Hello fellow chevelle lovers,

I am currently driving my chevelle about once a week (highway) due to the fact it constantly overheats in stop and go traffic... (not holding an idle, having to pump gas into it to keep it going... HORRIBLE) It currently does not have a temp gauge (idiot light), or fan shroud.

On to the questions, I find that information in my straight 6 is hard to come by.

(1)Would anyone know what the ideal operating temp is for a 66 230 straight 6?

(2)Will a smallblock fan shroud fit my 6? and if so what type of cooling improvements should I see?

(3)Would switching to an aluminum 6 blade fan also increase my cooling?

(4)Any other ideas to help keep my 6 cool?

Oh, and i plan on installing a temp gauge to tell what i am running at...

Thanks for the help!!!

Hello fellow chevelle lovers,

I am currently driving my chevelle about once a week (highway) due to the fact it constantly overheats in stop and go traffic... (not holding an idle, having to pump gas into it to keep it going... HORRIBLE) It currently does not have a temp gauge (idiot light), or fan shroud.

On to the questions, I find that information in my straight 6 is hard to come by.

(1)Would anyone know what the ideal operating temp is for a 66 230 straight 6?

(2)Will a smallblock fan shroud fit my 6? and if so what type of cooling improvements should I see?

(3)Would switching to an aluminum 6 blade fan also increase my cooling?

(4)Any other ideas to help keep my 6 cool?

Oh, and i plan on installing a temp gauge to tell what i am running at...

Thanks for the help!!!

Ideal operating temp somewhat above 180 F. Needs to be hot enough to evaporate condensation from oil and vaporize fuel. Thermostat maintains minimum ops temp and has no effect on overheating unless its defective.

Not sure about the shroud. The fan centerline will ahev to be same location as for V-8. '65 has a spacer between the rad core and core support for V-8, so probably removed for six. I don't have my manuals here right now. I could look in the manuals for p/ns and illustration next weekend if still interested.

Stock fan arrangement is best arrangement all things considered. I think flex fans ar dangerous.

Most likely cause of overheating has been, is ,and will be poor heat transfer in the radiator due to corrosion clogging. Exception...if its fine under load and moving, but hot when stopped; insufficient airflow through radiator, assuming radiator is OK.

My $0.02

The stock fan on the 6 cyl is a little four blade thing. If you are planning upgrades, I would upgrade this first, assuming the rad isn't plugged up.

Make sure your timing isn't retarded. That will cause it to run hot and may also be why it's running rough.

First order of this operation is to make sure the radiator is flowing properly, and if not have it cleaned. This is more than likely your problem.

Start with the basics: Test your thermostat, flush out the rad, make sure your return hose is not collapsing (it should have a spring coiled in it to prevent collapse). Make sure your water jackets are not full of rust or crud (you haven’t been switching between conventional coolant and Dexcool have you?

I have a 250 / Powerglide with a standard radiator and it never has an overheating problem, and that is without a shroud (which came only with h.d. rad or with a/c). No, a V8 shroud does not fit (the six is longer and the rad spacer is omitted so the rad mounts directly to the rad support.

1966 & earlier Chevy sixes used a 180 degree T-stat; for 1967 the revised it to a 195 degree, but that coincided with a revised thermostat location so they could run it a bit hotter due to more accurate sensing.

How’s your timing? If your timing is retarded too far you can run hot and cause problems.

STAY AWAY from flex fans! Stock on your car is a 4 blade, but a larger 17.6" 5 blade was used with a/c on the six, and is common to other V8 fans with a/c (as far as I know).

Thanks for all the advice.

To those who asked about the timing, i have no idea if it is retarded or not but i will look into it and get back to you.

JJ'65: Yeah its fine as long as it is going over 15 MPH... (filled it up to the brim and drove 400 miles fine on the way up to college...((average speed 55-65)))