Running-Snail
NAXJA Forum User
- Location
- West Michigan
I've searched, lots of help found - this is a great forum!
89 limited 4.0 AW4 242; 120k miles
Knocking at idle and higher rpm; changes with rpm.
Knocking at cold and normal temp.
Knocking under load and coasting.
Noticed some noise around thanksgiving when the jeep came home for break from school (it was 3 quarts low on oil!).
Oil pressure seems ok. around 37 at normal temp.
Tried the flexplate test - load the transmission/power brake. Still knocking.
Pulled the pan (just did rear main last weekend) and pulled front two mains - looked ok (so did the rear last week).
Pulled all rod bearing inserts. Top of #1 was worn to copper at top of cap, bottom insert on #1 had slight wear. All the rest looked pretty good. Took these to local NAPA machine shop mechanic - he said he wouldn't think the wear would be enough to cause a knock - "keep looking" he said!
Checked play (front to back) in crank - none apparent.
The sound is a definite knock, not a tick (tappet) sound. Tried to locate with stethescope - sounds more pronounced at lower front.
Timing chain looks tight from what I can see under the cover from behind.
Harmonic balancer (?) appears OK - no separation.
The jeep would normally go back with my son to school - 550 miles to get there. Any ideas or suggestions would be great.
(I have a .wav file but can't post attachments)
89 limited 4.0 AW4 242; 120k miles
Knocking at idle and higher rpm; changes with rpm.
Knocking at cold and normal temp.
Knocking under load and coasting.
Noticed some noise around thanksgiving when the jeep came home for break from school (it was 3 quarts low on oil!).
Oil pressure seems ok. around 37 at normal temp.
Tried the flexplate test - load the transmission/power brake. Still knocking.
Pulled the pan (just did rear main last weekend) and pulled front two mains - looked ok (so did the rear last week).
Pulled all rod bearing inserts. Top of #1 was worn to copper at top of cap, bottom insert on #1 had slight wear. All the rest looked pretty good. Took these to local NAPA machine shop mechanic - he said he wouldn't think the wear would be enough to cause a knock - "keep looking" he said!
Checked play (front to back) in crank - none apparent.
The sound is a definite knock, not a tick (tappet) sound. Tried to locate with stethescope - sounds more pronounced at lower front.
Timing chain looks tight from what I can see under the cover from behind.
Harmonic balancer (?) appears OK - no separation.
The jeep would normally go back with my son to school - 550 miles to get there. Any ideas or suggestions would be great.
(I have a .wav file but can't post attachments)