Quote:
Originally Posted by Rasta Monsta
Never had a problem cracking the bleeder with engine hot and running. Bubbles come out first, then stream of coolant. Done.
|
I wouldn't do it with the engine running because if the coolant is flowing the bubbles themselves can be forced through the system and therefore may not be at the high point. Letting the system rest for 30 seconds or so with the engine off lets the bubbles migrate back to the bleed screw point but doesn't give the thermostat time to cool off and close.
This may be more of an issue with turbo models since the bleed screw on turbos is on the side of the elbow at the front of the head, not on top of the elbow.
What I like most about this, as opposed to pressurizing the expansion tank, is that I can leave the vent screw open and flowing for a while (just to be extra sure) without having to closely monitor the level in the tank since the funnel holds about a quart. If I were to let a cup or so of coolant out of the bleed screw with the pressure test method, I'd be risking the expansion tank level getting too low and ending up sucking more air into the system.