1988 300ce fan clutch

[anfieldassasin]

Hi guys correct me if I'm wrong but my car should have a viscous fan clutch (I recall my 230ce m103 had an electric one).

Anyone have a diy on how to replace this? From what I searched they call for belt removal but I don't understand why this is necessary surely you just undo the bolt holding the fan onto the pulley replace the clutch on the back of the fan and button up.

Am I missing something or does anyone have a decent diy?

Recall on my.230ce with the electromagnetic one it wasnt so hard.

In traffic car rises to 100c and i dont hear the fan roar ever seems to spin at same speed regardless, not done the carrot test yet that I read so much about

 

[stwat]

Here's an MB pdf that should help.

https://www.startekinfo.com/StarTek/outside/12253/program/Engine/103/20-312.pdf

 

[RichardF]

I find the Pelican Parts "how to's" invaluable

Mercedes-Benz W124 Cooling Fan and Shroud Removal | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article

 

[anfieldassasin]

Thanks guys will look into the stuff you posted and see where to go from there. Any recommendations for brand of viscous fan clutch?

 

[hotrodder]

I'd buy a Sachs fan clutch (probably from Autopartstechnik but there's various sources) if genuine examples are 'kin spendy which i suspect they are?

Bear in mind that the official lock up temps are 96 - 104°C so if it's barely nudging 100° the existing clutch might be fine, mine cuts in at about a needles width over 100° for example. http://www.w124performance.com/service/w124CD1/Program/Engine/104/20-0020.pdf is a list of switching points for the cooling system

Personally i've never been much of a fan (sorry!) of the carrot test or stuffing anything into a running fan to see if it gets diced or just stalls the fan... with the engine switched off there's a noticable difference in resistance between freewheeling and engaged when turning the fan by hand

 

[grober]

Bear in mind these viscous clutches should always be stored vertically or with the bimetal strip uppermost - on the "shelf in store" as well as on the car. Like most things a short time horizontal is probably OK But several months stored flat or upside down in a factors is a different story. Something to do with the fluid leaking out through the bimetal activating pin seal??
http://web.archive.org/web/20081206...lutches/general/englisch/0032004_SITIP001.pdf

 

[anfieldassasin]

Thanks hotrodder. I'm. Not sure to be honest it's never gone above the 100c mark. I'm. Just thrown by the swinging Temps, it will quickly rise to 80-85 and then at standstill rapidly goes to 100c at which point I turn the heater on and it drops to 80's. Oddly the heat in the cabin at even the low setting is uncomfortablely hot and when I take my key out or check in glove box after long journey it's too hot to touch.

I'm going to start with coolant flush and fill with rad flush and reservoir cap plus thermostat. From there see what happens and if no change then viscous clutch next. The 3 sensors on the head as far as i am aware are not for switching fan on and off. One is temp sender for dash the rear most is for the ecu and the first is a thermo vacum valve but I have no idea what it does.

Will report back in due course

 

[hotrodder]

As Grober said there's a bimetallic strip on the fan clutch making it self contained

While your viscous fan could be dead none of your symptoms point to it yet... if the 'stat was stuck open/partly open it'd take ages to warm up instead of reaching 80/85ish in a couple of miles. If the stat was jammed closed it'd overheat even when moving, jammed mostly closed and it'd take longer to warm up but probably still overheat even when moving as it's the stat that's mostly responsible for maintaining a stable temp. If the rad cap is dead or there's a coolant leak from somewhere preventing the system from pressurising then it'd boil over sooner than it should but FWIW a 50/50 water/coolant mix boils at ~107°C at sea level. If the system is pressurising properly then it shouldn't start to boil until ~132 - 135°C
Changing the stat and cap regardless is still a good call as they're cheap

Only getting hot in stationary traffic suggests waterpump or maybe a rad that's on it's last legs

If the heater chucks out uncomfortably hot air regardless of heat setting and cabin temp then duo valves are the common suspects

Bits of dashboard and a key that's too hot to touch is more worrying

 

[WDB124066]

Is the engine air intake exactly as it should be, I had a case of overheating from sucking in hot air right off rad, inlet temps of approx 75 to 80 Deg C iirc.

