Hot at highway speeds

roccodart440 said

So my GVOD controller took a ****. I have a new one on order. This has however exposed a cooling issue.

My car has 4.56 gears with 28" tall tires. It has a GPS speedo so 55mph is 3,000 RPM.

Around town, at idle and slower speeds with fan on it's fine. 180ish.

On the highway it will go to 200, even approach 210. If I turn fans on it will come down slowly. Get into town and leave fans on the temp comes right down.

This was not an issue witht he GVOD and lower cruise RPm.

What would cause a temp increase at highway speeds when traveling at more RPm?

Click to expand...

Mine also does this and I don't like seeing 210 either, even if it isn't technically overheating. It runs 3100 ish rpm at 60 too. I'm running an electric water pump so obviously no thermostat. I've put a restriction washer in but I think it actually made things worse. The reasoning behind it (I think) is because the restriction washer is actually causing the coolant to shoot through the washer at a high velocity and thus creating aeration (this I can see). With all the aeration in the coolant, this leaves less surface area when it goes through the radiator and does not cool as efficiently. At least that's my theory. I'm probably going to end up taking the restriction washer back out. Sealing around the radiator would be another good idea. I've also been suggested to add a front air dam (kind of like a lot of newer cars have). This will create an area of low pressure behind the radiator and help pull air through it. But unfortunatly our old cars don't always look right with an air damn up front and it's not like you can just go buy one and bolt it right on that I know of.