Cooling Issues

[CDMBill]

I think it would be cheaper/easier to find a factory style dual fan w/integral shroud set up to clear the water pump pulley. Since the issue is low speed the likely culprit is the fans IMHO. I'd address that first remembering that CFM rated seems to be a marketing game. I use the Lincoln Mark VIII fan which draws a lot of power and requires the wiring and alternator, relays etc.to support it. A smaller but still powerful OEM unit is still the best in my book. The Chevelle experts on here will know better about radiator size and configuration for your car, but the electric fan's are a proven commodity now if you get a good aftermarket or OEM unit of the right size to fit your core.

[Scott Liggett]

I have a pair of Spal 12" on my Impala and a Mattson dual pass radiator.

Go down to a 160 or 180 thermostat. Drill two 1/8" holes on the thermostat surround to allow air bubbles out of the engine.

A flat piece of aluminum covering the back of the radiator with two holes for the fans will work on your tight setup as a shroud.

The previous owner thought all those 1" holes would help on the freeway. If my car didn't run right at the thermostat temp, I would make a new piece.

[cal67ss396]

The radiator is a direct replacement for a brass 4 core. I will get exact dimensions on it tomorrow. I have often thought about making a aluminum sheet metal shroud for it. The fans are the biggest and thinnest that I could fit on the core surface.

[Dan Barlow]

Fan shroud, cooler t-stat. You'll be fine.

[MR P-BODY]

If you look at your dual 11" fans the center of each fan moves ZERO
air... so those 11" fans are now about a 7" pair... with the trans cooler
blocking part of the air flow and the small fan area you are really limited
on air movement... timing might be high also... like you said, check that...
and get the measurements on the rad but just looking at it, it should be
large enough if you were using all of it... if you run 70mph do you have
any problems ... at speeds of about 50 and up you shouldnt need any fans
so if its fine at speed and your problem is just low speed and stop and go
its a fan or blocked air flow issue... the cooler would be part of the blocked
air flow... you could move the cooler as a test.... I would drop down to a
180 stat also

[cal67ss396]

Okay haven't had a chance to really mess with my car yet. However I did find some time to measure the radiator. The tank is approximately 3-1/4 inches wide and the core appears to be roughly 2-3/8 wide. Looking down into the rad it has two rows and the rows look to be 1"or bigger. The radiator was also low on coolant, I know that could be part of my issue as well.

I really need to spend a little time with the car and check the timing, change t stat and change the oil. I also think that I have a burnt plug wire.

[BOOOGHAR]

do you have the fans hooked up properly? ive seen some cases where they were wired backwards so instead of pulling air they were pushing air

[632STANG]

I would look at picking up a factory Lincoln fan. They work very well and can usually be found cheap. The factory fans seem to work lots better than the aftermarket stuff.

[1970camaroRS]

All things point to the fans/shroud. I've run a Taurus single speed fan for years and years on three different motor combos, 355", a supercharged 454 and my 500+ HP 6.0L LQ4. All on a stock 3 row HD copper radiator. The key to the success of the fan was it moved a bunch of air, but more importantly, it had a shroud that fit tight to the radiator and covered almost the entire surface.

Your main issue is that you have almost no room for something like that, even though my fan is pretty slim. I can measure it tonight if you want to see if something like the Taurus or Lincoln fans will work for you. Or you can get the fabbing a shroud. I guarentee that will fix your problem.

On other thing that hasn't been asked, but is your temp getting to 220 and staying at 220, no higher? And where is your temp reading coming from?

[Deaf Bob]

How are you on this?

[cal67ss396]

UPDATE.....

1. Changed the oil.
2. Checked the timing at full advance I am at 35* RPM's are approximately 3000ish . I had my 7 yr old daughter helping me. Not quite sure of the RPM's. she said the little pointer thing was at the three!!!


