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Intercooler Pump not circulating coolant

8074 Views 7 Replies 4 Participants Last post by  sqidd
I was following klrstangs thread on his KB blower where he had issues with an air lock in his intercooler and realized I recently installed a larger intercooler collection tank, and in doing so drained the system. I drove the car today and after 20 minutes the coolant was not even warm in the tank. I opened the tank and could not tell if the coolant was circulating. I can hear the pump come on when I turn the key on. So what is the easiest way to get the pump primed and/or the air bubble out?
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Check it again after it sits for a while. It was frustrating to find that the pump lost it's prime over night. By re-routing the hose to the pump's intake, I made it so the hose goes directly from the reservoir to the pump without dropping below the pump.

These coolant pumps can't pull more than an inch or so of air, and practically have to have the water poured directly in, so make sure the coolant line going to the pump doesn't drop more than about a half inch below the level of the intake at any point or it will likely lose prime again.
Is there no way to effectively bleed the air from these?
The pump that I got with my kit can move a lot of water, but is really bad at self-priming, so it can't pull air worth a damn.

When I tested the pump, I held the intake end in a bucket of coolant and it wouldn't pull 1" of air to prime. I had to tip the bucket almost horizontal before it would pull the last 1/2 - 1/4" of air and start pumping.

When the line drops below the level of the pump and air gets trapped just in front of the inlet of the pump, the water below the pump was not allowing the air to escape, and the water above it was not enough weight to push the air out, and since the pump can't pump air worth a damn, the air just sits there and the pump doesn't prime.

By moving the hose so that any air will just bubble up the hose to the reservoir, this is no longer an issue and you always have prime. I drew a couple crude pics real quick to help explain whats happening. In pic 1, the air is stuck at the inlet with no where to go.. if you loosen the intake clamp it will escape and prime is restored, but that is a high point and air will collect there. In fig 2, you remove that high spot and now the reservoir is the high spot, so no air collects.

I don't know if any of these coolant pumps are any good at pumping air, but I know this bosche brand that I got is not.


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