94 Accord--Engine temp goes up when fan is off

My 94 Honda Accord has a strange problem. The engine temperature would go up if I don't turn the heat and fan to the extreme to let the heat go.
If I turn off the fan, the temperature will go up in 20-30 minutes. But if I leave the fun on to the maximum, the car would run without any problem. But I have to get this done before summer comes.
Any suggestions would be appreciated.

most likely its a bad thermostat.

does radiator fan turns on when temperature gauge shows high temperature?

The radiator works well -- just had it changed a couple months ago.
Thanks a lot for your suggestions. I'll have the thermostat checked.

Your thermostat is stuck closed, and must be replaced. When you run the fan over the heater coil, its acting like a mini-radiator and cooling the engine coolant thats running through it. Not a hard or expensive job to do. If you do it yourself make sure you get the larger ROUND thermostat gasket and not the O-Ring type for the other radiator hose port. Honda delaer will know what to sell you, the thermostat and gasket should not run you more than about $15 if you pick it up at the parts counter.

The radiator works well -- just had it changed a couple months ago.

just to verify, radiator fan works when engine gets hot?

FYI:........Turning the heat on inside the car is a trick that keeps the car from overheating when the temperature is rising. It just deferrs the problem but doesn't help or solve.

"just to verify, radiator fan works when engine gets hot?"
-- How could you tell whether radiator fan is working when engine is on? I know it works when engine is off.
My engine temp went up to about 3/4 level on the panel when I first noticed it. I don't remember whether the radiator fan was on or not at that time. But ever since I turn the heat on inside the car, the engine temp was actually staying below 1/2 level. It will go up to 1/2 when I turn off heating. But I never let the engine overheat again.

I brought it to the mechanic last week. He let the engine run for over 40 minutes and didn't see any problem (the heating was on inside the car). That's why I come here to seek help.
Should I replace the coolant too if I want to do it by myself?
Thank you guys for all your suggestions.

A good way to check and see if your fan(s) (mine has 2 ) are working properly is to run your car at idle ... then turn AC on if you hear or visually see the fans turn on the voila they are operating normally....Ive got an accord that I just replaced the thermostat in and found that the NAPA, Autozone...etc. thermostat acts differently than what the Honda OEM thermostat does. For whatever reason I put this one in and worked like a charm.

A 3/4 temp gauge is not normal. Your gauge should be between 1/4 and 1/2 when everything is running properly. As Methodman said, if you turn your A/C on and the fans run, they are not faulty. If your shutting your engine off and they are on, then your running too hot. When your at 3/4 gauge and your heat is off, if you drive the car does the temp lower to 1/2 gauge or lower? If not your thermostat is definitely 100% stuck closed. Replace your thermostat. Your mechanic saw no problem because he circumvented the problem by running the heater blower in high. You already know this helps to keep the operating temp nearer to normal. If your coolant has not been replaced recently, definitely replace it, and the radiator hoses as well. The lower hose at the radiator is a peach to get to, so make sure you can get under the car to get it off before you start. Cut the old ones off with a single edged razor! They will be bonded on pretty well from age and heat, and yanking on them or twisting them will break your radiator as its only plastic at the connections. If you ever had the timing belt changed, and on a 1994 if you have 90/K miles or more on the car you should have, the shop should have replaced the coolant at that time. Look at the coolant, if its bright green and clear, its probably fresh, if its murky and/or brownish its old and needs to be replaced.

How do I replace a/c fan myself?? I have problem with my fans, when the temp is high, onlyradiator fan is running good while my a/c is turning slowly.
or are both fans supposed to run at high temp?

I try to remove the 2 bolts on top of a/c fan, something is holding down the fan but I couldn;t see what it is.

BTW, I have 90 accord. Help..

This is such a friendly forum. I got a lot of useful information. Thanks to everyone!
I got the thermostat replaced and now everything works fine. The coolant is changed, too.
My90AccordEx -- I don't know much about cars. Sorry I couldn't answer your question. If you don't get much feedback, you might want to start a new thread on this forum so people will pay attention to it. Good luck!

I think these guys are right, it's probably your thermostat that's going bad, you might even have a small crack somewhere in your radiator. Either way it's probably because that dang thermostat. I would change it first becuase it's easy and cheap. It was located on the back left of the engine right under the throttle body on my 1994 accord ex. check out thread "radiator" I explained how to change one but you could use the part where I changed the thermostat 20-30 min job! In and out!