple mix from Lowes soakings for 24 hours.

Honestly you might be able to buy a new pickup fairly cheap.


Sent from my iPhone using Tapatalk
 
Check the accuracy of the oil pressure gauge before tearing anything apart
Factory gauges are not all that accurate and do go bad.
Low pressure is seldomly caused by sledge in the pan or a worn pump.
Worn bearings are are normal cause.
 
Check the accuracy of the oil pressure gauge before tearing anything apart
Factory gauges are not all that accurate and do go bad.
Low pressure is seldomly caused by sledge in the pan or a worn pump.
Worn bearings are are normal cause.

I had a mechanical test done and unfortunately it did confirm the low pressure. This is just a last ditch effort in hopes that the Jeep gods will go easy on my wallet and let me get out there wheeling again.
 
My 4.7 stroker runs at 50psi under acceleration, and roughly 25psi at warm idle, off auto meter gauges...
Not too far from your numbers once you compensate for old inaccurate gauges... I wouldn't worry about it, unless your oil pickup screen is caked in gunk of course.

Your numbers are nearly identical to my beater Comanche with 200k+ on stock gauges...


Welcome to the site, don't worry about reposting questions that have been asked before.
 
I had a mechanical test done and unfortunately it did confirm the low pressure. This is just a last ditch effort in hopes that the Jeep gods will go easy on my wallet and let me get out there wheeling again.

I have read about cases of sludge building up in the elbow off the oil filter. One guy plumbed a hose into that put the other end in a bucket and whomped on it. Problem solved. Start with the easy stuff first. Unless you have the pan off and are looking at sludge you are just guessing. Low oil pressure can come from wiped cam bearings, worn mains, worn pump ... not only the oil pickup screen.
 
I have read about cases of sludge building up in the elbow off the oil filter. One guy plumbed a hose into that put the other end in a bucket and whomped on it. Problem solved. Start with the easy stuff first. Unless you have the pan off and are looking at sludge you are just guessing. Low oil pressure can come from wiped cam bearings, worn mains, worn pump ... not only the oil pickup screen.

Behind the oil filter or the sending unit?
 
This might be a stupid question... Will I need to replace the oil pan gasket if I go forward with this? The PO replaced the gasket before I purchased it, so it's only been on there for less than 1500 miles. Thanks.
 
Thanks for all the helpful info. I'm going to try the trick with hooking a hose up to the sending unit port, then pull the pan, and if the screen is gummed up I'll just replace with a new one from NAPA. I'll post some pics when I'm done. I've heard a lot about Rotella oil and Lucas additive, any particular blend come recommended?
 
If the install was done correctly, you will end up with RTV in several locations, I just replace the gaskets because for $30 it ain't worth fussing over. If you are on a budget and curious you may try reusing if Felpro. Cork, no. as an xcm suggested.
 
Let us know, we always like to hear feedback whether or not you're a newbie or an experienced member.
 
Check rockauto for the cheapest oil pick up. Got mine there as mine was bent from the oil pan getting bent on a rock. Also check Amazon for a mopar high volume oil pump. It's meant for the 4.2l and will have a pick up tube for that but just buy the right pick up tube for yours and use that instead.
 
If you insist on replacing the oil pump and its pickup, search how to install the oil pickup, the tool needed to install it into the pump and how to set it at the right height above the bottom the pan.
Set it too low and you will have restricted flow.
In fifty years of engine work, I can't remember ever finding an engine that was so sludge filled, that it had low oil pressure which was cured when the sludge was removed.
I have not seen too many bad oil pumps that had not already damaged the bearings.
Just be prepared for the worse.
 
I don't think the 4.0l pick up needs a special tool, the tab that bolts it to the oil pump basically sets it at the right height. Or at least that's what it was for me
 
I haven't seen it asked yet.....what brand of oil and viscosity are you running?
 
I haven't seen it asked yet.....what brand of oil and viscosity are you running?

Sorry I forgot to mention this the first time around. Old oil was Valvoline 10w30, new stuff is Mobil synthetic blend 5w20. Oil filter is a Pronto, just bought a NAPA Gold to replace that with.
Not sure if it makes a difference or not, but I live in Phoenix and each day noticing this issue it has been 100 degrees or more outside. Honestly I'm afraid to drive it for fear that I'll make it worse. pretty bummed about the situation.
 
Back
Top