Engine Tick

[cherokeebob1966]

Hello Everyone, first post.
1991 Jeep Cherokee 4.0 HO 4x4 Briarwood 200000 miles

Ticking coming from valve cover, around #1 sparkplug.
Tried to isolate by pulling spark plugs, one at a time, while running. I heard this can tell you if this is hydraulic lifter or oil pressure issue. No difference in ticking noted. Getting strange readings from oil guage (up and down). Absolutely no tick when first started cold, ticking starts after 2 minutes and gets worse until sounding loud.
I did change oil (no difference noted)
My guess is oil pump. Could someone help diagnose please? Before I spend $350 on oil pump replacement, or spend a dirty day under my Jeep

Thanks!

 

[mud4feet]

First off, welcome to the "Z"!!!! Bunch of knowledgeable, friendly folks here.

Unfortunately, I'm not one of the more knowledgeable. If there's no noise when you first start it, I'm thinking your oil pump's allright. You've got 200K on the engine.....have you ever used one of the "oil flush" products on it?? Sounds like you might have some build-up in an "oil channel" in the block somewhere?? possibly??? Ticking after warming up maybe a valve???? Have you tried listening with a wooden dowel (or something similar) to isolate the location?? Strange oil gauge readings could be a bad sending unit. Just a few thoughts.......wish I could help more. Good luck and keep us posted.

 

[Bounty__Hunter]

Consider replacing a qt. of oil with a qt. of ATF and let us know if it makes a difference. They're known for noisy lifters.

 

[cherokeebob1966]

Thanks for the replies.

ATF is Automatic Transmission Fluid? What would this accomplish?

 

[Bounty__Hunter]

Automatic transmission fluid has been used for decades to quiet noisy lifters. My mechanic's wife drives a Grand with a 4.0L and he found the only way to keep the lifters quiet was a qt. of ATF at every oil change. He had tried spinning the noisy lifter in place but that only quieted it for a short time. The ATF worked better, and easier.