Should the radiator fan be running all the time?

weejai · 30th December 2008, 16:57

Hi,

On my OHC 1.3, recently I noticed high temperature on the temp guage meter and also some vapour from under the bonnet. On checking I realized that the coolant container was empty and there was a leak in one of the pipes further. I got this pipe replaced and the meter was showing the normal temp. But after replacing the pipe and coolant, the car was switched off for about 30 mins. Once the engine was started, I noticed that the radiator fan was not running.

1. Is the radiator fan suppose to run as soon as the engine is started? the mechanic said, it will start only when the temp goes up??
2. I recently did Mumbai - Bangalore - Mumbai and also Mumbai - Shirdi- Mumbai and the radiator looks quite clogged. Is it possible to get it cleaned or as Honda says, replace it?

Please help.

ImmortalZ · 30th December 2008, 17:15

Radiator fans are temperature controlled. They cut in and out to maintain the engine temperature at the optimum level where maximum efficiency is reached. Usually, the radiator fan will not start up the moment you fire up your engine.

aaggoswami · 30th December 2008, 17:16

Quote:

Originally Posted by weejai

Hi,

1. Is the radiator fan suppose to run as soon as the engine is started? the mechanic said, it will start only when the temp goes up??
2. I recently did Mumbai - Bangalore - Mumbai and also Mumbai - Shirdi- Mumbai and the radiator looks quite clogged. Is it possible to get it cleaned or as Honda says, replace it?

Please help.

1) Your mechanic is correct. It is the same for our Maruti 800 and Baleno.

2) Yes, radiator can be cleaned.
If you are sure your radiator is clogged, then it is possible to clean it. But if it is damaged, replace it.
Also make sure you get the radiator replaced at honda service center. The aftermarket buys some times are not of very high quality.

tazmaan · 30th December 2008, 17:26

Engine Heating problems are always a nightmare. On my Palio when I got the LPG kit fitted the Socket of the Engine fan got disconnected. Result was overheating and one of the pipes burst leaking all the coolant.

I was not aware that the fan was not working and thought that the pipe burst was the root cause of heating. I realized it when the car overheated after fixing the pipe and refilling the coolant.

The point is that over heating can be because of multiple reasons and is always tricky to solve.

It is normal for the fan to cut in only after the car has reached a certain preset temperature, but the fan should cut in within few seconds once you start the Aircon.

Good-luck.

weejai · 30th December 2008, 17:32

Got it...
Finding a garage is another 'penidng item' for me in Andheri (e) ever since I moved to mumbai a year ago!!! If the radiator can be cleaned, will get it cleaned. IF requires repalcement, will go to Linkway.

Thank you Immortalz and aaggoswami.

snaronikar · 30th December 2008, 17:56

+1 to aaggoswami. It is same with all MPFI cars or the cars that are getting launched in recent times. 2ndly, ask the local mechanic whether it is really necessary to change the radiator fan or only cleanignis sufficient. Follow his advice.

weejai · 30th December 2008, 18:24

Right, in continuation:
1. When I switch the A/C on, both the fans cuts in immediately
2. When the A/C is off, but just the 'Fan' is on, neither the radiator fan not the a/c fan are actually running? though there is air blown from the vents?

this is getting quite complicated for me now. IS this normal?

Jaggu · 30th December 2008, 18:45

Quote:

Originally Posted by weejai

Right, in continuation:
1. When I switch the A/C on, both the fans cuts in immediately
2. When the A/C is off, but just the 'Fan' is on, neither the radiator fan not the a/c fan are actually running? though there is air blown from the vents?

this is getting quite complicated for me now. IS this normal?

No complication, the AC radiator and Engine Radiator fan doesnt feed air inside the cabin. Inside the cabin there is a separate fan to take care of this. So:

1) Its ok, but neednt cut in immediate also. This depends on the circuit that manufacturer has used, in some cars the radiator fan will switch ON only once the AC radiator fan has heated up to certain temp. Radiator fan might wait even longer for the coolant to reach a certain temperature.

In others as you said, as soon as comp switch is pressed fan/fans might switch ON immediately.

