My 59k mile W202 C200 classic (auto)

[Wigglesworth]

Indeed it is....

I have taken some pics to outline what I have.

These are the fan wires coming in from under the headlamp, the green one is from the ac pressure? Switch, the 2x black ones are from the fans!


These are the 2x connections for the ac switch thing!


These are the relays that live under the washer bottle! The forward most black one switches the fans on when contact is made (and my fans indeed are spinning up when you do so). I have fitted the central relay as it was all taped up... not made a difference to anything so I will likely remove.


And this is my fuse box!

I can tell you that the rest pressure on the ac (engine off and pump not running) is around 55psi!
I am not going to try adding more gas as that is a big No No without all of the weights and being able to evacuate the old gas and oil.

I have pondered if the gas pressure is just too low in the ac, it blows cold but that's no set guarantee that it is all as it should be.

Oh and before I forget entirely....


Proof that there is no fan control module

Even the Haynes book of lies outlines it's existence.
Interesting that the previous owner had folded over that particular page! Me thinks this has been a gripe for a long time.

Thanks for all of the help guys by the way it is greatly appreciated, I would be stuck without it in all honesty

 

[Dec]

Unless there is a fuse gone in there, the non-working fan maybe controlled from somewhere in the below modules.

Explanation below is for my car, yours may be different, not much help but worth knowing what’s what

Connectors 0, 1 and 2 are on the ESP/ETS/ASR module - no.1 is the CAN wires.
Connectors 3 and 4 are engine ECU - you can again see the CAN wires in plug 4.
All the rest are on the K40 module, which is mainly involved with voltage supply and starter output. 11 is the starter relay, 12 is switched and permanent live supply, 6,7,8,9,10,13,14 and 21 are power outputs and inputs to eg switch the internal relays in the K40 (there will be 2x probably, in addition to the demountable starter relay).
Fuses are obviously there to protect the voltage outputs.
Source… Identify electrical connections? - Mercedes-Benz Owners' Forums

Regarding the fluctuation heating on the driver’s side, try turning the thumb wheel to full hot for 5 minutes and then to full cold for 5 minutes, repeat this regularly as you drive for a few days, perhaps a sticking duo valve or sticking thumb wheel switch might be the problem and maybe it might fix itself.

Dec

 

[Wigglesworth]

Brilliant stuff there!
Turns out that there is a relay within the K40 that is responsible for fan control (apparently).

I have already found that there is power on the high side for the fan relay under the washer bottle. As for the low side.... well this can't be switching I guess.
It would stand to reason that there could be an iffy solder joint in there as I already had to re-solder the N10 relay (other side and unrelated I know). My brain is saying that it would be possible that there are dry joints here too due to age and it has to be worth a look!

I never even knew that the K40 relay was even a thing so thankyou very much for that bit of information

 

[Wigglesworth]

Regarding the fluctuation heating on the driver’s side, try turning the thumb wheel to full hot for 5 minutes and then to full cold for 5 minutes, repeat this regularly as you drive for a few days, perhaps a sticking duo valve or sticking thumb wheel switch might be the problem and maybe it might fix itself.

Dec

This seems to be doing the trick regarding the heating/cooling issue

I took out the K40 module and took it apart as best as I could, which isn't much as this has the smaller unit that is pop riveted together.



Not sure if you can tell on the picture but there was uniform corrosion across the bottom of the board...


I decided that the best option was to clean it up thoroughly and touch up all the solder joints as a couple were looking like they could have been dry joints.

I think as a matter of course, I will be changing both coolant temperature sensors over next week.
From what I can gather, the fans are controlled by a combination of signals. These come from the engine temp sensors (both on the thermostat housing), the ac pressure switch and the temperature controls and switches in the cabin!
The relay for the fans (I imagine) will be switched by a feed signal from the K40, as too will the ac compressor (which is functioning correctly).

Wow this thing is over engineered

 

[Dec]

Keep at the thumb wheel trick into the future, I do that on a regular basic as I think it can avoid sticking valves, never had sticking valves so don’t know if it works for sure.

Do you have the temperature sensor in the centre of the picture in below link?

Dec

Imgur: The most awesome images on the Internet

 

[Wigglesworth]

Umm I think so??



Looks like I need a new front cover now too as age has made it brittle and this happened ....


Plus, because at the moment it seems to like being a hateful old thing! The transmission has started leaking on the drivers front corner
Around the plug for the contact plate thing looks rather wet. I can only assume that is where the leak is from! All of the sump bolts are tight so I can't see another reason.
Annoying to say I have only just done the gasket, filter and atf at great expense. I'm told that the o' rings and new plug are available from MB for not very much though so that is going to have to be investigated asap.

 

[grober]

Mercedes M111 Engine Front Cover Trim A1111580385 | eBay

check the MB dealer price too!

 

[Dec]

That cover could be even cheaper in a scrap yard.
You have the sensor alright, don't know what the other one to the right is.

Is it oil that’s leaking, there is a rain drain under the windscreen wiper motor, I think rain drips down around there.

