DMartin1986

Can anoyne shed more light on the problems with Enigne/AC Coolant Fans.

Ive got a 57 reg 220CDI and if im ever stuck in traffic it goes from roughly 80rpm to about 95rpm then my Temperatue light comes on and i can hear the fan kicking in.

This only ever happens in traffic, i can drive for hours on the motorway with it being fine but in traffic for 5 minutes then it overheats.

Ive had an independent mercedes garage look at this and they had it on diagnostics which showed - Engine/AC Coolant fan - open circuit.

This is going to cost £390 for the fan from MB plus maybe 60-70pound labour from my independent garage. I was just about to book it in to get done but upon reading this thread it worries me this may not fix the problem. Could anyone help please?

Thanks

mercedes4ever

Sounds like your fan is not cutting in soon enough in traffic stop / start conditions. Get it fixed as per your Indie Specialist diagnostic check.

bcapjoe

I'm having some of the same problems. 2003 c240 coolant visit workshop.
Radiator fan was running full blast all the time. Everything else was working normal. When getting the part number for the Radiator fan I noticed it was was a Mercedes part manufactured in 2011. I changed the radiator fan and the engine them sensor. Now fan comes on full blast when I start the engine and then stops after about 30 sec. and doesn't come back on never. ?????????

bzliteyear

big bummer - i've got the same mssg on my 2006 CLK55 cab.
up until 2 months ago, SUPER reliable car never needing anything except oil change.

when i changed the battery out, the fan wouldn't go on and temp gauge started to run "hot" - but after 1 hr labor, turned out it was the fuse.

NOW...i'm getting the coolant message - topped off the fluids, including the windshield washer, and getting it on when the engine is on in position 3 - no message in position 1 or 2.

anyone have thoughts on how to diagnose - and the sequence - pls correct if i'm wrong:
1) star test diagn
2) check fuses
3) check line/short under battery
4) check wiring under hood
5) check sensors, etc...
Thx everyone
Patrick

Tump43

Hey Guys,
I have the same issue. My C55 radiator cooling fan does turn on when the car is over 80c or even 90c, and does not come on when the a/c is turned on. I did a lot of research on this forum and elsewhere. I replaced the coolant temperature sensor; that didn't fix the problem. Checked the fuse (#51), it was fine.

I then removed the fan assembly and replaced the fan motor and the the fan control unit, cleaning the electrical connections between the engine harness and the the fan assembly, the fan control unit and the fan motor. However, this did not solve the problem. The fan still does not come on when it should; i.e. when the a/c is on or the engine is over 90c.

Any help diagnosing this would really be appreciated. I didn't check the relays; I'd like to do so, but I do not know how. From this forum someone suggested swapping the same color relays systematically (taking notes) to see if any one of them is defective. Any help here would also be appreciated.

But before I can do any of that I have one really big problem. Removing the fan assembly required that I remove the top cross member at the front of the engine bay between driver's and passenger's side. It looked easy, held on by 4 bolts, but really required the removal of the hood latch, two blind bolts attaching it to the rear of the front crash bar and various bolts holding the horn, transmission cooler etc. However, when I re-installed the hood latch (the part on the driver's side behind the light released by a wire connected to the red lever in the cabin on the driver's side under the steering wheel where the driver's left knee would be), I did it incorrectly and cannot now unlatch the hood. Does anyone have any ideas as to how to remedy this *#4%!*! mistake to open the hood, short of cutting through the hood itself? I can reach the fail safe release under the center of the hood, but without releasing the main hood release on the driver's side, the hood will not open. Again, any help would be really appreciated.

Oh, and before I started this project, I had my independent mechanic diagnose the problem, he told me that the cooling fan motor was fried since he could not jump it and his computer diagnosis said that there was an "open circuit" at the fan motor. The car runs fine, gets up to temperature and stays at the right temperature when moving over 35mph, however at long lights, in stop and go traffic, or just idling, it overheats. The new coolant sensor works by correctly and quickly registering those temperature changes.

