Replaced rad now overheating
#1
Newbie
Thread Starter
Join Date: May 2013
Location: Mars, PA.
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1998
Model: Cherokee
Engine: 4.0
Replaced rad now overheating
I have a 1998 xj 4.0 that had a leaking rad but never overheated, always stayed in the 190's. The other day I changed the rad with a brand new one and yesterday the temp gauge was reading 210-215 on the way home and I noticed that the electric fan doesn't seem to kick on. I hard wired the fan to the battery and it works. Any ideas? Could it be a temp sending unit? Thanks
#3
Senior Member
210 to 215 isn't overheating, 240 to 245 or more is. And everything I've ever heard is the XJ is supposed to operate right at 210, that's why the gauge is top dead center at 210, so its easier to read. Mine has NEVER varied from 210 unless it goes a HAIR above when crawling in super hot traffic, towing or before dumping the coolant for new stuff. The electric fan only kicks on with some settings, so its quite possible it wasn't supposed to kick on.
Last edited by bigvig; 03-15-2014 at 02:13 PM.
#4
Senior Member
Join Date: Dec 2008
Location: Gloucester Virginia
Posts: 584
Likes: 0
Received 2 Likes
on
2 Posts
Year: 2001
Model: Cherokee
Engine: 4.0 I6
Electric fan doesn't kick on till about 218, or if you have the A/C on. One of the best mods I've done was a override switch so I could turn the fan on whenever I wanted.
#6
CF Veteran
Join Date: Nov 2010
Location: In the middle of Minnesota!
Posts: 5,804
Received 99 Likes
on
88 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
First step to any suspected overheating is to verify. Don't want to be chasing a ghost.
Get an infrared point and shoot thermometer (inexpensive and everybody should have one) and point it directly at the thermostat housing of a hot engine. Then you'll know for sure.
If what you measure differs from what you are seeing on the dash gauge, start with replacing the coolant temperature sensor, located on the thermostat housing of your 98XJ.
Electric fan should kick in at around 218 degrees, AND it will cycle when you are in defrost or air conditioning mode.
Get an infrared point and shoot thermometer (inexpensive and everybody should have one) and point it directly at the thermostat housing of a hot engine. Then you'll know for sure.
If what you measure differs from what you are seeing on the dash gauge, start with replacing the coolant temperature sensor, located on the thermostat housing of your 98XJ.
Electric fan should kick in at around 218 degrees, AND it will cycle when you are in defrost or air conditioning mode.
Trending Topics
#8
Newbie
Thread Starter
Join Date: May 2013
Location: Mars, PA.
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1998
Model: Cherokee
Engine: 4.0
I realize that a lot of jeeps run 210-215 but mine always ran 190-195 so when I change the rad and nothing else and it jumps up 10 degrees or more when in traffic then I start to wonder what up?
#10
CF Veteran
Join Date: Nov 2009
Location: The Republic of TEXAS
Posts: 8,172
Likes: 0
Received 14 Likes
on
14 Posts
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Backtrack/review your repairs and do what tjwalker and salad said.
#11
Moderator of Jeeps
Join Date: Jul 2011
Location: Frederick, MD from Cleveland, OH
Posts: 21,029
Likes: 0
Received 3 Likes
on
3 Posts
Year: 1993 YJ Wrangler
Engine: 4.0 I6
Burp your cooling system. Park it with the front end elecated and run it with the rad cap open (16lb cap), and fill the rad until the fluid stops bubbling. That's the easiest way. As several people have said, 210 isn't overheating. you may have an air bubble blocking some tubes, though.
#12
CF Veteran
Join Date: Nov 2009
Location: The Republic of TEXAS
Posts: 8,172
Likes: 0
Received 14 Likes
on
14 Posts
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Maybe the OP should have said "running hotter" instead of "overheating". The bottom line is, for some reason his usual temp is displaying 15-25 degrees higher after replacing the rad. Hopefully the OP has checked the coolant level in both the rad and bottle after several heat/cool cycles. The rad should be full to the top hot or cold. The coolant level in the bottle should rise a little (hot motor) and fall a little (cold motor).