My fans turn on the instant the AC compressor is activated. Makes sense as airflow is needed over the condensor...

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#dieselFLEET
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'97 E300
'99 E300

Mine cycles on briefly and then off when the car is set in the run position. NHDOC said he had a bad fan and it might be a variable speed one. Any one know if it is a fixed speed or variable?

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Does your aux fan come on with the AC? I was able to read some voltage at the plug when I turned the AC on, it started as a few volts and gradually got up to 9-10 and then dropped back again. That's why I think it is a variable speed fan which gets fed voltage according to what the AC unit needs.

I figured since it was non-functional I would remove the entire assembly until the replacement unit arrives. The silly thing is that it blocks a significant portion of the airflow if it is present but not working. I would say something on the order of 30-50% of the radiator's area is blocked either by the fan blades themselves or the frame around them. Removing them sure opens up the front for better airflow through the condensor and radiator.

I figure I could easily get away with leaving the assembly out because our weather is relatively cool most of the time. We rarely see 90°F+ temps but I think it is prudent to replace it so I ordered a new aux fan assembly and will install it when it comes in.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

The electric fans are variable speed. The engine driven fan has a viscous clutch. This engine should never run hot - my viscous clutch was not engaging last summer and even in the Florida heat it never topped 100*C. After about a year of freewheeling, the clutch eventually seized and started spitting out its bearings.

The smoking aklim referred to at the beginning of this thread is from overfueling at low RPM, and it disappears once the boost comes on about 2000 RPM. Lightman has had one of these chips in his car for about a year, and he also mentioned that it smokes like a freight train if you floor the accelerator from a dead stop. IMHO, a little smoke is a small price to pay in return for performance when you want it. I plan on getting a chip soon.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

The fans do come on when I turn the key and put it in run mode. Briefly that is. Also, it they would come on irrespective of whether the AC was in "EC" mode or not. IOW, they come on when you turn the key into the run mode.

I don't know about Lightman but there were 2 versions of the chip. The one they listed or the stronger version. Guess which one I got. When you drive normally, there is no smoke and it behaves nicely. When you hit the accelerator, it will smoke like a frieght train. Also it does seem like I picked up 1 mpg with this mod.

Benifits
Wife is happy.
1 mpg more
I get to smoke out a tailgater

Cons
Costs $325 which includes overnight back and forth

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

I am about to have my car done up by SpeedtuningUSA.. I have been emailing back and forth with Oliver.. Only thing I am concerned with at this point is how the engine will respond with the upgrading timing and fuel delivery that the reflash gives.. in other words.. how safe is it for the engine long-term? Do you notice if the engine runs any wamer than with the stock program?

I had my '99 E300TD reprogrammed at Speedtuning 2 weeks ago. Got the K&N as well. Its transformed the car. Had my Mercedes mechanic drive it -he was going to take it around the block -a couple of miles later he was stilling exclaiming wow! this really feels like a lot more power.

Needless to say I'm happy. The car has 130,000 miles on it. Right before I had it chiped it got a complete overhaul. New nozzles, tie rods, AMG springs, Bilstein sport shocks, H+R sway bars, new bushings, etc. As soon as I put in the Magnaflow turbo-back dual exhaust I'll be ready for the next 130,000 miles.