small block overheating

small block 350 in a 94 S10, It has a brand new radiator in it, however it is the same model as the one that came with the original 4.3 liter vortec. I went with this radiator because the guy at the shop said it would be more than capable. I have also installed two electric fans (1 ten inch and one 12 inch) in the front of the radiator (and yes they are both blowing not pulling). I swiched the original thermostat with a 180 degree one. temp climbs to 210 in just a few minutes. Could it just be that I do, in fact need a bigger radiator? or are there any other areas I would need to look into first? Thanks for any help

Hey Joshua,

You are experiencing a common problem associated with S-10 V8 conversions. Some of the reasons are: small engine compartment, radiator too small (stock usually not efficient enough), too much anitfreeze, faulty pump, ect.

A radiator from a 1986-1988 Corvette( I think this is correct) is highly recommended for its high flow rate and heat exchanging ability. Or an aluminum 4 core radiator should work as well. If you are running headers, that contributes alot to the heat as well as how much power you are making. Some folks remove the inner fenders to provide assisted air flow, but this can get kind of messy if you are a daily driver (rain, snow, ect.). I tried it and it didnt seem to improve things much. You also need to make sure the engine is tuned correctly. With the fans mounted on the front of the radiator I would think that alone would restrict airflow to it. Try to mount the large one on the back so it will pull ( if it is reversable) and see how that works. I dont think you are going to have much luck with the stock rad. But it you are not making that much power or running headers you might luck out and get by.:)

BTW, 210 doesnt scare me that much. But you have to run enough pressure on the system to keep coolant from boiling. A 50\50 ratio of antifreeze should be plenty if not too much. I go about 40\60 and have no problems.

Hey man thanks for the info. definitely some things to think about. I am running headers, and do still have the inner fenders, but im not making that much power (probably only about 300hp). I originally had the fans mounted in back but with the same results. This is my first build so I don't know that much, What would be a critical temp if 210 isn't that bad, This is where I have always shut it down?

Thanks in advance

Where your coolant boils depends on the mix of antifreeze and the pressure on the system. With a 50\50 mix, the coolant would have a boiling point of approx. 225F. Adding 14 to 15 pounds of pressure to the system adds about 45F to the boiling point thus providing about 265F boil over protection. If my engine was at 225 to 230 and would not cool down with fans, then I would consider that as a little too warm, but it all depends on what type of setup you are running. Someone else on the forum may be able to explain this better as far as aluminum verses cast iron and heat tolerances. This is the extent of my knowlege. Also, if you are making 300HP and running headers for a s-10, you will most likely need to go with a custom radiator setup. I dont think the small stock rad will perform if you want to stay below 200F.Hope this helps.:)

We've run a 350 S10 for years. You do need more radiator. Ours has a custom four-core with half-ton truck tanks, built as big as will fit the support. No heating problems at all, with engine fan only.

Thanks guys for all the advice.

Turns out the engine had lost timing due to the fact the bolt holding the distributor had only been hand tightl. I went ahead and put in a 160 thermostat as well and it hasn't been over 185 yet.

I set the timing at 5 degrees btdc. does this sound about right? If not, what would be optimal?

thanks again

I would think that if your engine is mechanically sound that you could run about 12deg. BTDC initial advance. Of course this all depends on the fuel as well. Most of the time the more octane you run will allow more advance, but make sure you dont have detonation. If she pings then back the timing off until its gone.

to also decrease heat in a tight engine bay with headers.... wrap them... you would be amazed how much that'll help you... goodluck