Amaurym1970

Hello guys I have a 2004 Mercedez benz C240 sedan with 82K Miles, wondering if you can please help me solve this situation.
today I just started getting the "Coolant - Visit Workshop" message, My warning only goes on after the car has been driven for quite a while and when it is warm outside. Drove over 20 miles this morning before it came on and it only did so after sitting in line at a drive through for a few minutes at idle. The temp gauge goes 80*c and the warning comes up. I also don't hear the fan running and i check every hose and the cooling water tank is in the right level.

when I turn on the A/C is working but is not putting out the cold air either.

Please give me a solution to this, i will appreciated it..

samaritrey

Fill up your washer fluid and see if the error comes back. (can't remember when that was fixed if ever lol)
If that doesn't take care of it I would check the wiring and the sensors on both the coolant and the windshield washer.

Amaurym1970

Thank you very much.

Amaurym1970

I went to advance auto parts to purchase a thermostat and the censor just in case and I asked the staff to please diagnosis the vehicle to find out what was wrong and he gave me the code and I searched it on google and was #6 cylinder not working and what I did is disconnect and connect every spark plug cable and a check all fuses and one of them #5 was bad.
At that point when everything was done I turn the car on and everything is back to normal

Amaurym1970

Does The temperature stays always between 80 or less?

Amaurym1970

I'm driving my 2004 MERCEDEZ BENZ C240, over 40 minutes, and than Goes off, i try to start again and doesn't go on, is giving me that sound when you starting a car.
I open the hood and start touching all the cylinders cables and nothing.
than I open the fuses box and take out the big fuse and put it back in and the vehicle start but the engine light is on and the fuse is good.
What can I do?

samaritrey

Honestly I would get it hooked up to a star machine to do a full proper diagnostic. The dealer will have them as well as any good MB Indy shop and some members on here like me have one.
Sounds sort of like a CPS issue but hard to say you should get a CEL or at least a pending code.
Your car should run around 87C when up to temperature and not really move around much.

Drakhan

Hope someone can help. I have a
C CLASS - C200K Elegance SE 4dr Auto 2002 W203 with 162,000 miles on clock which i bought Nov 2014.
I was in London 2 weeks ago and in the hot weather and typical London traffic, the engine overheated and lost coolant and possibly washer fluid.
I managed to drive it home.
The temperature , once i was travelling on motorway never went above the normal 80.
When i topped up with coolant at home it emptied within 30 mins.
Today i topped up the coolant and washer fluid and so far no leaks but i am worried that something else is wrong.
Anyone any ideas.
I am NOT mechanically minded and probably could just change a fuse.
Anyone know what type of radiator fan my model has as i suspect it may be this.
Or could it be something else.

Drakhan

Just found out yesterday that the radiator fan is not coming on at all when temperature reaches the normal 80-85.
No more leaks, so far.
Only problem is when i'm stuck in traffic the engine then starts to overheat, probably due to fan not coming on.
Any idea of the cost to replace the radiator fan.

bzliteyear

this happened to me on my CLK 55 shortly after I changed the battery. I'm not sure if it was related or not, but it was the radiator fan as well. From my recollection, you cannot change just the fan as it is attached to some kind of module as one piece, & I think it was approximately 400 or 500 dollars for the parts and labor total from an independent. Good luck.
PL

Drakhan

Thanks.
Love my Merc. Just wish the parts weren't so expensive to replace.
Have to wait until bank holiday is over to find out the amount it's going to cost as they are shut until Tuesday.

samaritrey

You could try to find one out of a wrecked car IDK where you live but here in the USA I have seen those fans go for around $100.

You have tested the fan right? Don't want to replace it and find out its not the issue. With Star you can also force it on which would be a good way to test it.

Drakhan

Live in High Wycombe, 35 miles outside London.
The guy that tested it said that the fan doesn't come on when it should.
Will find out cost on Tuesday when i take the car in to get tested.
It's my 1st Merc.

jrc5465

I had a coolant visit workshop notification that kept coming on after my engine warmed up and the my fan would turn to emergency mode and run high. The problem was that my a/c would stop pumping cold air too. After spending a lot of time reading the forums and driving it I recognized a pattern that I just mentioned. It was consistently following the same pattern.

