I installed an alumitech radiator, flex-a-lite 298 fans and a stewart stage 1 high flow water pump on the 402 (in a 70 chevelle). This is the first big block I’ve had and I’m having issues with it running too cool going down the road.

I have a 180 stat and the fans kick on at 185 and off at 170 like they should. The temp runs great with the car idling in the shop but when I get on the road (Kansas temps of 40-50 for a high), the car won’t get past 160, even after driving for 10 miles with the heater off.

I have the bypass hose hooked up. Is this causing my issue or is the cooling system just working too dang good?? Any ideas? It’s not cold for long in central Kansas and I built the cooling system to handle the extreme Ks heat and humidity so I can live with cooler temps in the winter if need be.

Thanks,
Jason

Jason,the almatech rad is doing its job very well,you will be happen with that in 90 deg summer weahter.

But 160 is too cold for best oil temp and perf in general,maybe you need to run a 190 deg stat for colder months but make sure to reinstall 180 deg high flow stat for summer.

You could use a piece of cardboard or clear plexy to cover approx 1/4-1/3 of rad to let it warnm up a little. Doing this would be the esiest way out if you dont plaln on much driving over the winter months,would avoid the hastle/mess of changing stats 2x yrly.

Scott

If the thermostat is functioning, the temperature can't remain lower than the thermostat setting because the coolant can't circulate through the radiator until the thermostat begins to crack open. Either the thermostat is not functioning, or the temp indicator is inaccurate. Radiator and fan got nothing to do with this situation. Its either the routing of coolant or operation/non-operation of the thermostat.

I bet it is your gauge I would buy a seperate gauge and run both for awhile and see if they match. I live in Kansas also.:D

It's possible you are using the heater too much. ;) Seriously - run a 190° T-stat all the time, it won't hurt anything. You're cooling system is working well - but do check the gauge just for good measure.

Jason,the almatech rad is doing its job very well,you will be happen with that in 90 deg summer weahter.

But 160 is too cold for best oil temp and perf in general,maybe you need to run a 190 deg stat for colder months but make sure to reinstall 180 deg high flow stat for summer.

You could use a piece of cardboard or clear plexy to cover approx 1/4-1/3 of rad to let it warnm up a little. Doing this would be the esiest way out if you dont plaln on much driving over the winter months,would avoid the hastle/mess of changing stats 2x yrly.

Scott


<sigh> For those of you who have spent any time in the colder latitudes you already know that the piece of cardboard Mr. SWHEATON refers to is a large squarish piece of cardboard out of which you have cut a circle in the center carefully placed such that your fan will not be unbalanced by the interrupted airflow of a random chunk of cardboard stuffed in front of your radiator.

Golly Gee! I haven't typed a coherent sentance that long in quite a while :)

I wish we had that problem down here, we can never get them cool enough ! I'd go with a 180
dave

I've read a LOT of old posts on this very topic where people have trouble getting the engines to cool with a 180 stat in cooler climates. I believe I'm correct in saying the stat is not simply an "open/closed" piece. It will start to open prior to the nominal 180 temp. I'm wondering if the high flow stat I have starts to crack open at 160 and the flow at this point, teamed with the flow of the high flow water pump and the bypass hose are keeping the car at that particular temp driving down the highway at 55 mph??

My autometer gauge is reading accurate I believe. I've verified with another known good gauge. Plus with the car idling in the shop (on the same 45 degree day), the temp gets up to 180 like it should, when the temp reaches 185 the fans kick on and cool the car to 170, then the fans kick off. This is all proven by the gauge.

Again, I could not find a given answer with this question in the previous posts. I'll try a 195 stat to see what that does which means I'll also have to install a sending unit for my fans that works with the high flow 195 stat. It'll probably be another week before the parts get here. If theory holds true, with a 195 stat the car should only reach approx 175 or so going down the road on a cool day. We'll see.

Any other insight is appreciated.

Same problem here...
Aluminum heads, intake and radiator, large capacity water jacket block, clutch fan/shroud, 180* hi-flow thermostat.
There have been times where I've left the car running in the staging lanes just to get some decent heat in the engine.
NEVER runs over 180 and I'm sure the gauge is accurate.

Just a recap,i never said to completely cover the radiator,i just said to cover only 1/4 to 1/3 of it max (from the bottom up is what i do) just to reduce some airflow to get temps up a few deg. He can watch his tep gauge to ensure things are ok if he overdoes it covering too much of the radiator.

This works great for me and is not an issue,i have lived in upstate NY for 51 yrs and used this process many times for more heat. There is really no need to go nuts covering the complete rad with cardboard or what ever and then cutting a hole for the fan,eps if he runs a clutch fan that will not likely be engauged anyways since he runnign on the cool side.

I just suggested this as a quick easy way to raise temps a little if he wants for limited crusing in the winter without bothering to change t/stats and slight mess involved to do so.

Scott

Scott,

I know just what you are talking about. I've used cardboard before. I'm borderline redneck in this part of the country and enjoy every second of it. I am going to only cover one side of the rad approx 1/4-1/3 to see what that does for the temp on the hwy.

I am running electric fans with an alumitech radiator so the cardboard shouldn't hurt the fans too much. I'll keep you posted. I appreciate the suggestion as I don't want to change the stat and sending unit (for the fans) if simple cardboard will do the trick for now.