91 LX 5.0 getting hot when a/c is running

[91lx14gt5.0s]

91 LX 5.0 getting hot when a/c is running. Even going down the road, it gets hot. Fan runs and radiator was replaced a couple of years ago. What’s the most common issues I should check first?

 

[fasterthangas]

What temps are you seeing? I assume you have an aftermarket gauge.

 

[91lx14gt5.0s]

What temps are you seeing? I assume you have an aftermarket gauge.

Everything is original. Only has 80k on it. Getting up to 230

 

[gkomo]

I just want to clarify the 'everything is original', but how do you know the temps are getting up to 230degrees? You are using an aftermarket gauge then?

 

[AeroCoupe]

Is the car missing the air dam and or side deflectors?

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Replace that broken, or missing 1987-1993 Mustang radiator air deflector with this direct replacement from DCR!

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https://lmr.com/item/LRS-8310B-K/5-0resto-mustang-frame-rail-air-deflectors-79-93

 

[Mustang5L5]

Is this mostly while at idle? Or while driving or both?

 

[Mindseye007]

91 LX 5.0 getting hot when a/c is running. Even going down the road, it gets hot. Fan runs and radiator was replaced a couple of years ago. What’s the most common issues I should check first?

What thermostat do you have might be stuck closed?.

 

[91lx14gt5.0s]

Yeah, I meant to reply back to everyone, but my mom’s on chemo and it’s been a trying week. I’m going to change the thermostat. Also, it has only the one deflector, but everything I read, the LX only had the one piece, the gts had to have the others because of the ground effects.

 

[91lx14gt5.0s]

Also, my temp gauge goes from 130 - 270 with 5 increment lines between and a small red line at 270. It is original

 

[91lx14gt5.0s]

Is this mostly while at idle? Or while driving or both?

Is this mostly while at idle? Or while driving or both?

Both when it’s really hot outside but pretty fast at idle. Cut ac off and cools down pretty quickly while driving

 

[91lx14gt5.0s]

I just want to clarify the 'everything is original', but how do you know the temps are getting up to 230degrees? You are using an aftermarket gauge then?

The gauge goes from 130 to 270. Red line at 270 and 5 graduated increments between. The only things that are not original are the parts I changed myself, like the radiator and upgraded alternator

 

[91lx14gt5.0s]

The gauge goes from 130 to 270. Red line at 270 and 5 graduated increments between. The only things that are not original are the parts I changed myself, like the radiator and upgraded alternator

The gauge goes from 130 to 270. Red line at 270 and 5 graduated increments between. The only things that are not original are the parts I changed myself, like the radiator and upgraded alternator

 

[Mustang5L5]

SO what's the state of the cooling system? I assume stock?

WIth engine off, grab the cooling fan and try to spin it. How much resistance do you have? A decent amount or does it almost freewheel?

 

[fasterthangas]

The factory cooling gauges are notoriously incorrect. That won't be a good indicator of actual coolant temp. For reference, 220° or even 230° is not overheating. New factory cars are designed to run at higher temps. The 94-95 GT's low speed fan doesn't even switch on until 220°.
My '94 coolant temps climb with a/c on as well. My cooling system is all new and optimized with some mods.

 

[manicmechanic007]

Are you able to check the ECT sensor voltage output hot?
When hot, that voltage will be down around .64v where the electric cooling fans should come on if equipped
** Just know that your gauge will fluctuate as it heats up and the thermostat cycles once or twice
Also, the gauge will go nuts if the coolant is low and air is on the sender