91 Jeep cherokee problem Help! - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Engines & Drivetrain > 91 Jeep cherokee problem Help!

Dan's Old as Dirt Birthday Sale!Premium LED Lighting by VISION X, Proudly sold at ROCKRIDGGEARSHADE Pocket Tops in stock and available at ROCKRIDGE

Reply
Unread 12-31-2013, 06:40 AM   #1
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
91 Jeep cherokee problem Help!

OK the engine in my 91 Cherokee ticks/knocks after i drive it for about 30min(engine at normal temp), i turn it off let it sit for about 10 minutes then thats when it does it when i start it back up. I have to let it sit for about 1hour for it not to do the knocking non stop but it does it for 2 seconds after its been sitting for awhile and at that point the engine is cool. O and the engine does not lose any HP the check engine has never come on. So any ideas what it could be? Lifters, rockers,pushrod. Any Help will be apperated.

91Cherokee7 is offline   Reply With Quote
Unread 12-31-2013, 12:02 PM   #2
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,918
Hi and welcome.
Sorry this had to be your first post.
Can you tell where the knock is coming from? Top or bottom of engine. You can use a piece of hose to help narrow it down.
How's the oil pressure? Does the knock increase tempo with rpms?
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote
Unread 12-31-2013, 05:20 PM   #3
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
I say top part but i could be wrong its hard telling without taking off the valve cover, the noise is loud and slightly gets louder when i increase rpms and the oil pressure is around 35-40 sometimes 45. Its normal for it.O i forgot to say that now since its winter and cold 25 degrees it does not do it as much but then again the engine does not get as warm in the cold.
91Cherokee7 is offline   Reply With Quote
Unread 01-01-2014, 05:31 PM   #4
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,918
If the engines not warming then I would think u have the wrong or no thermostat.
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote
Unread 01-02-2014, 05:41 AM   #5
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
I replaced the thermostat about 2 years ago. I may just take the valve cover this friday and check the lifters. I just hope its nothing mayor because i want to keep the 4.0 engine as original as possible. I want to see how long it last's. I keep everything about my Jeep update on here and i might make a video when i take off the valve cover.
91Cherokee7 is offline   Reply With Quote
Unread 01-02-2014, 11:17 AM   #6
uberxj92
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2012
Location: umatilla, florida
Posts: 1,918
Use cardboard to make splash guards. Or you'll have a mess.
__________________
http://www.jeepforum.com/forum/f177/92-xj-sadness-2075657/index2.html
uberxj92 is offline   Reply With Quote
Unread 01-08-2014, 06:49 AM   #7
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
Its been really cold and snowing so i have not been able to take the valve cover off yet. I hope to do it soon.
91Cherokee7 is offline   Reply With Quote
Unread 01-09-2014, 04:39 PM   #8
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 9,811
What brand oil filter are you using?
__________________
Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
Refresh*Connections*Before*Replacing*Components
cruiser54 is offline   Reply With Quote
Unread 01-10-2014, 07:45 PM   #9
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,040
Quote:
Originally Posted by 91Cherokee7 View Post
OK the engine in my 91 Cherokee ticks/knocks after i drive it for about 30min(engine at normal temp), i turn it off let it sit for about 10 minutes then thats when it does it when i start it back up. I have to let it sit for about 1hour for it not to do the knocking non stop but it does it for 2 seconds after its been sitting for awhile and at that point the engine is cool. O and the engine does not lose any HP the check engine has never come on. So any ideas what it could be? Lifters, rockers,pushrod. Any Help will be apperated.
What is your oil pressure when the engine is cold and at hot idle? Metallic noises usually means too much space between parts. or no oil pressure for a number off reasons. One being blockage but then the noise would be there when cold also. The other....too much space.
__________________
Chicks dig me.....Fish fear me

Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 01-11-2014, 03:30 PM   #10
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
I have been using STP oil filters but i may switch to NAPA GOLD.............. Engine oil pressure when cold is 32 (ish) When hot 40 to 45.
91Cherokee7 is offline   Reply With Quote
Unread 01-11-2014, 04:41 PM   #11
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 9,811
Quote:
Originally Posted by 91Cherokee7 View Post
I have been using STP oil filters but i may switch to NAPA GOLD.............. Engine oil pressure when cold is 32 (ish) When hot 40 to 45.
STP filters are absolute ****.
__________________
Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
Refresh*Connections*Before*Replacing*Components
cruiser54 is offline   Reply With Quote
Unread 01-11-2014, 05:06 PM   #12
laybackman
Bikini Bridge Inspector
 
laybackman's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2002
Location: Massachusetts
Posts: 6,040
Quote:
Originally Posted by 91Cherokee7 View Post
I have been using STP oil filters but i may switch to NAPA GOLD.............. Engine oil pressure when cold is 32 (ish) When hot 40 to 45.
Usually....cold oil pressure is higher than hot oil pressure. That is odd.

