4kcsq questions

[IraT@aol.com]

Hello q.
I have a couple questions concerning my '86 4kcsq. 1st  sometimes have trouble
locking/unlocking diffs, is there a common problem that causes this, what
procedure do I need to do to correct the problem?  2nd Engine coolant while
traveling at highway speeds 65-85 stays just above the C on the engine coolant
gauge, oil temp normal.  I thought VW/Audi liked their cars to run a bit on
the warm side due to quicker warm up and less emissions etc.  My '82 Rabbit
truck 1.7 stock runs very warm, my '92 SLC runs very warm, except for my '88
16v Scirocco but it has 180 degree fan switch and thermostat  Any insight
would be helpful. Thank you.
Ira