Hi,

I was wondering if anyone has any ideas to try and help my car run cooler. I am driving a 69 GS with a 68 430 in it. Let me give you some background:

The car is an original stickshift car. I dropped a 430 in it, because the 455 that was in the car had a spun bearing when I got it. Last summer I added A/C to the car (come on, I live in Phoenix). It is a standard aftermarket unit that uses the original compressor and brackets, and a newer style condenser up front.

The car was missing the fan shroud, so I have installed a 12" electric fan to help the mechanical fan (clutch fan).

My problem is that everytime I cruise down the freeway, the car runs at 235 or 240. Even when I turn the ac off, the car still runs really hot.

I recently replaced the heads, because one was cracked. Other than that the car is completely stock, never been rebuilt.

I have tried everything that I can think of. I run a 195 thermostat, and have flushed the system.

Oh yeah, the car runs hot on city streets too, but not as hot if I keep moving. Once I stop at a light, it heats up.

My only thoughts are: The fan pulley is not the right size (however, it is stock) or the timing cover could be corroded, therefore not moving enough water.

Please any help would be great!!

Thanks,

Trevor

Put the fan shroud back on. If you don't have a 4 core radiator, get one.

You have a few things working against you.

1) is that those engines make some good heat.

2) The air in phoenix is hot.

3) the air in phoenix is dry (believe it or not, humidity will help transfer heat into the air)

4) You have a condensor in front of your radiator, which blocks some airflow (and makes the air warmer if operating).

5) No fan shroud.

That is pretty much a worst-case scenario as far as cooling goes. In my opinion, you are going to do whatever possible to keep it cool. Here is what I would do if it was my car:

1) Put the fan shroud in, just like gmranch suggested. This is the first step, no question.

2) I would put in a cooler thermostat, like 180 or 160- chances are that you will run hot enough that the thermostat will usually run full-open most of the time anyhow, but having a cooler thermostat will allow it to reach full-open sooner. There is also a "high flow" thermostat available from Robertshaw, but I have never seen those make a difference.

3) I would run distilled water with about 20% antifreeze. Antifreeze decreases the heat-transfer ability of the mixture, so the more water you can run the better. (In my car, I run NO antifreeze).

4) Add a bottle of "water wetter". This increases the surface contact between the water and metal, increasing heat transfer (in both the engine and radiator).

5) Look into a bigger (thicker) radiator, or aluminum. In my car, I run a 5-core radiator (copper/brass). I used to run aluminum, but I found out the hard way that if they develop a leak, they cannot be repaired, where copper/brass can be fixed at your local radiator shop. Having said that, a lot of people run aluminum radiators for many years with no problems. If you do go with a bigger radiator, also consider one with more fins/inch- most radiators have between 10 and 14, and having more fins will generaly transfer more heat into the air (although having too many fins can block the airflow at low speeds).

6) Consider running more electric fans- because of the airflow situtation there, getting more air through that radiator is key (make sure there is nothing blocking airflow like driving lights etc.). On my car, I run no mechanical fan (which is why I need such a thick radiator), but I run three electric fans (two pullers, one pusher). Frankly you may not need to do this if you put in a good shroud, but airflow is important and you should see if there is any way to get more airflow through the radiator.
(Note: I consider a fan to be most important at idle, and my electric fans generally never run when I'm moving over about 25 MPH. If you are having trouble at high speeds, an electric fan that isn't moving can actually block some airflow, so you gotta think about your driving habits.)

7) Make sure your timing is advanced enough- retarded timing can heat up your engine.

8) Consider an oil cooler setup. Oil takes away a lot of heat (it touches a lot of engine internals), and if you cool the oil then that will help the whole engine. Of course you don't want to block too much more airflow through the radiator, so this may take some creativitiy.

9) Make sure your fan clutch is working properly. Some clutches don't grab until very high temperatures, maybe you can find one that will come in a bit cooler.

10) Make sure you aren't detonating. If you had a cracked head, that could have been caused by overheating or detonation (more likely overheating). Maybe you need some more octane, or have to play with your advance curve.

Hope those help get you started in the right direction.

-Bob Cunningham

the thing that happened to me...... i have a 63 401 with 60,ooo original miles on it and at times it would also run hot i flushed it and put a new pump on it but when i took it apart to rebuild it down deep in the coolant passage between the cylinders there was a thick build up that made the passages very small was the motor you put in sitting for a great deal of time?was it rebuilt and cleaned?(hot tanked or something)that could be something

I also had the same type of heating problem. Mine happend to be with a 350. I cannot stress strongly enough the need for a fan shroud. Without that I doubt if you will ever get it cool enough. I had a custom shroud built with 2 electric fans controlled by a thermo switch. It also has 4 small doors that open when I am driving on the freeway to allow air free flow. I now run cool in all conditions even with A/C. It cost about $300 but thats cheap compared to a new engine.
Jim