Okay I drove it and if you don't drive it hard and the outside temps are in the 75 to 80 degree range I can keep it in the 195 range. That was this evening. If you start hammering on it the temps rise moderately. Here is my problem once i get it at or above 200*. Its real hard to get it back down.

I am still working on a shroud for my fans.
Still planning on switching to 180* t stat.
Is my timing right?
Would you move my trans cooler?
I have a stock shroud and mechanical fan would you try this?
I am going to buy some water wetter or whatever is at the auto parts store.
Current pulley drive ratio is about one to one. I will need to see which ones I have on there. I have an under drive set and a overdrive set. What is optimal?

[yellomalibu]

UPDATE.....

1. Changed the oil.
2. Checked the timing at full advance I am at 35* RPM's are approximately 3000ish . I had my 7 yr old daughter helping me. Not quite sure of the RPM's. she said the little pointer thing was at the three!!!


Okay I drove it and if you don't drive it hard and the outside temps are in the 75 to 80 degree range I can keep it in the 195 range. That was this evening. If you start hammering on it the temps rise moderately. Here is my problem once i get it at or above 200*. Its real hard to get it back down.

I am still working on a shroud for my fans.
Still planning on switching to 180* t stat.
Is my timing right?
Would you move my trans cooler?
I have a stock shroud and mechanical fan would you try this?
I am going to buy some water wetter or whatever is at the auto parts store.
Current pulley drive ratio is about one to one. I will need to see which ones I have on there. I have an under drive set and a overdrive set. What is optimal?

What is optimal? Experimentation. What was optimal at the factory is long gone for your ride, I imagine.

I would lean towards the mechanical fan and factory shroud... and there is a pdf file somewhere on TeamChevelle that shows how to adjust a fan clutch to engage at a lower temperature.

The timing seems about right, give or take a couple degrees.

My business partner has a warmed up 455 pontiac in his Firebird. Apparently they tend to run hot, as does his. He added an electric fan that he uses in slow traffic. Added, meaning he still has a mechanical fan and shroud. Adding the electric fan made a big difference for him... the big aluminum radiator alone wasn't enough.

Hope this helps:

http://midamericachevelles.com/tech/fan_clutch_adjust.pdf

[cal67ss396]

Yesterday I added water wetter to the radiator and changed the t stat to a 180*. However to my surprise it already had a 180 in it. I went ahead and installed the new t stat and I drilled to 1/8 holes in it. I took the chance to drive the car around a little bit to see if those changes helped. Yesterday when I drove it acted like at low speeds it was doing okay never really got above 190. Then I tried some extended higher RPM cruising 3000 to 3500 RPM's. The car rose to 190 then to 195 almost to 200. I thought this just reinforces the shroud issue that every one is suggesting.

Then today I drove the car to a waterpark the next town over which is approximately 16 miles one way. It did reacted similar to the way it did yesterday. Slow speeds where okay temperature rose on higher RPM cruising. It was approximately 80* to 86* out when I drove there. Things were a little different on the way home. The car went to 198 to 200 and never went any lower than that. I really babied the car never really got on it. If I did I guarantee that it most likely would have went over 200.

Am I being unrealistic to think that this car is going to run at 180 to 185 degrees. I am hopefully going to get a shroud made up this week. I have a mechanical fan and stock shroud that I am going to try if the shroud for my electrical fans doesn't work. You here about all of these guys with 1000 plus horsepower cars that run 180 degrees all day long on a 100 degree day in Arizona. I just want it to run 180 to 190 on a 90 degree day in Indiana.

I am slowly trying everything to figure this out.

[Bamfster]

I'm another fan of the factory fan (LOL). I have twin 2100 cfm electrics on my chevelle. In an effort to free up some power, I yanked the engine driven fan .... immediately temp jumped to 210 ish constant. With the engine driven fan, it runs at a steady 185 to 195 no matter what the outside temps are doing .... now I use the electrics for slow speed cruising and cool downs at the track.

[cal67ss396]

I dont have enough room to put on a mechanical and electrical. For me its one or the other.