When I took it to the shop I told them what I knew and that I didn't want to spend a fortune on an A/C fix and to keep me posted on their findings. 2 days later after a few calls we had it fixed. So you know, the coolant visit workshop notification is in regards to the radiator fan. But the fix for my car was the auxillary fan. Once the aux fan was replaced, they recharged the ac (and service my car since it was due for A service) and the notification was gone and the a/c was working fine again.

Good luck guys and gals! Don't let them run game on you and milk you for your money!

master Maometto

Hi guys
I have problme in my car,, show computer check , coolant visit work shop,,,and engin fan not work,,, what must I do now ,,, please answer me friends

samaritrey

Well first step would be to check what codes are being thrown in the computer using a Mercedes star diagnostic computer or at the very least a decent Can OBD2 reader.
Once you have the codes you can analyze what is going on and if it is something simple or above your pay grade.
I would also take a look at the coolant level.
Do not drive car as it may have low coolant or a stuck thermostat and until you know whats going on don't want to potentially destroy the engine.
The engine fan could either be a computer issue, Wire issue or the fan itself.
You could wire up 12 volts to the fan to see if it power up and do other diagnostics if you understand wiring.

If what I said doesn't make any sense I would try to find a good local MB repair shop that has the tools and knowledge to help you out.

quip11

I've been getting a "check coolant" message from the message display and have been filling the reservoir with coolant. so I finally had the radiator replaced from a local radiator shop. It had a crack on the side from which the leak was most likely coming from.

So I've been driving the car since and no message. Then a few days after the radiator was replaced, on my way to work one morning, about 35 minutes in, I see a new message: Coolant Visit Workshop with the thermometer image at 80. As I was driving, the message kept coming on intermittently, with the temp gradually rising until about 90 when I got to work. I opened the hood and checked the reservoir and its full!

I remember seeing the radiator shop guy hosing the radiator in front of the engine block after he was done with the installation of the replacement radiator. I don't know if that may have caused this or not. On my drive home on the surface streets, the message kept on re-appearing with the temp steadily increasing to just over 100 deg. Then, the AC fan started to blow or sounded blowing hard, but no cold air. When I finally got on the freeway and able to drive continuously, the temperature gradually came back to just above 80 deg AND the cold air came back.

Went straight to my indy and told him the issue I was getting. He turned the key to the position 2 and said that the fan should've turned on already. The car was hooked up to his STAR computer and found "code p2073 electric fan for engine and AC, open circuit". He turn the key to position 2, unplugged the wire socket from the fan and tested the ends with a simple volt tester. The tester lit up so the voltage is coming through and he concluded that the fan is the culprit. He did not, however, check the fan independently from a different 12V source.

Long story short, the radiator cooling fan need to be replaced. It probably got damaged during the radiator replacement since it needed to come out. Its probably old and worn out that it doesn't kick in when it's supposed to.
After a lot of searching on what replacement radiator fan to buy, I stumbled upon this:

Radiator Cooling Fan Assembly New for Mercedes Benz C CLK Class | eBay

It's about half the price of the OEM from either the dealer or autohaus. I gave it a lot of thought, considering the age of my C240 (2002) and the price of the OEM part and I decided to buy the aftermarket. One big factor in my decision is the 10 year warranty. I figure, If it fails within a year, I'll get it replaced. If not, it'll grow old with the car.

The brand is DEPO, installed it just a little over a month now and it's been working fine, so far. The AC is now continously blowing cold air and the message have yet to re-appear.

http://www.ebay.com/itm/Radiator-Cooling-Fan-Assembly-NEW-for-Mercedes-Benz-C-CLK-Class/130969193403#ht_1963wt_1362

Vishal Sharma

Steve, I have the exact same issue as you had back when with my CLS500. Can you please advise what the solution was?

peterwashere

Hello.

