Cooling Fan upgrade

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ruduger

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Greetings all:
I realize this subject has been discussed and resolved for some time now. ( Mr. Potsch 2001 Tech info). However, in the FAQ section, it speaks to a 'relatively" simple conversion/upgrade to the 9 blade, provided the fan clutch is swapped also. My question would be, what model and its year(s) can accommodate?
Mine is a '72 with no A/C, and recently installed water pump.
Any info is much appreciated, thanks
 
I did the swap to larger blade and newer viscous unit a couple of years ago. I believe the new viscous clutch and fan was introduced in 10/73
 
Pretty much any M30 fan will work. I used one that was paired with the water pump, so a B35 water pump and a B35 clutch/fan. I have ~1/2" clearance between the front of the fan and the radiator.
 
If you replaced the water pump you will need the nose piece that bolts to pump pulley to mount the new viscous unit with a single bolt plus new fan blade. Mesa Performance can help you. There is an even newer pump that is set up for the single bolt without that nose piece, gives a little more room betwqeen fan and radiator. Must be the one x atlas references.
 
My Bav is a 72 with no A/C also, and I removed my cooling fan entirely. I put the small electric auxiliary fan from a mid-90's 325 as a pusher fan and I have had no cooling issues at all. The electric fan rarely comes on. Even in the warmest weather, I have to sit at a light at least 5 minutes for the low speed to come on, and it takes about 30 seconds to cool the engine down to the point where the fan shuts off. On the highway, the faster I go, the cooler it runs.
 
ruduger said:
Greetings all:
I realize this subject has been discussed and resolved for some time now. ( Mr. Potsch 2001 Tech info). However, in the FAQ section, it speaks to a 'relatively" simple conversion/upgrade to the 9 blade, provided the fan clutch is swapped also. My question would be, what model and its year(s) can accommodate?
Mine is a '72 with no A/C, and recently installed water pump.
Any info is much appreciated, thanks
Click to expand...

Per the other posts, gobs of information on this topic can be found in the archives and from other sources.

Most, if not all M30 engines (6 cylinder - like yours) can be fit with basically three different pump and fan combinations. (Technically, there are more variants if you consider the availability of a 9 blade fan (11521271846 or 11521723573) and an 11 blade fan (11521723363).)

The earliest version was the simplest - 5 blades.

The second iteration used the same pump but with a viscous clutch and different 9 blade fan. For parts, their numbers, and cross-references to other models start here: http://www.realoem.com/bmw/showparts.do?model=7031&mospid=47808&btnr=11_2535&hg=11&fg=35 and here http://www.realoem.com/bmw/partxref.do?part=11521271846&showus=1&showeur=&details=1

The third version employed virtually the same pump, except for a simpler receiver for the viscous clutch. This third version also employed a presumptively more efficient 11 blade fan Pn11521723363.

Note that the diagrams can be misleading in that they do not necessarily depict an accurate final assembly of the viscous clutch and fan.

As indicated, unless you change your recently installed pump, you appear to be limited to the second style viscous clutch assembly. Hence, your most likely choices lie here: http://www.realoem.com/bmw/partxref.do?part=11521260459&showus=1&showeur=&details=1 For other considerations, e.g., fan shrouds, clutch makers and thermostat choices - search the archives. :wink:

Version 1:
28.png



Version 2:
5.png

Version 3:

7.png


Per Luis A's link and in the interest of further understanding, a picture may be worth 1000 words in any language. :wink:

wdslk1zba1g2.jpg
 
Last edited:
Thank you all for your input. I checked the clearance (~3/4"), so the nosepiece adapter might prove too tight, without upgrading the pump. I wonder if my rad might need a re-core also. My rad shop advised me there is a re-core version which improves effeciency, but is slightly thicker (extra line).
The car is fine at speed, but when your in an urban setting, the temp. rises to 1:30 mark, and takes quite an excessive amt. of time to return to 3:00. 160 deg thermostat also.
Should I try that first, or will it always run too hot in traffic without the 9-blade fan?
 
ruduger said:
Thank you all for your input. I checked the clearance (~3/4"), so the nosepiece adapter might prove too tight, without upgrading the pump. I wonder if my rad might need a re-core also. My rad shop advised me there is a re-core version which improves effeciency, but is slightly thicker (extra line).
The car is fine at speed, but when your in an urban setting, the temp. rises to 1:30 mark, and takes quite an excessive amt. of time to return to 3:00. 160 deg thermostat also.
Should I try that first, or will it always run too hot in traffic without the 9-blade fan?
Click to expand...

Mine ran hot in stop-n-go frequently until I switched in an AC radiator. Now it never moves. The extra 1/4" really made a difference. I snagged it used on ebay from a Bav that was being broken down. If I had to do it all over again, I'd bite the bullet and get a custom aluminum one.
 
