[gm_fan]

I have installed a 302 in my 68 camaro and it seems to get warm if idling long periods of time. I installed an electric fan in front of the condensor [yes its an ac car] and need to know what type of switch to use to control the fan, from maybe 210 on to 190 off..any suggestions?? thanks gm_fan

[pjbizjak]

IMO, ditch the a/c unless it's not a real 302/290hp!

[Steptoe]

If it idles at a nice low rpms there is less water going thru the radiator, and therefore most engines get a little warmer if left for longer periods just idling
10 to 15 sec of a higher rpm drops the temp back real quick

If you have a/C there is even a larger load on the engine with idle flow...of caorse the engine will "warm" up even more above the thermostat rating.

Have the fan cut in 195/200 , or about 5 deg above normal highway cruise temp

The is a good chance the extra fan will make very little difference...it is the rate of flow rather than air flow that is the issue...
The time the water takes to flow thru the engine, heat up and eventually get to flow around the temp sensor.

[DjD]

The front mounted (pusher) fan is most likely doing more harm than good... Being between the core(s) and the air it blocks more surface area and air flow restricting the cooling ability of the core. Run either a stock style belt driven clutch fan in a proper shroud or an electric (puller) fan mounted on the engine side of the radiator.

[gm_fan]

Sorry, I cant do away with the a/c..Although at 8 grand the belt is hard to keep on!! Probably why they did not come with a/c. I am 54 and grew up with these cars and I know the a/c is just a creature comfort when easing around, but I only have the overheating when the a/c is on , hence my radiator[new] doesnt like having the a/c condensor farting in its face, but for the time being I hooked up the relay for the electric fan off the a/c clutch. Again ,the question I asked is what type of switch is available to operate the fan off the coolant temp instead of the a/c off and on...the cooling fan out front takes care of the warming problem, just control is the question??? thanks gm_fan

[zdld17]

Originally Posted by gm_fan

Sorry, I cant do away with the a/c..Although at 8 grand the belt is hard to keep on!! Probably why they did not come with a/c. I am 54 and grew up with these cars and I know the a/c is just a creature comfort when easing around, but I only have the overheating when the a/c is on , hence my radiator[new] doesnt like having the a/c condensor farting in its face, but for the time being I hooked up the relay for the electric fan off the a/c clutch. Again ,the question I asked is what type of switch is available to operate the fan off the coolant temp instead of the a/c off and on...the cooling fan out front takes care of the warming problem, just control is the question??? thanks gm_fan

In deep south Texas, I had to install an under dash FrigaKing unit to drive my car around as the new and only car I ever had, served many purposes. Using the stock 7 blade fan and clutch, I never had issues when using a 160° stat. Today I still use this type of clutch and blade but with a 4 row 23" core radiator and newer Vintage air. Usually run 100° over ambient alway's but I don't have the compression I once had..

[srode]

What kind of radiator do you have and how wide is the core? Are you running a fan shroud around the engine mounted fan? An AC Radiator in a 68 has a 23 inch core and there's a shroud designed just for it. (sorry, can' help with the relay question)

[bwcamaro68]

Originally Posted by zdld17

In deep south Texas, I had to install an under dash FrigaKing unit to drive my car around as the new and only car I ever had, served many purposes. Using the stock 7 blade fan and clutch, I never had issues when using a 160° stat. Today I still use this type of clutch and blade but with a 4 row 23" core radiator and newer Vintage air. Usually run 100° over ambient alway's but I don't have the compression I once had..

x2 on the 4 core radiator

Do you have the ability to remove the ac belt when your pushing the 8k, at that rpm 2-60 (aka 2 windows down 60mph) works at that stage.

[gm_fan]

The compression issue brings on more talk. I am running the stock trw .030 with a set of fast burn aluminum gm heads. I am using .060 head gaskets for correct clearance,with a performer rpm vortec style intake and 800 holley..You know for some dumb reason, it never dawned on me that the engine is probably saturating the system with all the heat it can disapate and the a/c is the straw making it hard on the camels hump..I have a 4 core and an aluminum racing water pump and I need to be sure on the thermostat. The late model junk I work on all takes 195 and it may turn out to be something stupid I done.Thanks for reminding me the only thing worse than being dumb is not knowing it,,I will let you folks know when I find out ,,thanks again gm_fan

[ace's68]

190* is not hot at idle, 210* is getting hot at idle, but not if it remains there.
You need a radiator that would have come in a non base car, so like a 3 or 4 core, and a puller fan with a decent CFM rating should do more than enough. 180* stats always worked best for me. My car never gets above 190* idling in the TX heat. I do not have AC, I do have a STOCK water pump 4 row from a BBC or 350 Camaro (it's not HUGE) and a 1,250cfm puller fan. Engine is almost 11:1 compression.

