M42 Fan Removal... Tried Almost Everything

**Bairdogg** · 02-25-2017, 10:43 PM

Hey all, I know this has been beaten to death but I've read nearly every thread on the subject to no avail. I want to take off the fan and shroud to access my thermostat for a coolant flush and t-stat replacement. I can't loosen this damn nut though. I went out and bought the $30 32mm wrench (you can bet I'm returning that the second this job is over). I've hit the wrench with a hammer, jammed the bolts in the pump with a screwdriver (favorite screwdriver, ruined), pretty much all except for buying the tool, which isn't really an option as I A. Can't find it online B. Am in patient. When I first started trying the nut was difficult to turn and made a squeaking noise. I hadn't read up on this too much and put wd40 on it (mistake?), now it turns easily and quietly. I don't know what to do, I've given up for the night. Not sure if there are any tricks I'm missing, any help is great.

-Alex

P.S. I know you can take the thermostat housing off with the fan attached, but to flush it I want to remove the t-stat put the housing on. Going through that four times with the fan on would suck, but I will if I have to.

P.P.S. I know it's a reverse thread

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**95BMWIC** · 02-25-2017, 11:15 PM

The nut could be cross threaded - so spinning it out could be tough.

You could make water-pump tool by taking a flat iron bar, drilling a hole to fit over the water pump pulley nut and dremel-ing a c - notch in the bottom (so to fit snuggly around the fan nut) and hold the water pump pulley easier than the 2 screw drivers.. You can use it as leverage.

I bent mine to make it a bit easier to snug over the fan nut and on to fit around one of the water pump nuts.

fan tool.jpg

**jclausen** · 02-26-2017, 12:07 AM

Have a shop knock it loose

**Bairdogg** · 02-26-2017, 09:35 AM

Originally Posted by 95BMWIC

The nut could be cross threaded - so spinning it out could be tough.

You could make water-pump tool by taking a flat iron bar, drilling a hole to fit over the water pump pulley nut and dremel-ing a c - notch in the bottom (so to fit snuggly around the fan nut) and hold the water pump pulley easier than the 2 screw drivers.. You can use it as leverage.

I bent mine to make it a bit easier to snug over the fan nut and on to fit around one of the water pump nuts.

fan tool.jpg

If they were cross-threaded, what would that mean? A new nut, water pump, fan clutch... what? As long as I can get the fan out I don't mind leaving it out for a few days while parts come in. I'll try to fashion one of those later today, but the nut and waterpump as so tight together I'm not sure I'll be able to keep the tool from rotating with the pump.

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**Bairdogg** · 02-26-2017, 09:37 AM

Originally Posted by jclausen

Have a shop knock it loose

Last time a had a "small-job" for my local specialty shop (2 helicoils, one short gas line replaced and a simple bushing and a few other things) it ended up taking nine weeks, $2,500 and not all of the things I asked for were done. Yes I need to find a shop, no, now is not the time for me to be looking. I'm on somewhat of a time constraint.

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**15Michaeljoseph** · 02-26-2017, 09:41 AM

You could try using a punch on the corner of the nut, to break it loose with impact force.

I've never tried this, but my old fan clutch had marks on it from someone doing it

**95BMWIC** · 02-26-2017, 03:56 PM

Originally Posted by Bairdogg

If they were cross-threaded, what would that mean? A new nut, water pump, fan clutch... what? As long as I can get the fan out I don't mind leaving it out for a few days while parts come in. I'll try to fashion one of those later today, but the nut and waterpump as so tight together I'm not sure I'll be able to keep the tool from rotating with the pump.

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The tool gives you leverage, so the waterpump cannot rotate - The tool goes across the waterpump from the left side (being held in your left hand turning counterclockwise) locked onto the waterpump nut and bolt - On the right side you hold the wrench you bought on the 32mm nut and tighten (turn clockwise) - the dual force will break the nut - as you have leverage. Screwdrivers are not strong enough.

If the nut is stripped - you will find out once it is off - loosening the nut will not cause any more damage (if it is stripped).

**95BMWIC** · 02-26-2017, 04:04 PM

Also - just to be clear - when you say "the nut and water pump are so tight together" - the c notch in the tool goes over the back side of the fan nut - This is the key part of making the tool - make it so you can lever over the fan nut and onto the pulley. Remember the drilled hole fits over the water pump pulley nut. The lever comes from the C- notch and the fact that it is attached to the nut on the pulley.

The bar stock should be thick enough to be sturdy and not easily bendable by hand - but not thick enough to block putting the 32mm wrench on the fan nut.

**RomeoMike** · 02-26-2017, 09:27 PM

Clockwise on a reverse-threaded nut in this case means toward the driver-side fender. I've had good luck with an M42 and M54 fan clutch nut. With the first M20 water pump I changed, the nut was on so tight I had to remove the water pump, put it a vice, block the impeller from moving, and finally was able to break the fan clutch nut free (impeller shaft snapped in the process).

**Bairdogg** · 02-27-2017, 07:14 AM

Realized there was a roughly 100% chance I would mess up measuring the homemade tool, but found out my coworker has a generic fan clutch tool, which he's letting me borrow. (He made sure to rub it in that HE'S never had to use it) We'll see how much of a miracle worker it really is. I'll update hopefully tonight if I get a chance to try it.

