Turbo Coolant Troubleshooting (4)

 4 hours

I needed to revisit the turbo cooling system because the last time I tried to fill it, there was almost no flow from the pump and I couldn't really figure out what the problem was.

Sonex put out a message saying that the thermostat could protrude too far into the "T" fitting on the front of the turbo, which could block some of the coolant flow.  Seemed reasonable to me, so I ordered a new T fitting and a bushing to move the thermostat up from the T somewhat.

Here's the old setup:

I removed the original T fitting, but I found that the thermostat didn't protrude into it at all anyway.

As far as I could tell nothing was blocking any flow at the turbo either.

I installed the new parts anyway since I had them, and at least now the thermostat is a lot easier to access if I ever have to replace it.

I don't think there was any blockage, so the problem must be trapped air in the system somewhere, probably the radiator.  I decided what I needed to do was try filling the coolant again and force the air out somehow.  I went and got a little hand pump for transferring fluid, and I tried disconnecting one of the lines at the radiator and forcibly pumping coolant through, and that forced a lot of air out.  However, I had no real good way to disconnect the pump and reconnect the lines without air getting sucked right back in.

Finally what I ended up doing was just adding a little T at the radiator outlet, to act as a bleed port.  Then I was finally able to fill the system, and the air was able to travel out of the radiator and escape out the top of the T.  When it was full I just clamped a cap on the T.  I had to reroute one of the lines from the T around the right side of the engine mount to get to the coolant pump, but that was it.  I can't really tell for sure if it's finally working properly or not now, so we'll have to see how it cools the turbo once the engine is running!