Running hot with AC on!

[95ep5.0]

Hello everyone! I am a newbie here, but i have always loved the mustang. i have a 95 GT, working on posting and editing my profile. anyways, my mustang consist of holley heads and cam, ford 1.6 rockers, bbk heads, borla mufflers, summit radiator(1yr), new water pump (3wks), alum drive shaft, 3.55 gears, custom chip and 5sp ( with second gear issues). My problem is that the temp in El Paso ("The Sun City"), TX. is getting pretty close to 100* and my car will over heat if i turn on the AC. the radiator fan will come on. i have had this issue for several years now and every year i try something new like the radiator and water pump, since income is low (i am a student). I'm pretty much fed it with is and i wnat to resolve the issue once and for all. I read a post and saw this by hissin50,

If a car runs hot at speed:
Ensure the coil is not clogged with debris.
Ensure the air dam is present under the car.
If the above is true and the car becomes even hotter and struggles to cool down with the A/C being on, that can suggest the coil is simply unable to reject enough heat. A new radiator is often the best move from a monetary standpoint (as this allows an upgrade at the same time. Nice for hotter climates or modified engines).

I have serveral questions to this.

1) what coil is hissin50 talking about?
2) where is it located/ any pics?
3) what does the air dam look like?

adnd of course, does anyone have what is wrong with my car or any suggestions?
thanks you guys.

 

[95ep5.0]

Sorry guys. the stock ( i know it is carppy at best ) will read A in NORMAL, but i am pretty sure is will go past L is the cur is not turned off. Working on getting an autometer gauge. but if the AC is not turned on the gauge will read R and will go back to O. When the dyno tune was done, the lower speed fan was to turn on at 120* and the high speed fan at 150*. And again High speed will kick in as soon as AC is turn on to high.

 

[HISSIN50]

A radiator is a coil. Anytime you see me mention coil, think radiator (and thank you for the feedback. I will change the term coil to radiator in my write-up).

The stock air dam is a little rubber dealie that mounts to the front clip about where the clips for the plastic bumper cover attach. It is flanked by two 'ears' on either side of it. I do not have a picture uploaded but will see if any of my other pics show it.

I went through a similar type of thing with my 94 (I live in So. AZ - it was triple digits today - same crap temps you see). Though it's just an educated guess on my behalf, it sounds like your radiator simply is not rejecting enough heat. You will more or less be able to deduce this once you get that air dam (it's 15 bucks at the dealership). Since you noted temps going up with AC, it's quite likely. You may even find that the load of being on the freeway (after you have an airdam) allows temps to go even higher than they were while in traffic. The motor is working harder than it was while idling, and the radiator is maxed out.

You have to also remember that with a maxed out cooling system, the operating temps tend to phase shift as ambient temps go up. This is because there is less temp delta (difference) between your target operating temps (say 190*F) and the ambient temps. An overkill radiator can actually deal with this much better than a maxed out radiator.

Though you wisely already checked, re-check your fan operation to ensure that high speed is coming on and staying on with the AC. I've seen several issues where the AC only triggered low speed. Once it gets to be 100* or so, low speed cant begin to cut it with the AC on.

If you get a reburn done on your chip, I'd have them run the fan temps back up. Simply stated, you want your fan to shut off about 7* higher than the thermostat rating. For low speed (and a 180*F balanced thermostat), I'd have low come on at 195 and off at 187. Remember, once your t-stat closes, having the fan turned on is pretty useless (that's the reason for changing this).

There is a group buy for a given radiator right now. I need to really examine the specs since I have not heard the technical info I desire, but it might be a neat way to go if it's deemed sufficient. Radiators are one thing we cannot skimp on in climates like ours.

Random thoughts.
Good luck.

 

[95ep5.0]

Thanks for clearing that up for me! I'll go over and buy the air dam tomorrow. hopefully that makes a difference. do you think the radiator buy in is any better than summit's? just asking because summits was about that price but it wasn't a direct fit. thanks you was again.

 

[The Green GT]

My car does the same thing. I dont have my air dam, but that would not matter when driving in the city. My car gets hot going 80, or 8.

So Im in on the radiator group buy.

 

[HISSIN50]

Thanks for clearing that up for me! I'll go over and buy the air dam tomorrow. hopefully that makes a difference. do you think the radiator buy in is any better than summit's? just asking because summits was about that price but it wasn't a direct fit. thanks you was again.

You brought up a great question. I myself have not yet seen a reply from a source (though we have asked myriad times) about the heat rejection ability of that 'other' radiator (Eric's been paying more attention than I - maybe he can chime in with info and insight I don't know about. ). Right now, my thinking: If I lived in Seattle, you bet I'd give it a shot. But I'm not convinced that it's gonna be enough. I'm on the fence about actually buying one of these group buy rad's. It would sit on the shelf till my current aftermarket rad craps itself but I always like the idea of OEM fitting parts if all else is equal. I have questions about the group buy unit - I need to email the guy (I dont do radiators with epoxy in them, I need heat rejection info and actual precise physical measurements for the entire radiator since I have some custom crap up front, etc).

If you can do real slight fab work, the universal rad's are the *known* way to go IMHO (it's what I have experience with. If we can get some feedback from the folks on here about that other unit, this could sway my opinion). If you are a DIYer and *need* a known combo, the universal is where my money would go *right now*.

Just my perspective.