Fan assembly detaches from pulley

rdtompki

New member
New 2020 Sprinter. I'm not familiar with the engine (yet), but at 4400 miles (picked up at 4000 from Winnebago dealer). The fan assembly, which appears to be threaded on to one of the pulleys, has "spun off" and is simply flopping around inside the shroud. I'm having it towed next week to the one and only local MB dealer, but what on earth can cause this to happen? I heard intermittent clattering on a short drive, parked in my driveway, and discovered the issue. Fortunately, this did not happen on the 400 mile drive from the RV dealer. I'd assume the normal rotation of this pulley would tighten the threads! Anyone else experienced this?
 

Bobnoxious

GONE FISHING
Not personally but Mercedes is aware.

You are saying the entire fan assembly come off, not the fan common to viscous clutch?

IMG_4796.JPG
 

rdtompki

New member
The fan is still attached to the clutch, but the entire assembly is just hanging by the pictured hose. I'd seen references of fan failures, but nothing akin to what happened in my case. Picture, below. Fan seems firmly attached to the clutch assembly.Details of Cooling Fan Issue.jpg
 
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Bobnoxious

GONE FISHING
Fortunately under warranty. Don't allow them to reinstall old fan assembly.

I believe the hose is a torque strap.

IMG_4799.JPG
 

lindenengineering

Well-known member
Not totally unusual.
It wasn't fully secured .
Any shop should be able to reinstall it.
The mounting is a commonplace fitting seen on numerous modern vehicles.
Dennis
 

sanomechanic

Well-known member
Those do not typically just come off on their own. They have reverse threads and tighten with the spin direction of engine. Someone had to have taken the fan off and not spun in back on. BMW uses the same set up on older 3 and 5 series
 

rdtompki

New member
Those do not typically just come off on their own. They have reverse threads and tighten with the spin direction of engine. Someone had to have taken the fan off and not spun in back on. BMW uses the same set up on older 3 and 5 series
That was my initial thought. This is a new van; the 4000 miles from the Winnebago dealer was the result of factory delivery and a remote customer who changed her mind after the RV arrived. Does the fan assembly need to be removed when installing the auxiliary alternator? If this is the case and Winnebago is doing the installation in their factory they may have bungled reinstalling the assembly.
 

sanomechanic

Well-known member
That was my initial thought. This is a new van; the 4000 miles from the Winnebago dealer was the result of factory delivery and a remote customer who changed her mind after the RV arrived. Does the fan assembly need to be removed when installing the auxiliary alternator? If this is the case and Winnebago is doing the installation in their factory they may have bungled reinstalling the assembly.
That's probably the most logical explanation. The fan must come off to install the serpentine drive belt. The WB mechanic most likely forgot to put it back on during install. The chewed up spots are from the pulley spinning around beating on the coupling. As long as the van is in motion above 10 mph it will not overheat. But sitting idling the coolant temp will increase and eventually cause catastrophic engine failure. If this van has been driven like that for 4000 miles. More likely than not at some point the coolant temperature has risen up well above normal. Get this documented.
Like I said the fans can not come off on their own.
 
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lindenengineering

Well-known member
That was my initial thought. This is a new van; the 4000 miles from the Winnebago dealer was the result of factory delivery and a remote customer who changed her mind after the RV arrived. Does the fan assembly need to be removed when installing the auxiliary alternator? If this is the case and Winnebago is doing the installation in their factory they may have bungled reinstalling the assembly.
Yes and some changes in accessory belting etc
Dennis
 

rdtompki

New member
I did find a site that could decode the more recent VINs. No aux. alternator from MB, just N62 which is "Front Engine Power Take-off with Carrier for Additional Alternator. Will be interesting to see if MB considers this a warranty repair.
 

sanomechanic

Well-known member
I did find a site that could decode the more recent VINs. No aux. alternator from MB, just N62 which is "Front Engine Power Take-off with Carrier for Additional Alternator. Will be interesting to see if MB considers this a warranty repair.
They will probably point the finger at Winne
 

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