New thermostat, followed by squeal/no acceleration

[Rig]

Our 98 Jetta makes a squealing noise when the accelerator is pushed in gears 2 and up, and a drop in power. Perhaps limp mode, but no warning lights.

This problem started immediately after we replaced the stuck coolant thermostat. I mean right out of the garage.

Does this ring any bells?

Background on the car: All original equipment, 5 speed, 120k miles, top speed over 100 mph with power to spare, average 50 mpg on the interstate, VW engine oil, regular diesel with diesel fuel lubricant added every so often. New timing belt, according to maintenance schedule. The thermostat was stuck open, causing the heater to blow lukewarm air.

 

[runonbeer]

Spin your water pump by hand. See how it feels.

 

[KLXD]

Coolant on the belts? Belts not tensioned correctly after change? Bad harmonic balancer but odd that it would suddenly go bad.

 

[Rig]

Thanks. I've checked those out. But I haven't spun the water pump by hand.

Other ideas are that the turbo vanes are hitting or that there is a restriction on the air intake or the exhaust.

But I'm looking for something having to do with engine temperature.