W124 - Cooling problems.

W124 - Cooling problems.

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Discussion

MarshPhantom

Original Poster:

9,658 posts

138 months

Monday 7th November 2016
quotequote all
Hi, we have a 300CE 24V that has had a bit of work done. Running well but getting a bit warmer than it used to.

Occassionally the temp gauge will rise to a fair bit over 100c (normally around 90c, max is 120) generally when your making slow progress or going up hill. Engine running while parked or making progress and it's fine. The fans cut in eventually but it seems later than it should and they don't run when the ignition is off which I thought most cars did.

confused

There's also an extra small pump in the system, pumps water around the heating system I believe. That isn't working as no power going to it. Had it working and it hasn't made much difference to the engine temp.

Any ideas?

Thanks for looking.

iluvmercs

7,541 posts

228 months

Monday 7th November 2016
quotequote all
I had two heating issues this year on my E320 Coupe.
First one turned out to be a slight leak from the radiator. I first noticed this when the car was running, but not moving, then noticed dried coolant marks all over the engine bay, thanks to the water going on to the fan blades - they were a bugger to remove!
The second was down to old coolant pipes. They hadn't split, but the ends had frayed slightly, so when driven in very warm weather or under load for an extended period, the pressure meant coolant leaking from some pipe ends, and it even loosened the jubilee clips.

Maybe worth checking all your pipes, connections, clips, etc, and the radiator, plus perhaps the thermostat. Get the fan system checked too, to ensure that kicks in as it should.

In traffic, particularly in warmer weather, my temp rises to a little over 100 with no issue. Even my old 4 cylinder 230E reached that temperature.
It quickly goes down when moving or when the fans kick in.

Darren

PositronicRay

27,057 posts

184 months

Monday 7th November 2016
quotequote all
The small electric pump doesn't do much, most are unserviceable unless they've been replaced.
The idea is they'll provide some residual heat if you stop the car for a short time. They'll also re-circulate coolant around the engine, if it's too hot and you switch off. Prevents hot spots.

I thought the 124 had an engine driven fan and the electric fans were for A/C? Anyhoo the fans won't do much except when stationary or crawling in traffic.


100c isn't too hot for one of these, depends on ambient temp and the work it's doing, expect 5c more with A/C on.



Edited by PositronicRay on Monday 7th November 17:36

MarshPhantom

Original Poster:

9,658 posts

138 months

Monday 7th November 2016
quotequote all
iluvmercs said:
I had two heating issues this year on my E320 Coupe.
First one turned out to be a slight leak from the radiator. I first noticed this when the car was running, but not moving, then noticed dried coolant marks all over the engine bay, thanks to the water going on to the fan blades - they were a bugger to remove!
The second was down to old coolant pipes. They hadn't split, but the ends had frayed slightly, so when driven in very warm weather or under load for an extended period, the pressure meant coolant leaking from some pipe ends, and it even loosened the jubilee clips.

Maybe worth checking all your pipes, connections, clips, etc, and the radiator, plus perhaps the thermostat. Get the fan system checked too, to ensure that kicks in as it should.

In traffic, particularly in warmer weather, my temp rises to a little over 100 with no issue. Even my old 4 cylinder 230E reached that temperature.
It quickly goes down when moving or when the fans kick in.

Darren
Darren, thanks for that. We've had a fair bit of work done on the cooling system as the head gasket went due to a duff radiator. Could well be the thermostat. Also noticed it gets warm if you're moving well but you're coasting

MarshPhantom

Original Poster:

9,658 posts

138 months

Monday 7th November 2016
quotequote all
PositronicRay said:
The small electric pump doesn't do much, most are unserviceable unless they've been replaced.
The idea is they'll provide some residual heat if you stop the car for a short time. They'll also re-circulate coolant around the engine, if it's too hot and you switch off. Prevents hot spots.

I thought the 124 had an engine driven fan and the electric fans were for A/C? Anyhoo the fans won't do much except when stationary or crawling in traffic.


