fan-tastic 3G!

Space1999 · Post by **Space1999** » Fri Aug 09, 2013 1:48 am

Is it just mine, or does everyone's 3G Prelude cooling fan cut in AFTER you've turned the engine off?

My fan seems hyperactive - it goes on in heavy traffic as it should and then off when it's cooled down a bit, but when I've turned the engine off and taken the keys out when I get home, it sometimes starts up again and runs for 5 or so minutes before switching off again!

Before you ask, temp gauge runs just under the half way mark and never goes higher, and the coolant was recently changed...

Is this a fault with the fan, or do they all do this? My friend had a Fiat X1/9 that behaved like this, but that's because it was a knackered old Fiat, but my lovely Prelude is a mint low mileage machine...

Edd · Post by **Edd** » Fri Aug 09, 2013 6:12 am

My old 3rd gen used to do that too, I'd forgotten about that.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Fri Aug 09, 2013 8:23 am

Various cars do this by design, so wouldn't worry about it.

Don't think the 4g does it though?

It's normal for engine temp to increase after switching off (no coolant or oil circulation, with big mass of hot metal in the middle)

All then depends where the coolant switch is located and whether the fan feed is taken from ignition or permanent live.

Confused · Post by **Confused** » Fri Aug 09, 2013 8:27 am

When you switch off the engine, your water pump stops circulating water around the coolant system.

However, the water does not instantly start cooling down, there is a lot of heat still in the engine block, so the coolant system is still "active".

Therefore, some cars have the fans hooked up so that they will still run whilst the engine is off so that it can still provide cooling to the engine, and stop the coolant getting too hot by taking away the additional heat that's dumped into the cooling system when you switch off.

Perfectly normal

More so on cars where the fan isn't controlled by the engine ECU but instead by a temperature switch in the coolant system.

Post by **NafemanNathan** » Fri Aug 09, 2013 8:37 am

My 3rd does exactly that (more recently with the hot weather we've been having to).

Space1999 wrote:Before you ask, temp gauge runs just under the half way mark and never goes higher, and the coolant was recently changed...

This statement ^^^ applies to me completely as well.

We noticed at the national meet that @CrunchyAdams82's 3rd however didn't come on after we'd been out on the exact same drive, but I believe he suspected he had a fan fault or something ???...

Don't worry, ours are running as Honda intended

91pREluDe · Post by **91pREluDe** » Fri Aug 09, 2013 10:04 am

Mine does that too and its all good. Nothing to worry just enjoy the ride!!!

'92 Si VTEC · Post by **jjmartin349571** » Fri Aug 09, 2013 12:45 pm

My 3G Accord does it too. It's a nice little bit of reassurance that it's all working as it should when I switch off and the fan hums away

Post by **RattyMcClelland** » Fri Aug 09, 2013 6:22 pm

Both of my 3rd gens did it. Its a turbo timer if anyone asks.

CrunchyAdams82 · Post by **CrunchyAdams82** » Fri Aug 09, 2013 7:01 pm

Na, my fans work just fine. Cut in just as they should do when out on the road, and temperature just below halfway.

The only difference is; if my fans are running when I park up, when I turn off the ignition/engine the fans cut off as well. Turn the ignition back on & they start up again.

So mine appear to be wired in line with the ignition. Not caused me any problems, but would be better if they kept running until the engine was suitably cooled.

Post by **RattyMcClelland** » Fri Aug 09, 2013 7:04 pm

CrunchyAdams82 wrote: The only difference is; if my fans are running when I park up, when I turn off the ignition/engine the fans cut off as well. Turn the ignition back on & they start up again.

But when you walk away from you can and go back 5mins later the fans will be on.
Mine never stayed on after ignition off but came on a few mins later.