Correct spark plugs.

Check fuel mixture.

Have you done a pressure test?

MB sell hoses and a blank stat for flushing.

A clip on the Duo Valve, https://www.youtube.com/watch?v=8jhPEfLI45s

 

[anfieldassasin]

Is the engine air intake exactly as it should be, I had a case of overheating from sucking in hot air right off rad, inlet temps of approx 75 to 80 Deg C iirc.

Correct spark plugs.

Check fuel mixture.

Have you done a pressure test?

MB sell hoses and a blank stat for flushing.

A clip on the Duo Valve, https://www.youtube.com/watch?v=8jhPEfLI45s

Duo valve working OK, full cold gives me cold air but slightly hotter setting gives me some really hot air and higher still gets even hotter.

No leaks anywhere no coolant level drops no boiling over. Only key and glove box interior get hot.

Plugs new and bosch OE from dealer
Leads new Beru silicone ones

Air in take aligned properly

Fuel mixture adjusted to around 1% as measured by CO at exhaust

I did wonder if a thermostat that was taking too long to fully open could cause this? Can it behave relatively normal for the first portion of its travel and then slow down due to a fault at the upper temp ranges?

I noticed yesterday the temp ran to the 100c line I didn't do anything and it dropped by it self, but I couldn't hear the fan roaring (I couldn't get out and check).. Might try and see on way home from work today if I can pull over and check fan.

 

[anfieldassasin]

Right so to report back.

Flushed coolant out including with rad flush solution, flushed rad with hose also. Colour of stuff that came out wasn't so bad.

Replaced thermostat with OE 87degree one from dealer, replaced temperature guage sender with OE one, replaced tank cap with OE and refilled with 50 50 coolant
Mix (comma g48 Mb 325.0, which I've used successfully before on my other c124). Bled all air out that I can.

Now I've gone from previously where car would stay at 80degrees if above 30mph and then towards 100 degrees in traffic to it staying at 95-100 degrees whilst driving at any speed!

I've actually made it worse lol!! No temp spikes indicating air pockets etc just a steady rise to 100.

No leaks of coolant and none from water pump with no funny bearing noises etc

What am I missing?

 

[grober]

Another possibility is to borrow* an infrared remote temperature monitoring device and check the temperature of the various parts of the radiator to see if there are any dead areas signifying a partly choked radiator.


*a professional one is best but even the cheap and cheerfull ones ain't bad. especially if you can calibrate them with a known temperature source around the same temperature you want to measure. Also in checking for rad dead spots you are more concerned for areas of very different temperatures rather than absolute accuracy.


Infrared Thermometer with Laser Targeting | Maplin

 

[anfieldassasin]

Another possibility is to borrow* an infrared remote temperature monitoring device and check the temperature of the various parts of the radiator to see if there are any dead areas signifying a partly choked radiator.


*a professional one is best but even the cheap and cheerfull ones ain't bad. especially if you can calibrate them with a known temperature source around the same temperature you want to measure. Also in checking for rad dead spots you are more concerned for areas of very different temperatures rather than absolute accuracy.


