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i just bought a '93 civic with an ls/vtec yesterday and had to drive it home 7 hrs. during the drive the temp. gauge would climb and then fall back down again(almost instantly) it was not a steady drop. now, the front bumper is completely smooth(no openings) except for two four inch holes in front of the radiator(stock 95 ex). the guy i bought it from said he never had any overheating poroblems and the car never smelled/sounded/looked like it was having problems. i was wondering what would cause this? if it was the temp. sensor or if maybe the guage is messed up. any help is appreciated!

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Kamin

why the **** is the front bumper completley smooth?

YES this can cause overheating problems, think about it, no air can get into the radiator.

HondaCivicAddict

Could be your radiator fan. Its probably not working. Make sure it turns on. Connect the fan with two wires straight onto the battery and it should turn on. If it does it could be your fan relay. If your fan doesn't turn on then you need to get a new fan.

ncnative

I think your fan is working, it may not be working like it should, ie, coming on at the correct temp, but the fan is what is causing the temp to drop, once the water temp gets high enough the fan is coming on. So what you are seeing on your gauge is the water temp goes high- the fan kicks in- the water temp drops- and then the cycle is repeated. I just had the same problem on a 1994 Civic, mine ended up being the head gasket, not what you wanted to hear I'm sure. First, let your car cool down, then check the water level in your radiator. If your radiator is full it could be an air flow problem. If it is low, fill it, drive the car until it has had time to reach normal operating temp, see if the temp gauge stabilizes, if so then you will know the problem you were seeing before is the result of low coolant. If the water was low you will have to find out where you are losing water. Either it is leaking out or it is leaking in, out, meaning you should see liquid dripping somewhere, in, meaning the coolant is getting into the engine and being consumed along with the fuel or possibly mixing with your oil and ending up in the crankcase or both, neither of which are good. Also as you have read, checking the fan is quick and easy (we should always the quick and easy things first), replacing the thermostat is another quick and easy, even though it dosen't sound like a thermostat problem. GOOD LUCK

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the bumper is completely smooth because he used this as a drag car before. but it does have two, four inch holes in it. i am replacing this asap though to a stock bumper.

the fan does turn on, it has a switch mounted in the dash to turn it on. and yes, i have heard it running while the car was off. the water level in the car was fine as i checked it during the trip home a couple of times. when i would cruise at a steady speed of 70 mph the gauge was fine. or if it started to climb and i would hit the gas a little it would fall, also letting off the gas to slow it down(using the engines compression) would also make the temp. drop. i do believe it is the bumper and such a long trip. thanks for the suggestions keep em coming

SlowReaction

Could possibly be a air in the system. I would flush the system and fill with new coolant. Will only cost you few bucks.

Zakar

hondas are very touchy about air in the cooling system... park on a hill with the front end up in the air... and open the little bleeder on the engine side of the upper rad hose... you may need to rev it a little to get all the air out...

i bet thats your problem

94civicexlsvtec

hey man good to see you made it back.. i should have told you that it doesnt have a thermostat in it so it does act kinda strange going at highway speeds.sorry i forgot to tell you that

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thanks i guess i will be adding that to it

yeah, it took me 8 hrs to get back because of stops and such, even had an offer from a guy with a turbo integra to race, in knoxville. i had to turn him down being so far from home.

other than the temp. the car ran great and again, i appreciate you meeting me at the airport again

litterbox

Install thermostat
Drain, flush, replace coolant.

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thats the plan now

NismoNX

I can't believe it made it. You've got ballz dude.

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i cant believe i didnt get pulled over, i saw atleast 20 cops on the way. about 10 of them in knoxville.