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**nick325xit 5spd** · 02-27-2017, 09:22 AM

A suggestion: Cut the fan off the water pump and replace the water pump. If it's that welded on, you're going to need to replace those parts anyway. IIRC, a sawzall should work. It's been some years since i had to do that, but you're burning money and time trying to take apart ruined parts anyway.

**Bairdogg** · 02-27-2017, 09:37 AM

Originally Posted by nick325xit 5spd

A suggestion: Cut the fan off the water pump and replace the water pump.

If this tool doesn't work I'll try to take off the water pump and fan together. If that's too difficult I'll just hack it off. I hadn't thought of that as an option before, thanks.
I ordered a new all metal water pump this morning. If it wasn't messed up before, it is now after being struck by a hammer 50+ times. That means this job has gone from a thermostat replacement to almost an entire cooling refresh. Talk about a slippery slope.

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**DRVN2WN** · 02-27-2017, 12:37 PM

When was the timing belt last replaced? If you're pulling the WP, might as well do the TB and tensioner if they're due (or unknown).

**RomeoMike** · 02-27-2017, 05:27 PM

^ If the OP has an M42 he has a timing chain instead of a belt.

**Bairdogg** · 02-27-2017, 06:16 PM

Originally Posted by RomeoMike

^ If the OP has an M42 he has a timing chain instead of a belt.

M42 does have a timing chain, but I assume he was referring to the belt that runs around the water pump, which I also plan on replacing. Just gotta find the part on ECS and that will be ordered too

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**DRVN2WN** · 02-28-2017, 11:46 AM

I was referring to a timing belt; I just lost the fact that it was an M42 in the process of reading through the thread. D'oh.

**Bairdogg** · 03-01-2017, 10:07 PM

Well, haven't gotten a chance to try out the tool and I'm heading to Florida tomorrow, so the car's saying disassembled until I get back. Hopefully parts will be waiting for me when I'm back.

**Bairdogg** · 03-07-2017, 05:07 PM

Well, borrowed one of these belt holder tools from a friend, hasn't helped much. It stops the belt but I still can't break the nut loose. I for sure need torque in the opposite direction with one of those belt holders. On a side note, is the fan supposed to stick out this much from the shroud? The blades are sitting about a 1/4 inch outside of the shroud, and I can't remember if they were always like this or I'm slowly breaking something.

Belt holder tool

Photo of fan blade protrusion/source of paranoia

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**nick325xit 5spd** · 03-07-2017, 05:36 PM

Pretty sure.

Anyway, the tool you want is a sawzall. :p

**Kershaw** · 03-15-2017, 09:32 AM

Originally Posted by nick325xit 5spd

A suggestion: Cut the fan off the water pump and replace the water pump. If it's that welded on, you're going to need to replace those parts anyway. IIRC, a sawzall should work. It's been some years since i had to do that, but you're burning money and time trying to take apart ruined parts anyway.

Hah, yes. I'm right there with the rallyx ix with the brakes. I'm not even trying to disassemble those rusted connections. Cut everything and replace with new from the ABS pump. It's just not worth the time screwing around with it.

Bair, have you tried making a fan clutch tool like 95BMW suggested? You can find metal stock at Home Depot. You just need a flat long piece. Or just buy the tool off Amazon. $20. https://www.amazon.com/dp/B017VLLQ6M?psc=1

**hotdish** · 03-15-2017, 10:54 AM

Originally Posted by Kershaw

Hah, yes. I'm right there with the rallyx ix with the brakes. I'm not even trying to disassemble those rusted connections. Cut everything and replace with new from the ABS pump. It's just not worth the time screwing around with it.

Bair, have you tried making a fan clutch tool like 95BMW suggested? You can find metal stock at Home Depot. You just need a flat long piece. Or just buy the tool off Amazon. $20. https://www.amazon.com/dp/B017VLLQ6M?psc=1

You can also get flat 32mm wrenches at bicycle shops because some bicycle hubs are the same size.

**Kershaw** · 03-15-2017, 12:16 PM

OP said he already has the 32mm wrench, he needs the tool to stop the hub from rotating.

**Bairdogg** · 03-15-2017, 07:11 PM

Originally Posted by Kershaw

Or just buy the tool off Amazon. $20. https://www.amazon.com/dp/B017VLLQ6M?psc=1

M42 isn't listed in the product description as one of the compatible engines. I see it includes the 32mm wrench, but is the water pump bolt pattern the same on M50s? (Edit: As in M50s one of the compatible engines listed)

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**Kershaw** · 03-16-2017, 10:14 AM

It says m4, I'm willing to bet that's a typo for m42. And if it's not, it's something you can easily modify with a drill or an angle grinder.

**Bairdogg** · 03-17-2017, 12:28 PM

Ended up ordering the same tool but manufactured by AlphaMoto. It's a few bucks more but everyone was complaining of the soft steel not holding up on the other one, and if it breaks for them it'll surely break for me. We'll see when it arrives on Sunday

https://www.amazon.com/dp/B004NUZ50I..._R4aZyb0HPPWDH

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