Highway cooling issue
- Thread starter nawlins-tim
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Is this a wide V-8 style radiator? The core support/radiator seal sheet metal was used to fill the hole when a narrow 6 cyl radiator was used but the V-8 radiator filled the whole area. Also, highway speed airflow should be enough all by itself to cool the radiator without a fan at all. You might try temporarily duct taping/cardboard any gaps and leak spots until you pinpoint the problem. What temp stat are you using? 160º I hope. Did you test it in boiling water? Many fail that test.
205 is a good temperature for the engine to operate, boils the moisture out of the oil and increases engine life. You are worrying over nothing. 220 is when you should worry.
I'm thinking with the engine being a new rebuild, it's still a bit on the tight side, which equates to additional friction and increased temps.
My engine never ran over 185-190 on the highway. I've always used a Modine 3-row radiator, with of all things a 7-blade Hayden flex fan. I changed back to a 7-blade manual fan with new HD clutch.
I would also think it would run cooler at highway speed with air being forced thru.
I've always used a 160 thermostat.
How is it jetted? Could it be running a little lean?
My engine never ran over 185-190 on the highway. I've always used a Modine 3-row radiator, with of all things a 7-blade Hayden flex fan. I changed back to a 7-blade manual fan with new HD clutch.
I would also think it would run cooler at highway speed with air being forced thru.
I've always used a 160 thermostat.
How is it jetted? Could it be running a little lean?
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I had a 180 thermostat in my car and around town the temperature was fine but when I drove on the freeway it would climb hotter and hotter. I put the correct 195 AC Delco high flow thermostat on there and it keeps the temperature right where it needs to be (which for me seems to be just a little under the 220 mark). I believe most cars run on 195 thermostats, so if your car is running on a 180 or lower then I'd suggest replacing it.
It may seem counter-intuitive but the higher temperature thermostat actually helps to cool the car better and more efficiently.
It may seem counter-intuitive but the higher temperature thermostat actually helps to cool the car better and more efficiently.
As others have said, 205 is just fine. But what you're experiencing is an airflow issue. With the fan off, it blocks airflow, especially if it's sealed/cowled to the radiator effectively. It doesn't hurt any to have it run all the time BTW...unless it's an expensive fan you don't want to wear out. The other common issue is missing seals/close-outs around the radiator in the support area. I closed those holes out and dropped my cruise temp by 10 degrees.
Guys Please!! I know 205* aint too hot but that is where I stop it from increasing by turning on the Taurus fan. I have a new champion 3 row aluminum radiator too. You cant say my temps should jump up when going highway speed.
There is a couple inches of space on each side the radiator, which is why I'm looking for some of that original insulation that feed air into the rad instead of around it. some pics of that material on a Malibu or the actual pieces is all I need. Thanks anyway.
There is a couple inches of space on each side the radiator, which is why I'm looking for some of that original insulation that feed air into the rad instead of around it. some pics of that material on a Malibu or the actual pieces is all I need. Thanks anyway.
Do you know what thermostat you are running right now? I had similar problems to you a few weeks back. I changed the thermostat back to stock and now I can drive on the freeway when it's 100 outside with 4 people in the car and AC on without a problem.
With the fan off it does not block air flow, the fan on puts up a wall that blocks air flow. Travelling at 60 mph drives the air through the rad faster than a fan can do it. Just because the engine raises to 205 there nothing wrong with that, in fact it's a great temp for a sbc.
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