Throttle Body Coolant Bypass

[bszopi]

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[drupal=136]Throttle Body Coolant Bypass[/drupal]

This isn't so much a myth, as it is exaggerated. The lines were put in by GM for cold climate conditions, which is said to cause ice to form on TB, which could cause a lot of problems, like a stuck open condition that can cause an accident. There have been no known reports of this happening, but there hasn't been any research either.

[Dave96z34]

Yeah if any ones seen my rig my tb sticks 5in out of my hood and I drove year round all the way down to -29F with out problems. Just rust forming on the my m90s boost bypass valve shaft.

[Wragie]

Carb/injection iceing happens. Had it happen to me on a bone stock Bronco. Doesn't stick anything open it kills the power by choking off the bore. You will have your foot glued to the floor thinking the tranny has died and getting slower and slower. By the time you pull over get the hood up and swear a bit the ice is gone. FYI that was on a rainy day in Vancouver in May.

[dskopek]

I have had carbs ice up but never a throttle body, and I live in northern Wis and drive all year around with no heat to my intake anywhere.

[Wragie]

It has little to do with where you live. It depends more on humidity in the air than anything else. Given the right conditions you can get this on a humid summer day as a friend in Florida found out. It happens more when the temps are cooler but not all the time. There is a chart called a Koch chart that shows humidity verses temp and the possibility. Aside from temp and humidity the other factor is the shape of the air passages etc. What happens is the air accelerates around or through (venturi effect) and get cooler. If there is any moisture in the fuel or air you can get ice.

[Azrael]

The Venturi effect is much more pronounced in a carb though as it's necessary for fuel to flow. Icing is pretty rare in a throttlebody. I've had issues with the ball-bearings for the throttleshaft getting sticky from shear cold (-40ish) but never ice.

[Wragie]

-40 is too damn cold for iceing and humans (which is why I escaped from Sask). Get the temps just above freezing on a rainy or humid day and that will be you ebest shot for doing this.

Don't forget the venturi 'effect' can occur any time air has to flow around or through something. All it needs is an obstruction such as a bump bend or butterfly valve, shaft etc and you have all you need to get freezing. Not that it happens much in injected engines, rather rare but does.

[DefEddie]

Thought I would throw in a couple cents,for the heck of it.

Iceing does happen,Wragie hit on all the high points actually.
Generally happens around here (eastern oklahoma) during high humidity with low temps above freezing.
We don't see it on TB's near as much as we see it on IAC's here at our dealership (Ford)
But we do get 3-4 come in every years with a "sticking" IAC.
For the most part it happens after a cold start takeoff,before the engine has fully came up to temp.
Ford has TSB's for some vehicles that include a reprogram.