Adding clutch fan to 240D - PeachParts Mercedes-Benz Forum

mabbonizio · #1 01-08-2018, 07:28 PM

Im curious if anyone has added a clutched fan from a 300D to a 240D?

There are two 300Ds in the junkyard near me and I'm hoping that by adding the clutch fan to the 240D it will quiet the motor down a good bit on the highway?

Only thing I wonder is if the engineers knew most people would be driving the 240D at full throttle for extended periods of time and therefore figured the fan should just be turning all the time to keep the motor cool?

I love my 240D but the motor is so loud at times it can be headache inducing and I wish it were hair quieter.

KJenkins · #2 01-08-2018, 07:50 PM

I did this a number of years ago to my 84 euro 240d. I did it mainly to improve cooling efficiency but I don't remember it having much of an effect on noise.

Diseasel300 · #3 01-08-2018, 07:54 PM

As mentioned above, you can add the clutched fan, I doubt it would help noise much unless it's the fan noise that's specifically bothering you. When revving the nuts off the engine, the engine is what's going to be making the bulk of the noise.

t walgamuth · #4 01-08-2018, 10:42 PM

Can't hurt much. Just a bit more weight and complexity.

Diseasel300 · #5 01-08-2018, 11:06 PM

In theory the clutched fan could help fuel economy a little bit by allowing the fan to freewheel when not needed and to slip and not run full-speed when engaged. Anyone ever convert a non-clutched fan to a clutched and notice any improvement at all? Theoretical stuff...

sixto · #6 01-09-2018, 04:26 AM

Slim chance a wrecking yard clutch is any good.

Sixto
98 E320s sedan and wagon

chrisgt · #7 01-09-2018, 08:39 AM

Even if the fan clutch is tired you can refill it with silicone fluid and bring it back to life. I wasn't gonna buy a URO fan clutch for my car, and an OEM is like $1000, so I refilled it with RC shock fluid and it works great.

Sugar Bear · #8 01-09-2018, 09:40 AM

Try running it without any fan, watch the temp gauge and see if it is quiet enough. If it is quiet enough an electric fan would be an option.

Look into sound deadening mat on the firewall also.

Good luck!!!

vstech · #9 01-09-2018, 10:05 AM

4500+ RPM 4 cylinder IDI diesel...

Yeah... loud...

Could quiet it by moving the resonator, replacing the exhaust pipe, and muffler, verifying flex joint is sound, adding a THICK layer of dynamat to a bare firewall inside and out...

I don't see the fan making much difference.

BillGrissom · #10 01-09-2018, 10:05 AM

In V-8 hot-rod world, people find that electric fans do not move as much air as mechanical. People use them more for space considerations, simplicity, or bling. The Ford Taurus 2-spd fan is best. The little electric fan on the front of 300D's is mainly for cooling the AC condenser, and barely suffices for that.

A clutch-fan will be more economical. First, insure you have room. If too thick, consider a Jaguar fan since many hot-rodders use that when pressed for space, though I don't know if any thinner. I think all fit your water pump since Jag and 300D both bolt to my 1960's Mopar water pumps (I think GM's have a larger shaft OD). To avoid rounding the 4 bolts, you might get bolts w/ a larger head like I did (Ace Hardware, JIC head I recall). That lets you use an open-ended wrench on them. The factory bolts require filing down a box wrench to fit and you will likely round off the heads using the open-end side.

Re noise, you would probably do better by insulating the cabin. First seal all openings (vacuum tubes, oil pressure, speedometer, wires, ..., since sound direct thru the air is loudest. Then consider adding dampening sheets to the firewall and front floor (Fat Mat, etc). Muscle car owners do that routinely and it greatly quiets the car. You can go further and add to the inside of the door sheet-metal. Most effective is adding mass to the center of a panel to stop the primary vibration mode. Also, insure the weather-stripping on the doors and windshields seal tight.

Mxfrank · #11 01-09-2018, 01:28 PM

The pusher fans on Mercedes cars pull around 21 amps (about .4 HP) and move 2500-3000 cfm, which is considerable. They are adequate to cool a 603 or 602 under most circumstances, but lack the control system for that job. Diesels need more airflow under load than gassers. A gas car at speed can usually get what it needs from natural airflow, not so a diesel. The opposite is true at low RPM.

The problem with a hard mounted fan is that it's horsepower consumption increases with the cube of RPM, although the CFM output only increases linearly. By the time the engine is at 4000 RPM, you're just wasting power. A viscous clutch can save a bit of that, because it's RPM limited to about 3500 RPM. An electric fan requires constant power (and supplies constant airflow) regardless of engine RPM, but may require a bigger alternator. Permacool 19126 is an especially thin and powerful electric fan, there's no reason rescue a fan out of the junkyard.

All that taken into account, I doubt the improvement in power consumption or noise would be worth the effort.