low oil pressure

[munkee]

I recently bought a 91 plus in need of some work. I has 105k on it and was knocking pretty bad so I started with the rod bearings. There were a few starting to show some wear but weren't too bad off except for the #6 bearing, which was badly worn and had a small chunk missing on the bottom bearing. I have a pic of the bearing but I can't figure out how to post them. Aside from a couple of light scratches the crank looked alright. A few hundred miles later the low oil light flickers on when you come up to a stop sign, usually as the tach hits about 6-7 hundred rpms. Then yesterday the light would start flickering at 1000 rpms and stay on at idle. Where do I start looking for problems? Supposedly the previous owner never changed the oil in the 29,000 miles he owned it, and judging by the sludge in the pan I wouldn't doubt it. Could this have hurt any other bearings causing low oil pressure? TIA, Chris.

 

[CheckerSHO]

Loose main bearings will cause low oil pressure too. Or bad oil pump. My 93 has a bad oil pump...when i got it, it was knocking... but seemed to have good oil pressure. dropped the oil pan and the rod bearings seemed to get worse from the front of the engine back. After i put in new bearings, i found out that after warming the car up that the oil pressure dropped to almost nothing even with the new rod bearings. bad oil pump im pretty sure...either way running without oil pressure has ruined this motors bottom end headbang Sounds like you may have spun a rod bearing. were the other bearings good?

 

[KM92SHO]

To check the engine light codes go to autozone and they will put on a computer for free.

Please take a look at my topic
TRANNY NEED HELP

can really need info

 

[wood_e]

First of all you don't need to go to auto zone. You can check your codes easily by yourself with a paper clip.

KM92SHO: Quit spamming the boards. We know you need help

 

[KM92SHO]

Sorry im asking for help and sorry i tell people to look at my topic for help man. not everyone may know how to do the paper clip thats all im saying

 

[munkee]

CheckerSho, the bottom halves of all the bearings were good except for #6. The top halves on three and four were also good. The top halves of 1, 2, and 5 all had a small patch of copper showing, less than a 1/4 inch. Both halves of the #6 bearing were showing between 80 and 90 percent copper. I didn't think about it then but I probably should have at least looked at the mains when I was down there. doh Is there a relatively easy way to check the oil pump?
KM92Sho, sorry about your tranny troubles but I did reply to your post last night before I started this one. Also, thanks for the advice on the codes but with 5 shos I unfortunately am able to practice the paperclip method quite frequently .

 

[CheckerSHO]

munkee:
CheckerSho, the bottom halves of all the bearings were good except for #6. The top halves on three and four were also good. The top halves of 1, 2, and 5 all had a small patch of copper showing, less than a 1/4 inch. Both halves of the #6 bearing were showing between 80 and 90 percent copper. I didn't think about it then but I probably should have at least looked at the mains when I was down there. doh Is there a relatively easy way to check the oil pump?
KM92Sho, sorry about your tranny troubles but I did reply to your post last night before I started this one. Also, thanks for the advice on the codes but with 5 shos I unfortunately am able to practice the paperclip method quite frequently .

Does the car knock when the light comes on? What kind of oil are you running in it? You may just have loose main bearings causing oil pressure loss. Although, a sticking relief valve on the oil pump can cause same symptoms. All i can think of is take it back apart and look at and plastigauge the mains. If it was a bad oil pump it would probably be dead by now when i pulled the pan on my 93 there was a pile of copper in the oilpan about 2cm deep.

edit-if it dosn't knock then theres a possibility that the sending unit for the light is screwin with you. If you have access to a mechanical oil pressure gauge, its a good idea to check actual pressure with that before tearing back into it thumb

<small>[ December 15, 2003, 07:57 PM: Message edited by: CheckerSHO ]</small>

 

[munkee]

I don't notice a knock, and I am using Castrol 5w30. I think I will pick up a tester and check the oil pressure to see if it is just the sender. I am planning on doing a lot more work on it during my seasonal layoff so if it isn't the sensor then I might be digging into it farther than I planned on. Thanks for the help, Chris.