Overheating at low speed (new coolant, new tstat, new fan clutch)

[Jamescad04]

well the signal runs from there to the ecu then to your scangauge. So if there is an error that the cts is sending to the ecu then the scangauge is going to read that error as well.

 

[winkosmosis]

I don't think there's anything wrong with the sensor. At 45mph on flat ground it reads about 210F which is what you'd expect

 

[Jamescad04]

Its a $14 sensor for having this issue for 3 weeks now id throw $14 bux at it and see if it works. Have you checked cleaned out the fins? What about check for a clog? I disconnected my radiator and hooked a hose up to it and flushed it, had a big chunk of stop leak that came out. May want to give that a try, you should have a drain plug on the passenger side at the bottom just unscrew it and run a hose to a bucket to get rid of the coolant.

 

[winkosmosis]

Can't do that, lease forbids it. The landlady just doesn't want fluids getting on the ground. So flushing would require finding a shop to do it, and changing the sensor would require draining and filling which is at least an hour of labor.

 

[Jamescad04]

You don't have to drain to change the sensor its right on top of the engine in the thermostat housing. Just do it when the engine is cool and you shouldn't have any problems, or leaks. Just make sure to use some teflon tape around the sensor.

 

[winkosmosis]

Ah OK. That might be worth doing

 

[winkosmosis]

After a few weeks, I've realized that the new fan actually does help.

The key is that it seems to keep temperatures from rising all the way to 240. I left it off the other day and did some stop and go driving in a tourist town, and temp went all the way up to 264 and the "check gauges" light came on. That never happens with the fan on, even though it will hit 230.

 

[Digger87xj]

I too Installed the ten inch fan, but on the passenger side, in front of the mechanical fan. I also removed the ZJ fan clutch as it just robbed too much HP... I need all I can get at altitude!.. and reinstalled the factory XJ fan clutch.

It lowered my temps considerably;
Before: 240*+ on a hard uphill climb @ 90* ambient w/o A/C on. Running the A/C would surely cause boil-over. I had to shut it off and switch to high fan on heat and windows down to keep the temps down to 240....

After: 220* with A/C on maxium, under the same conditions. Cools off in a flash after the climb, too.

Amazing!


Finer Details:

Both E-fans come on at the same time, either by the ECM, or by dash switch.

I wired in 2 new relays; one for each fan, fed direct from the battery with 10g wire, and controlled by the original fan relay. a diode isolates the oem relay from the dash switch.

The ECM triggers the oem fan relay, the oem relay triggers the new relays and they turn on the fans. they operate fully automatic, OEM style. cycling with the A/C clutch, etc etc...

The manual on switch allows for 100% on time, and no cycling with the A/C clutch.

a power feed switch to the manual on switch allows for fan shut-down at key-off or fans on with key-off.

So far So good!