Still Running Hot..... - JeepForum.com

 
LinkBack Thread Tools
post #1 of 7 Old 08-30-2013, 12:33 PM Thread Starter
TrucksBootsNGun
Registered User
1988 MJ Comanche 
 
Join Date: Aug 2013
Location: Flagstaff
Posts: 46
Still Running Hot.....

Ok so I am still running hot in my '88 MJ 4.0L even after I swapped the radiator for the '92 open design (also swapped heater control valve and made an overflow tank). While I was in there I decided to swap out the thermometer for a new 160* one instead of the stock 195*. I also replaced the water pump and I am still running the pure distilled water from when we tested it for leaks. At highway speeds the thermometer says exactly on 160* but when you are wheeling at lower speeds she runs at about 210* never got it much higher because it was a short trail but i feel like its gonna keep going up. I am slightly worried because living in Flagstaff we need antifreeze which means less water. Did I miss anything when I swapped everything over?

TrucksBootsNGun is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 08-31-2013, 08:56 PM
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott
Posts: 11,104
210 is normal. A 195* THERMOSTAT should work fine. 160* is too low. You'll be freezing your *** off in the mornings this winter in Flagstaff. The fan clutch is most likely needing replaced.

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
cruiser54 is offline  
post #3 of 7 Old 09-03-2013, 07:24 PM Thread Starter
TrucksBootsNGun
Registered User
1988 MJ Comanche 
 
Join Date: Aug 2013
Location: Flagstaff
Posts: 46
Quote:
Originally Posted by cruiser54 View Post
210 is normal. A 195* THERMOSTAT should work fine. 160* is too low. You'll be freezing your *** off in the mornings this winter in Flagstaff. The fan clutch is most likely needing replaced.
The reason this I went with the 160* is I am from SD just going to college in Flagstaff. That 195* was useless in San Diego stop and go traffic. When you say clutch fan you are not referring to the electric fan that kicks on when the A/C does are you? That fan won't kick on because the A/C compressor is bad (I think its the compressor because when the system was charged and the A/C was on there was freon coming through the vents according to a sniffer do-hicky my dad has. there is a big enough leak that it was completely unpressurized in less than 5 mins) The A/C has this weird fail-safe that if the system is out of freon it wont engage the A/C clutch.
TrucksBootsNGun is offline  
post #4 of 7 Old 09-03-2013, 08:14 PM
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott
Posts: 11,104
You'll freeze your balls off in flag with a 160 stat this winter.

https://www.google.com/search?q=fan+...w=1680&bih=806

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
cruiser54 is offline  
post #5 of 7 Old 09-08-2013, 06:48 PM
wgirvine
Registered User
1992 XJ Cherokee 
 
Join Date: Oct 2007
Location: Rosamond, CA
Posts: 652
Three things:
The thermostat regulates the MINIMUM operating temp of the engine. It does not regulate the MAXIMUM temp. When a 160 degree t-stat is open, it flows the same amount of coolant as a 195 degree t-stat when it's open. The max temp of the engine is controlled by the size and efficiency of the radiator. Forcing an engine to run cooler than it was designed to will cause poor gas mileage. And other problems...

The mechanical fan has a viscous coupling, commonly called a fan clutch. It allows the fan to slip a lot (run slowly) when the air coming thru the radiator is cool. It engages and speeds up the fan when the air coming thru the radiator is hot. Overheating at low speeds (low air flow conditions) such as stop-and-go traffic is usually caused by a bad fan clutch. Replace. They don't last forever, anyway. Make sure you get the one with the funny little flat coil spring in the front.

And the electric fan comes when (1) the AC is turned on, OR (2) when the coolant gets hot... around 215, I think. You need to get that fan fixed also.

The road goes on forever, the party never ends....
wgirvine is offline  
post #6 of 7 Old 09-08-2013, 07:31 PM
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott
Posts: 11,104
Quote:
Originally Posted by wgirvine View Post
Three things:
The thermostat regulates the MINIMUM operating temp of the engine. It does not regulate the MAXIMUM temp. When a 160 degree t-stat is open, it flows the same amount of coolant as a 195 degree t-stat when it's open. The max temp of the engine is controlled by the size and efficiency of the radiator. Forcing an engine to run cooler than it was designed to will cause poor gas mileage. And other problems...

The mechanical fan has a viscous coupling, commonly called a fan clutch. It allows the fan to slip a lot (run slowly) when the air coming thru the radiator is cool. It engages and speeds up the fan when the air coming thru the radiator is hot. Overheating at low speeds (low air flow conditions) such as stop-and-go traffic is usually caused by a bad fan clutch. Replace. They don't last forever, anyway. Make sure you get the one with the funny little flat coil spring in the front.

And the electric fan comes when (1) the AC is turned on, OR (2) when the coolant gets hot... around 215, I think. You need to get that fan fixed also.
208* or 218*.

If you own a Renix Jeep, you'll want to check this out.

An index to over 30 write-ups can be found in the link below

www.cruiser54.com

My Jeep Technical Photos

http://www.cherokeeforum.com/g/album/1725214
cruiser54 is offline  
post #7 of 7 Old 09-13-2013, 04:12 PM
carnuck
Registered User
1984 J-Series Truck 
 
Join Date: Nov 2004
Posts: 3,211
195 or 180 stat, 50% antifreeze, check the waterpump blades (mine were chewed up by the spring from the bottom hose!), loosen the temp sender to burp the head "air bubble" and add a bottle of Water Wetter from Redline (or similar like Purple Ice or Amsoil cooling booster)

"Usually found in a Jeep near Reiter, WA"
FOR SALE STUFF
http://tinyurl.com/jimsclads

'81 Eagle wagon with upgrades $2500
'87 Comanche shortbox 4.0/AW4/NP242 on 33" tires $3500
carnuck is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



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 On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome