I just bought all these things in early May. I'm experiencing the same symptoms as you. AC on and everything...

Planning to tackle this clutch change Monday as well as a whole water change (get that green stuff out and put in Zerex). I don't know if a new clutch and 11 blade fan as well as 80C thermostat will change much, but I don't want a head crack... Anyone disagree?

11 blade fan: 606-200-01-23
Fan clutch: 606-200-01-22
Bolts (fan to fan clutch): N-914020-006017

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It's not the years, it's the mileage.

Why are you concerned about this? You could run it at 105C. all day long and the engine wouldn't care.

I'm not concerned with the 100, I'm concerned with the clutch not engaging. When I take it over the pass and it is at 115 because the clutch is not engaging THAT is when I become concerned. Given what I know about the clutch, if the radiator is at 95 right in front of the clutch and it is still not engaging with good air flow, than even higher temps probably won't make a difference. So it is either fix it or take the hybrid. I can't show up at a Mercedes GTG in a hybrid.

So the test wasn't to see how hot I could get the car. It was to see if the fan clutch would engage after wasting a Saturday taking the radiator out and cleaning it and the condenser. I ran out of hill before the temp would get any higher. Again, and correct me if I'm wrong, if the radiator is at 95 in front of the clutch, I should have seen some lock up. I did not.

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Did you shut the engine down at that temperature and observe the fan? Did it freewheel for several seconds or immediately come to a stop with the belt?

I used the stop lever under the hood to shut the engine down at that temp (95 at radiator). It spun for 8 seconds. To me that means no lockup and thus a defective clutch. What is your take on the results?

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

Mine will spin for 10 seconds or more at 100 degrees. I bought the oil to put in the clutch. I will try to do that tonight.

There have been suggestions by others to file down the pin by 1 mm to get the clutch to engage at a lower temperature.

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Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

For $100 for the clutch and $40 for the fan I'm just going to replace them.

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


Be careful of the toes you step on today, as they may be connected to the ass you have to kiss tomorrow. anonymous

“Be who you are and say what you feel, because those who mind don’t matter, and those who matter won’t mind.” Dr. Seuss

The clutch needs servicing or replacement.

No, this is normal, or at least not a problem. My car will do the same thing, the hose is not usually totally flat, but there is often a slight vacuum in the system. This is sort of a good thing because it proves the head isn't cracked, lol (a cracked head will leave the system pressurized even when stone cold).



That is correct, it is not contributing to the cooling problems.

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Dave
Boise, ID
Check out my website photos, documents, and movies!

I agree 100%... sounds like a bad fan clutch to me. Replace (or re-fill) it post-haste and repeat the tests.



That ain't right. When engaged the fan should only spin 1-2 seconds when the engine is shut off. But remember that the clutch does not engage based on what any temp sensor says, including the dash gauge, which may be showing 100°C or higher. If a new clutch (or re-filled clutch) does the same thing, there are other problems besides the clutch.



Interesting idea, although you don't want it engaging too soon either. The noise, and drag on the engine (affecting MPG), simply isn't necessary under 95-100°C. The factory setting is fine when everything is working properly.

Bad fan clutch, mine did that before replacing. Afterwards it wouldnt spin longer than 1 sec or so. Remove and replace.

OM606 fan clutch works/fits/runs perfect on OM603. You can use OM603 metal fan as well. Much cheaper, but if you really want the plastic fan go 4 it.

OK its getting hot down here in ATL. Ive been beating on this thing trying to overheat. Ive mustered up 105C now (uphill flat out 90F outside).

I want to wire in the aux fan to come on at 90C. This will help A/C and should keep things under 100. Anyone do this ? Im not using the antenna switch on dash, could I rig it in easily? Or better yet, has anyone found a 90C thermoswitch to replace the 105/128 3 pin? 105 too hot.

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Paul
Benz-less
I need an SDL !

You can't wire the switch to engage at 90°C. or it will run all the time. The thermostat is not fully open at that temperature.

Get the 100/110 switch............p/n 006 545 42 24. It will start the fan at 100°C., which is perfect.

I don't mind the 105/120 switch... anything in the 100-105 range is fine to trigger the electric fan. There is absolutely nothing unsafe about temps in the 110-115 range, as long as your cooling system holds pressure and isn't boiling. The electric fan is quite noisy on high speed, and the stock alternator can't handle that load at idle speeds, so your voltage will drop below normal(which is just one more reason to do the 150A alternator upgrade, that I've done on all my cars).

I really recommend just using the 105/120 switch, but if you're the ultra-nervous type, the 100/110 switch will work... but remember you will lose A/C operation at 110C. I would seriously consider the alternator upgrade (described here) if you drop the engagement temp to 100C though.

Sweet! What year/make/model is that from?



Even still, is there any way to wire in my aux fan switch to my non-working antenna switch? It gets REALLY hot in Atlanta, when idling engine may not even reach 100C but AC is already fading. I bet if the aux fan were spinning it would do much (well, a little) better.

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Paul
Benz-less
I need an SDL !

Pretty sure the 100/110 switch is from a gasser of some sort (M102, M103?).

You could wire up a manual switch on the dash, all it needs to do is trigger the relay which turns the fan on high speed. You need a decent amount of electrical know-how, but the schematics are all in the ETM section (Group 24) of the FSM.

With a properly functioning mechanical fan clutch, the electric fan isn't going to do squat unless you're stuck in traffic or otherwise at idle... and again, you're going to want to do the alternator upgrade along with this.