Another "radiator fan not working" thread.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
05 Liberty 3.7L, auto. Now that that's out of the way, I'll get right to it.

The ONLY way I can get the radiator fan to turn on is by disconnecting the CTS. Wife got home tonight, parked in the driveway, and noticed the temp gauge was almost in the red. Upper rad hose boiling, lower rad hose ice cold. Has nice hot heat, and she says she can smell antifreeze.

I've already tried turning on the A/C. That does NOT kick the rad fan on. I swapped out the rad fan "high" relay and unplugged the CTS. This did get the fan to kick in but wow. I totally shouldn't have to do that.

Oh, and the thermostat is brand new, although I had some trouble installing it. The gasket did not want to seem to seat, but I eventually smooshed it in there and bolted the thermostat housing to the block. I've also read that the thermostat needs to be oriented correctly. I'm pretty sure I have it right. The bleeder on the thermostat needs to be at 12 o'clock, correct?

Bottom line: I think the reason for the near overheating and boiling rad hose is because the fan won't kick on.

Thoughts?
 

uss2defiant

Full Access Member
Joined
Jun 25, 2014
Messages
3,597
Reaction score
152
Location
Tucson, Arizona
Yes, the thermostat air bleeder hole would be at the 12 o'clock position with the spring side facing the engine.

Here's the condition to have the fan kick on.

From the FSM:
"Vehicles Equipped with AC: In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when air conditioning is selected and coolant temperature is above 95° C ( 203° F), or , air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when air conditioning is selected and coolant temperature is below 92° C(198° F), or air conditioning is selected and battery temperature is below 38° C (100° F)"

some membes have a switch to provide 12volt to the radiator fan to manually cotrol it.
 
Last edited:

KJowner

Full Access Member
Joined
Oct 20, 2022
Messages
911
Reaction score
534
Location
Uk
Stone cold radiator and boiling top hose would suggest a lack of water flow, at speed the fan isn't needed, ram air should provide plenty of cooling.
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
Stone cold radiator and boiling top hose would suggest a lack of water flow, at speed the fan isn't needed, ram air should provide plenty of cooling.
Very well. The water pump has, according to the previous owner, already been replaced.

I find any blockage hard to believe because I flushed everything while the engine was out.

Hmmm......
 

uss2defiant

Full Access Member
Joined
Jun 25, 2014
Messages
3,597
Reaction score
152
Location
Tucson, Arizona
OEM thermostat gasket has a registration key.

Sounds like could be a bad thermostat or bad WP or even both.

You can run without a thermostat, you'll need the gasket in the housing. it it still overheats then you know the WP is bad.
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
OEM thermostat gasket has a registration key.

Sounds like could be a bad thermostat or bad WP or even both.

You can run without a thermostat, you'll need the gasket in the housing. it it still overheats then you know the WP is bad.

I can try that first thing in the AM. I'll report back what happens.
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
OEM thermostat gasket has a registration key.

Sounds like could be a bad thermostat or bad WP or even both.

You can run without a thermostat, you'll need the gasket in the housing. it it still overheats then you know the WP is bad.

Sorry for the double post. In re-reading your post, I'm wondering what the registration key is. Is that the little metal bobbly thing in the thermostat or is it an actual number/icon?
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
The new thermostat from the dealer did come with a gasket, but the gasket does NOT have that registration key - although I can see where it's supposed to go in the thermostat housing.

So, here's the results so far....

I'm pretty sure this is in backwards:

You must be registered for see images attach


I'm not even going to run it without a thermostat. I'm going to put my new Mopar thermostat in and see what happens. Tell me this is installed correctly (with correct valve orientation).

You must be registered for see images attach


The reason I have the valve at the 1:00 position is because there is clearly a cutout in the thermostat housing for it to sit in.


Before I bolt this down and fill it, I'm just making sure this is all correct.
 

KJowner

Full Access Member
Joined
Oct 20, 2022
Messages
911
Reaction score
534
Location
Uk
The spring side goes into the engine, that's the wax cartridge that makes it move when it gets hot.
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
Ok! Bolted in the thermostat and filled the coolant... bled the system.... No overheating this time :) Hot heat - that's good.

Upper rad hose still gets pretty hot but no boiling this time. Lower rad hose is now heating up. All good signs.

The rad fan FINALLY kicked in by itself! The temp gauge never went past 1/2. More good signs.

Still smelling antifreeze, and still seeing some white smoke (which, smells like antifreeze) out of the exhaust.

I also did a compression check while the engine was cold. 185 - 195 psi across the board. That's good news, as well.

Now the bad. I did a spirited test drive. Nothing abnormal until I pulled in the driveway to check everything. Found this.

xc_hide_links_from_guests_guests_error_hide_media

Radiator has a pinhole I guess. The perspective of the video is, I'm standing in front of the left headlight, bending over the front grill, with the camera pointed toward the radiator and zoomed in just above and to the left of the upper radiator hose.
 

uss2defiant

Full Access Member
Joined
Jun 25, 2014
Messages
3,597
Reaction score
152
Location
Tucson, Arizona
you could patch w/ JB weld but it'll eventually get worse.
any time i mess with cooling system, i like to have the loaner tool kit to pressurize the system.
Radiator replacement is pretty easy.
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
you could patch w/ JB weld but it'll eventually get worse.
any time i mess with cooling system, i like to have the loaner tool kit to pressurize the system.
Radiator replacement is pretty easy.

I do have that tool to pressurized the system. I used it just the other day and everything seemed fine. That rad leak must have JUST happened.
 

DeCaff2007

Full Access Member
Joined
Apr 26, 2011
Messages
88
Reaction score
29
Location
Hazleton
New radiator came in today (a day ahead of schedule). I took my sweet time installing it. Could've had it done in less than an hour, but I had no motivation. It got done, though.

Everything seems fine now, EXCEPT for the white smoke still coming from the exhaust. So, I bought one of these:


The results:


You must be registered for see images attach


That's a fail. Eventually, I'll start killing spark to each cylinder to pinpoint where the exhaust is leaking into the coolant. It's just not a big enough issue right now.

Anyway, for right now, this is one more Jeep that's back on the road!
 
Top