What weight oil do you use? I use 10W-30 Mobile 1 Full Synthetic oil. I change it every 6,000 miles. I also use a Napa filter. The one for the 4.0 is a Napa 21085.... BUT..... I use a Napa 21515 which is actually a Ford 5.0 filter which has ~35% more filter volume. Has the same threads and diameter but is ~1 1/2" longer.

Oil pressure is not as important as oil flow. Oil pressure is a measurement of resistance not flow.

All oils thin to 10 weight when the engine is at operating temperature with some exceptions.

How does the oil flow when it is cold is most important. Even at air temperatures of 75F, cold regular oil is as thick as molasses.

Years ago a trick was done to clean up an engine oil system and remove small engine 'noises' like sticky lifters. This can be dangerous if not done properly.

One would add a quart of kerosene to the base pan oil. Then the engine would get fired up and left running AT IDLE for four or five minutes. LISTEN very carefully. Any increase in engine noises means shut it off. The biggest clogger in an engines is detergent mixed with oil/crud particulates. This basically is an engine 'physic'. Shut of engine wait for an hour and drain well and let it drain until nothing is coming out. Fill it with clean oil and a filter and see what that does for noises.

Spec this out;

http://www.youtube.com/watch?feature...&v=PDERMk_cYlo
__________________
Chicks dig me.....Fish fear me

Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

"If we cannot afford to take care of Veterans, then we should stop making them."
David C. Wilker Jr. USAF (RET)
laybackman is offline   Reply With Quote
Unread 01-11-2014, 06:05 PM   #13
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
Quote:
Originally Posted by cruiser54 View Post
STP filters are absolute ****.
I know. After I changed the STP filter on my moms car I will never again use them.
91Cherokee7 is offline   Reply With Quote
Unread 01-11-2014, 06:20 PM   #14
91Cherokee7
Registered User
1991 XJ Cherokee 
 
Join Date: Dec 2013
Location: Streator, Illinois
Posts: 13
Quote:
Originally Posted by laybackman View Post
Usually....cold oil pressure is higher than hot oil pressure. That is odd.

What weight oil do you use? I use 10W-30 Mobile 1 Full Synthetic oil. I change it every 6,000 miles. I also use a Napa filter. The one for the 4.0 is a Napa 21085.... BUT..... I use a Napa 21515 which is actually a Ford 5.0 filter which has ~35% more filter volume. Has the same threads and diameter but is ~1 1/2" longer.

Oil pressure is not as important as oil flow. Oil pressure is a measurement of resistance not flow.

All oils thin to 10 weight when the engine is at operating temperature with some exceptions.

How does the oil flow when it is cold is most important. Even at air temperatures of 75F, cold regular oil is as thick as molasses.

Years ago a trick was done to clean up an engine oil system and remove small engine 'noises' like sticky lifters. This can be dangerous if not done properly.

One would add a quart of kerosene to the base pan oil. Then the engine would get fired up and left running AT IDLE for four or five minutes. LISTEN very carefully. Any increase in engine noises means shut it off. The biggest clogger in an engines is detergent mixed with oil/crud particulates. This basically is an engine 'physic'. Shut of engine wait for an hour and drain well and let it drain until nothing is coming out. Fill it with clean oil and a filter and see what that does for noises.

Spec this out;

http://www.youtube.com/watch?feature...&v=PDERMk_cYlo


10w-30 Valvoline.. I may post a video up tomorrow 1-12-14 showing the oil pressure and maybe when I first start it up it might do the knocking should for a sec. I may also look into the kerosene trick (MAYBE). And that video showing the conventional oil when its -35 out is making me switch to Synthetic Oil.
91Cherokee7 is offline   Reply With Quote
Unread 01-11-2014, 06:23 PM   #15
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 9,811
So, does it tick on startup and then reduce and/or go away?

If so, shut it off immediately. wait a few seconds and restart it. Tick gone?
__________________
Quote:
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
Refresh*Connections*Before*Replacing*Components
cruiser54 is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.