Another overheating thread

[twobjshelbys]

Originally Posted by twobjshelbys

But isn't that what the surge tank is supposed to accomplish? Do I really need both of these?

Last night I filled the tank and let the engine warm up until the thermostat opened up and started to flow. It burped twice and then flowed nicely. I put the cap on and went for a drive. It still spiked to over 110C and stayed there for a while. By that time the oil temp was at 95C and then the water temp went down to 65C and seemed to stick. I was running about 4500RPM so I wonder if the lower hoses are collapsing?

Tonight I might just try to duct tape a liter coke bottle to the inside somewhere and see if that helps.

I also turned off the inside fan and it didn't change temp.

I'm going to leave it with my mechanic on Friday so he can drive it to see what it does, fully drain the system and pressure/flow test the radiator.

I did the coke bottle experiment:





And it shows some promise. There might have been another air bubble too. Tonight while I was putting in the coke bottle overflow tank I started it up until the the thermo opened, filled up the expansion tank to the top and put a 20lb cap on. I had put a little water (I marked it with a sharpie) in the bottom of the coke bottle so the tube would be a vacuum. Then took it for a drive.

This time it was behaving much better. I suspect there was still an air bubble yesterday and that today. Water temp only briefly (when I was going 65 in 3rd at about 4500RPM) went above 100. Oil temp was also about 110. The temp did go up but only when I was running high RPM. After I slowed down it went down slowly. By the time I was going street speed back in town it was back at about 80C, and the oil temp went back down too.

I don't have a good fast road - too many cops - so I was running in 3rd at 65 (speed limit is 60 but too many slow cars) at 4000RPM during the load test.

I still see some fluid weeping in the upper right corner of the radiator and I'm Positive it is not from the vent pipe. I'll drive it for a few days and see what happens but I'm still going to get the radiator pressure tested.

Tomorrow morning I'll check the cool engine against the sharpie marker. If this is all right I'll try to find one of the bladder type expansion tanks (like they used on the old Mustangs) and tuck it in the passenger side above the pipes.