2008 xl heater

[Doubeleive]

Doubeleive, I found one for sale like the picture I posted here and it appears to be like your right picture but with the long cooling (?) duct missing. Does that make sense?
It is the part number that GM parts sites list for mine but mine has the short duct like your left picture.
Would the right one on your pictures would properly without the cooling dict?

You might be able to transfer the cooling duct over from your old one not sure

 

[EddieC]

You might be able to transfer the cooling duct over from your old one not sure

I tracked down the current part number for my Tahoe on both GM parts sites and Rock Auto and RA had the clue to why there is a hole. There was a link to recommended auxiliary part; a replaceable long cooling tube like you showed on one of your pictures. The issue could be that my original fan has the integral short cooling tube, so, as you mentioned, clearances could be an issue with the long tube.

 

[EddieC]

Doubelieve,

In the blowers that you have had did you notice any play in the blower in the direction of the shaft length (in and out play of the shaft in the motor)?

I got mine out and cleaned the caked on dirt off the fan blades and noticed the shaft moves in and out of the motor enough to notice. It's like setting solid lifter valves at a few thous by feel. There is no lateral movement, just in and out. Curious if that is normal.
Putting it back in there is a ticking at slow speeds and an occasional complaining (lost for words) at higher speeds. Previously I noticed the "complaining" on the road if I turned the truck a particular direction listing the body.

 

[EddieC]

the catch here is with your 2008 you might want to pull the old one out and check the design
in my photos below the one I am pointing at is the old design on the right with a "airtube" that cools the motor from a corresponding slot in the airbox,
the one on the left is the new design and it is self-cooling
both will fit, but if you replace the old design with the new design you will have a open hole in the airbox and if you have the new design and put a old design on it will not have any cooling.
I am not sure what year they changed the design but it seems to be early on your 2008 could have either design.
both of my examples are OEM made in korea
rockauto shows either design for the same year so best to get under there and check it out before buying

***to remove the blower lift the orange locking tab from the harness connector squeeze the tab and the harness pulls out, then there is one screw to remove then you lift the plastic tab visible on the left blower motor in my photo then twist the whole thing I believe counter clockwise and then it will simply slide out.
View attachment 445484View attachment 445485View attachment 445486

I thought I would shed some light on this relative to my '08 by sharing a Service Bulletin that I found.

https://static.nhtsa.gov/odi/tsbs/2012/SB-10043510-2159.pdf

The short cooling duct version was phased out and the listed replacement just has a hole in the side where the duct went and there is a loose duct that has to be mickey moused to reestablish the cooling function. It seems like a pretty awkward place to be doing the alterations in.

Site Maintenance

It makes trying an aftermarket unit that emulates the original short integral cooling duct version.
VDO/Continental PM9272

 

[Doubeleive]

I thought I would shed some light on this relative to my '08 by sharing a Service Bulletin that I found.

https://static.nhtsa.gov/odi/tsbs/2012/SB-10043510-2159.pdf

The short cooling duct version was phased out and the listed replacement just has a hole in the side where the duct went and there is a loose duct that has to be mickey moused to reestablish the cooling function. It seems like a pretty awkward place to be doing the alterations in.

Site Maintenance

It makes trying an aftermarket unit that emulates the original short integral cooling duct version.
VDO/Continental PM9272

Ya that's kind janky I guess but it works, there are plenty of the original design blower motors around, until recently I figured the cooling duct from the air box was the old design not the new design