Coolant refill questions

[Wiscon_Mark]

I just installed a new temp sender in an effort to cure my gauge's insisting that I'm pegged (overheating) all of the time (it's not, sometimes the needle will jump back down to normal randomly, and then jump back up just as quick - it's not temp shifts).

Basically, I leaked a lot of coolant all over the place. I didn't know the crossover pipe could have that much in it, to be honest.

1. How long do I have to let the engine idle to get a full cycle of coolant through the system to bleed air out of it?

2. My plastic bleed screw cracked (head fell off) and it's not applying much pressure to the rubber washer. How urgently do I need to get a replacement? Is the pressure quite a lot? The washer is fairly snug in there right now.

[Huffer]

1. The idle time varies because of air pockets in the coolant system. Basically you run it until your HVAC system puts out hot air.

2. I'd get a bleed screw pretty promptly - the coolant system is only as good as it's weakest link, which should be the radiator cap because that's the failsafe in the event of high pressure.

[Thomistopheles]

Once the car's up to operating temp and the tstat opens up, run it until no more air comes out. Sometimes this takes ages, sometimes it's quick. Get a new screw right away.

[Wiscon_Mark]

The plastic screw is an M10x1.25, so I used a bolt for a temporary fix until I can get one of those screws. Not really common fare around here, so I'll have to order one from Subaru.

[Reason]

Once the car's up to operating temp and the tstat opens up, run it until no more air comes out. Sometimes this takes ages, sometimes it's quick. Get a new screw right away.


Exactly, it always seems different. It all depends on the state of the coolant system prior.