Dec

 

[Wigglesworth]

It is indeed engine oil

The oil filler cap had failed and oil was all down the intake side of the engine (about 1/2 a litre of it). This happened on my London trip and needless to say, I was not amused! The engine in this car looks almost new when you lift the bonnet and I'm desperate to keep it looking this way.
I'm not sure with the oil around the camshaft actuator though as this was the first time I have had the front cover off.... little worrying to be honest!

It does have a loud rattle on idle sometimes and the jury is out as to whether it's the tensioner damper or the actuator. I would rather hope it's not a failing/failed actuator because that's a very expensive and time consuming thing to fix... whereas the damper is £50 from MB and less than an hour to sort.

Any suggestions as to the best way to get the oil off the side of the engine without resorting to a jet wash?? As it's the whole side under the inlet where you can't really get you're hands.

This is my engine in the dark and what I consider "dirty"

 

[Dec]

The sealant that MB used on the cam magnet is a kind of cement that seems to fail over time, I resealed mine last year, I didn’t replace the magnet. Its still bone dry although my picture looks like it is wet/shiny, the shine is from the WD40 I used to clean up the area.

I cleaned and scraped both faces and applied a silicone seal, I see in the guide below that Mercedes have there own sealant for the job so best to use that, be aware, it takes 24 hours for the sealant to cure properly so you wont be able to drive for a while.

Guide at bottom of this page… 1998 SLK 230K gets a Smart little yellow friend! | Retro Rides

Very hard to get at that area, cleaning the engine with something you can spray on then rinse off with a garden sprayer filled with hot water, you need to make sure you aren’t going to hit any electrics’, you might get better advice if you start a new thread on the subject.

Dec

 

[gurpz]

Replace the camshaft adjuster magnet, almost any M111 that has that fitted that I have come across leaks there with age despite the mileage of the car. Its a simple 10 minute fix. Be sure to use a very thin smear of sealant only too much and it will go everywhere. Also the front plastic cover is super cheap from the dealer only £10-12 odd if memory serves well for that price why would you even bother with second hand.

 

[Wigglesworth]

Ok so today I have mainly been concentrating on the leak at the transmission!

I got this new part direct from MB which unsurprisingly they keep on the shelf it's that common of a problem!

As you can see this part is known as a "pilot bushing" and cost a mere £27.43!
I didn't fancy risking none genuine given the nature of it's purpose and the part number is on the picture.

Changing the item over is straightforward enough. But do be aware of the amount of fluid that you will lose.

This came out of the plug that fits into it (a very unwelcome surprise indeed)...

And this is the quantity that came out of the plug alone!

This is the state of the old removed and leaking part...



Guess that was overdue then!

And that concludes today! I will keep tabs on the sump pan over the next few days just to be sure that the leak is stopped.

 

[Wigglesworth]

Replace the camshaft adjuster magnet, almost any M111 that has that fitted that I have come across leaks there with age despite the mileage of the car. Its a simple 10 minute fix. Be sure to use a very thin smear of sealant only too much and it will go everywhere. Also the front plastic cover is super cheap from the dealer only £10-12 odd if memory serves well for that price why would you even bother with second hand.

Certainly cheaper at Mercedes Benz for the front engine covers £14 and some pence (I will update correct price and part number when it arrives)!
There is no way I'm going to pay £20+ from eBay for one when they are cheaper direct from dealership, thanks for that heads up!

Priced up the camshaft magnet at around £89 from dealer but forgot about the sealer.

The front engine cover has to come from Germany so I am having to wait 5 working days.

We are having trouble finding both of the sensors on the thermostat housing. The sensor on the left is listed but the single pin one on the right hand side is proving a little difficult to pin down on the Mercedes Benz system due to us not knowing what it is actually for :fail

 

[gurpz]

Certainly cheaper at Mercedes Benz for the front engine covers £14 and some pence (I will update correct price and part number when it arrives)!
There is no way I'm going to pay £20+ from eBay for one when they are cheaper direct from dealership, thanks for that heads up!

Priced up the camshaft magnet at around £89 from dealer but forgot about the sealer.

The front engine cover has to come from Germany so I am having to wait 5 working days.

We are having trouble finding both of the sensors on the thermostat housing. The sensor on the left is listed but the single pin one on the right hand side is proving a little difficult to pin down on the Mercedes Benz system due to us not knowing what it is actually for :fail

No problem I see its gone up since I last bought one several years ago but hey that's to be expected.

You can use Elring Dirko for the sealant Eurocarparts sell it its more than likely the same stuff MB use anyways as Elring is a popular OEM supplier for MB gaskets and sealants.

Elring Dirko Sealant Tube (70ml Paste)

As for the sensor the middle single pin one its the first I've ever seen that one, you sure you have not got anything aftermarket on your car such as the AC ?

 

[Wigglesworth]

The car has ac .... but this was fitted from factory.
I know that the car was originally a dealer demonstrator and still have the paperwork listing everything fitted.

electric front windows, mirrors, glass sunroof and ariel (windows and roof have auto close/open with the key remote and manual rear windows all standard fit. Along with the manual dual zone ac that is original to the car and listed on the paperwork with the car.

