124 300E fan shroud removed. Others have experience with this?
 

In an effort to improve the A/C performance on my 124 I set out this evening to remove the front fan shroud and clean the condenser. After removal I noticed just how much of the condenser was being covered by the shroud, not to mention the amount of crud that was trapped behind it! I don't claim to know as much as the Mercedes engineers and I know that around town with the auxiliary fans in operation the shroud will allow the aux fans to force more air through the coils. But since 90% of my driving is on the highway and it seems like lots more air would be forced through in that situation, I'm of the opinion that I'm better off shroudless. Does anyone have experience or input on this?
A cursory driveabout this evening showed marginally colder vent temps and I let it idle in the driveway for a while with no overheating but I am reserving final judgement until I drive to and from work in 90-100 deg weather.
For the record, I have the dual fan setup.
Thanks for any and all commentary.
Chuck.

Sounds weird! Usually a shroud improves cooling performance. I noticed about a "needle's width" improvement on my BMW when I retrofitted a shroud onto it from a 1980 model.

Is the shroud you're talking about in front of, or behind of the radiator?

You are probably correct in your thinking that the highway driving will not benefit much from the shroud. You might go one further and remove the fans as well and not suffer any more.

If it were me I would stick with the stock setup. Second guessing the factory engineers will not likely produce all around results that are favorable.

Good luck.

Tom W

Preliminary report
 

On the AM commute: Ambient temp of 77. I noticed 4-5 degrees improvement in the A/C output with slightly lower engine temp on the gauge. When I got to traffic near the office, the engine temp climbed slightly but the vent temp stayed the same. It's pretty much behaving like I suspected. Will report more after the drive home. Should hit low to mid 90's today.
Oh, and the shroud in question is in front of the radiator.

Do you mean it is between the radiator and the engine? Because the A/C condenser is what's in front of the radiator.

if you clean the paint off the condensor tubes with weak acid solution your numbers will improve much more.

Clarification
 

Shroud is in front of the condenser. (OP states front shroud, don't know how else to say it since there are only two. Guess there could be internal and external shrouds?)
And, I'm with you TomW, it's probably not going to be better all around than before but hopefully it will be better when it's 100 outside and I'm driving 70. And I know the engineers designed it that way for a reason but it was designed for R-12 and it's over 17 years old. (Guess I forgot to state that it's on R134 now) I'm just looking for a little edge. And I'm not entertaining the idea of removing the fans since I'm sure that would be bad in town and at idle (not sure if you were being sarcastic or not there). I can always put the shroud back if it's not an improvement. And the condenser needed cleaned anyway.
And David Poole, thanks for the tip. When I washed the condenser quite a bit of paint came off already.
Chuck.

Can that be done while the condensor is still in the car or will I risk eating my paint away?

I cleaned all that crud out of the bottom of my fan shroud. I was surprised at how much was trapped there. That alone made a big difference in cooling. I would not go without the electric fans, personally.

Update #2
 

Definite difference on the trip home. Ambient temp of 85 and a vent temp of 46. It had been a vent temp of maybe 58-60 under these conditions before. The engine temp was pretty much the same as before (85-90 deg C). I'm a happy boy. Of course, it's impossible at this point to tell if the improvement came from the crud removal (likely) or the absence of a shroud or some combination of the two. If I get to feeling energetic and bored I may put the shroud back on and see what transpires.

How to remove shrouds
 

I too noticed a lot of crud built up behind the dual fan shroud on my '92 300, but it looked really difficult to remove the shrouds. There is the horn mounting and some condenser tubes in front of the fans, and the bolts holding the fans are on the sides - barely visible, let alone accessible.



Is there some trick to removing the shround that I don't know about? How much time should I set aside for this project?

Thanks!

It's not as easy as one would expect.

Do a search and you'll find step-by-step instructions.

I second this emotion. My '95 E300D has the twin fans with a shroud in front of the rad. One fan failed so I replaced the whole dual fan unit. Tons of crap trapped between the shroud and the rad, and I decided to leave off the shroud. There is absolutely a noticeable drop in operating temperature of 3-4 degrees C, and the temp rise at a stop sign is slower as well. And this is with the aux fans off.

I've had it off for about 2 years now, no problems.

Rgds,
Chris W.
'95 E300D, 238K

Are you saying you left the shroud off but still have the fans? That would cut down dramatically on the effectiveness of the fans. The main reason I would not do that is because the fans/shroud go a long way toward keeping the AC pressures down. Without that cooling, the compressor would lead a tough life.

I can understand the claimed slower temp rise at a stop sign, but I believe the thermostat would not allow a noticeable drop in nominal operating temp.

Of course, I'll be the first to admit my disappointment with MB for designing a shroud that is certain to accumulate enough debris to block the air flow significantly.

My biggest obstacle was the plastic push-lock retainers that hold the shroud in place. I had to break their heads off and push the center section through in order to pull the outer expanding part out. There are 4 of these across the top and two near the lower corners of the shroud, all facing forward. If you look at what holds your glove box liner in you will see how they work and it will make sense. The horn mount has 3 bolts, one of which is behind the top of the radiator. Pull the 2 radiator clips and lean the rad. back to access the top bolt. The refrigerant lines will deflect enough to pull the shroud after removing the bolts that anchor them (2). The bolts holding the fans do not need to come out to remove the shroud. Just pull the shroud forward as far as able and work/flex it up and over the fan motors. My total time spent was 1-1 1/2 hours. But, I was having a talk with the 18 year old at the time :dizzy2: so yours will likely vary.
Hope this helps.
Chuck.