W203 Engine cooling fan runs as soon as engine starts.

[Oldspanners]

Just when I thought I had things sorted, I was putting the car up on the ramps to fit the new jack pad I noticed the fan was running from cold. No codes showing on the Carsoft.
Any ideas?

 

[LostKiwi]

Just when I thought I had things sorted, I was putting the car up on the ramps to fit the new jack pad I noticed the fan was running from cold. No codes showing on the Carsoft.
Any ideas?

Low gas in the Aircon?

 

[Oldspanners]

Low gas in the Aircon?

Showing over 5 bar and seems cold enough.

 

[LostKiwi]

What was outside temperature compared to Aircon setting?

 

[Oldspanners]

What was outside temperature compared to Aircon setting?

Thanks, I'll have to check that tomorrow. Been 4 years since a re-gas.

 

[LostKiwi]

If Aircon was set lower than ambient it may cause the fan to run.

 

[Oldspanners]

If Aircon was set lower than ambient it may cause the fan to run.

Well, as they say a little knowledge is a dangerous thing, especially in my case.
So thanks LK for having the knowledge that indeed if the air con temp is set at the lowest and the outside temp is higher the fan will come on immediately on start up.
This morning set the air con to the middle started it up no fan, very happy but looks like gardening for the rest of the day
Happy that the air con is still cold after 4years ahhhhhh why did I say that

 

[Rappey69]

The always running fan when aircon was on was one thing that annoyed me about the w203 as i could hear it !

 

[NBurns]

If Aircon was set lower than ambient it may cause the fan to run.

So what would be the recommended setting currently, as my fan has always come on when starting the engine?


Sent from my iPhone using Tapatalk

 

[NBurns]

If Aircon was set lower than ambient it may cause the fan to run.

The other point on my car is that my aircon system has never worked. I did get it assessed once and I was told the 'block in front of the radiator' had a leak on it. I never did get it fixed.
So how would that affect the engine fan running?
Obviously doesn't affect my aircon system.


Sent from my iPhone using Tapatalk

 

[LostKiwi]

The other point on my car is that my aircon system has never worked. I did get it assessed once and I was told the 'block in front of the radiator' had a leak on it. I never did get it fixed.
So how would that affect the engine fan running?
Obviously doesn't affect my aircon system.


Sent from my iPhone using Tapatalk

The block in front of the radiator is the Aircon condenser. A leak in that will stop Aircon working as the gas leaks away and that causes the fans to come on.

 

[NBurns]

The block in front of the radiator is the Aircon condenser. A leak in that will stop Aircon working as the gas leaks away and that causes the fans to come on.

Okay. So what setting should I put my aircon temperature to to stop my fan coming on all the time?


Sent from my iPhone using Tapatalk

 

[LostKiwi]

Okay. So what setting should I put my aircon temperature to to stop my fan coming on all the time?


Sent from my iPhone using Tapatalk

Until you fix the underlying issue (leaking condenser and regas the system) you can't do much except disconnect the fans (not recommended).

 

[NBurns]

Until you fix the underlying issue (leaking condenser and regas the system) you can't do much except disconnect the fans (not recommended).

Oh!!! Well in that case, it will stay broken then.


Sent from my iPhone using Tapatalk

 

[Rappey69]

you can't do much except disconnect the fans

A w203 only has the one fan. It uses the fan for cooling the engine when it gets hot (so very rarely comes on at all) but also uses the same fan at a lower speed when the aircon is on.
when my aircon was gasless due to perforated condersor i could do anything with the heater and aircon controls but the fan would never come on..
the first time i heard it was when i fitted a new condensor and had the system gassed.
Mine was a 2002. Would a 2005 be the same?

 

[LostKiwi]

A w203 only has the one fan. It uses the fan for cooling the engine when it gets hot (so very rarely comes on at all) but also uses the same fan at a lower speed when the aircon is on.
when my aircon was gasless due to perforated condersor i could do anything with the heater and aircon controls but the fan would never come on..
the first time i heard it was when i fitted a new condensor and had the system gassed.
Mine was a 2002. Would a 2005 be the same?

Don't know. I guess it depends on the programming of the control modules.
My 129 sounded like a turbo prop warming up when it was low on gas.