Volkswagen Repair: 2000 New Beetle Cooling Problem, pump impellers, engine cooling system

Question
QUESTION: Hello,

I replaced the thermostat on the 2000 New Beetle 2.0 SOHC engine and read where the water pump impellers were possibly plastic. While having the thermostat "gooseneck" off, I was able to actually see the impellers of the water pump and they rotated as they should while bumping the engine. If the impeller is rotating I presume it should be pumping. This leads me to believe I may have blocked lines or a severely corroded radiator. Any suggestions? The coolant was filled with rust and I am now planning on a flush. Also, have there been reports of bad electric motors on the fans for the radiator?

ANSWER: Bud..Hi there, did you do the thermostat replacement yourself?  When you refilled the engine cooling system, did you follow the factory guidelines on evacuating the entire cooling system to a pressure of 2 bar, and then refill with fresh, low phosphate, pink coolant from your Volkswagen dealer?  Since the gooseneck was off it should have been possible to feel the impeller with 2 fingers.  I always feel them to see if they are still secure on the drive shaft.  Cooling system problems are created, more often than not, by not getting the system filled with the right stuff, and not starting with a fully evacuated system.

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QUESTION: Additionally, we had no problems with overheating until my daughter hit a deer that tore up the front left of the vehicle. It started as a slow leak from an unidentified area. Then developed into boiling coolant. It's been parked since the overheating problem. I did the thermostat change. I was thinking that rust scale may have gotten dislodged when the impact occurred and later developed into the current problem.

Sorry to keep adding to the question list...

Bud

Answer
Hello again, Bud...If the car was hit in the front, and there was damage to the radiator core support, and the radiator, it may not be scale that has been dislodged...I think the cooling tubes in the radiator have just been compressed, and/or distorted to the point where they can't pass coolant fast enough to get the heat out of the fluid, and also this type of distortion could be causing the leak that is simply not detectable...in other words, it could be seeping out of the plastic "tanks" at either end of the radiator where they join the cooling tubes.  Good luck.  I'd recommend replacing the radiator, and doing the proper coolant flush with the vacuum refill.