2) I have explained in the beginning

ImmortalZ · 30th December 2008, 19:56

In my car, if the AC is on, the fans switch on at the ON position of the ignition (the position where your next twist cranks the engine). They don't even wait for the engine to start running. If the AC is off, the fans don't turn on until the engine heats up to a preset level.

toiingg · 30th December 2008, 20:09

Quote:

Originally Posted by weejai

Right, in continuation:
1. When I switch the A/C on, both the fans cuts in immediately
2. When the A/C is off, but just the 'Fan' is on, neither the radiator fan not the a/c fan are actually running? though there is air blown from the vents?

this is getting quite complicated for me now. IS this normal?

weejai,

Relax!!

That is very normal and supposed to be that way.

The 'fan' you are referring to when the a/c is on (or off), is called the blower. It has a separate motor and is not connected to the fans which are next to your radiator.

weejai · 31st December 2008, 09:43

Thank you all for clarifiying and patience

aka_iitd · 31st December 2008, 10:25

One more doubt guys
When we try getting hot air from the AC is really AC works or we get the hot air from the engine. I think first part is correct. Guru's enlighten me on this fact

ImmortalZ · 31st December 2008, 10:59

I believe that most AC systems use the radiator heat to provide hot air. Your manual should tell you how it works.

toiingg · 1st January 2009, 12:31

HowStuffWorks "How Car Cooling Systems Work"

HowStuffWorks "How Car Cooling Systems Work"

Go thru these.

IndigoXLGrandDi · 23rd April 2012, 20:56

I got the AC Blower Motor Assembly replaced on Friday at Local Electrician. It cost me Rs. 4500/- + Labour Rs. 600/-.

After that I noticed strange behaviour of Radiator Fan.

When the AC is switched ON (Compressor), the Radiator Fan also switches ON (even though the Engine Temperature is at C) along with Condenser Fan.

This used to not happen before.

When I showed this to that electrician, he said "Its normal. The Radiator Fan and Condenser Fan are in series (?), so the RF will come on with CF even if the Engine Temp. is Cold.

I suspect the battery would drain faster since the Radiator Fan is working continuously and drawing current from the Alternator.

Please guide me.

Should I replace any of the following Relays placed under the bonnet behind Battery--
1) AC Condenser Fan Relay,
2) Series Fan Relay,
3) Radiator Fan Relay (Don't remember correctly)?

EDIT:-
The Thermostat Valve was replaced @ 7-8K Kms ago.

30th December 2008, 16:57	#1
weejai BHPian Join Date: Apr 2007 Location: Bangalore/Mumbai Posts: 89 Thanked: 3 Times View My Garage	Should the radiator fan be running all the time? Hi, On my OHC 1.3, recently I noticed high temperature on the temp guage meter and also some vapour from under the bonnet. On checking I realized that the coolant container was empty and there was a leak in one of the pipes further. I got this pipe replaced and the meter was showing the normal temp. But after replacing the pipe and coolant, the car was switched off for about 30 mins. Once the engine was started, I noticed that the radiator fan was not running. 1. Is the radiator fan suppose to run as soon as the engine is started? the mechanic said, it will start only when the temp goes up?? 2. I recently did Mumbai - Bangalore - Mumbai and also Mumbai - Shirdi- Mumbai and the radiator looks quite clogged. Is it possible to get it cleaned or as Honda says, replace it? Please help.
	() Thanks

30th December 2008, 17:15	#2
ImmortalZ Senior - BHPian Join Date: Jan 2008 Location: Trivandrum Posts: 2,179 Thanked: 488 Times View My Garage	Radiator fans are temperature controlled. They cut in and out to maintain the engine temperature at the optimum level where maximum efficiency is reached. Usually, the radiator fan will not start up the moment you fire up your engine.
	() Thanks

30th December 2008, 17:26	#4
tazmaan BHPian Join Date: Nov 2008 Location: Mumbai Posts: 926 Thanked: 3,235 Times View My Garage	Engine Heating problems are always a nightmare. On my Palio when I got the LPG kit fitted the Socket of the Engine fan got disconnected. Result was overheating and one of the pipes burst leaking all the coolant. I was not aware that the fan was not working and thought that the pipe burst was the root cause of heating. I realized it when the car overheated after fixing the pipe and refilling the coolant. The point is that over heating can be because of multiple reasons and is always tricky to solve. It is normal for the fan to cut in only after the car has reached a certain preset temperature, but the fan should cut in within few seconds once you start the Aircon. Good-luck.
	() Thanks