Infrared Thermometer with Laser Targeting | Maplin

Thanks mate, I'll pick one up via amazon prime and have a look hand thermometer hasn't sensed any cold spots but will check with infra red. Currently the car has a behr radiator, online all i can find are the nissens units

 

[hotrodder]

First thing i'd do is test both the old and the new 'stat with a saucepan of water, thermometer and stove... based on the running temps you've had i'd bet the old one begins to open a bit early and the new one maybe starts to open a bit later than 87°C. Or it could be variations between the old and new temp sensor etc

Being pedantic bang on 80° is running a nats cool, a needles width (or 2) above 80 is where pretty much every 123 and 124 usually runs most of the time IME and while 95 - 100° is a bit hotter than usual (at this time of year at least) it's not close to overheating. Especially if it never climbs over 100

If you do end up replacing the rad for whatever reason there's nothing wrong with Nissens... they're good quality, usually fantastic value for money and when i fitted one to mine a few years back fitted perfectly. There are plenty of places about that can a supply a Behr rad for barely any more £££ but they ain't the same as the origional, it's Behr-Hella these days and the cheaper/aftermarket examples are made in China (Nissens are made in Denmark). OEM Behr from the stealer (assuming that's still what they supply) are a LOT more £££ and while the origional rad is cosmetically better finished than a Nissens it won't work any 'better' for example the copper reinforcing rings in the inlets/outlets of origional Behr rads is a crap way of doing things compared to Nissens take of using a thicker wall plastic that smoothly tapers out.

Duo valve working OK, full cold gives me cold air but slightly hotter setting gives me some really hot air and higher still gets even hotter.

No leaks anywhere no coolant level drops no boiling over. Only key and glove box interior get hot.

Heater temp thing sounds more like a problem either with the control panel or the little air sampling fan that's hidden in the dash (near the glovebox IIRC?) and is fed from the grille in the interior light

Unless the temp wheels are 'clicked' to full cold or full hot the heater should automatically vary it's output to attain the target temp set i.e. i haven't changed the temp setting in mine for eons, in the summer/when the interior is hot you get cool air and when the interior is freezing cold it should chuck out hot air initially and gradually taper the heat off to the set temp as the interior warms up

A hot key and glove box has me stumped

I did wonder if a thermostat that was taking too long to fully open could cause this? Can it behave relatively normal for the first portion of its travel and then slow down due to a fault at the upper temp ranges?

I noticed yesterday the temp ran to the 100c line I didn't do anything and it dropped by it self, but I couldn't hear the fan roaring (I couldn't get out and check).. Might try and see on way home from work today if I can pull over and check fan.

Yeah a stat could behave like that i suppose but i'd think it'd be fairly rare? They don't necessarily fully open much of the time anyway... they should start to open at the temp stamped on them and won't reach fully open for another 15 - 20° (or 102° according to WIS). When there's good airflow through the rad and the waterpump is working properly etc it's the 'stat that's mostly responsible for maintaining a stable running temp... coolant gets hotter it opens a bit more and diverts more through the rad/less back around the engine, coolant temp drops a bit and it closes a little sending less through the rad etc

When you're stationary there's little to no airflow across the rad so it's less efficient and shunting more coolant through it isn't necessarily enough to stop temps climbing hence having fans cut in when the coolant gets hot enough
You don't want the fans to cut in too soon because that doesn't help rad effiency either... temp drop across a radiator isn't as much as common sense would suggest because the closer the rad gets to ambient temp the less well it works i.e. want to run the rad as hot as practical because the larger temp difference between it and the surrounding air the better it works.

After i'd checked the opening temp ranges of the new & old 'stats i'd go back to the fan... 100° isn't quite hot enough to confirm it's dead but with the engine switched off it should be stiffer to turn than when the engine is cool. Carrot (or whatever) tests won't achieve much unless it's hot enough to properly engage and the noise from the amount of air they shift gives that away

 

[anfieldassasin]

Thanks for the comprehensive post hotrodder! Ran the car at idle yday till temp went upto 2 needle widths above 100 Dan didn't spin any faster but temp dropped by it self to 85-90 and then began to climb again and the cycle. Continues. I'm assuming that's normal. At cold the fan has resistance to shining and does not free wheel at all, I'll give it a shove and it will go like 1/4 rotation. No roaring of fan or change in air quantity shifted when at 100. It may be that I have a few things wrong at the same time I'm just hoping it's not the water pump given its a pain on the m103.

