Interesting find

[X53Jay4.8is]

So today I was about to change out my mechanical fan clutch, it was starting to make a little noise but no seized up. I ordered the replacement clutch fan as indicated by the part number on bmwfansinfo and when I wen to install the clutch fan on my X5 4.6is I find out that its completely different. So I take the part number off the clutch fan currently on the X5 and find out that the part number is for the BMW E38 750IL. The fan blade itself is a 11 blade fan with 3 mounting holes for the clutch fan as opposed to the 9 blade that came on the X5 4.6is. Anyway I will have to return the new clutch fan and acquire the 750il one to make the repair. I just returned from a 3500 mile round trip over the Thanksgiving holiday and the vehicle performed flawlessly so I know the 750Il fan set up is a good one. This was just a interesting find that I though I would share.

[crystalworks]

Are you getting the E38 fan because that's what was in there? Would the original 4.6is 9 blade be a downgrade I guess is what I'm asking?

[X53Jay4.8is]

Originally Posted by crystalworks

Are you getting the E38 fan because that's what was in there? Would the original 4.6is 9 blade be a downgrade I guess is what I'm asking?

Yes somewhere during previous ownership the fan blade and clutch fan was changed out. The original fan is 9 blade but the 750il one is 11 blade and carries a different clutch fan than the 9 blade fan. I do believe the 11 blade is an upgrade over the 9 blade. Of course I have no conclusive evidence to support this aside from just tell you it works really well. 11 blades of cooling as opposed to 9 blades I think most can get the picture.

[crystalworks]

It would be an interesting experiment if you would test that. Run the 4.6is one for a week monitoring engine temps (OBD2 or perhaps unlocked cluster) and then swap for the 7 series clutch and fan to see if there are any changes.

I thought the thermostats did more of the fine tuning of the engine temp on these and so was curious if the temps would change or not.

[X53Jay4.8is]

Originally Posted by crystalworks

It would be an interesting experiment if you would test that. Run the 4.6is one for a week monitoring engine temps (OBD2 or perhaps unlocked cluster) and then swap for the 7 series clutch and fan to see if there are any changes.

I thought the thermostats did more of the fine tuning of the engine temp on these and so was curious if the temps would change or not.

I would love to conduct this experiment but the vehicle has been running with the E38 Fan and clutch set ever since I have owned it. I would have to purchase another fan the X5 4.6is fan and then install it with the 4.6is clutch fan. I can tell you that my temperatures have run really well for the 4.6is with the E38 750IL clutch fan because the electric fan has not had to run high in the summer months and the temp needle has always been at half or slightly less. During the summer months at 100+ degrees the electric fan has not revved up nearly as high as the electric fan on my 540it wagon at the same temperatures so I have come to the conclusion that the E38 750IL fan and clutch is a nice mod over the original. Like I said before I just stumbled across this since this is what was installed in the vehicle prior to my ownership and now I am just changing out an old clutch fan. Just to add more credibility to this over thanksgiving I went to my parents house in Florida 3500 miles round trip and we ran the X5 between 80-85mph and the temp needle never went over half. Most of the time trip the temp gauge was just a little below the halfway mark. By the way the X5 was loaded down with 4 family members, our luggage and the Brembo calipers with new rotors in the back to be taken to my friends machine shop in Miami (for the next upgrade). I completely overhauled the cooling system at the time when I did the timing chain, guides, and tensioners and the only thing I didn't change was the clutch fan. It was still good. I have to believe that the 11 blade fan is better at air distribution than the 9 blade. Furthermore the 11 blade fan and clutch fan is for the V12 engine so I can't imagine that its not enough if not better for the 4.6is.

[crystalworks]

Good info and I certainly agree that it seems to be an upgrade that, at the VERY least, will help to extend the life of the Efan.

I suggested because for some reason I thought you had ordered the complete assembly, 4.6is clutch AND fan blade (don't know why I thought this)... not just the clutch. I thought you had the stuff on hand for the "experiment." Knowing you don't, I'd do the same as you and just throw what has been working back on there.

[srmmmm]

If the total fan blade surface area is the greater on the 11 blade, and the blade pitch is the same as the 9 blade fan, than the 750 model has greater airflow capability. The next variable would be the fan clutch engagement characteristics.

I would think the 750 sedan has a more restricted airflow through the radiator and engine compartment than the E53 and would call for a fan capable of overcoming that additional resistance. On the E53, the 750 fan should provide a quicker heat transfer under high engine load conditions.

2002 X5 3.0 313,500 miles
2014 428i 23,600 miles

2004 2004 325i sold at 123,600 miles
2001 2001 325i sold at 66,000 miles

1970 Firebird Under restoration

[X53Jay4.8is]

Originally Posted by srmmmm

If the total fan blade surface area is the greater on the 11 blade, and the blade pitch is the same as the 9 blade fan, than the 750 model has greater airflow capability. The next variable would be the fan clutch engagement characteristics.

I would think the 750 sedan has a more restricted airflow through the radiator and engine compartment than the E53 and would call for a fan capable of overcoming that additional resistance. On the E53, the 750 fan should provide a quicker heat transfer under high engine load conditions.

2002 X5 3.0 313,500 miles
2014 428i 23,600 miles

2004 2004 325i sold at 123,600 miles
2001 2001 325i sold at 66,000 miles

1970 Firebird Under restoration

Your reasoning is sound. I just know that it works remarkably well. Either someone was thinking when they applied this mod or it was just exchanged because the right one was not available at a time of some service. I personally believe that someone was thinking on this one.

[srmmmm]

Originally Posted by X53Jay4.8is

Your reasoning is sound. I just know that it works remarkably well. Either someone was thinking when they applied this mod or it was just exchanged because the right one was not available at a time of some service. I personally believe that someone was thinking on this one.

And it never hurts to have a little more reserve cooling in Texas

[X53Jay4.8is]

Originally Posted by crystalworks

Good info and I certainly agree that it seems to be an upgrade that, at the VERY least, will help to extend the life of the Efan.

I suggested because for some reason I thought you had ordered the complete assembly, 4.6is clutch AND fan blade (don't know why I thought this)... not just the clutch. I thought you had the stuff on hand for the "experiment." Knowing you don't, I'd do the same as you and just throw what has been working back on there.

Yeah I just stumbled across this because of what was installed on the X5 4.6is but I just wanted to share this insight with the X5 community in case anyone wanted to take the same approach. What amazed me the most was how little the electric fan was running in the 100+ degree Dallas weather in the summer compared to my 540it wagon. I just thought it was because they are two differently designed vehicles but I have to believe that this fan upgrade is the reason why. In addition the trip to Florida at sustained high speeds even gives this mod more credibility. I'm a believer.