Re: Water distribution tube

Posted by Owen_Dyneto On 2010/7/6 8:25:11

That is a really severe condition, can't say I've ever encountered that one before, at least not to that extreme. I suspect something is restricting the higher volumes the pump puts out at higher engine speeds. I suppose if the water distribution tube was more than marginally blocked, let's say severely blocked, enough water might pass thru to cope with the pump volume at idle, but at higher pump speeds (road speeds) and consequent volumes it was unable to handle the larger flow volume. Thus you might have the same coolant volume flow at idle as you had at road speed. So the answer to question #1 might be "perhaps".

Answer to question #2 is that you'd likely run the risk of a cracked engine block at the exhaust valve seats on one or more of the rearmost cylinders as the cool water flow would tend to take the easiest exit first, that being from the most forward cylinders.

It's a good practice and should be a standard practice to remove and examine the water distribution tube whenever the pump is removed. You should of course do that, but I have the feeling there may be some other culprit at play here. When you say the "radiator is like new", just what do you mean? It "looks like new"? It's been boiled and flow-rate tested? It has a new core? I'd be inclined to consider a partially restricted radiator as a prime suspect.

Somewhat of a lesser possibility is a restricted or soft radiator hose that collapses and restricts flow at higher engine speeds. This is why many cars used coiled springs inside the lower radiator hose to prevent it from collapsing at higher suctions.