Even Mercedes Benz were confused as to that sensor, I guess that there will be a part number on it somewhere (here's for hoping)

 

[grober]

If memory serves the multiconnector plug on the left is the temperature sensor for the fuel injection system the single pin sensor in the centre should be the sensor for the instrument cluster temperature gauge? Easy to test with the car warmed up - disconnect it and see what happens to the gauge?

by analogy here are the same sensors on the related M104 engine but with a different water pump they are located on the thermostat housing.
http://www.pelicanparts.com/techart...R-Coolant_Temperature_Sensors_Replacement.htm

possibly
https://translate.google.co.uk/tran...rekt.de/oenumber/a0055422617.html&prev=search
but check against your chassis no

 

[Codger49]

I have had a look at EPC for those sensors. Not conclusive, but may help you make progress.


EPC for your VIN (with M111.945 engine, as stated on the data card for your VIN) only had the left hand sensor (A 005 153 63 28 SENDER UNIT COOLING WATER TEMPERATURE GAUGE). Guess the MB partsman also saw this page with only the one sensor shown.


However, the M111.941 engine (also used in W202.020s) excluded this particular sensor, but had 5 other possibilities for the 3 bushes:

A 005 542 10 17 SENDER UNIT COOLING WATER TEMPERATURE GAUGE (Optional with A 005 542 26 17)

A 009 542 35 17 SENDER UNIT MOTRONIC INJECTION SYSTEM B11/3 [023] ONLY FOR VEHICLES WITHOUT IMMOBILIZER
A 011 542 51 17 SENDER UNIT MOTRONIC AND COOLANT TEMPERATURE INDICATOR B11/4 [024] ONLY FOR VEHICLES WITH IMMOBILIZER

A 008 542 45 17 TEMPERATURE SENSOR USED WITH AIR CONDITIONER B10/8 [023] ONLY FOR VEHICLES WITHOUT IMMOBILIZER

Maybe you can find one of these numbers on the RH sensor?

If you wish to PM me your email address, I can send you pdfs with the EPC diagrams and parts lists for the M111.945 and M111.941 sensors, and your datacard as well if you don't already have it.

 

[Wigglesworth]

If memory serves the multiconnector plug on the left is the temperature sensor for the fuel injection system the single pin sensor in the centre should be the sensor for the instrument cluster temperature gauge? Easy to test with the car warmed up - disconnect it and see what happens to the gauge?

by analogy here are the same sensors on the related M104 engine but with a different water pump they are located on the thermostat housing.
Mercedes-Benz W124 Coolant Temperature Sensors Replacement | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article

possibly
https://translate.google.co.uk/tran...rekt.de/oenumber/a0055422617.html&prev=search
but check against your chassis no

Thanks for that, I will disconnect the sensors and see what happens to the temp gauge (one at a time of course) to see if it affects the temp gauge.

I have had a look at EPC for those sensors. Not conclusive, but may help you make progress.


EPC for your VIN (with M111.945 engine, as stated on the data card for your VIN) only had the left hand sensor (A 005 153 63 28 SENDER UNIT COOLING WATER TEMPERATURE GAUGE). Guess the MB partsman also saw this page with only the one sensor shown.


However, the M111.941 engine (also used in W202.020s) excluded this particular sensor, but had 5 other possibilities for the 3 bushes:

A 005 542 10 17 SENDER UNIT COOLING WATER TEMPERATURE GAUGE (Optional with A 005 542 26 17)

A 009 542 35 17 SENDER UNIT MOTRONIC INJECTION SYSTEM B11/3 [023] ONLY FOR VEHICLES WITHOUT IMMOBILIZER
A 011 542 51 17 SENDER UNIT MOTRONIC AND COOLANT TEMPERATURE INDICATOR B11/4 [024] ONLY FOR VEHICLES WITH IMMOBILIZER

A 008 542 45 17 TEMPERATURE SENSOR USED WITH AIR CONDITIONER B10/8 [023] ONLY FOR VEHICLES WITHOUT IMMOBILIZER

Maybe you can find one of these numbers on the RH sensor?

If you wish to PM me your email address, I can send you pdfs with the EPC diagrams and parts lists for the M111.945 and M111.941 sensors, and your datacard as well if you don't already have it.

That would be excellent! I have sent you a pm with my email address.
I note that there are at least 2x sensors that look identical when you see them although have separate part numbers.
Might help get to the bottom of exactly what each sensors function is and acquire replacement parts.

 

[gurpz]

I make it A0055421017 according to the EPC which supersedes A0055422617 but as Codger49 has previously stated it only shows the far left 2 pole sensor against your VIN but once you remove the filter the middle single pole sensor becomes available

 

[Wigglesworth]

Part number on the right sensor is.....

006 545 3724. (110 degrees)

I make that an auxiliary fan switch, usual fitted to a 190E!
Most strange indeed because it certainly isn't a 190E and it's definitely supposed to be there.
This would explain why people really couldn't place it and the part number was awkward to read but I have made sure the above number is what is on the sensor 100%