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Reply to "Oil Temp is driving me nuts"

After hearing from Lane about his fun with getting his fan shroud out and back in and also because I had my engine out around the same time, I changed the alternator stand mount from studs holding it down to same size bolts.  At least now it's easier to remove and then the fan shroud pulls right out (theoretically).  

Earlier this morning I was also wondering what you have for a shroud - old 36hp style or newer, flat-top, '71 and later with th bigger cooling tower and if you have the air vanes inside of the shroud, and the bellows thermostat below the head on one side AND if all that mechanical linkage is working properly.  Sometimes that linkage can freeze up for a myriad of reasons (rust, corrosion, dead bellows, linkage falling off or binding, etc) and mess things up.

Again, usually you have to pull the engine to check that out, but if the thermostat bellows is dead (they poop out sometimes) or the vanes are stuck partially closed the engine will overheat, too.

You CAN get to the bellows from below.  It's under the passenger side head in between and below the cylinders.  Get the car up on jack stands and remove the tin work below the passenger head (6mm slotted screws) on that side and you should see the thermostat bellows.  Remove it from the mounting bracket (8mm bolt in the bottom).  You should be able to spin the bellows off of the shaft it's attached to, then grasp the shaft and try pushing it up and down.  It should move easily and you should hear the vanes in the shroud moving.  Also, have someone watch the little vane shafts where they extend out of the bottom of the shroud to see if they are ALL moving (there are four vanes in there).  If not, find out what's binding and free them up - there is an interconnecting linkage bar behind the shroud.

Now for the bellows: The bellows expands linearly (quite a bit) when it heats up.  The easiest way to check them for proper operation is to heat a cup of water to boiling and submerge the bellows in it (don't burn yourself).  It should extend in length 1/2" or more in a few seconds.  If it doesn't expand, it's dead and you need a new one.  Some new ones aren't a bellows design, but they seem to work as well according to the Samba (I have not used the newer design).  www.bugcity.com has German ones.  Be prepared for sticker shock, Jus' sayin'.

If you get this far, either refer to a VW service manual for proper adjustment of the thermostat or ask on here - it's easy to do and outlined in a Bentley's manual.

Last edited by Gordon Nichols
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