rudyy

I replace a couple of hose clamps that requires unplugging the coolant hose and because of that, a lot of coolant has been drained out. I refill the reservoir back to max level, let the car idle for a few mins and turn it off and refill the reservoir again. I repeat the same process three times until I do not see the coolant level in the reservoir drops before I start driving around. Everything looks ok.. no engine light, temperature gauge bar is right at the middle after the engine warm up. However, when I turn the heater to the maximum, it blows hot air, and yet not as hot as it used to be. I check the radiator upper hose. It is hot which is a good sign. Do I still have some air trapped inside the radiator circulation which stops it from operating under maximum efficiency? If yes, how can I let it out?

EELPIE

Sounds like you do have air in the system.

Look above in the D.I.Y. stickies and find Billman's coolant bleed procedure.

Follow this and you should be good.

When I flushed my coolant I followed those steps.

I have Blast Furnace heat. And the car runs at the factory spec temps.

climhazzard

These cars can be a pain to bleed, and it's a risk if there's air in the system. When it's done properly the heater output will be unmistakably hot.

I agree with looking at Billman's coolant bleed procedure. Last time mine was done (even with the clever funnel that helps with bleeding) there was still air. Make sure to utilize the front bleeder.

rudyy

Thanks for the info. I follow Billman's advice and do it twice, and I notice that the coolant reservoir drops by half an inch after closing the bleeder valve next to the engine valve cover. Does that mean the coolant from the reservoir has displaced the air coming out of the bleeder valve?

honda4eva89

I've always recommended getting the lisle coolant funnel kit. Guaranteed way to purge out all air pockets from the system. It's only about $30 on Amazon

HarryD

I hope you're not fooling around with the bleeder on the firewall, because Billman's instructions explicitly say NOT to do so:
https://www.s2ki.com/forums/s2000-un.../#post22956201

rudyy

The front bleeder is the one right next to the engine valve cover on the driver side. That is the one I open up.

Billman250

Do not concern yourself with the coolant in the resovior right now. The level in the radiator comes first.

rudyy

OK. The heater is now getting hotter than it is earlier today. Previously, it is more on the warm side. In the previous round, I can still hear the hissing sound but the squeeze of the upper hose squirts some cooIant out of the bleed valve. I think I am getting close to getting rid of all the air out. Maybe just one or two more rounds.

Thanks for the great writeup.

windhund116

Cool! No, hot!

Very good, anyways. Think it's the height of the radiator being lower than some water passageways in the engine. Hard to get those last bits of air out.