Last 2 weeks I noticed when outside temperature 80+ and AC on truck over heats. Truck does not overheat when AC is not on. recently replaced water pump and new coolant.

Noticed this morning the electric fan was not on when the AC was running (as test). Outside temperature is around 60 degree now. I read here that outside temp need to be higher than 80 before the electric fan kicks on.

Is the electric fan always on when AC is on?
How to test the electric fan. I can certainly connect directly with battery to see if the fan is ok.

Will appreciate anyones help

 

What temperature are you considering overheated? What are you using to read the temperature?

Temps might rise a touch with AC on. Engine is doing more work driving the compressor.

Tell me you are not using the dash gauge to monitor temperature.

 

Yes I am using the Dash Temperature gauge. Goes close to red. what other method can you check? I can't take risk driving if overheating. I have a temperate measure probe on my multi-meter.

Thanks

 

You'll need an OBDII reader. There are smartphone apps and dedicated code reading devices such as the Ultragauge. These devices read the engine computers and report any trouble codes and they tell you real time operating parameters like temperature.

You'll need more information to diagnose the problem which the reader may help with.

Broadly cooling system issues and or head gasket issues can cause overheating. The dash gauge is an idiot light that only moves off center above 250 degrees.

The electric fan comes on at 212 i believe whether or not the AC is on. You will need to know your actual temp to see if the fan is working properly...

If you are just now noticing this only when the AC is on you may be catching something early, like a non op fan if you are lucky, so don't be driving it until it is diagnosed and repaired.

 

Thanks I will be careful not to turn on the AC. well this just started and only when the AC is on. That tells me the cooling system is ok under normal condition. I do have Torque and OBDII that connect with BT.

Question to anyone here. is AC fan supposed to come on when AC is on?

 

sorry, i added that info in an edit while you were replying.

 

If the fan isn't running with the compressor running, I would check the electric fan, and the fuse for that fan. If the fuse is blown, there's a good chance that the fan motor has seized.

I don't recall the p/n off hand, but there's a Toyota fan that's an acceptable replacement that costs a fraction of the Land Rover part.

 

Thanks Dave. I am just getting all the information together before I dive in. 1st thing I want to do is test the fan to see if fan is ok. then move up from there.

 

Is this the first time the engine has gotten close to the red zone? Here's why folks got jumpy - the temperature gauge on your dash is not accurate. Basically it has three modes - cold, operating range (+ or minus 25 degrees) and overheated. The gauge doesn't tell you the engine is overheatING, but rather it only jumps AFTER the engine has overheatED. Once it goes past the mid-zone it is too late.

If it was once and only brief, the head-gaskets may be ok. Otherwise you might have warped them or compromised the gasket. At this point, all you can do is monitor things for a while and see.

You can get an OBDII scanner for about $70-90 at Harbor Freight, plug it in to your truck and monitor temps real-time. You really need to know what temps you are running.

Definitely check the fan fuses and a new fan clutch is pretty cheap at Auto Zone. I just replaced mine not long ago.

Definitely watch those temps and get something that gives you temp numbers.

You might already know all this stuff, but wanted to share. Example: Temps can get up to 225F which is still too hot, but the dash gauge still looks "normal".

 

Jamie (assuming this is your name)

Wylie, TX? you got some good lakes there.
I have all the tools in the world. I was trying to see if anyone had the similar experience. Overheats only when AC is on and hot outside. do we know if there are any fuses for the fan circuit?

Thanks