[Everett#2390]

Bored block, read thinner cylinder walls, alum heads, and maybe OE pulleys, certainly could be saturating the coolant.

However, the hotter the radiator is, the more heat it gives off. Late model engines run hotter for emissions, cuts down on NOx.

You might find either a smaller w/pump pulley or a larger crankshaft pulley to overdrive the w/pump by 30%. You might try a standard flow thermostat, Duralast brand as Robert Shaw, who makes for Mr. Gasket, Moroso, and others, may have a bad batch on a recent production run. Duralast is made in Israel, much better quality. Check new thermostat in a pan of water and meat thermometer, or a known thermometer and check its opening temp, the number stamped on it, and its full stroke.

As a last resort, try just water in the system as water is the best coolant by itself.
Maybe a bottle coolant ice, for lack of a better term, the liquid poured in to lose more heat - it only works with straight water - provides better surface coverage - water will 'sheet' rather than 'bead' just like before and after a wax job.

[onovakind67]

Originally Posted by gm_fan

Sorry, I cant do away with the a/c..Although at 8 grand the belt is hard to keep on!! Probably why they did not come with a/c. I am 54 and grew up with these cars and I know the a/c is just a creature comfort when easing around, but I only have the overheating when the a/c is on , hence my radiator[new] doesnt like having the a/c condensor farting in its face, but for the time being I hooked up the relay for the electric fan off the a/c clutch. Again ,the question I asked is what type of switch is available to operate the fan off the coolant temp instead of the a/c off and on...the cooling fan out front takes care of the warming problem, just control is the question??? thanks gm_fan

If you go to the boneyard and look at Mercedes or BMW cars, all of them have a pusher fan in front of the condenser. BMW has a two speed setup with a 91°/99° sensor. Is your fan a single speed one?

[srode]

Originally Posted by gm_fan

I have a 4 core and an aluminum racing water pump and I need to be sure on the thermostat.

Is the core on your radiator 20.75 or 23 inches wide? The 23 inch wide ones provide about 10% more cooling. (although I am sure if you have a new radiator you are probably not wanting to change it already). Also, a 2 core Aluminum radiator with 1" thick channels provide an additional 30% cooling over a standard 4 core brass/copper radiator. You shouldn't need a pusher fan or be running hot if you have enough radiator, fan, and shroud.

[Steptoe]

Exactly how "warm" does it get
If not going over 220, then drops to normal operating temps when not sitting idling
...bottom line you really dont have an issue to spend money on

What is the idle rpms? below 800? (I doubt)
Do you leave the car to idle? or are still in it?
If in it a little throttle for a few secs ..upto about 1000 rpms will set the temp drop any way

Pull the radiator cap off, and watch the coolant dribble out of the cores at idle
increase rpms a couple 100 or lease and watch at the huge increase in flow

You might find either a smaller w/pump pulley or a larger crankshaft pulley to overdrive the w/pump by 30%.

Thats gettingf a little dicky fooling around with those ratios, may fix at idle, but once rpms get up (and 8k was mentioned) that exra pressure and flow could be a new issue emerge.

AND YES check the thermostat is a stock GM spec unit

[gm_fan]

Where I have noticed the problem is when I pull up to a Sonic carry out and with the ac on and the car idling , the overheating problem. It will climb up to 220 which may not be hot to anyone else , but when I leave , I get some detonation at this temp with my base timing set at 16 degrees and no vacuum advance and total at 35 degrees..It takes me getting out and running the car down the road to cool back off. One other very important thing is that its been 90-100 every day for past 3 weeks..Now its getting a little cooler and my problem is not so consistent..I think October will be the answer??? I really did not caremuch about the idea to put the pusher fan out in front , but I only covered half of the condensor with a 10 inch fan> As far as the idle , its about 1200 or so rpms..I am running a solid roller comp cams camshaft with stud girdle ..I may look into overdriving the water pump pulley, but 8000 to 9000 rpms concerns me as it may keep the flow so high at higher rpms, it may cause a overheating problem when the fun factor is in play,As someone else pointed out, I probably need to cut the belt and forget the a/c, but my wife probably will be a problem with that..thanks for everyones help, you have sure give me some things to ponder on,,gm_fan