'91 Civic questions

[Stian]

Hi,

Just bought a 1991 Honda Civiv 1.4L hatchback with 265k km on it.
I have a question about temperature of the engine, the radiator and its fan..

The car starts perfectly fine, but it sounds like it constantly runs on a high rpm. Also I have never observed the radiator fan turning on.

The temp gauge inside the car is not showing any signs of overheating no matter how far I drive.

There doesnt seem to be any extra usage or leakage of coolant from the external tank.

I just think it is weird that the radiator fan never turns on.
I have read on a forum that the fan only kicks in when either the A/C is on (a feature this car doesnt have) or when the temp of the engine is too high.. (obviously). Is this correct?

Could it be a thermostat problem regarding the high rpm and the fan?

Any advice would be much appreciated.

[crxlvr]

might just have a bad sensor. test the fan switch.

[Stian]

Thanks for reply
I tried to search the forums for "fan switch", but didnt get any smarter.
Could you please elaborate?

Thanks again.

[viper-blue]

there is a sending unit on the back of the engine right under the intake manifold. It works with the cooling fan relay to tell the system when to turn on the fan, and lets the ecm know what the temp is. The relay is near the rad. If your revs are fluctuating its likely the sending unit on the back of the engine though. Try to get a manual so you can troubleshoot it, or just get a used one from the wrecker

[Stian]

The idle rpm is not fluctuating. Its just a steady high rpm which doesnt go any lower even when the car has been idling for 10-15+ minutes.

I dont really know where to begin. As I mentioned it is not overheating. Its just that the fan never comes on.

I`ll see if I can get hold of a repair manual.

Should I be worried about the radiator fan not turning on?
Since the temp gauge in the car is showing no sign of overheating could the temp sensor be defect (as mentioned in the first reply)?

Thanks for helping me out.

[turbcivic]

could be a lack of a thermo. the car will never come up to the proper temp so the ecu will still be stuck in cold start mode, giving you the higher idle.

[viper-blue]

The temp gauge isn't the best indicator of actual temperature. The fan rarely comes on in cooler temperatures as cooling systems on civics are very good. But if your sitting in rush hour traffic for hours on end than the car is definately overheating if the fan isn't coming on. The idle air control valve will also cause high idle, but you might wanna check the thermostat to. The gauge should be sitting at about half even while on the highway. If your in doubt replace it anyhow. That will make the idle stay high, and prevent the car from getting to optimal temps, or overheating. Let the car idle for 15 or 20 mins then feel the rad hoses..both should be nice and hot

[Stian]

Hi,

Thanks again for reply.

My wife tells me I am making problems out of nothing.. hehe.
Well the radiator hoses are very warm.
Temps here in this part of Norway is not very high. We are talking +15 degrees Celcius mostly (been a shitty summer). Do not spend hours in rush traffic either.

I checked the cars previous EU tests (we have to do these tests once every two years). Mechanics go over every inch of the car in order to make sure it is up to the task of driving on our roads. This car has had zero errors the past four years. That is an amazing feat. Other cars I`ve owned have had long lists over things needed to be fixed to get it through 100%.

Regards,
Stian