Hi

I've been driving my Brat more or less daily without any major issues since I bought it in August. A few days ago I drove it to work and when I started home that night the temperature gauge shot up to just under the red area. I did some reading, looked at HTKYSA a bit and decided that maybe it was the thermostat so I went to the dealer and ordered a new one but it won't be here for two weeks, so I went to an auto parts store so I would have a cheapie one to swap in, in the mean time (the brat's my daily.) Pulled the old thermostat (it was wide open... hmm) put in the new one.

By the time I was done sealing everything up again the old t-stat was closed, so obviously it's working fine. Started it up and after about 10min of idling the temp gauge was back within about 1/8" of the red area. Felt the inlet/outlet hoses on the rad, inlet was noticeably warmer to the touch, roughly what I would expect (ie can't hold on to it for more than a few seconds) outlet was pretty cool. So I'm wondering if it isn't just the temp sending unit but I can't figure out how to test that.

 

There's no play in the water pump, the hoses to the firewall for the heater core aren't leaking although they need replacing as they're pretty banged up.

It seems to be leaking a little bit of coolant on the passenger side, but I can't figure out where it's coming from. I need to put it up on stands so I can take a better look at it, but the rainy season is here so it's miserable to work on it.

 

I made sure the radiator had coolant up to the little fill-plate thing.

 

HTKYSA mentions using an engine thermometer in the radiator, but I can't seem to find anywhere to buy one.

 

Thoughts/help?

 

Thanks

Are the fan/s coming on?

Yes, but only when it idles for a few minutes, not constantly as I would expect if the thermoswitch was working correctly AND the engine was overheating.

Sounds like low coolant, or air in the block. Try filling aththe thermostat neck before installing the thermo.

 

squeeze on the hoses to help burp some air.

 

You will want to hold the idle up 1500 or 2000 rpms to draw in the fluids and circulate. When you let off the throttle, air will burp out.

 

you may have initially had a coolant loss.

 

if there is not enough coolant, no water passes over the thermostat, and it will not open. It is a little tricky to get it to open on fill up to get all the air out.

 

If and when you are sure the coolant is full, and you still have symptoms, check to see if bubbles are rising out of the radiator when it is running at temp. This could be clue to other problems.

Alright I'll try burping it, the thermostat was open (maybe just from high air temperature) when I pulled it. So it was functioning. But there was white crust underneath the thermostat cover, like possibly coolant was leaking there.

Miles was right, I parked it on a handy hill right by the parts store and ending up pouring a good 1/2-2/3 of a gallon of coolant into the poor thing. The gauge sat at the second line (not quite half way) all the way home. Now I just have to figure out where it lost all that coolant from....:-\