Oil Pump Life

[sabre65]

Anyone heard of issues with the oil pumps in the 3.4? Still chasing a knock when engine is warm at idle or just above idle in gear. Toyota techs are kind of puzzled too.

 

[Stick Figure]

I would really doubt the oil pump was the cause of the noise unless you have noticeably low oil pressure as well. Usually those type of pumps just work until a gear actually shatters. Which isn't a concern outside of a highly modified engine from my experience.

Describe the noise, and what you tried doing for diagnostics?

 

[sabre65]

The knocking (which sounds like a rod knock) is only present when the engine is warm and in any gear. Goes away when rpm reaches 1200 - 1500. Not present in park or neutral. It can get real noisy sometimes and hardly audible at other times. I never heard a rod knock go away at higher rpm. Had three Toyota techs look at it and drive it. Had a timing belt and water pump installed and all the pulleys were good. Accessory belts are new. Unhooked belts and the noise is still there but not as loud when there is less of a load on the engine. Frustrating enough that my ownership of this one might end soon.

 

[BrianSD_42]

How long have you had the vehicle?

I was wondering about oil pump life recently as well. I am currently at 208,000 miles and have owned my 4Runner since 2003.

From what I was told, the 4Runner has a gear driven oil pump that is very reliable even past 200,000 miles.

 

[Stick Figure]

Did you replace the tensioner when you did the t-belt? if it can't keep up the belt could be slapping around a bit.

Have you pulled the oil cap off while its knocking? does it get louder or is it unchanged?

 

[LittleCaesar]

Have the techs hooked up an oil pressure gauge to the engine?

If you are not the original owner, then the truck may have been starved of oil or it was changed infrequently.

 

[sabre65]

I've only had it 2 months and didn't hear the knock during the test drive since I didn't leave it in gear idling. When in park or neutral the engine sounds good. The service history shows it was never back to a dealer for anything since new and from some of the things I've repaired the owner didn't spend anything on routine maintenance. The price was good and since it drives solid I figured with Toyota's reputation it would make a good second vehicle. The Toyota techs that did the timing belt and water pump said the tensioner was fine and it doesn't sound like a belt at all. It sounds like the thrust bearing is worn and allowing the crank to move forward/backward when in gear. The techs say it might last forever like that but I can't drive something that sounds like it's coming apart at times. Did not check the oil pressure yet but it makes no bad noises cold or in neutral or park warm. It runs super.

 

[sabre65]

I have a feeling it had infrequent oil changes along with other items.

 

[brian2sun]

I recommend picking up a mechanic's stethescope at Harbor Freight. Listen around the engine and it should pinpoint where the knock is coming from (i.e. from under the valve cover, the side of the block, etc..). Hopefully that will help you determine if it's a rod knocking or maybe a tapping valve, lifter, cam lobe, or whatever.

 

[sabre65]

Update to my post. Hooked up a mechanical oil pressure guage and found the following pressures;

cold idle - 70 to 80 psi
hot idle in gear 5 to 10 psi
hot driving around 1500 to 2000 rpm 25 to 35 psi.

Still knocking at idle in gear when hot.

 

[rjaudi]

Mines been doing this exact problem for 70k miles. I tried chasing it but gave up since its not worth putting money into. My dad was the original owner and it has been maintained perfectly. I also changed the tensioner and that wasn't the problem.