[2000jack]

I have just started taking my "new" rat rod on the street for taking out the kinks. There is one kink I can't get out. What happens is I drive for about ten minutes to fifteen minutes and the car heats up to 235 degrees. That is when I stop driving it. I have a new mechanical gauge in it that I tested before I put it in the car. When I stop and put it in neutral I can rev up the engine to about 1500-2000 rpm for about 30 seconds or less and watch the gauge drop to 230. Wait 30 seconds and rev 30 secs and it drops to 230. Again with the cycle and it drops 220, you can actually watch the gauge needle fall. Over the course of 4 minutes or so it will drop to 205 and stay there. I first thought that I had a bad thermostat, I change it with one I had tested, a 180 degree one and had the same results. I tested the old one and it worked fine anyway. It has a new aluminum radiator. When I got out of the car I looked to see if the bottom hose had collapsed, but it didn't. The top one you can see as you drive down the street. Any ideas?

[burnt olds]

you want see the hose collapse at idle .
is there a spring in it ?
how much is the cylinders bored to ?
are you running a serpentine belt and the wrong water pump , direction of flow , or v belts and wrong water pump .

[2000jack]

Originally Posted by burnt olds

you want see the hose collapse at idle .
is there a spring in it ?
how much is the cylinders bored to ?
are you running a serpentine belt and the wrong water pump , direction of flow , or v belts and wrong water pump .

these are new hoses and the top I can see when it is running and I looked at both when I got out of the car and they both looked fine. The cylinders are stock as far as I know it, seems to be a standard 305. It runs a V belt system and I know that when I bought the rebuilt water pump for another car but did not use it, I got for a 68 Camaro or something like that. I actually took the plate off at that time and double checked it to make sure that it rotated in the correct direction. Under power it seems tro get hot and at idle it cools down.

[2000jack]

It seems that I put a serpentine fan on instead of the correct one. I will change it today. Well I drove for twenty minutes and it never went over 190, before it was 6/7 minutes and it was 230.