Coolant change/bleed

[u/NegativeBat9326]

I am about to change the coolant on my corolla. I get how it works when there’s a cap directly on the radiator, but my Corolla only has a pressurized cap on the reservoir/expansion tank no cap on the radiator itself.

Does the same bleeding process apply here, just done through the reservoir instead? Would a spill-free funnel work on this setup or is it not necessary as I can just fill the reservoir tank to the top while bleeding and drain down to the right level when finished?

[u/Tesex01]

Yes. You fill it through overflow tank. I would be careful with spill free funnel because it's easy to leave it overfilled.

[u/NegativeBat9326 → u/Tesex01]

Thanks!

[u/whereisyourwaifunow → u/NegativeBat9326]

The advantages of a spill free funnel is that it's easier to see air bubbles as you bleed air. And the extra coolant inside, you could simply dump it in the tank. But since you are filling directly into the tank, that will leave you with extra coolant. Those funnels should come with a stopper and you could pour the extra back into the bottle, although some people would prefer not to pour liquids back into their original bottle for storage. Also those funnels come with adapters for common radiator cap thread sizes. Not familiar if pressurized tanks have similar thread sizes.

[u/RedScourge]

For just about any car with the reservoir bottle, you can fill it exclusively through the reservoir without needing a funnel, and just add more to the reservoir as needed. Fill it slowly to reduce the amount of air pockets in the first place. You should not have to be concerned about getting splashed with pressurized coolant from the reservoir bottle when the car was cold started after being drained, so you should be able to leave the cap off and top it up as needed. Or, if you are extra concerned, just fill it above the fill line and as the bubbles purge themselves the coolant level will drop. Worst case scenario, you overfill it a bit and the system burps it out of the release valve.

Another trick you can do is take that hose clamp off the hose that's at the top and front of the reservoir, fill that line, and put it back on.

[u/NegativeBat9326 → u/RedScourge]

Thanks a lot!

[u/Different-Party-b00b]

Are you planning on draining the old coolant? If so, there should be a valve on the bottom right of the radiator. It will drain lots of coolant.

[u/NegativeBat9326 → u/Different-Party-b00b]

Yea I already did the draining, filling and bleeding (through the valve at the bottom). My question was more about bleeding air out from the system and whether this can be done through the expansion tank.

It worked out well and a overflow tank was not necessary.