1994 cobra with a new 347 overheating only when ac is on...HELP??

[93lxtc]

Has anyone had an issue with a 1994 cobra...that when you turn on the ac system is on...it overheats? I do have a huge new 2 row radiator, new motor, new water pump, new whose, new t-stat, new fan motor, modified pin # 17 green with purple...to keep high speed fan on...and yet still have an issue when the ac is on...the car overheats.....any ideas? The shop that works on my car said they think its a condenser that needs to be cleaned out, and or the orifice tube?

Need some input, please help!?!
Car runs very smooth...new temp sensor as well.. replaced most everything... except ac system...car was a Florida car...any ideas?


thanks to all..

 

[CC'S95GT]

Please explain about the pin 17 mod.
I'd try to remove the thermostat to see if that's the prob.
I also don't see how a clogged orifice/filter could cause it to overheat. But if the shop put the guages on it and says it needs to be replaced then do it. I've recently seen an orifice tube clogged and it caused the system to split open.

 

[Paul]

What do you mean it's "overheating?" You mean it's blowing coolant out of the car? What temperature is it getting to?

 

[uncltrvlnmatt]

Don't remove the thermostat. It will cause the coolant to flow to quickly in r=the system and it won't have time to cool properly. If you want you can remove the center valve that opens and closes, that should restrict coolant flow enough to cool properly.

How much is you engine bored out??? If it is .030 or more you may have to deal with it, unless you put in a larger radiator.

The orifice tube will have nothing to do with overheating. If you condensor is clogged with dirt/bugs your A/C won't work for crap due to lack of air flow.

Like Paul said, is it pushing coolant, or is it boiling out, what is your temp gauge reading????

 

[CC'S95GT]

I wasn't saying to remove it permantly. Just long enough to determine if that may be the problem.

 

[uncltrvlnmatt]

I wasn't saying to remove it permantly. Just long enough to determine if that may be the problem.

Gotcha.

 

[mikey94gt]

Hmm, I would say a dirty radiator. look in the cap when it is cold, do yo see lots of scale and lime buildup? that will cut your heat transfer by as much as 70%. a rad. flush kit works wonders if that is the problem.

 

[Ryno8705]

I don't know what the pin mod you are talking about is, but I am going to guess you have had a chip tune for your 347. If that's true, which it should be, you can modify the high/low fan on/off temps. It's much easier than swapping pins. There are 7 scalars which control the fan, 5 of which control temps.

 

[x182dan]

I think he means he modified it so he could turn the fan on via a switch

 

[LAFENATU]

Im gonna say either

1.) The fan is not locking @ low RPM's

2.)Radiators plugged, either airflow or heat transfer issue.

Both are common..

 

[BlackStallion]

My car did the same exact thing. I had flushed the radiator and engine and it seemed to pretty much clear it up. I had it flushed once a loooong time ago, but shoot it was like 70-80K ago. Just had it flushed a month or two before I parked it and it ran very cool.


...and I think not having a front bumper cover may have helped me... :lol:

 

[93lxtc]

Hey all....sorry been off the site for a while...busy with work...

Toby (blackPony) has the car and is redoing a lot for me!

Here is a link to the mod.

http://neptune.spacebears.com/cars/stories/fanrelay.html

(also another great site-with wirring diagrams etc: http://www.veryuseful.com/mustang/tech/engine/ )

It just allows you to run your fan on high all the time or by a switch.

Now regarding the issue witht the car getting hot with the ac on,,,here we go.

The car does not blow out any fluid...the factory gauge just goes all the way to L..and sometimes close to the red mark, on the facory gauge. I have purchased a fluidyne type radiator, new, new water pump, new rad. hoses etc. Car also as a 180 T- stat in it.

I currently, am going to replace the entire ac system- We are also going to put an electric fan a 12" in front of the ac condenser (wich the ac condenser) will also be brand new. and we are fitting my 1994 cobra, with auto meter gauges the phantom 2 1/16" gauges, right under neath the radio, so it should look good, and hopefully get us a better reading.

This all happend before I installed the 347- so hopefully this might fix the issue. Has anyone else had there car get very, very hot with the ac system on? Has anyone else ever installed an electric fan to help push air through there ac condenser? If so, did it help any?

thanks to all...
and great site!

BTW- the factory fan motor is also brand new as well...the cobra i have came from florida, and allmost everything on it has been replaced.

 

[Ryno8705]

Well I think I have something interesting to add. I noticed when I had my A/C on, my aftermarket gauge showed the car was at 210*. I have a 180* stat and normal temp is about 186*. I was like WTF, Really? I got busy and just didn't use the A/C.

Well, during the time of not wanting to mess with it, it got hot as balls outside and I turned the A/C on, this time I wanted to see how long it took for the car to get to 210*. Instantly. I thought, "no eff'ing way." Turns out, my blower fan messed with the ground resistance somehow and threw off the gauge. So, I moved the ground and bam. Barely moves at all with the blower fan (like a degree or two, not even a needle width). I'll find a better ground over the winter during the car's down-time, but right now, it works.

In hindsight, I could have probably referenced my stock gauge to see if it moved with the aftermarket gauge, but I give almost no credibility to the stock gauge and I didn't really think about it at the time.

 

[93lxtc]

Can you show or tell me how you fixed this ground issues step by step please?

 

[mikey94gt]

I installed a set of Summit aftermarket gages, and they require the ground to be on the block, because the sensor is on the block. otherwise, everything throws them off. something to think about!!!!

 

[5.0boi]

on my motor it over heats when i step on it and even faster when the a/c is on and its cause i have a blown head gasket on my exhaust side

 

[Traidmarx]

mine does the same thing never did it before i put the underdrive pulley's on my car though.

 

[93lxtc]

no over drive pulleys on this car..

 

[Ryno8705]

I grounded my gauges by the battery where the little wire attaches to the frame. I am going to ground everything at the back of the block when I get around to it.

 

[Paul]

Before you go replacing everything on the car, a real gauge is in order. Most people freak out unnecessarily when they don't even know what the real water temperature is.

Paul.