Overheating issues

Hello,

Great forum here, been sat browsing looking for answers to an issue a friend is having.

The car is a 98 CRV (I think) can confirm this if need be.

Basically it's overheating.

Friend said it gets very hot when idle.
A friend had a similar issue on his bike, and it was the fan.

So popped the hood. Started the engine and low and behold, neither fan spinning. Although from what i've learnt on here. on is for AC and one for engine.

I've checked the fuses and the relays and still no fans.

After stumbling on to this forum and a few previous posts. I hit the AC button and turned that up and started it. Both fans kick into life.

So fans and fuses and relays are all ok i assume.

So is it a sensor issue, if so what/where/how/why
or is it a switch issue, again if so what/where/how/why

Any and all help would be appreciated.

I've already looked at these threads if anyone else is looking for help on temp issues.

http://www.crvownersclub.com/forums/showthread.php?t=4049
http://www.crvownersclub.com/forums/showthread.php?t=5450
http://www.crvownersclub.com/forums/showthread.php?t=4242
http://www.crvownersclub.com/forums/showthread.php?t=3666
http://www.crvownersclub.com/forums/showthread.php?t=1816

the fans dont come on at start up, its only when the engine is hot, have you checked the thermostat and water pump?

oops


should of said, i waited until temp gauge gets to half way before i decided they weren't starting

At what point would/should they kick in

Your thermostat is half stuck closed not allowing coolant to cool engine. My 1995 accord would do this also on and off. Replacing the thermostat fixed the problem.

okiedokies,

so, is the thermostat on the crv the same as my bike then.

A spring loaded thingie with holes to let fluid out.

And even if it was wedged shut as you say.

Surely the fans have to kick in at somepoint.


Without turning on the AC, i can't make this happen.

I'll try again later, let the temp gague run higher this time and see.

okiedokies,

so, is the thermostat on the crv the same as my bike then.

A spring loaded thingie with holes to let fluid out.

And even if it was wedged shut as you say.

Surely the fans have to kick in at somepoint.


Without turning on the AC, i can't make this happen.

I'll try again later, let the temp gague run higher this time and see.

There are a couple things working against you here:

Firstly, Most Thermostats these days (at least the Honda ones) will not fail CLOSED, so there isn't much chance of the engine overheating.

BUT an aftermarket T-stat will often cause erratic temperature control. Seems they don't always pass as much coolant as the OE parts.

Secondly, the temperature gauge does not actually change with temperature once it is in the warmed-up zone. It is "damped" so that it will always point at the "normal" setting.

The best way to test is to remove the rad cap (cold) and insert a thermometer. Then run the engine until the coolant starts to flow (you will feel it get hot)

The thermometer will measure the temperature for you.

Some scan-tools will do the same for you. I have a ScanGaugeII and that tells you EXACTLY how hot the engine is.

will have a look at it tomorrow then,

but still looking to know,

Roughly when should the fans come on?