I had my radiator triple re-cored and it made a big difference. I run the stock 5 blade fan and have no overheating problems.

ruduger said:
Thank you all for your input. I checked the clearance (~3/4"), so the nosepiece adapter might prove too tight, without upgrading the pump. I wonder if my rad might need a re-core also. My rad shop advised me there is a re-core version which improves effeciency, but is slightly thicker (extra line).
The car is fine at speed, but when your in an urban setting, the temp. rises to 1:30 mark, and takes quite an excessive amt. of time to return to 3:00. 160 deg thermostat also.
Should I try that first, or will it always run too hot in traffic without the 9-blade fan?
Click to expand...
 
ruduger said:
The car is fine at speed, but when you're in an urban setting, the temp. rises to 1:30 mark, and takes quite an excessive amt. of time to return to 3:00. 160 deg thermostat also.
Should I try that first, or will it always run too hot in traffic without the 9-blade fan?
Click to expand...

By itself, the fact that your engine temps are normal at speed suggests the main problem is airflow. Yes, this might also involve a lazy thermostat or one that is too hot for your needs, or a plugged radiator. But rather than condemn with a blunderbuss approach, is your original fan clutch still functioning? Sounds as though it may be tired and not fully engaging. How old is it? Consider how many years it successfully managed to move enough air to keep things going.

Absent other knowledge, e.g., the true condition of the radiator, you might consider modifying the original unit by substituting two longer bolts to disable the clutch and have the fan turning all the time. That ought to be a fair indicator of where your cooling problem lies. Additional fan blades and other cooling-related parts may be a good thing, but they may not always be necessary.

 
I run this setup in summer here in the tropics and have not seen it go above 3pm in the heat of summer with a/c on. 5 blade fan. It's so hot here that the fan clutch is going to engage anyway, it eliminates the possibility of a bad clutch at the wrong time.

MMercury said:

Absent other knowledge, e.g., the true condition of the radiator, you might consider modifying the original unit by substituting two longer bolts to disable the clutch and have the fan turning all the time. That ought to be a fair indicator of where your cooling problem lies. Additional fan blades and other cooling-related parts may be a good thing, but they may not always be necessary.
Click to expand...
 
Thanks Fellas:
I think I'll take the path of least aggravation for now, and have the rad re-cored and upgraded. If Steve's can withstand the Louisiana heat with a 5 blade, it should improve immediately.
 
I have version 2, original auto and A/C radiator and there is room but you need to pull the radiador to remove the fan and clutch, with version 3 you have a little more room, no need to pull radiator. My temp gauge stays around 4:00, it has to be really hot outside to get to 3:00, 9 blade fan, no shroud, A/C inoperative at the moment.
 
Stevehose said:
Does the pulley from version 1 work with version 2?
Click to expand...

A qualified yes. Have not made a study of all available double row pulleys, but if you are asking about the 2 / double row pulley available off of later model M30's, they seem to work fine.

There are three different pulleys listed, but the pictures and descriptions are somewhat ambiguous as to exactly which is single row versus double row. Based upon limited info, PN 11511255356 (version 2) seems like the correct choice. Still, there are two other numbers to consider/exclude: 11511251234 (probably single row) and 11511271423 (unknown at present). Reasons for favoring the double pulley setup have been discussed in archives. However, depending upon your reasoning, you might also consider the need or usefulness of additional pulley rows for the the crank, e.g., PN 11211258274 (no."2" at bottom).

hth

j5jvau.jpg


7.png
 
Fan Clutch / Fan / Pulley Question

It's the thread that won't die...

My new 1.5" Mark Preisendorf 3-core radiator should be arriving any day. Since the radiator is currently out of the car, prophylactially changing the water pump seems like money well spent. My E9 has an engine from a 533i I happened into very cheaply about 15 years ago; I can't imagine the water pump is any newer than that. I was hazy on what I did for adaptation of the ancillary components, but I just looked at it and see that I have what's described as the "#2 style" earlier in this thread (the flat-faced water pump with the nose piece bolted to the front of the single-groove pulley, the viscous fan clutch with the bolt through the front holding it to the noise piece, and the 9-blade red fan).

So, I can either buy a new flat-faced water pump and keep the existing nose piece, fan clutch, and red fan, or I can buy the newer-style water pump with the threads on it, lose the nose piece, and also buy a new fan clutch and new black 11-blade fan.

Any opinions? Reading these posts, am I correct that the newer fan should theoretically give better cooling and have a bit more clearance between it and the radiator, but might have less clearance to the underside of the hood?

--Rob
 
Some info for you....

Mark is well known on the left coast as "Bubba"- and a great guy to deal with.

Use the crank pulley from the m30 b35... its bigger which clocks the alt. and water pump along with the smaller 130 mm water pump pulley which clocks the water pump further
Use the 142 mm crank pulley: Pulley D=142MM 11231716270
Use the 130 mm pulley for best cooling -11511706781

note that the 4 holes are assymetric and available everywhere used.

http://www.realoem.com/bmw/partxref.do?part=11511706781 &showus=on&showeur=on

Do not use the Sachs or Behr fan clutch- they are notorious for being defective NIB

Use the Napa fan clutch [rebuilt] with the old style spring rather than the poly-metallic strip.
Cheap and they work great.

The m30b35 fan clutch and fan is much bigger than earlier clutches and 9 bladed fans should be from earlier cars so that the blades don't hit triple cored radiators:

http://www.realoem.com/bmw/partxref.do?part= 11521271846

Make sure you bolt the fan clutch to the correct side of the fan- think of this as the same as offset on a wheel- do it wrong and you will hit blades on the crank pulley or the radiator.
 
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