m00nr0ck Si

Here in the last month or so my radiator cooling fan stays on for a few minutes after i kill the car...I noticed that sometimes it will stay on for a few minutes ,go off and then come on again....it never stays on for more than 5 minutes....any help is appreciated .....

snobordboy

Thread on the second page for ya.

https://honda-tech.com/zerothread/2289667

m00nr0ck Si

Thanx man....lazy>Me

I guess its perfectly normal for it to kick on after the car is off....? Ive just never noticed it before .....Im going to flush the coolant and change the thermostat and go from there.

snobordboy

Totally normal, flush and fill may be good if you havent done it, always nice to know its got the right fluid. I would leave the t-stat alone unless you start overheating.

mattsnooz

If its not broke don't "fix" it.

Your car is doing what its suppose to.

When your car shuts off, so does your coolent cooling and supply. There for the second you shut your car off, your temp actually starts going up a bit depending on environmental factors. So to prevent your car from over heating after it shuts off, your fans have a secondary control (off a relay, controlled by your t-stat) that turns your fan on to prevent it from overheating when your car is off.

It should only do that in +0 or above temperatures usually, and will do it more so when it gets warmer and warmer.

As long as your temp display doesn't go above normal (opperating temperature) your car is doing as it should be. Please don't mess with anything. If you coolant hasn't been changed in 2 years, it wouldn't hurt to get it changed. Don't mess with the t-stat though, thats just asking for trouble.

m00nr0ck Si

ok cool ....So i wont change the thermostat....

m00nr0ck Si

Just another thought ....My car has never done this until a month ago....its so wierd the fan will wait until after i shut the car off and it will come on for at least 4 or 5 minutes....

m00nr0ck Si

Bump for some reassurance that this is normal..... Im kinda thinking that the fan switch or fan relay might be going out.....

smackdown

if it keeps going on evrytime it can drain your battery overtime

m00nr0ck Si

I just got back from getting the coolant flushed ....They used a machine that pressurized it with some kind of acidic cleaner and then evacuated it and filled with fresh and the fan is acting normal now. I noticed that the old coolant had alot of nasty brown and black crap in it....

dixxon

take a careful look at your rad just to be safe...the same thing was happening to me, i though it was just because it was getting hotter out. but today i took it out to take a look and this is what i found haha:



so yeah make sure its in good shape. its been hot all day and since i put my new rad in the fans haven't come one once after i've shut the car off.

flyrod

That is normal operation of the fan control unit, but the underlying cause may not be normal. Check your coolant level, etc.

m00nr0ck Si

After having it flushed and filled I drove over 300 miles to houston yesterday....The car began overheating about 60 miles from home so we pulled in a car wash and replaced the thermostat with a fail safe and topped the coolant off.
I continued driving about 50 or so miles and then it started getting hot again...
The car has never had any kind of problem like this until this shop flushed the coolant so I called the guy and he said to bleed the air out ....I sat on the side of hwy 59 for over an hour and bled it ,got a good sunburn ,but managed to get the prelude home safely....It never over heated after I bled the air out but I did notice that the overflow tank was full....Any suggestions?

spoolinlude

Sounds like there is a TON of air in your system. When the car was running did you notice any bubbles coming from the overflow? Reason I ask is that if you've overheated a few times you may have popped the head gasket. Which I hope isn't the case. It can be a pain to get the air out of the system, when I used to do mine I would jack the car up in funny positions, trying to make sure all the air was able to get out (doubt this helped, but made me feel better). Also check your coolant hoses, if they feel extremely pressurized, chances are you still have some air in there.

m00nr0ck Si

Thanx for the reply....There are no bubbles coming out of the overflow tank,however there are quite a few coming up when I pull the radiator cap and crank it up...Im going to let it cool down and try bleeding it off again using the technique that mgags7 uses.....cap off until fans cycle twice then put cap on and crack the bleeder bolt on the thermostat housing until a steady stream of coolant is coming out .....

So to recap ....
4/07 bought the prelude Si with no problems

8/07 Brake job

3/08 Fan started kicking on after car is shut off

4/08 valve seals,crank seals,balance shaft seal and retainer,cam seals,oil pan gasket

6/08 had the cars coolant system flushed and cleaned , new fail safe thermostat installed.

6/11/08 car started overheating after 100 miles of driving and continued doing so until I pulled over and bled the coolant and filled ....GOD that was a long day

coojoe59

that looks horrible!!!!!!!!

m00nr0ck Si

Well I solved the problem by simply bleeding the coolant and putting in a new thermostat

jabarty

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smackdown &raquo;</TD></TR><TR><TD CLASS="quote">if it keeps going on evrytime it can drain your battery overtime </TD></TR></TABLE>

the voltage drain it puts on your battery running only 4-5 minutes at a time isn't nearly enough to drain it. once you start it, the dizzy will just recharge the tiny amount that was lost. this is normal operation, don't stress it.

mattsnooz

Dizzy doesn't recharge things. Dizzy is the mechanical timing for your spark.

Alternator might do the trick though

The shop you had do the work should have bleed the shiet out of your radiator. I'd never take your car back to them. If they know how to flush, than they should know how to bleed.

About your radiator too. When your driving , this is forcing air into your rad much like your fan would. The fan usually only needs to be on when your not moving or stopped. My fans never come one with my new radiator, untill I'm stopped or idling. This is a good indication that the radiator is efficiently doing its job.

Your cooling system should be good now though. You've bleed it, and did the T-stat (even though it probably wasn't the problem). So that covers almost everything

slyx620

I've never had my fan go off on my prelude after the cars been turned off . . .

my9thtry

I've had my prelude since 2001, the running of the fans is completely normal. Almost every car with electric fans now a days does the same thing.

Get a refund from that mechanic, thats total .

prelude_93vtec

Ya just make sure there is enough fluid in the radiator NOT just in the reservoir! And make sure there is no air in the system

m00nr0ck Si

After doing some searching here on honda-tech I went out and checked the radiator cap out and compared it too a brand new one ....Wow mine was so wore out , the spring was gone .....My brother and I noticed that the top hose had no pressure when the car was running ....So I started with the cheapest solution and it worked ....

rayrayh22a

when your radiator fan comes on after you turned of the car and have the keys in your pocket,(IT IS NOT NORMAL) the problem is in the cooling sensor. test the sensor, if it is not good replace it ASAP the next step will be overheating engine.IAT (the one with light green connector) sensor turns on and off the fan so if it is coming on when engine is off not normal. it is not alternator or starter or battery or thermostat or radiator fluid it is cooling fan switch(IAT sensor)


Modified by rayrayh22a at 12:35 AM 6/29/2008

codyz0r

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