yorkee

After replacing water pump last year, I start having mile overheating issue. I just want to share my experience…

My mild overheating issue originally started with temp gauge shoot up over 1/2 after exiting highway and fans turn on consistently. There is a little bit of coolant loss thought out few weeks. I start to fill it with distilled water, and try to vent it 100 times differently suggested by interweb… I tried to cycle the fan several times, tried to do it on a slope, try to lift up the front of the car (almost 30 degrees!) tried to use syringe to fill the air pocket, try to blow it by mouth, tried the brake bleeder method, I start replacing/filling coolant with water wetter instead of distilled water. None of those help.

There is no sign of coolant leaking anywhere. However, I always have an air bubble in the vent. I end up buying a coolant tester and blow it with 10psi. bang! coolant is leaking from the radiator. I guess I must've hit it with tools accidentally when I try to pull the front seal out.

so... $$$ new radiator, as well as low temp thermostat and low temp fan switch. $$$

Afterward, the car is running nice and cold. rarely over 1 bar on the temp gauge. I almost feel like its running too cold but rather this than overheat. That said, its still cold here. (less than 60F) However, the fan still turn on after I exit the highway. I hate listening to the fan turn on especially when its only 1 bar on the gauge.

This morning, I brave up and run the car with the fan unplugged. 58F this morning and I drove almost 30 miles on highway, exit the highway and go into mild traffic jam for few blocks, drive up 5 level of parking structure and the temp gauge was only 1.5 bar!

Knowing the overheating issue is fixed, I still hate the fact that the fan turn on too early. That said, I will probably hook the fan back up and run it as it and try the same test when its mid 80F out there. I am thinking about swapping the low temp fan switch to a normal temp fan switch, and leaving low temp thermostat there. I’ve heard low temp thermostat should go with low temp fan switch but I want to try with this combo.

Will see how it goes. Water-cooling adventure continue...

StoogeMoe

Well yeah. If you put a lower temperature fan switch in with the stock thermostat, the fans will run almost all the time. Not good for the wear of the fans. You should do them together. I'm not a big fan of the lower temperature thermostat and fan switch anyway, especially where you live. You shouldn't need it.

My fans never come on with highway use. They shouldn't. Not even in the summer when exiting, until you stop at a stoplight or something, and sit for a couple of minutes. Then the fans should be able to bring the temperature down to a point where they shut off.

Do you have an early car or later car?

yorkee

I have an earlier car.

I was using stock thermostat and fans switch before I swap out radiator. I have low temp thermostat and fan switch afterward.

I am thinking of low temp thermostat and normal fan switch.

Might consider switching normal thermostat and normal fanswitch if the combo above works well.

Going to be a pain in the butt to drain coolant and get that thermostat out that many times...

mytrplseven

Just spit-balling here, but are you sure the temp gauge is accurate? My car, as most do, runs at about 2/3rds the sweep of the temp gauge before the normal fan comes on. All three of my cars (85 1/2 and above) have all operated identically.