W124 Overheating - Fails carrot test when engine cold.

[Bolide]

Anyway, on a trip into London yesterday the car behaved itself. It warms up mush faster than before, and the temp gauge goes up to about 85, where it stays, with only slight movement. No real traffic jams to speak of but a lot of stop and go city driving. The only time it rose higher and started to worry me was stopping at a traffic light, just after the long climb betwen junctions 3 and 4 on the M40. Once we were moving again, it was back to the 85 degree area

Sounds bang-on to me

Nick Froome
www.w124.co.uk

 

[Ade W124]

Glad its working better - my CE 24V gets up to 110 with AC on in slow traffic.... Runs between 85 and 90 on the open road..

Have undertaken carrot test, flushed and changed coolant and intend on fitting a new thermostat next weekend - hope this will help it cool down.

Can an undercharged AC make things worse? A trip to Kwik Fit is also on the cards.

Ade

 

[television]

Glad its working better - my CE 24V gets up to 110 with AC on in slow traffic.... Runs between 85 and 90 on the open road..

Have undertaken carrot test, flushed and changed coolant and intend on fitting a new thermostat next weekend - hope this will help it cool down.

Can an undercharged AC make things worse? A trip to Kwik Fit is also on the cards.

Ade

The air con will not affect the car, only you

 

[Ade W124]

what I meant was my aircon blows coldish but I reckon its probably not been looked at for years and could do with the refridgerant replacing. The pump/condensor makes a fair bit of noise when switched on with the engine at tickover.. I was wondering if it was having to work harder to compensate for lack of refridgerant/ age/ knackeredness...

the car quickly gets to 110 with AC on in traffic or stationary, without it will creep up to 100 in slow moving traffic or stick at 90 at tickover in the drive.

Ade

 

[Bolide]

The a/c dumps heat straight into the radiator as the two rads are so close together

Interesting that a 300 or 320 has one viscous fan but all the a/c cars have two big electric fans as well. I imagine it's because airflow is minimal in traffic and the fans are needed to dump some of the heat

I don't think underbonnet airflow management is a W124 speciality but the cooling must have been sufficient when the cars were new. I suspect a lot of the problems now are caused by sludged-up old radiators

Nick Froome
www.w124.co.uk