dedicated transmission cooler in 1995 E300D
 

When reading through the workshop manual of the 1995 E300D I came across a dedicated transmission cooler to be mounted in the RHS wheel well along with a strange looking shroud and a fan that is run via a relay in the relay box and a 100 degree centigrade switch.

Is it worth looking for it?

Do you tow?

Sixto
87 300D

If Mercedes was prone to the "pink milkshake" that many of the 3rd generation Toyota 4runners suffer from, I'd say go for it, but I haven't heard of many, if any, cases in a w124 and older Mercedes. I'm sure there have been cases, but it seems the probability is rather low; especially if you regularly flush your cooling system and keep the trans fluid fresh (maybe not, but it's never a bad idea:cool:). It may be a 'good' idea for added cooling if you tow as sixto pointed out, or live in a very hot climate and cruise through the hills often. I'm not sure if the pastricular unit you're referring to is a bypass for the internal stocker, or is for additional cooling, and I know a trannie's big nemisis is heat, but it may not be worth it for most of us regular commuters.

I do not tow with this car, but living in texas we see HEAT, as in 100 degrees in the shade heat. I do regularly change trans fluid and coolant in all my cars, but I was wondering if it might be of any help to the transmissions service life.

the repair manual speaks of it as upgrade and the original ones going to the radiator are blocked off, both lines then go to the oil cooler.

I'm listening to this one...

Gets hot down here in Australia too, up and over 100 outside on a warm day.

I worry about that recycled hot water from the engine's heat going into the radiator and then tranferring out to the transmission. I sometimes wonder if the [standard] setup is a transmission cooler or transmission heater.

I can't imagine what the cost of the parts from a dealer would be, given that it was an option at the time and probably not many made in the first place: add almost 20 years of MB parts storage costs...:eek:

I'd definitely be interested in seeing a diagram or picture of this setup, or at least a part number to figure out exactly what it would cost. I wonder if there's room in front of the radiator for a large external cooler like you'd see on a truck or SUV...

This dedicated transmission cooler sits in the right front wheel housing ahead of the wheel, with a conical duct and a fan, it also speaks of installing a splash shield part no. that has louvres in it. Currently my car has no splash shield at the front of the front wheel and I can see the bumper from there. All the W124 E300Ds I have seen are like this.

More to consider is that the OM606.910 uses an engine oil cooler that taxes the engine cooling system too.

If you're going through the trouble of fitting a transmission cooler in the right fenderwell then fit a 603.96 style engine oil cooler in the left fenderwell. Leave the area ahead of the condenser below the aux fans free for when you upgrade to a 606.962 with intercooler :)

I don't understand the need for a fan for the transmission fluid cooler. The transmission doesn't run hot when there isn't much load and the car is moving when there is a load. Case in point, the external engine oil cooler doesn't have a fan. Or does the same document show an optional external engine oil cooler with fan?

Does the external cooler have a thermostat? One of the benefits of using a radiator end tank to cool transmission fluid is that it speeds up getting transmission fluid to operating temperature and sets something of a lower limit for transmission fluid temperature. As I understand, you don't want transmission fluid cooler than 180*F.

Sixto
87 300D

This is interesting, and I bet removing the internal cooler in favor of a dedicated external cooler would benefit those in hotter climates in other ways. I know that when 4runner guys do this, many have reported a drop in their coolant temps as well when running in very hot weather (keeping it closer to the "ideal" engine temp without going up too much), removing some of the load on the radiator, although I'm sure Mercedes had thought of that when designing the car. Still, I can see how it would help those in Death Valley or some other extremely hot place..at least on paper, real-world numbers may be negligible for our cars vs. the Toyotas.

I measured the trans fluid temperature with infrared and it showed about exactly what the gauge on the dash shows for engine.

This means that it must be for wagons with towing package or something else. Or maybe its not hot enough here.

Not hot enough in Texas??? :)

Sixto
87 300D

Not yet, its still pretty cool 50 - 60 degrees, no biggie - I'll check it in June and decide then.

Do you have a part number(s)?