Have a 2005 C55 and the dreaded coolant workshop message has displayed.
What's going on:
-fan does not turn on when above temperature
-starting to reach upwards of 100c. I don't let it get any hotter as I shut car off if gets warm.
-fan does not turn on when a/c or front defrost is switched on.
-discounted the coolant sensor (by thermostat) as a test and the fan did not turn on.
-heater does work as well as a/c blows cold aso long as temperature doesn't get to high.
-turning on heater will keep Temps down but it does still like to climb.
-engine heats up as expected, somewhat fast maybe?

Where should I go now?

History:
Replaced radiator because it was leaking on drivers side bottom. Coolant changed and topped off etc. (Did this repair myself)
-during the radiator install one of the transmission lines did not set to well and popped out and transmission fluid line leaked at connection to radiator. FIXED by snapping it in correctly with clip etc. Did have to add some fluid as "enough!" Leaked.
-no leaks anymore from coolant or transmission.

I've read all over here that many are finding fan assembly to be okay but a loose wire or relay is issue.
Other say fan assembly replaced works..


Questions:
1) which fuses or better (locations) should I check. I looked at obvious #51 and it's ok. As for relays not sure which ones to ticker with and location of them?

2) Can I use alligator clips to connect to fan assembly and power to battery to see if works, or is that a bad idea?

3) Should I just replace the fan? If so I noticed to different fan models. 800 watt and 650 watt (around there can remember exactly #'s but I know there is 2 selections for the C55 when searching?

4) Could the connector bemail bad due to fluid leak and transmission fluid leak on the splash gaurd. I know the plug is in the corner so not sure if that would do it? I also had to use some water down there to clean up the mess?

Any ideas or suggestions would be greatly appreciated.

richardpietersz

Hi everyone,

This has been a long journey from what started as a 'Coolant Visit workshop' message a year ago. My car started to overheat in traffic, reaching 120°c a couple of times. I initially took the car to a local dealer who said the usual BS - "your thermo fan control unit is gone". Bought a reconditioned one off eBay and installed it with no luck. Took it back and was asked to replace the thermostat and temperature sensor.

Months passed with no progress after installing/swapping all the above, I had to constantly switch on the HVAC to full speed at 30°c drawing some of the heat and venting
it in the cabin to stop the engine from exceeding 100°c. Luckily it was winter so I was able to manage the heat by rolling the windows down. I eventually bought an aftermarket 8" electric fan and installed it to the front of the radiator/condenser (just behind the oil cooler fins and horn), this did not stop the car overheating however it did prolong the time taken for the temperature to rise. I also installed an OBDII bluetooth adaptor and the used Torque app on my phone to monitor the temperature while driving, and I would manually switch on the fan when in traffic.

I'm in Australia and we are now coming into spring, I took the car to an indie who said he will need to hook up the ecu signal wire to an oscilloscope to check the square wave signal generated. (If this is faulty then I would have to replace the ecu). Last week I was on the verge of giving up and decided to bypass the ecu completely by installing an aftermarket thermo switch (90-95°c) to the upper radiator hose. The w203 thermo fan has 4 wires - 2 thick heavy duty wires for power (positive and negative), an ACC wire to activate the fan, and the ecu signal wire which tells the fan how fast to turn. By cutting off the signal wire the fan controller assumes that the ecu is dead and defaults to operating at full speed. So hooking the ACC wire upto a set of relays activated by the thermo switch and/or the aircon was my going to be my last resort.

A couple of days ago I was stuck at work as my car wouldn't start, it only cranked but did not click over. Ended up diagnosing the problem as a dead fuel pump. $290 later with a new fuel pump the car is running AND the thermo fan is working fine again! I was skeptical at first and left the car running at idle a couple of times and the fan switches on like clockwork at 96°c. I honesty do not see the connection between the two, the car does run a bit smoother, better acceleration, and the idle rpm seems a bit higher which means it was running lean before whilst the old pump was failing. Could it be the alternator generating a higher current at idle? Or data gathered by sensors at lean operation affecting the PWM fan controller signal? I can't say for certain but it did finally fix the issue.

I hope this post helps someone out there.