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slight knock at idle

C

cdawall

NAXJA Forum User
Location
EAFB
after a recent oil change i have noticed high oil pressure and a slight low RPM knock. did i do something wrong? i have changed the oil on dozens of vehicles and never had issues like this. checked the oil today and it was just a smidge low so i filled it up to just over the fill line oil pressure went up to 72-75PSI at start up then drops down to around 40PSI after it warms up. before i sat just under 70PSI start up and closer to 50PSI after warm up.

edit: i have put around 1000miles (2 weeks) on it and the knock just showed up in the last 2 days. has not been rev'd or stressed. just DD and been taking it easy on her to try and get some better gas mileage out of it. also when i shut it off it sounds like a drain. same noise when i added a little oil...
 
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what year is she and how many miles on her and what weight oil did you put in??
 
OCOD it was free. planning on changing it tonight or tomorrow. used 10w-30 its got 119K on it. today it seemed a little calmer after it sat in the sun all day. oil pressure was just under 70PSI which is were it has always sat. as for the HV oil pump no idea what ever was stock on the jeep. it comes stock with a lot of oddball parts though since its a forestry service model.
 
It's amazing how messed up Fram filters are. Mobil 1 makes the best retail filters out there. They use a special synthetic filter media that has a more consistent pore size. That allows them to capture smaller particles, and still have better flow than conventional filters, which use cellulose/polyester filter media.

If you want to use a conventional filter, Wix is usually regarded as one of the best.
 
montanaman said:
It's amazing how messed up Fram filters are. Mobil 1 makes the best retail filters out there. They use a special synthetic filter media that has a more consistent pore size. That allows them to capture smaller particles, and still have better flow than conventional filters, which use cellulose/polyester filter media.

If you want to use a conventional filter, Wix is usually regarded as one of the best.
Click to expand...
they had the Mobil 1 stuff on sale so it wasn't that expensive. may as well spend the extra couple of bucks and keep my DD running. did the extra 10 mins of research on this one which is why i ended up with the Mobil 1.
 
You shouldn't have that high of oil pressure with a stock pump. I suggest checking the oil pressure with a mechanical gauge. It might be reading very high and perhaps the oil is lower than you think.. maybe a lot lower.
 
you an see the wonderful OCOD. the crushed center is from me using a screwdriver to get it off the jeep.

IMG_3864.jpg


IMG_3865.jpg


IMG_3866.jpg


IMG_3868.jpg


the filter media was disintegrating and flowing out of the filter. thanks fram.


Talyn said:
You shouldn't have that high of oil pressure with a stock pump. I suggest checking the oil pressure with a mechanical gauge. It might be reading very high and perhaps the oil is lower than you think.. maybe a lot lower.
Click to expand...
i am going to be 100% i do not care that much its not knocking anymore if the gauge is off so be it thats not really going to affect the performance of anything.
 
Except the fact that the oil pressure could actually be below acceptable at a hot idle. I.e. little to no oil pressure resulting in the knock. It will effect performance when the lifters bleed down and your bearings get damaged.
 
Talyn said:
Except the fact that the oil pressure could actually be below acceptable at a hot idle. I.e. little to no oil pressure resulting in the knock. It will effect performance when the lifters bleed down and your bearings get damaged.
Click to expand...
but whats the actual likelihood of that. it had no knock before the fram filter/oil change and has no knock after the fram filter is gone...i will probably hook a manual later this week just to be sure since you seem to enjoy freaking me out :p

if it ends up being wrong this is the correct replacement correct?

http://www.autozone.com/autozone/pa...mString=search&itemIdentifier=103750_0_0_5673
 
Yes, that is the correct sending unit.

Your oil pressure numbers are just too high to be close to correct, especially since you have 119k in it. For example my fairly new stroker with a HV oil pump is 40psi at hot idle and about 55 psi hot around 2000 RPM with stock bearing clearances. Every other Jeep I had idles around 20 psi hot with stock engine and pump. Another option is that the oil pump has a stuck pressure relief valve.
 
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