[Vwdiesel] Ways of cooling an AAZ

[Doyt W. Echelberger]

I followed this thread with considerable interest, having encountered 
similar problems in my own 1.6 liter cars over the years. So I took a close 
look at what Pablo has told us:

"...... at 90 Km/h temp stays at 80ºC, as I accelerate it a bit, reaching 
100 km/h temp
reaches 100 ºC and continues increasing. Engine sounds a bit stressed, could
be that? "

His mention of "....engine sounds stressed....."  to me is the key, and 
makes me think of intake and/or exhaust restrictions. (And I'm biased 
toward suspecting the exhaust side of the equation.) Chances are that the 
air filter is OK, because it is a routine item of maintenance. Exhaust 
systems rarely get any attention. Maybe his muffler is has fallen apart 
inside, or is the wrong size, or is partially plugged up, or the pipes are 
on the small side, or are dented.

I'd get under there and look, first.

If the look-see was unremarkable, then, I'd try some easy tests.

I would remove the air filter and check it for being clogged with dust or 
debris or oily fluids, or even water.

If the filter was clean, I _might_ then risk running the engine without an 
air filter and see if the vehicle performed the same way with no air filter 
(assuming that is possible.). If it ran the same, I'd replace the air 
filter and turn my attention to the exhaust. But it probably isn't the 
filter (see original bias admission.)

I haven't noticed any comments mentioning the size of the exhaust system, 
or what components make it up.

A larger diameter set of pipes with fewer restrictions is a reasonable 
thing to consider, since the problem  appears when the engine is being run 
at higher speeds.

A test that might help would be to disconnect the existing system just 
beyond the down pipe, to see if the problem described by Pablo was 
affected. The half-hour test would be noisy and the driver could keep the 
window open.

If the "engine sounds stressed...." went away and the temp did not creep up 
during the acceleration and the 100 kph phase, then Pablo could move toward 
larger pipes or perhaps a straight pipe or just a resonator, depending on 
the laws governing such matters.

Doyt
Who doesn't have an AAZ engine and is only guessing.