2000 Passat Cooling System Diagnostic

Hello

Does anyone know what the criteria needs to be to get a diagnostic code of
P1296 Malfunction in Cooling System?

Does the system give the car x amount of time to reach x temp and if not a
P1296?

The dealer claims I have a bad thermostat however the car gets up to temp.
I opened the reservoir cap one morning with the car cold and stated it, I
kept sticking my finger in the coolant in the expansion tank and it stayed
cold for a good 5-10 minutes, and I did not see any ripple or movement of
the fluid. Then after about 10 minutes the temp started to increase and I
could see at the movement of the water like a ripple stream. So this I
thought proved that the thermostat was not stuck open. It was closed
initially ( cold temp and no circulation , then warm temp and circulation.

An ideas?

They found this along with what they said was a bad spark plug. I checked
the plugs they were fine. They also said I had a bad thermostat.

The valve cover and timing chain tensioner gaskets were leaking badly, I
thought that they were trying to add jobs so they could makes some $?

I had them do the two valve cover gaskets and the timing chain tensioner
gaskets. I replaced the plugs myself a week after this work and tons of oil
in #1 and #4 spark plug tools, I guess the new spark plug tube gaskets are
leaking. On one side there was a puddle of oil on top of the valve cover
just above #2.

SO I am taking it back for them to do the valve covers over. They claim it
takes a few days. NOT! They are giving me a rental. They say that when
the do warranty work the do part of a job and put it back together and then
drive it then they take it apart and continue the job, what a crock!!!