Aux. Water Pump: To what extent does it help when NOT at idle?

[shertex]

Since I have heat but very weak heat at idle, I know I have a bad auxiliary water pump (91 300D). However, the heat when I'm moving, while pretty good, does not seem as hot as it should be.

My question: does the auxiliary water pump contribute to any significant degree to the system's ability to heat the cabin when the car is NOT idling?

[Eric]

it restricts it more than helps when above idle.

[shertex]

Originally Posted by Eric

it restricts it more than helps when above idle.

So are you saying that a bad AWP would have no negative impact on heat while above idle? Just want to make sure I'm understanding you.

[Eric]

a bad pump will choke water flow at any speed. a good working pump only helps heat at idle.

[shertex]

Originally Posted by Eric

a bad pump will choke water flow at any speed. a good working pump only helps heat at idle.

So then it does make sense that, while a bad AWP will be MOST noticeable at idle, it can also be manifested in diminished heating ability above idle. Is this correct?

[Eric]

yep