100c isn't too hot for one of these, depends on ambient temp and the work it's doing, expect 5c more with A/C on.



Edited by PositronicRay on Monday 7th November 17:36
Ray, thanks. Only difference is it was always around 80c before I had the work done.

PositronicRay

27,057 posts

184 months

Monday 7th November 2016
quotequote all
MarshPhantom said:
PositronicRay said:
The small electric pump doesn't do much, most are unserviceable unless they've been replaced.
The idea is they'll provide some residual heat if you stop the car for a short time. They'll also re-circulate coolant around the engine, if it's too hot and you switch off. Prevents hot spots.

I thought the 124 had an engine driven fan and the electric fans were for A/C? Anyhoo the fans won't do much except when stationary or crawling in traffic.


100c isn't too hot for one of these, depends on ambient temp and the work it's doing, expect 5c more with A/C on.



Edited by PositronicRay on Monday 7th November 17:36
Ray, thanks. Only difference is it was always around 80c before I had the work done.
What work?

r129sl

9,518 posts

204 months

Monday 7th November 2016
quotequote all
I've had similar problems on my s124 which manifested themselves in heavy traffic or hard running or both during the summer. My car's problem was the fan clutch and I expect that will be yours, too. If not, then it will be the radiator. Neither is horrifically expensive. www.adrad.co.uk supply a Behr Hella rad for less than £150. It is always worth doing the thermostat; use Merc, they're very reasonable. My money is on the fan clutch.

The electric fans at the front are a fail safe. Their primary purpose is to ventilate the air con condenser.

Edit: I note you've had a rad, so unlikely to be that.

MarshPhantom

Original Poster:

9,658 posts

138 months

Sunday 4th December 2016
quotequote all
Thanks for all the helpful replies so far.

(Very hopefully) the cooling/running issues appears to be down to a missing fuse for the gearbox cooling (which would explain why it gets hotter on the move rather than standstill)/carb electrics circuit. The new fuse seems have improved the running already.

It's the electric cooling fan that is still a bit dodgy, got rather hot the other night and the fan didn't come on. I will give it a bit of use this week to see how it's going.

I now need a new front windscreen Anyone know what sort of cost these may be, where to go?

The one I have has the blue sun strip across, are these still available?

Cheers.

r129sl

9,518 posts

204 months

Sunday 4th December 2016
quotequote all
New windscreens are £100 aftermarket. Last time I checked (2014) a MB windscreen with tinted band was £250.

ClassicMercs

1,703 posts

182 months

Sunday 4th December 2016
quotequote all
Had my windscreen (with shade band) done a year ago for 180 (thanks to some corrosion build up underneath and car flex causing a cracked lower corner) - my radiator (after a work-out up Hard Knott and Wrynose) was a bit more !! Still not sure that the fan is cutting in properly - but all's fine for now.

MarshPhantom

Original Poster:

9,658 posts

138 months

Monday 5th December 2016
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Thanks people, just emailed the local dealers to get a price.

MarshPhantom

Original Poster:

9,658 posts

138 months

Thursday 15th December 2016
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Right, the cooling problems seem to have been caused by a bit of gunk left in the narrow pipe that runs between the top of the radiator and the expansion tank after the head gasket went.

Been a rather expensive year, I now not only need a new windscreen but a new headlight (looks like it got hit by a stone) and wing mirror glass (ordered both from Ebay) after some fool came at me in the middle of the road.

But it's going well again, which is the main thing.

Thanks for all the help and advice so far.

Kneetrembler

2,069 posts

203 months

Thursday 15th December 2016
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Are rear screens for 1992 e500 just as easy to get hold of ?

MarshPhantom

Original Poster:

9,658 posts

138 months

Thursday 15th December 2016
quotequote all
I don't know, ordered from this guy in Germany, might be worth checking what else he has for sale.

www.ebay.co.uk/usr/gebrauchtteile.secretzero_de?_t...

Kneetrembler

2,069 posts

203 months

Sunday 18th December 2016
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Many thanks for the info