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burping the cooling system from air bubbles

you will need to burp the cooling system if you hear bubbles or a waterfall sound in your dash on cold start up etc

so here's what to do :)

Quote:

Originally Posted by mrnickleye

Mine had it, too. Air trapped in the heater core, cause its higher than the radiator cap.

Make sure heater water valve is open. I would by-pass the vsv for this

***note... water WILL pass thru heater core when thermostat is closed, (on a cold engine)***

Not too hot engine. Heater controls in max hot, with fan on low setting.

Using ramps, or jackstands, Raise the front of car as high as possible (I went 3 feet on mine, till the exhaust pipe tip was almost touching the ground).

Remove cap and drain off (at drain plug into pan) coolant until you can see the radiator core inside cap area. Tighten drain plug. Start engine and let idle for about 20 min. until nice and warm.
You can raise the idle up to about 1000rpm to make the water flow better.
***Note...Don't rev the engine, as it will cause the coolant to shoot out like a whale spout***

The trapped air will be forced out because doing this proceedure makes the core lower than the radiator cap.

Shut off engine, pour drained coolant back into radiator, install cap (new prefered). Lower car. Fill overflow bottle 1/2 way. Test drive.

No more waterfall sound ? Good !

I had to do mine 2x to get it all out. Next day, Check and fill 1/2 way the bottle, as the removed air will be replaced by coolant, so bottle may be low.

Gasses get into the heater core due to a BHG.

Air gets into the heater core when the coolant level is allowed to drop in it. I suppose you could pinch the 2 heater hoses before you open the system, to prevent the coolant from coming out.

But I don't recommend this with old hoses, as it may cause them to leak later.

Also, the dangly thing on the thermostat can be snipped off before you put it into place. This will allow air to 'more easily' escape from the engine, and into the radiator, where it eventually will be pushed out into the coolant recovery bottle.

And....even opening up that hole by drilling it to 1/4" will NOT effect the operation of the thermostat, as it will still open and close normally, to allow the flow of coolant.

When your system is up to temp, the thermostat is wide open anyway.

Remember, the 7m motor (with a standard pump) does not flow much coolant at idle. AND...the fan does not draw much air at idle. I read many threads where the fellow says it gets hot at the stop light. Thats why I use an electric fan here in the desert.

I am mostly driving in town, with the A/C on, so I want lots of air thru the radiator at all those stops.