I asked about the rad because I read some rads leak between the transmission oil cooler and the coolant part, I have no problems with Nissens per se as long as it works and last. On the 230ce I put in a generic rad from ecp and it lasted 2 months before leaking coolant at the plastic junctions on sides so dont want to make that mistake again.

I only get 1 or 2 days per month to tinker so will report progress back when I've had a chance to do more work (I might just put the old sensor back also in mean time as quick job and see what happens to temp guage).

Oddly I had a similar issue on my 230ce ran bang on 80degrees and then after coolant change thermostat new sensor and water pump with new rad it ran hotter at 85 (although i didn't mind as that's normal as you say)

 

[hotrodder]

Cheers. I think the transcooler deal was specific to one batch of OE Valeo rads for later E classes?

From memory i think it's normal for fan clutches to be stiffer when stone cold/the engine hasn't been run? They then loosen up a bit when run before gradually getting stiffer as they warm? Either way sounds like you've confirmed yours isn't properly locking up when hot but is working enough to keep temps in check

 

[anfieldassasin]

Hi guys so checked temp with the laser thermometer thingy ma Bob across rad. Where the coolant enters its. Hot at around 90+degree on the passenger side as I move towards the drivers side at the top it drops to 70 or 80 ish. Also the top of the rad is hotter than the bottom and the middle area.

Also I notice on a cold engine spinning the fan as I said before gives resistance with only a about a quarter to half turn of the fan. What I noticed is that if I keep spinning the fan it will get progressively looser and will rotate for a few turns. Turning the car off from a hot engine 90 degrees plus the fan has little resistance to turning it but as it cools after a few mins it increases in resistance.

So question is do I have blocked rad and a bad fan clutch?

So have replaced coolant and thermostat and temp guage sender both old and new sender show same temp behaviour so it's not that.

 

[DSB SL AMG]

Have you checked the water-pump function?

Hi guys so checked temp with the laser thermometer thingy ma Bob across rad. Where the coolant enters its. Hot at around 90+degree on the passenger side as I move towards the drivers side at the top it drops to 70 or 80 ish. Also the top of the rad is hotter than the bottom and the middle area.

Also I notice on a cold engine spinning the fan as I said before gives resistance with only a about a quarter to half turn of the fan. What I noticed is that if I keep spinning the fan it will get progressively looser and will rotate for a few turns. Turning the car off from a hot engine 90 degrees plus the fan has little resistance to turning it but as it cools after a few mins it increases in resistance.

So question is do I have blocked rad and a bad fan clutch?

So have replaced coolant and thermostat and temp guage sender both old and new sender show same temp behaviour so it's not that.

 

[anfieldassasin]

Have you checked the water-pump function?

My understanding is that when it goes bad it has a tendency to leak, mine doesn't. I put a stethoscope on it and no unusual noises either.

 

[grober]

Hi guys so checked temp with the laser thermometer thingy ma Bob across rad. Where the coolant enters its. Hot at around 90+degree on the passenger side as I move towards the drivers side at the top it drops to 70 or 80 ish. Also the top of the rad is hotter than the bottom and the middle area.

Also I notice on a cold engine spinning the fan as I said before gives resistance with only a about a quarter to half turn of the fan. What I noticed is that if I keep spinning the fan it will get progressively looser and will rotate for a few turns. Turning the car off from a hot engine 90 degrees plus the fan has little resistance to turning it but as it cools after a few mins it increases in resistance.

So question is do I have blocked rad and a bad fan clutch?

So have replaced coolant and thermostat and temp guage sender both old and new sender show same temp behaviour so it's not that.

temperatures you need to monitor are at the inlet [top] hose and bottom [outlet] hose there should be a drop of approx 20 F temperature and should drop evenly down the radiator top to bottom - an abrupt change or cool spot might indicate a blockage.

Troubleshoot Engine with Infrared Thermometer