A question for you 4.0 owners. - North American Grand Cherokee Association

Inglbrute · 04-01-2010, 08:49 PM

How noisy is your engine? Seafoam took care of the lifter noise, but jeeze this thing is a knocker. Everyone says it's normal, but... really?

I's a 93 GC with a 4.0. It has 230,000 miles and while it's cold, is is quiet as a kitten. But after 10 minutes or so, it has a pretty good knock. I absolutely hate it. Runs great tho.

mperk12000 · 04-01-2010, 10:02 PM

I have the same exact jeep as you, and there is no knock in mine, or noise whatsoever. And when I say same I mean 230k mile too!

Inglbrute · 04-02-2010, 12:08 AM

I have been around a few myself, although i have heard alot of exhaust leaks and some clicking valve trains, i don't remember hearing any knocks like mine either.

jeepinjosh · 04-02-2010, 05:08 AM

No knocking in my motor... actually not very noisy at all.

phantasmacy · 04-02-2010, 06:43 AM

I have a slight tick like a lifter but that's about it.

prymetime1 · 04-02-2010, 07:20 AM

throw some lucas oil treatment in there.. itll quiet it down some... 204k on my 96 and it sounds strong... my 93 knocked like a majama but ran like one too.

Inglbrute · 04-02-2010, 08:50 AM

Alright, so any ideas what would cause it to run quiet when cold and knock when hot? The sound doesn't change any when I undo the injectors one at a time and gets quieter when I rev it up. Freeking annoying..

Doctor W · 04-03-2010, 06:33 PM

....It could be your oil's thinning out as it gets hot........Change the oil unless it's fairly fresh, using 20W/50 OR add some Lucas Oil Additive.

country_boy454 · 04-03-2010, 06:43 PM

My 97 4.0 sounds like a freaking diesel when it is cold but quiets down after reaching op. temps. has ~210k and runs strong!

Inglbrute · 04-03-2010, 06:50 PM

Quote:

Originally Posted by Doctor W

....It could be your oil's thinning out as it gets hot........Change the oil unless it's fairly fresh, using 20W/50 OR add some Lucas Oil Additive.

I have tried that, my oil pressure is right about 33 or so when hot. I hate to admit it, but I am starting to think it's a wrist pin.

Hopefully it will last a while. Maybe I'll Slick50 it or something.

"My 97 4.0 sounds like a freaking diesel when it is cold but quiets down after reaching op. temps. has ~210k and runs strong! "

Mine is the opposite, it is quiet as new when cold, and a one cylinder diesel when it's hot.

04-01-2010, 08:49 PM	#1
Inglbrute Junior Member Grand Rookie Join Date: Apr 2010 Posts: 9	A question for you 4.0 owners. How noisy is your engine? Seafoam took care of the lifter noise, but jeeze this thing is a knocker. Everyone says it's normal, but... really? I's a 93 GC with a 4.0. It has 230,000 miles and while it's cold, is is quiet as a kitten. But after 10 minutes or so, it has a pretty good knock. I absolutely hate it. Runs great tho. __________________ 93 Grand Cherokee Laredo 4.0

04-01-2010, 10:02 PM	#2
mperk12000 Senior Member Grand Junkie Join Date: Jan 2010 Location: Springfield MO Posts: 287	I have the same exact jeep as you, and there is no knock in mine, or noise whatsoever. And when I say same I mean 230k mile too! __________________ -93ZJ 4.0 SOLD -01WJ 4.0 3" IRO lift, stock CA's, 16x8 Ion alloy wheels, 265-70/16.

04-02-2010, 12:08 AM	#3
Inglbrute Junior Member Grand Rookie Join Date: Apr 2010 Posts: 9	I have been around a few myself, although i have heard alot of exhaust leaks and some clicking valve trains, i don't remember hearing any knocks like mine either. __________________ 93 Grand Cherokee Laredo 4.0

04-02-2010, 05:08 AM	#4
jeepinjosh Junior Member Grand Rookie Join Date: Mar 2010 Posts: 13	No knocking in my motor... actually not very noisy at all. __________________ 1997 ZJ 4.0L Limited

04-02-2010, 08:50 AM	#7
Inglbrute Junior Member Grand Rookie Join Date: Apr 2010 Posts: 9	Alright, so any ideas what would cause it to run quiet when cold and knock when hot? The sound doesn't change any when I undo the injectors one at a time and gets quieter when I rev it up. Freeking annoying.. __________________ 93 Grand Cherokee Laredo 4.0

04-02-2010, 06:43 AM	#5
phantasmacy Junior Member Grand Rookie Join Date: Oct 2009 Location: Central PA Posts: 24	I have a slight tick like a lifter but that's about it.

04-02-2010, 07:20 AM	#6
prymetime1 Member Grand Rookie Join Date: Jul 2009 Location: NW new Jersey Posts: 56	throw some lucas oil treatment in there.. itll quiet it down some... 204k on my 96 and it sounds strong... my 93 knocked like a majama but ran like one too.

04-03-2010, 06:33 PM	#8
Doctor W Member Grand Rookie Join Date: Mar 2010 Location: Sydney and Cairns, Australia Posts: 64	Check this..... ....It could be your oil's thinning out as it gets hot........Change the oil unless it's fairly fresh, using 20W/50 OR add some Lucas Oil Additive.

04-03-2010, 06:43 PM	#9
country_boy454 Senior Member Grand Addict Join Date: Apr 2006 Location: "Da Range" Virginia, Minnesota Posts: 989	My 97 4.0 sounds like a freaking diesel when it is cold but quiets down after reaching op. temps. has ~210k and runs strong! __________________ 1996 ZJ Limited 5.2

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