Sylvain04

Hi, first post here

I have a Honda Civic 2004 LX (Canadian version) with a 1.7l and 5-speed tranny. 130k miles.

Here's what happens when the radiator fans kick in. No matter if AC is on or off

If I hold RPM steady at 1500, when the radiator fans kick in, the rpm increases 200-300 RPM for 2-3 seconds and then returns to normal.

At idle speed (around 850) when the fans kick in, the RPM just slightly (100 RPM) increases and drops back to normal.

I cleaned the IACV, seafoamed the engine and the relearn procedure has been done. Also PCV valve has been replaced.

At driving speed, around 60MPH, I can feel the radiator fans turning on cause the car acts like if there was a trailer attached to the car. A push and pull feeling while driving.

No ECL and no code. Otherwise, the car goes really well.

Is this normal, is this something I never noticed before?

Thanks for your help.

GriFFIthS

its normal.

Sylvain04

This Is annoying

Sylvain04

I did the exact same test on my wife's 2012 Civic and the RPM didn't raise when the fans kicked in

doood

iTrader: (1)

db1st

what GriFFIthS said, it's normal. normally when the fan kicks on, it takes electrical power away from the alternator. the ECU reads the lost in electrical power and raises the RPM to compensate and helps gain the power lost in the alternator. with higher RPM, the alternator charges more efficiently. you may also notice that when you roll down your windows, the lights will dim (this is more noticeable if you have a cheap OE replacement alternator). it's also pointless to compare a brand new 2012 car to a 7 year old car with 130k on it.

Sylvain04

Sounds good but idle increases more when the engine is at higher rpm when the alternator usually produces more power.

+100 RPM @ idle
+300 RPM @ 1500 RPM

It happens only with the radiator fans. I did the same test with rear defrost, high beam... nothing weird happened.

I noticed that the little ground strap connecting the engine head to the front of the car is in bad condition.

Can it be a bad ground ?

elwoodblues

even if that would not be the cause, it would still be good to change that, a good ground wire is 5$

chawski

next time youre at idle, turn the steering wheel... the power steering will have the same effect. its completely normal. it did it the day you bought the car too. only difference is it now has 130k miles worth of rattles and vibrations, so you notice it now

bairdandrew77

My brother's wagon does the same thing, it is normal