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last nite i was driving to my boyz house and my car started over heating, i mean it took about 3 seconds to get to red line, i pulled over and blasted my A/C in case my cooling fan wasnt kicking in, i checked under the hood, and the cooling fan was working. I then checked my coolant, and its full, but looks extremely dirty. What can it be... please tell me its not my waterpump.

PS: heat in my car doesnt work - blows cold air.

 
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Uhh.....Thermostat?

 
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yep or water pump....

how many miles?

year make modle.

or do you drive an R34?

 
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03 civic Si (EX in U.S.)
94 K KM

 
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sounds like your thermostat. it sounds stuck closed. thus why the car overheats and why you have no heat.

 
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I'm going with thermostat here too. Whenever I've had a water pump start to go, it leaked first. It's possible that it could fail and never leak, just seize up or something, but you would probably hear the belt on the pulley that wasn't turning. Either way, the thermostat is the cheaper fix, and the more likely problem. Definitely replace that first.

 
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and if you want to be sure...take out the thermostat and throw it in a pot of boiling water and see if it opens...simple check...but its so cheap..i would just replace it anyway.

 
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^ good idea

 
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I agree its probably the thermostat!! but if your coolant is dirty i would also be save and flush it (not hard) so that you are sure that it is not gunking up in your radiator and blocking anything.

 
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check the thermostat anyway to verify it was that. Because if it opens, then you know you have a bigger problem.

 
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thermostat then flush, flush will do nothing if you have a stuck thermostat