W124 E280 Auto (Est), HRW, External Temp Gauge, Heating

[JensH]

Hi all,

I wonder if some W124 gurus could help me with these (on a facelift model):

1 HRW, I have condensation and rear window demister problems. Condensation has improved with a clear out of both rear side wells, both of which had the little 3 hole air vents obstructed by previous owner clutter. The HRW works only top and bottom, never clearing the middle, which I presume must be element rather than fuse (checked and replaced) or N10 relay (presume if it was this, wouldn't work at all). Have ex-VAT quote of £216.65 fitted for new window, next day, from Autoscreens - seems very good. Is that the sensible option given the symptoms?

2 Have replaced external temp display with refurbished console module. Lights up but no data displayed. In most people's experience, what are the logical best steps for resolving this? Start with sensor presumably?

3 Is it general experience that the heating in the W124 is not actually that great? Mine is slow to adjust and never really that hot at the highest setting - I can always comfortably hold my hand in front of any outlet at maximum setting...

Cheers all,


Jens

 

[television]

With the rear screen only a replacement will fix it unless you can find the break in the wire on the glass. even then it depends on the size of the break for it to be repairable.

What temp is the engine getting up to, anything under the high 80's it will not be hot.

If no temp display it must be the display at fault I think, when the probe is faulty the show something like 38c all the time

 

[JensH]

Thanks for this Malcolm:

1 New HRW going in tomorrow - thanks for the feedback.

2 Outside Temp Module sold as working. I have a test/fix worksheet for the system, so will try that, before falling back on my 30 day warranty with Mercman;

3 Heating: Yes, I'm allowing for engine warming up. I have heard the heating is modest from a couple of sources, but I don't mind too much. I find that small adjustments on the regulators work best and the inside is warm enough. My daughters are the sensitives ones.

About to spend some time clearing all the water ducts with some bicycle brake cable wire. Will report!

Btw, a propos of nothing, today's chores include replacing a Gliptone leather aroma pad which sits under the front N/S seat. Lost count of the number of chums who have said how lovely the car smells! Perhaps not to everyone's taste - bit like being near someone smoking a Cohiba, I expect!

Anyway, works for me! Should be a matching aftershave

 

[kth286]

Perhaps the engine thermostat needs changing for better heat.

I am always impressed with mine within the first half mile (same engine type)

 

[JensH]

Engine Thermo

Perhaps the engine thermostat needs changing for better heat.

I am always impressed with mine within the first half mile (same engine type)

Cheers for that. I have ordered a new remote key from MB in Stratford today (£199!), so will ask the service department for a view when I pick the key up, in addition to asking them about my u/s cruise control.

Thanks,


Jens

 

[JensH]

HRW Update

New HRW fitted today by efficient and fast (next day) Autoscreens, based in Aylesbury. £216.65 ex VAT, fitted and also had a very good chat with the fitter about how he loves W124s, because they are joy to work on; everything goes back together perfectly, quality components and none of the rubbish plastic fittings found on current motors. He was also helpful with tips on checking and maintaining seals (including the car-wide seal along the base of the windscreen) and what I might do about the rear bay side window colour trim panels, which are the car's most obvious cosmetic fault (corrosion bubbling). Very impressed with the service.
http://www.autoscreens.co.uk

Working perfectly (tailgate screen clears in about 3-5 mins), so pretty pleased, and seems a reasonable cost to me.

Jens

 

[television]

That was a good price and well done

 

[hotrodder]

As David mine'll be kicking out warm air within 1/2 mile (lukewarm/above ambient within 1/4) and the coolant will be upto operating temp/over 80 within 2 miles/less than 5 minutes even when it's subzero outside

The heater on every w124 i've owned has been capable of chucking out uncomfortably hot air when cranked up but the estates are fairly big cars i.e. can roast your legs in the front while someone in the back remains chilly on shortish journeys

These cars have a cabin temperature sensor that uses a tiny fan to suck or blow 'sampling' air across it. I think that a fault with this would be more likely to effect cooling rather than heating but i don't know as the only bits of the heater i've ever had to deal with are dead blower motors and duo valves

 

[JensH]

Heating

As David mine'll be kicking out warm air within 1/2 mile (lukewarm/above ambient within 1/4) and the coolant will be upto operating temp/over 80 within 2 miles/less than 5 minutes even when it's subzero outside

The heater on every w124 i've owned has been capable of chucking out uncomfortably hot air when cranked up but the estates are fairly big cars i.e. can roast your legs in the front while someone in the back remains chilly on shortish journeys

These cars have a cabin temperature sensor that uses a tiny fan to suck or blow 'sampling' air across it. I think that a fault with this would be more likely to effect cooling rather than heating but i don't know as the only bits of the heater i've ever had to deal with are dead blower motors and duo valves

Cheers for that - is the sensor the one in the roof console, next to the interior lighting switch?
& in the rear load area, is heating channelled to the vents behind the wing covers or are these just for outside air? - maybe I can find a vent system pdf on w124-zone.com or similar...

I'm planning to check all warm air outlets tomorrow...

I suppose the thing about the automatic heater control is that it is designed to maintain a constant temperature, and if the max is 26º, it's not going to pump out hotter than is needed once the ambient temperature is right. The car is never uncomfortable, for sure. I just sense the heating is less efficient in the very rear, but it's a large volume of space, as you say.

The above would also explain the "window" setting on the heater controls; presumably this overrides the automatic heating and maintains "max", which is why the manual says only use for brief periods. Same at the other end, also - the locked ("click") blue zone (marked with a dot on wheel) turns off any auto heat function altogether?

