Oversized Radiator??

[squeekyM]

Hi Everyone,

I am looking at a few 60's. One of them, the owner replaced the radiator with a larger capacity one. He says ever since it was replaced, the temp gauge dips into the hot section every now and then, but isnt acutally over heating "its just that sensor is setup for the older/OE sized radiator."

From everything that I know, why would increased capacity cause the gauge to fluxuate like that? The temp sensor is merely a thermometer and regaurdless of capacity or water flow should read accurately. Am I wrong? Do these gauges go faulty? are they considered to be electrical(sending unit) or a mechanical gauge?

Thanks for the help.

 

[Waggoner5]

No it should not do that. There is no way that a larger radiator could change the way the gauge works. If it has a larger radiator, it should run cooler. If it fluctuates, it sounds like a thermostat.

 

[lovetoski]

Could also be the ground gremlin in the guage. There is a known problem in that the fuel guage and temp guage share a ground. The ground on the fuel guage gets corroded over time, and it starts to "act up." What this means is that you are driving along enjoying the scenery when all of a sudden both the temp and fuel guages spike to the top. It'll freakin' scare you out of your seat the first time it happens. Then the needles go back down and you realize something wierd is up...the gauge ground gremlin gotcha good!

 

[squeekyM]

Thanks for the replies. The owner mentioned that the fuel gauge trips out every now and then. Sounds like the grounding issue. Would this ground happen to be attached to the gas tank??? or somewhere else in the cab? Thanks again.

 

[MR.FJ60]

I'm going to go with Wagg on this one, there is no way that a bigger Rad would do that.

 

[Waggoner5]

The ground issue is usually found at the back of the cluster. It causes the fuel gauge and temp gauge to simutaneously run to the red. If the fuel gauge seems to work fine but the temp gauge is moving, I would look elsewhere.

 

[Pluton]

The main reason to put a larger cap. radiator in is if you move to a larger displacement(higher horsepower) engine. The stock water pump is intended to push the correct amount of coolant through the STOCK radiator. The flow rate is lower through the larger radiator. Therefore, you get higher coolant temps, especially at highway speeds, when the fan does less and you're depending more on the natural air flow through the rad.