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I been having a overheating problem when my fan aren't kicking in. I found out that my lower radiator hose is cold when the engine is warm up. Upper hose was hot... so I suspect that my thermostat has fail so I pulled it out and replace it with a new one. I filled the radiator up and leave the cap off and started the engine. The coolant didn't suck it/move so I thought to myself maybe the thermostat haven't open yet. Waited till the engine get warm up and still it didn't move. So I end up pulling the new thermostat out and tested it along with the old one in a boil pan. The old one didn't open up but the new one did...
I closed everything and run the engine without the thermostat to see if the fluid is circulating and yes it does. I have to top off the radiator since fluid got suck down and I can see circulation. Both upper and lower hose got warm up so I wait till the engine cool down and open the thermostat housing and stick the new one back it. Started the car and the problem still presist. Engine got overheated and lower hose is still cold. I running out of option so my question is when I was running the engine without the thermostat and see that fluid is circulating, does that mean the water pump is good? I really don't want pull the water pump but is that my only option? The new thermostat open when I tested it but should I just go ahead and buy another one? Anyone have this problem before? Any advice is welcome...

Car was running fine and fan always kick in right after I turn off the ignition before.

boostlee

well i bought the mugen thermostat for my prelude but it does not fit on a h23 engine. what i did was i took my old thermostat and cut out the internals so it runs open all the time. its better for me in the miami hot weather and it wont hurt the cooling system. plus its cheapr than a new thermostat.

the thermostat you have is probably faulty or maybe did you install it backwards?

http://www.cardomain.com/id/boostlee

boostlee

i think your water pump is fine if it works when you take out the thermostat

AndyD

iTrader: (1)

Hmmm, this is VERY strange!!! The only thing I can think of is that your thermostat is the problem....but you tested it and it worked fine when placed in boiling water.

Do you think there is an issue with your thermostat housing??

Is it possible that you didn't install the thermostat the correct way?? Myabe you put the front part of the thermostat in the opposite direction??

special_edition

I take great detail of every parts I changes beside I have a helms manual so I positive that I have install it correctly. I can't seem to understand how the housing could be faulty since it's just a hole.

I went to exhange the new thermostat and ordered a new one. Mean while, I stick the old one back in which I pull it open and leave as it is. Engine tempt. is stablize but the fan doesn't seem to kick in. Let the car idle for like 10 min. or so, turn on A/c and both fan turn on. ??? Drove it to the bank and the parts store that like another 20 min and fan haven't turn on. Before I have the overheating problem, my fan would kick on everytime I turn off the ignition.

--boostlee-- Are you positive that its okay to run with the thermostat open all the time? Well, seem logical since it should be alway in the opening position when your engine is warm...side effect is it just take a while to get it warm up. Wait a minute, you basicly cutted the internal and leave a hole in there? I just pulled the coil back and leave it at a slight opening not all the way to the full position. Does your fan kick in like it suppose too?

boostlee

like you said, it will just take a little longer to warm up, but i cut out the internals with wire cutters. totally gutted the thermstat so it has a big hole in it. if you fans are not coming on, you might want to check the thermostat switch. i put in the mugen thermostat switch in my lude

does the fans turn on when you put on your a/c?