Another "Running Hot / Overheating" thread...

[bigcatchdaniel555]

i just got ac on my car and sitting in traffic with a new 3 row radiator the temp gauge goes right to the h mark when i start to move it drops however from this thread i have learned my gauge may not be accurate so i will get a thermo cap for the radiator i am still thinking though of a fan gaurd or and electric fan will these help i have heard good things about a fan gaurd.

 

[MustangSix]

i just got ac on my car and sitting in traffic with a new 3 row radiator the temp gauge goes right to the h mark when i start to move it drops however from this thread i have learned my gauge may not be accurate so i will get a thermo cap for the radiator i am still thinking though of a fan guard or and electric fan will these help i have heard good things about a fan guard.

You may need a fan shroud. When you think of the restriction of the condenser, then add the 3 row radiator, without a shroud you are probably not moving enough air thru the radiator. Air is like water - it will follow the path of least resistance. Your fan, no matter how big it is, will find it easier to simply beat the air behind the radiator than to pull it thru.

 

[66 Fastback]

Are you running a stock 4 blade fan? I think when A.C. was installed, the factory used a 5 blade fan on the car.
Doug

 

[bigcatchdaniel555]

the car had ac once before but the system was shot so it was removed however the 6 blade fan and a couple other things still remain i went to the junkyard and modified a ford ranger fan guard to fit and it seems to work didnt get a chance to test it because the car was a little low on water so it got hot anyway also i went to have the system charged today before the guard was on and they couldnt even charge it all the way because the condenser was getting too hot. i also just went and got 2 10 inch radiator fans as pushers in front of the condenser i will hook them up tomarrow right on the solenoid so when i turn on the key the fans will come on.

 

[61Futura]

If your talking about the starter solenoid, don't hook them directly to the solenoid "I" terminal. Use the terminal to energize a relay which then energizes the fans. Even then You don't get a full 12 volts because it goes to the coil + terminal.

If you are talking about the compressor clutch solenoid, you won't get the fans running unless the A/C compressor is pumping.

 

[mugsy]

A rule of thumb is that after the car reaches 30 mph the fan is not needed. The speed of the car/air is greater than what a fan can move/suck. You stated that the problem is "at speed" i.e. the "Interstate". More fans and a shround will not help move more air thru the radiator over 30 mph. They do help around town and stop-n-go traffic, definetly(sp). I would still take the time and remove the radiator and get it flow tested. Also inspect the fins, here in Michigan with the salt during winter it can corrode the fins.

 

[bigcatchdaniel555]

sorry i should of been clearer when i said in traffic i meant sitting like at a light for 5-10 minutes or in the drivethru at speed the temp comes right down the car has always had this problem just mainly in the summer because the heat index right now in south florida is about 100-105 i got everything hooked up and it appears to be running much cooler i am taking to get the final charge of freon this afternoon by then i should know.

 

[bigcatchdaniel555]

one more thing now with the added load of the compressor it drops the idle down quite a bit i know there is some type of switch which goes from the compressor to the carb and it bumps up the idle when the compressor is on and down when its off does anyone know the right name for it or know who sells them.

 

[Anonymous]

big catch daniel 555....where in south florida are you? would I have seen your ford around?

chaz

 

[66 Fastback]

I'd have to check a shop manual, but I think they were called curb idle solenoids. I don't know who might carry them. My Mustang could use one. My old 73 Comet had one. You typically found them on cars with smaller engines since is loaded up the engine and dropped the idle. Most V-8s could handle the additional load.
Doug

 

[bigcatchdaniel555]

you may have seen it around i live in the pompano beach ft. lauderdale area i am going to check into that curb idle solenoid but my heating troubles are over i think i took the car out for a ride and in typical traffic at each stop light with the compressor running it would just hit the half mark with the shroud and fans running.

 

[66200i6]

Here are some things that I have run into when looking into this problem on my 66' Coupe and Camper Special.

There was a Ford Tech Page regarding overheating on this engine the fix was to move the heater hoses away from the block and hang from a leather strap at the engine bay crossmember. I don't know it is did anything but, there it is.

Another thing I found was that there are some spec's that call for the fan to be within a "minimum" dimension from the fins of the Rad. I have seen this work on my 390 Camper Special. All I did was move the fan to within .75 in and I noticed a difference.

Also, I have actually seen the freeway speed movement of air through the Rad. reduced by adding a shroud if the spec I mentioned above is not followed. Apparently if the combination is incorrect the fan and shroud create pressure that blocks flow through the Rad at freeway speeds.

There’s alot going on here, keep it simple and clean up the stock system.

Good luck, Ric.

 

[66 Fastback]

Years ago I was surprised to learn how important a hood was in engine cooling. I had taken the hood off of my Vette for installation of a new engine. While I was repainting the hood, I drove around town with no hood but it still had its fan shroud. My intuition told me it ought to cool better since heat was free to convect off of the engine and not be trapped under the hood. The engine temp got close to overheating. When I installed the hood, the temps returned to normal. Later I surmized that without a hood, the air was free to flow into the engine bay and create higher pressure in the engine compartment. I think with the hood in place, air flow into the bay has to come through the radiator and down under into the low pressure region under and behind the car. Without a hood, the air can short circuit that path. I bet most open hooded Street rods with cooling problems would cool better with a hood in place.
Doug

 

[Anonymous]

Yes a cloged ac condensor in front of your radiator can cause it to over heat.

 

[66 Fastback]

I looked up the solenoids in my 73 shop manuals and they were referred to as Throttle solenoids.
Looking on the web, some refer to them as Fast Idle Solenoids or anti-dieseling solenoids. In the 73 shop manual, that is what they were used for because they were energized anytime the ignition was on.

You basically use the same solenoid for use as a anti-dieseling solenoid or fast idle A/C solenoid. It just depends how you wire it. The fast idle solenoids on emission era cars were wired to come on with the ignition. The carbs were jetted so lean and timing retarded so much that you needed to open the throttle plates more and increase the engine rpm to get it to idle. Problem is that when the engine was shut down, the throttle plates were oen too much and combined with the higher engine temps due to lean mixtures and retarded timing, the engine dieseled. Enter the solenoid. The solenoid was on when the ignition was on and it held the throttle open at the desired idle speed. When power was cut, the solenoid retracted letting the plates shut completely and prevent the dieseling.

For A/C applications you wire it to A/C clutch wire. When the compressore kicks in, the solenoid is activated to hold a higher rpm. With the A/C off, the engine returned to its normal idle.
One thing I am not sure of is if the strength of the solenoid varied with the application. The Shop Manual states that the throttle solenoid used on the '73 cars does not have enough power to push the plates open, but rather it will hold them open once it is powered. On AC solenoids, you would think that you would want the solenoid to push the plates open when the compressor kicked in at idle or the engine would get real rough. I don't know if they used a more poerful solenoid for those applications.

Holley & Edlebrock sell solenoids and mounting brackets. I am not sure the prackets would fit a 1 bbl carb. Solenoid is about$78 at Jegs.
http://www.holley.com/46-74.asp

Doug

 

[Lazy JW]

Another thing that will speed up the idle is to have a valve that switches the advance to full manifold vacuum. My 81 F-150 was originally equipped with this setup using a thermally actuated vacuum switch.
Joe

 

[bigcatchdaniel555]

i have been looking for the solenoid and found a couple on ebay unfortunitly they arent going cheap and the ones that are have reserves hopefully i'll get lucky.

 

[bigcatchdaniel555]

i found an idle stop solenoid it looks to be the same as a throttle solenoid it supposed to open and close the throttle plates to prevent dieseing any thoughts its cheap and new.