Took my Cherokee to the dealer today due to very low oil pressure. Oil light comes on a idle.

Last week the pressure censor was changed and this wasn't the issuse. I have been told today that I need a new engine as the wear between the crank bearing is too great. This was checked with an oil pressure gague right off the enngine.


This makes no sense to me what so ever as one day the oil pressure was above normal, quite a bit above spec the next it was so low at idle there was no pressure. Maybe someone can tell me the following. If the oil pump was shot, or the oil pressure releaf valve was stuck open (is there one?) would the machanic have the same reading.. This engine has done 185,000k my prevoius two jeeps with the same type of engine had over 350,000k on them when I sold them and they were still going strong. I am very **** about oil changes and this engine on the surface seems/sounds purrrrfect. Between 6,000 k oil changes it uses no oil at all.. So to sum up if the pump was shot or pressure value stuck open could/would this give the same result.


Pressure at idle is 9psi spec is 35psi 2 weeks ago the pressure on this engine was higher than normal.


New engine or new oil pump.

PS do you have to push the engine up to get the sump off?


Thanks

David Elvin

 

what engine is this?

in order from best scenario to worse scenario you are looking at:

clogged oil pump pickup screen

bad oil pump

shot crank bearings

 

The Engine is the straight six 4L

I understand the best to worse scenario but the dealer is telling me for sure I need a new engine. To test the engine they put a gague directly on the engine and go a reading of only 9psi. However wouldn't they get the same reading if the pump was shot or the pressure releaf value was stuck open. Can they tell 100% that the engine is shot by doing this kind of test? Not only this but the key I think here is that the oil pressure has not been falling steadily over the last year or so. It went from normal to very low over night.

 

The Engine is the straight six 4L

I understand the best to worse scenario but the dealer is telling me for sure I need a new engine. To test the engine they put a gague directly on the engine and go a reading of only 9psi. However wouldn't they get the same reading if the pump was shot or the pressure releaf value was stuck open. Can they tell 100% that the engine is shot by doing this kind of test? Not only this but the key I think here is that the oil pressure has not been falling steadily over the last year or so. It went from normal to very low over night.

 

did they do anything else to come to that conclusion?

 

No they didn't

 

You wouldn't all of a sudden wear bearings to see a oil pressure drop like you are seeing. The only way you'd see a drop like that due to a bearing is if you spun one and it would probably be a main (also would be assosciated with a knock that I hope you are not experiencing).

I'd highly expect something going on with the oil pump (clogged screen, stuck check valve, ...).

There is one stupid suggestion that I have.... what about doing a oil/filter change (maybe clogged filter)?

 

hey man i have the same issue on my 00 xj. ive done a ton of research because like you i was scared the motor was bad. what i have found is that they had a huge problem with the gagues going bad. when mines cold i get 60 psi when warm at idle i get 9 or sometimes drops to 0 and trips my dummy light. ive changed oil and filter and oil sending unit with no luck. next ill change the pump and check the screen. honestly i think its just the gague. it goes up to 30 when warm driving on the interstate and i still have a ton of power without burning any oil. i hope this helps ya