W124 230E vents

[markalexander]

Hi People, I am mark from South Wales, 6 months into ownership of a 90K, 1987 230E, which is proving great. the only problem I have is that even when set to minimum, I only get warm / hot air from the cabin vents (no aircon fitted) anyone know what is wrong?, correct coolant levels, and the car does not overheat at all, staying at 80 degrees when driving.
Any help greatly appreciated

 

[stwat]

Hi.

It's most probably the duo valve. https://www.youtube.com/watch?v=8jhPEfLI45s

[YOUTUBE HD]8jhPEfLI45s[/YOUTUBE HD]

 

[markalexander]

Quality result! Next saturday's job (After taking it to north yorkshire for a run out)
Great website, absolutely enthralling.

 

[stwat]

I'd advise giving the cooling system a good flush out using citric acid. Then replace with genuine MB antifreeze/coolant and a new thermostat. The antifreeze is not expensive from the dealers and is perfectly matched for the alloy head cast iron block engines.

I have used Comma fluid in the past and it quickly turned brown. I flushed it out and replaced with Mercedes fluid and it has been nice and blue for two years now. I have some new MB fluid ready for a change next weekend.

 

[Vlad]

Also check that the air sensor up by the mirror is not clogged up with fluff.....mine was and once cleaned my heating returned to normal.

But as has been said the duo valves are also a prime contender.

 

[optimusprime]

Vlad without aircon do they still have this sensor your talking about up by the mirror ?

 

[Druk]

Also check that the air sensor up by the mirror is not clogged up with fluff.....mine was and once cleaned my heating returned to normal.

But as has been said the duo valves are also a prime contender.

Vlad without aircon do they still have this sensor your talking about up by the mirror ?

Mine did...and there's the accompanying little pump encased in foam under the glovebox liner which sooks air down the A pillar from the little sensor.

 

[optimusprime]

Druk Thanks i will check it out

 

[markalexander]

Duo valve was the culprit, unplugged, cleaned contacts and gently caressed with a small hammer, works perfectly- 600 mile round trip in hot weather with cooler on full chat,(honest, in yorkshire !) no problem, followed by another 260+ trip to birmingham and back. Right! next questions, seem to be getting around 40- 45 mpg on the motorway with very gentle throttle , so well pleased for a 1.5 tonne car, but using a bit of oil, about 1 litre per 1000 miles- about normal? using correct lube- just passed MOT with no comments, so o.k.?