I generally operate the controls in EC mode btw. I think (manual, again) that in this mode only unheated air comes out of the centre vents, whereas AC pumps heated, unheated or cooled air (depending on settings). Last owner spent a lot on AC refurbishment (including a complete new compressor - SEIKO) only a couple of years back, so maybe I'll get a better sense of the overall heating/cooling performance in warmer weather.

Thanks,

Jens

 

[hotrodder]

The cabin temp sensor (or at least it's fan) is buried in the dash, behind the glove box/airbag i think and it draws air from the grille by the light/sunroof switch
The vents in the rear inner wings are just vents to let air out of the car, it's predecessor the w123 had 'em hidden behind the rear edge of the side window trim and many old cars they were very visible, sometimes used as a styling cue, often ugly things nailed onto the C pillar.

As you say when the temp dials are 'clicked' to min/max it overrides the cabin sensor. I endured 'full hot' for a while once when i was being too lazy to replace a knackered rad and got stuck in bad traffic. Wasn't fun!

Being American i think it only covers the single zone/automatic climate control but much of it is the same as dual zone aircon... http://www.w124performance.com/service/Index/Groups/83ClimateControlSystem.htm A quick at look at 83-602 shows a test of heater output, apparently to full hot demist the air should reach > 55°C

AFAIK the centre vents are cold/fresh air only, certainly have been on every w124 i've owned although i've heard otherwise- might be to do with aftermarket aircon versus factory?

Use your aircon, less likely to play up if exercised and you'll have less need for the rear screen demister as it'll keep humidity in the car down

 

[JensH]

Heating (W124)

The cabin temp sensor (or at least it's fan) is buried in the dash, behind the glove box/airbag i think and it draws air from the grille by the light/sunroof switch
The vents in the rear inner wings are just vents to let air out of the car, it's predecessor the w123 had 'em hidden behind the rear edge of the side window trim and many old cars they were very visible, sometimes used as a styling cue, often ugly things nailed onto the C pillar.

As you say when the temp dials are 'clicked' to min/max it overrides the cabin sensor. I endured 'full hot' for a while once when i was being too lazy to replace a knackered rad and got stuck in bad traffic. Wasn't fun!

Being American i think it only covers the single zone/automatic climate control but much of it is the same as dual zone aircon... http://www.w124performance.com/service/Index/Groups/83ClimateControlSystem.htm A quick at look at 83-602 shows a test of heater output, apparently to full hot demist the air should reach > 55°C

AFAIK the centre vents are cold/fresh air only, certainly have been on every w124 i've owned although i've heard otherwise- might be to do with aftermarket aircon versus factory?

Use your aircon, less likely to play up if exercised and you'll have less need for the rear screen demister as it'll keep humidity in the car down

Cheers, this is really helpful.

I do get warm air through the centre vents, even on economy setting, but wonder whether this is simply engine temp affecting the air as opposed to heating controls. I spend most of my time driving around central London, av speed around 5-10 mph, which is why I tend not to use AC. Average 15-20 mpg in this routine, so a bit worried about returning even worse on AC. I'd have to fill up every other day!

With that typical driving pattern I am maybe not getting enough speed for good airflow?

Thanks v much, and have a good week-end.

Jens

 

[television]

I only ever got cold air from my 1990 300te, very cold with the air con and never warm air,,, I wish that I had cold air on my 216, the same as I have on my 140, on the 140 its switchable warm or cold.

 

[hotrodder]

I don't really keep close tabs on mpg* but have never noticed any difference by turning the aircon off. The compressor isn't running constantly unless the dehumidifer (button above EC) is on anyway and so probably isn't that different to the extra load on the engine when the alternator is working harder to provide leccy for heavy consumers like HRW or heated seats?

* brutal on fuel in slow stop/start traffic no matter what you do and (for my driving style at least) need to make a conscious effort to see 30ish on a long run. They're from an era when economy was less of a deal and the prehistoric slushbox with daft gear ratios doesn't help things

 

[JensH]

MPG / AC

I don't really keep close tabs on mpg* but have never noticed any difference by turning the aircon off. The compressor isn't running constantly unless the dehumidifer (button above EC) is on anyway and so probably isn't that different to the extra load on the engine when the alternator is working harder to provide leccy for heavy consumers like HRW or heated seats?

* brutal on fuel in slow stop/start traffic no matter what you do and (for my driving style at least) need to make a conscious effort to see 30ish on a long run. They're from an era when economy was less of a deal and the prehistoric slushbox with daft gear ratios doesn't help things

I don't fret too much about the mpg, just monitor it, to look for improvements. 26 mpg is best I've done so far - out of town, of course. Will try a week or so with AC on...

Cheers,

J

 

[television]

Is the fuel economy so important, you have no depreciation on these cars, the average new E class buyer will lose £20k in the first 5 years.

 

[JensH]

Is the fuel economy so important, you have no depreciation on these cars, the average new E class buyer will lose £20k in the first 5 years.

No it isn't... Just looking at how I might do a little better.

If I ever find myself without the money to fill the tank, I can still look at it and marvel at the build quality, and sit in the driving seat making "brrrm" noises, whilst practising my German...

 

[television]

No it isn't... Just looking at how I might do a little better.

If I ever find myself without the money to fill the tank, I can still look at it and marvel at the build quality, and sit in the driving seat making "brrrm" noises, whilst practising my German...

My beautiful 1990 300TE will always stay with me as the best car that I ever had, yes the build was superb in every way, if it had not been for the fact that it was a left hooker I would still have it today.

 

[nyx]

i haven't had my 124 on a run yet but it does 23mpg purely on local driving and a few cold starts a day

 

[JensH]

i haven't had my 124 on a run yet but it does 23mpg purely on local driving and a few cold starts a day

Which engine is that?

J

 

[nyx]

1988 230e auto