Engine Knock

[mnjeepmale]

About a month ago I just bought a 2001 Chevy Tahoe LT with 145k miles on it. Excellent condition with new tires. Needed a newer truck to pull my boat and winter driving. Never owned a Chevy before.

A few days ago I was pulling my boat. Everything was going fine and the oil pressure gauge usually shows in the middle at 40 but when pulling the boat it went down to about 1/4 of the guage about 20. After about an hour later the engine was making a knock sound from like a lifter/piston. I was still able to drive but the noise was loud and very noticable. Dropped off the boat and started driving back to my house. The oil guage stayed the same. 30 minutes later the noise went away and pressure guage went up to about 23-25. Then before arriving home the noise came back.
I don't know if this is related to the oil guage but Im not sure where to start. The dip stick level is in range and no oil leak. Engine temp is at normal.

Advice? Hope the engine isn't going south.

 

[chevyboy831]

sounds like very possible lifter problem. these engines are known for this unfortunately.

 

[mnjeepmale]

Thanks for the information. I will try to find someone to look at it.

Is that a big fix? Hopefully it doesn't cost more then 1k

 

[chevyboy831]

Thanks for the information. I will try to find someone to look at it.

Is that a big fix? Hopefully it doesn't cost more then 1k

kinda hard to say. once they tear into it and thoroughly examine whats going on, may be more than that. then at that point, weigh out the options you have. post the progress and what they find so we can help u out to the fullest.

 

[mnjeepmale]

They are going to start with replacing the oil pump since it seems to be going bad with the low oil pressure. Hopefully I haven't done much damage to the engine at this point. Found it interesting that the oil pump replacement is more expensive then the lifters.

 

[Haro504]

I haven't heard your sound but did they say where it was coming from because bad rod bearings will knock and cause a drop in oil pressure. When the bearings go they don't hold pressure well

 

[chevyboy831]

I believe they have to pull the pan to get to the oil pump... if im not mistaken, so bearing material should be in the pan if there is any. and if he looked at the bottom of the rotating assembly (as he should) he should be able to notice if something wasnt right. it doesnt surprise me that the oil pump is more expensive.

 

[04SS99Denali]

did they check the oil pressure with a mechanical gauge? the stock gauge clusters suck there not reliable at all. if it is a stuck lifter you can try the transmission fluid in the engine trick. ive never done it but ive heard many good things about it freeing up stuck lifters. i would start with that before getting into the motor