LSx coupe running too hot w/AC on. Any tips?

[dville_gt]

Just bought a new radiator cap and thermostat. Going to try those along with an air deflector and a good bleeding of the system and see where that gets me. If that doesn't work I can get a replacement LT1 radiator for $90 shipped from Amazon.

[BlackGT]

I had this exact problem on my 96 mustang later in it's life. Temps fine until you turn on the AC in traffic and then it would steadily climb. I sold the car to my friend who replaced the radiator and that seemed to solve the problem.

[dville_gt]

So I took a good look at the car tonight and think I might have figured out at least part of my problem. The belt wrap on the water pump is probably allowing the waterpump to slip and not spin at full speed. If I grab the waterpump pulley I can spin it pretty easily since the belt just goes under the pulley and only has a very small contact patch.



So I looked through my parts bin and found an idler pulley that will work with my f-body alternator bracket. I'll have to shim it out a little and get a new belt otherwise it looks like it should work perfect. This setup will increase the contact patch significantly. I took a piece of wire and soldered it together to figure out the length of the belt I need and have ordered it. So hopefully between a new thermo/radiator cap/and rerouted belt I should be running cooler.

Here is the new belt routing:

[UserX]

That should make a big difference, good luck.

[dville_gt]

That should make a big difference, good luck.

New belt should be here today so I will update as soon as I get it on. All the lettering on the current belt is gone which makes me think it was surely slipping (the smooth part of the belt rides on the w/p pulley. The fact I could pretty easily turn the pulley even with the belt on makes me think it probably slipped quite a bit during operation.

How much resistance do waterpumps have on them with the motor running anyway? I know some guys pick up 8-10rwhp when they go to an electric pump so I guess they have some resistance behind them.

[Chas_svo]

Dville, did this fix it?

Curious minds want to know.

[dville_gt]

Dville, did this fix it?

Curious minds want to know.

Belt comes in today (odd size that auto zone/o'reilly didn't have so I bought it off Amazon), will update as soon as I get it on (should be tonight).

[Lason]

Holy crap!! Yeah I would venture to say that the belt wrap is most if not all of your problem.

[dville_gt]

Holy crap!! Yeah I would venture to say that the belt wrap is most if not all of your problem.

Well since the car runs fine temperature wise with the belt like it is a/c off I'd assume the additional flow created by the w/p actually spinning full speed will hopefully get everything in check with the waterpump on.

Still haven't pulled the trigger on the front air deflector, car is so low as it is and I think I'll be dragging that thing on everything so hopefully this will work.

Planning to take the coupe out to my FIL's shop in Weatherford this weekend to modify the exhaust (going to add in 2 3.5" ultraflow mufflers to hopefully quiet it down a lot). It will be the longest trip I've taken in the coupe as of yet so hopefully all goes well. I think I am going to borrow the wells off of the Cobra to drive there on (don't want to ruin the ET Streets for nothing), but the reduced RPM's from the 28's will be missed on the highway.

[dville_gt]

Got the new belt on, took it for a little cruise. I replaced the IAT sensor that was residing in the MAF and replaced it with a thermistor and mounted it in the front bumper. This threw my tune way off since the car was seeing 130-150* heat soaked IAT temps and now see's 95-100* (actual temp) IAT's. So I drove it around for 20-30 minutes messing with the tune and leaning it out (lower IAT's = more fuel). I didn't run the a/c though since I want to put the gauges on it and see what my high-side pressure looks like before I go running it and damaging the compressor or something.

Anyways, ran between 198-205 the entire time. Granted this was at like 8pm so the temps were not at their peak, but this is definitely an improvement. Going to run by Buick355's tomorrow night and see get the a/c pressure sorted out then on Saturday I am driving it to Weatherford (about 40 miles), so that should give me a good indication of if it is fixed or not.