4.0 Overheating above 40mph - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 07-06-2011, 11:36 AM   #1
Jeeper
 
Join Date: Jul 2010
Posts: 16
4.0 Overheating above 40mph

So I read a couple threads on this but still need to ask the question (gotta love noobies!) I have a 93 YJ, 4.0L and setup is stock gears/axles and 33's. About a month ago, it overheated going over a steep bridge pulling a trailer (small one). Only way to cool it down was to stay under 35/40mph. So I replaced the thermostat and housing. Also took it to get the radiator flushed and filled (I know, garden hose.....what can I say, I was being lazy). So since then I have had it out a few times, no problems hwys speeds and all. Even pulled the trailer again.

Well this past Sat I took it out for a run and after about 20 min at hwy speeds it started climbing over the normal 200/210 range. It was a slow climb but it was going up. I got off the hwy and slowed to 35/40mph and it cooled down.

When going back home, hit the hwy again and tried staying in 4th thinking maybe not enough RPMs in od since it's not geared. Nope, started heating up again so got off the hwy and slowed to the 35/40 range. Again it cooled down. It doesn't seem to have any issues as long as I stay under 40.

Soooooooooo...... what could it be? Tstat is new, housing is new. it was fine for a while but now issue is back (that is the part tripping me up).

I read it could be a fan clutch. I also read it could be a loose intake manifold. Temp sensor too. Checked intake/exhaust and they are tight. No visible leaks of any sort either. I am guessing the temp sensor was right cuase it was pretty hot under the hood. Not sure how to check the fan clutch. When the engine is off, I can rotate the fan and feel some resistance. When running, it is spinning (of course).

So any words of wisdom on this? Any help ya'll can provide would be great.

itlyngld is offline   Quote Quick Reply
Old 07-06-2011, 11:41 AM   #2
Jeeper
 
banks316's Avatar
 
Join Date: Apr 2011
Location: Longview, WA
Posts: 2,089
Is it just your gauge saying your over heating? Or is it both gauge and your getting steam/water boiling out?

__________________
93 YJ I6 5spd
My YJ Build +1.5 inch SOA ,37 12.50 15R Swamper M16's, 5.22:1/2.97:1 Stak Tcase with 92 Crawl Ratio--------SOLD...
banks316 is offline   Quote Quick Reply
Old 07-06-2011, 11:48 AM   #3
Jeeper
 
Join Date: Jul 2010
Posts: 16
Well I haven't seen steam yet but I did look at the overflow and it was full so I am guessing if I let it keep going up I would have seen steam. Good point though. I had the same thought of maybe it is just a bad sending unit or sensor or something. Don't know. Since the overflow was full and looked like some fluid got pushed out of the cap I am guessing it got pretty hot.
itlyngld is offline   Quote Quick Reply
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Overheating in Ohio cdparmer440 WF New Member Check In 1 02-18-2011 09:05 PM
Overheating Issues elijah.caine TJ Tech Forum 22 09-13-2010 05:10 AM
Need help. Rear axle overheating iix23 TJ Tech Forum 36 06-05-2010 08:27 PM
Litt's Overheating Hypothesis slf41002 TJ Tech Forum 12 10-02-2008 07:32 AM
Need help! engine overheating 02blacktj TJ Tech Forum 15 08-03-2007 11:05 PM



» Featured Product

All times are GMT -5. The time now is 08:46 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC