Civic hybrid: rad fan always runs on shutoff?

samwichse · 11-05-2011, 10:39 AM

Hello...

I've got a Civic hybrid, and the dang thing has been bugging me... the radiator fan always comes on after I turn off the ignition. My Insight didn't do this, and I could come back 10 minutes later, drive off and be autostopping withing .1-.2 miles. With the cooling fan running every time the engine is cut off, now I come back 10 minutes later and the temp gauge is back at the minimum and I have to either idle at every light for 1.5 miles or manually turn the car at lights.

So far it has happened down to 50 degrees (haven't seen any temps lower than that).

What gives?

Sam

Cobb · 11-05-2011, 06:08 PM

I had an 81 rabbit that did that. Seemed the t-stat for the electric fan worked with the key off and the car got hotter when off than on as the coolant quit circulating.

My Insight shuts down at key off and even hear the fans power off when it goes into auto stop.

samwichse · 11-06-2011, 09:59 AM

I'm just wondering if anyone else has seen this behavior or not.

I mean, I don't think the car is overheating, but the "half bars" temperature gauge also seems to work identically to the one in the Insight: near uselessly.

timny1984 · 11-07-2011, 12:20 PM

That is "correct" behavior for the HCH. It really annoys me too. I have no idea why they decided the fan needs to run so much. And the thing is pretty loud too! I finally parked next to someone with a HCH one day and they weren't in their car but the fan was running so I took that to mean it's "normal" to run like that.
I can't remember last winter if the fan is on as much since it was so long ago. maybe we (not me, haha) could figure out a way to change that. Winter is closing in fast and soon we'll need all the heat we can get.

Tim

Ps this behavior is completely different than the Insight

samwichse · 11-07-2011, 01:26 PM

Maybe as simple as splicing a resistor in line with a temperature sensor somewhere? I assume the ECU is getting the outside temperature from somewhere and making the decision based on both engine temperature and outside temperature... this morning when I got into work it was about 45 and the fan finally didn't come on when parked.

kennysmith · 11-07-2011, 02:18 PM

My 2003 HCH also has the fan running forever after shut off. I never thought about AS being affected but it makes sense. Maybe because we don't drive short distances. I drive the Insight, wife drives the HCH but I'll try to notice next time I drive it.

Willie Williford · 11-07-2011, 06:15 PM

You have to understand that Honda programs the ECU to keep the engines running in such a narrow temperature window (min vs max) both for economy and emissions that the fan will be running when you least expect it.
HTH
Willie

Cobb · 11-07-2011, 06:45 PM

I guess you could try one of those anti battery drain devices that you hook to your battery post and connector. This way it would interrupt the larger current flow, but allow the smaller one for radio stations and the cars computer.

Interesting though, the Toyota pumps its coolant into an insulated bottle to reuse it on the next start up to aid in a fast start up. Honda turns on the cooling fan to lower the engine temp.

samwichse · 11-07-2011, 06:48 PM

Google searching turned up a million people asking about this, and a million "it's probably normal" responses... but I'd like to change this behavior to more like my old Insight.

Someone did suggest a kludge method to get around it:

Turn the car off, then turn the ignition back to on for second, then back off... supposedly the fan won't come back on the second time. I'll try that tonight.

Again: very annoying to leave your car in the grocery parking lot for 10 minutes, come back, and have to warm back up all over again.

samwichse · 11-08-2011, 08:04 AM

Last two times I drove 20+ miles it was below 45, and the fan didn't come on... so I still haven't tested that little kludge.