30th December 2008, 17:32	#5
weejai BHPian Join Date: Apr 2007 Location: Bangalore/Mumbai Posts: 89 Thanked: 3 Times View My Garage	Got it... Finding a garage is another 'penidng item' for me in Andheri (e) ever since I moved to mumbai a year ago!!! If the radiator can be cleaned, will get it cleaned. IF requires repalcement, will go to Linkway. Thank you Immortalz and aaggoswami.
	() Thanks

30th December 2008, 17:56	#6
snaronikar Senior - BHPian Join Date: Jun 2007 Location: Bengaluru Posts: 2,845 Thanked: 29 Times View My Garage	+1 to aaggoswami. It is same with all MPFI cars or the cars that are getting launched in recent times. 2ndly, ask the local mechanic whether it is really necessary to change the radiator fan or only cleanignis sufficient. Follow his advice.
	() Thanks

30th December 2008, 18:24	#7
weejai BHPian Join Date: Apr 2007 Location: Bangalore/Mumbai Posts: 89 Thanked: 3 Times View My Garage	Right, in continuation: 1. When I switch the A/C on, both the fans cuts in immediately 2. When the A/C is off, but just the 'Fan' is on, neither the radiator fan not the a/c fan are actually running? though there is air blown from the vents? this is getting quite complicated for me now. IS this normal?
	() Thanks

30th December 2008, 19:56	#9
ImmortalZ Senior - BHPian Join Date: Jan 2008 Location: Trivandrum Posts: 2,179 Thanked: 488 Times View My Garage	In my car, if the AC is on, the fans switch on at the ON position of the ignition (the position where your next twist cranks the engine). They don't even wait for the engine to start running. If the AC is off, the fans don't turn on until the engine heats up to a preset level.
	() Thanks

31st December 2008, 09:43	#11
weejai BHPian Join Date: Apr 2007 Location: Bangalore/Mumbai Posts: 89 Thanked: 3 Times View My Garage	Thank you all for clarifiying and patience
	() Thanks

31st December 2008, 10:25	#12
aka_iitd BHPian Join Date: Aug 2008 Location: Bangalore Posts: 630 Thanked: 45 Times	One more doubt guys When we try getting hot air from the AC is really AC works or we get the hot air from the engine. I think first part is correct. Guru's enlighten me on this fact
	() Thanks

31st December 2008, 10:59	#13
ImmortalZ Senior - BHPian Join Date: Jan 2008 Location: Trivandrum Posts: 2,179 Thanked: 488 Times View My Garage	I believe that most AC systems use the radiator heat to provide hot air. Your manual should tell you how it works.
	() Thanks

1st January 2009, 12:31	#14
toiingg BHPian Join Date: Oct 2006 Location: Calcutta Posts: 639 Thanked: 266 Times	HowStuffWorks "How Car Cooling Systems Work" HowStuffWorks "How Car Cooling Systems Work" Go thru these.
	() Thanks

23rd April 2012, 20:56	#15
IndigoXLGrandDi Senior - BHPian Join Date: Aug 2009 Location: Solapur (MH-13) Posts: 1,784 Thanked: 566 Times	Re: Should the radiator fan be running all the time? I got the AC Blower Motor Assembly replaced on Friday at Local Electrician. It cost me Rs. 4500/- + Labour Rs. 600/-. After that I noticed strange behaviour of Radiator Fan. When the AC is switched ON (Compressor), the Radiator Fan also switches ON (even though the Engine Temperature is at C) along with Condenser Fan. This used to not happen before. When I showed this to that electrician, he said "Its normal. The Radiator Fan and Condenser Fan are in series (?), so the RF will come on with CF even if the Engine Temp. is Cold. I suspect the battery would drain faster since the Radiator Fan is working continuously and drawing current from the Alternator. Please guide me. Should I replace any of the following Relays placed under the bonnet behind Battery-- 1) AC Condenser Fan Relay, 2) Series Fan Relay, 3) Radiator Fan Relay (Don't remember correctly)? EDIT:- The Thermostat Valve was replaced @ 7-8K Kms ago. Last edited by IndigoXLGrandDi : 23rd April 2012 at 20:58.
	() Thanks