Knocking @ Start Up
JK Jedi Master
Joined: Feb 2008
Posts: 12,904
Likes: 185
From: Maine
Cold weather is a contributing factor, but not the cause.
A ticking valve train on start-up is more common. It's not good, but doesn't really hurt anything in the short time it occurs.
Piston slap occurs on some engines on start-up, but I don't know of any JKs with piston slap. It is very common on Subarus. It doesn't appear to be harmful, though. I've heard it from friends' Subarus for years. They are still running well.
A knocking in the bottom end on start-up is a much worse thing. It indicates impending bearing failure.
A ticking valve train on start-up is more common. It's not good, but doesn't really hurt anything in the short time it occurs.
Piston slap occurs on some engines on start-up, but I don't know of any JKs with piston slap. It is very common on Subarus. It doesn't appear to be harmful, though. I've heard it from friends' Subarus for years. They are still running well.
A knocking in the bottom end on start-up is a much worse thing. It indicates impending bearing failure.
Last edited by ronjenx; Dec 3, 2010 at 06:17 AM.
Thread Starter
JK Enthusiast
Joined: May 2009
Posts: 121
Likes: 0
From: Hunstville, AL
Cold weather is a contributing factor, but not the cause.
A ticking valve train on start-up is more common. It's not good, but doesn't really hurt anything in the short time it occurs.
Piston slap occurs on some engines on start-up, but I don't know of any JKs with piston slap. It is very common on Subarus. It doesn't appear to be harmful, though. I've heard it from friends' Subarus for years. They are still running well.
A knocking in the bottom end on start-up is a much worse thing. It indicates impending bearing failure.
A ticking valve train on start-up is more common. It's not good, but doesn't really hurt anything in the short time it occurs.
Piston slap occurs on some engines on start-up, but I don't know of any JKs with piston slap. It is very common on Subarus. It doesn't appear to be harmful, though. I've heard it from friends' Subarus for years. They are still running well.
A knocking in the bottom end on start-up is a much worse thing. It indicates impending bearing failure.
I guess there could be several kinds of noises that people are hearing: ticks, knocks, rattles. I know somebody who said theirs' sounded like a diesel when it cranked up this morning ..........
I know when my bearing went south, I got less than a week's worth of start-up knock before it finally self-destructed. It wasn't anything major at start up, but when it went, it sure did make a racket!
Anthony
JK Super Freak
Joined: Oct 2010
Posts: 1,255
Likes: 1
From: clinton, ok
Mine has been sitting now for over 30 days since it last ran and went out and started it this morning and it was 28 degrees last night. I run mobil1 5w30 and it didn't tick at all. I bought it used and I had heard that sound you refer to before I switched to this oil, since the switch I have never heard it again.