617 fan - Page 4 - PeachParts Mercedes-Benz Forum

OM617YOTA · #46 10-04-2014, 07:46 PM

I went with an electric cooling fan on my Yota conversion due to the stock clutch fan and radiator mounting location not matching up. I went with an adjustable fan controller, and had originally planned to also wire in a manual switch in the cab. It turned out to not be needed.

I have tested it's abilities. Minutes at near WOT with all four wheels spinning in mud on a 30 degree incline. High output, not much forward progress and a decent amount of sliding back down the hill. Dragging another vehicle up that same incline in dry weather in 4 way low, again high output and low speeds, this time it was 85 degrees out.

A properly built electric cooling system will absolutely keep up.

vstech · #47 10-04-2014, 10:46 PM

Quote:

Originally Posted by OM617YOTA

A properly built electric cooling system will absolutely keep up.

Sure, but electric, with mechanical is more reliable.

leathermang · #48 10-05-2014, 09:09 AM

Quote:

Originally Posted by MBeige

Compared to the previous situation with overcooling, I'm happier the engine temp is back to 85 - 90 deg C range (it would previously dip below 80 C with a seized clutch + 9 bladed plastic fan).

The plastic fan was cracked so I opted to buy a new one.

During those overcooling situations... which is pretty rare..... did you check your engine thermostat ?
' Too much air ' going through the radiator should have been compensated for by the thermostat.....

MBeige · #49 10-05-2014, 10:28 PM

Quote:

Originally Posted by leathermang

During those overcooling situations... which is pretty rare..... did you check your engine thermostat ?
' Too much air ' going through the radiator should have been compensated for by the thermostat.....

Since I did not touch the thermostat, I did not introduce another variable. Checking the clutch confirmed it was seized. Replaced it with the new 9-bladed plastic fan and temps went back to normal.

The overcooling only happens while on the highway. So when I checked back after the new clutch and fan were installed (also while on the highway), the aforementioned symptom went away.

leathermang · #50 10-06-2014, 06:51 AM

Millions of cars over the years have been made without a viscous clutch and did not have ' over cooling ' problems on the highway. I suggest you check your thermostat. If it has failed in one direction it can fail in the other and cause you grief a long way from home.

Here is the wiki description of a viscous fan clutch... notice NO mention in the symptoms of failure being ' over cooling' .... because they are assuming a working thermostat.

Function...
"""When the engine is cool or even at normal operating temperature, the fan clutch partially disengages the engine's mechanically-driven radiator cooling fan, generally located at the front of the water pump and driven by a belt and pulley connected to the engine's crankshaft. This saves power, since the engine does not have to fully drive the fan.

However, if engine temperature rises above the clutch's engagement temperature setting, the fan becomes fully engaged, thus drawing a higher volume of ambient air through the vehicle's radiator, which in turn serves to maintain or lower the engine coolant temperature to an acceptable level."""

""
A fan clutch is as reliable as any other component on a vehicle, yet sometimes they fail. A common symptom of fan clutch failure is overheating at idle or in heavy traffic. Bad fan clutches can also cause poor performance of the car's air conditioning system because the fan also cools the air conditioner's condenser, which is directly in front of the radiator. A fan clutch can also fail in a stuck on position where engine power is lost even when the fan is not necessary. This type of failure can also decrease fuel economy.

Another potential symptom of fan clutch failure (always drawing air at a high rate) in a cold weather climate is that the heating system blows lukewarm air never delivering sufficient hot air.

Another symptom is an extra (abnormal) grinding sound from the engine area, which may be caused by worn bearings in the fan clutch."""

from ...
Fan clutch - Wikipedia, the free encyclopedia

vstech · #51 10-06-2014, 07:04 AM

Quote:

Originally Posted by leathermang

Another potential symptom of fan clutch failure (always drawing air at a high rate) in a cold weather climate is that the heating system blows lukewarm air never delivering sufficient hot air.

Fan clutch - Wikipedia, the free encyclopedia

I would categorize this explained symptom as over cooling...

leathermang · #52 10-06-2014, 09:27 AM

Quote:

Originally Posted by vstech

I would categorize this explained symptom as over cooling...

Why do they only mention the lower temperature of the water going to the passenger heater core ?

How do you explain all those cars.. like my 240 ... which have direct drive fans not having ' over cooling ' problems ?

Over cooling of the engine would be a major problem.... our thermostats are an unusual design and very sophisticated ... I say his thermostat should have compensated for this ' excess' air flow through the radiator and should be checked.

Mxfrank · #53 10-06-2014, 10:09 AM

You can't "overcool" a car that has a working thermostat. Can't. Can't. Can't.

The thermostat in a Mercedes controls the temperature of water entering the block. The only way you could "overcool" is if the thermostat is stuck open, slow, or if some fool has drilled holes in it. Generic articles are fine as far as they go, but the heater in a Mercedes is fed directly from the engine bypass circuit, so you won't lose cabin heat if the fan is stuck as long as the thermostat is working.

I have no doubt that the poster had a bad clutch that needed replacing, but the thermostat is bad as well.

OM617YOTA · #54 10-06-2014, 03:37 PM

Quote:

Originally Posted by vstech

Sure, but electric, with mechanical is more reliable.

You'll get no disagreement from me. That's what I'd have done, had my engine and radiator lined up right.

OM617YOTA · #55 10-06-2014, 03:37 PM

Quote:

Originally Posted by Mxfrank

You can't "overcool" a car that has a working thermostat. Can't. Can't. Can't.

The thermostat in a Mercedes controls the temperature of water entering the block. The only way you could "overcool" is if the thermostat is stuck open, slow, or if some fool has drilled holes in it. Generic articles are fine as far as they go, but the heater in a Mercedes is fed directly from the engine bypass circuit, so you won't lose cabin heat if the fan is stuck as long as the thermostat is working.

I have no doubt that the poster had a bad clutch that needed replacing, but the thermostat is bad as well.

At least it failed open instead of closed.