to block or not to block UIM coolant

[enslow]

I've got my hands on two ATP UIM from APN, ready to install early this summer. I'm now trying to decide whether or not I should plug the coolant ports that feed the UIM. As I understand it, the only purpose for the coolant in the throttle body it to prevent the throttle from freezing up in cold weather.

Neither of my previous vehicles ever had coolant running through the throttle body, and I never had a problem with the throttle freezing. However, they were different in that they were V8 engines, one was carbureted, and the other was fuel injected like the Buick. Temperatures in my area rarely get below -10C (14F), and normally gets down to -2 or 3C only. I have observed from my scantool that the intake air temperature measured from a sensor near the MAF is normally at least 10 or 20C above the actual outside air temperature once the engine is at operating temperature, although the reduced air pressure could allow water to freeze at a higher temperature. I'm not sure how large that effect would be.

The bottom line is this: I'm not comfortable having coolant running through the plastic UIM. I hear of the occasional coolant leak around the throttle body. If I can safely block those passages as some of you in the US have done, I'll do so. However, if there is a real possibility of the 3800 freezing up in the throttle body, I will leave the coolant flow as it is.

Enslow

[willwren]

You won't have a problem with the APN, since the EGR port is improved and won't eat through to the coolant passages. Leave it alone. 99.9% of the cars on this forum retain that flow, and have no issues.

[enslow]

I'm not talking about leakage from the EGR. I'm talking about leakage from the throttle body gasket. This kind of leakage seems to be far less common, but does happen:

http://www.pontiacbonnevilleclub.com/fo ... nt#p154890

I will probably get the GM black throttle body gasket. However, if no one has ever had trouble with throttle bodies freezing up after they've plugged the coolant ports, I'd rather eliminate the possibility of a coolant leak at the throttle body by blocking the related coolant ports.

[willwren]

Leaks from the TB gasket are so rare, you can ignore they even happened.