coolant drains

[rick Kirchner]

In draining the coolant, is it sufficient to just use the main drain at the bottom of the radiator?  Or is there another one somewhere?  My pinto race engine for example, has a second drain on the side of the block that's required to totally change things out. 

also, with a change, is there a lot of "burping" necessary to get the air out of the system, or is it OK to just fill with coolant, let it reach a temp where the thermostats open, let it run for a little more, and then top off once cool? 

some systems take a lot of work to get all the air out. 

[Steve Huber Co-Admin]

Rick,
The radiator drain is the only one. To refill you can crack open the hex nut at the thermostat housing to allow trapped air to escape. If you are changing from ethylene glycol to ELC, the following procedure will ensure that the system is full cleansed of the green stuff. Any mixed with ELC will cause foaming and reduce cooling capability.
Drain coolant from engine, refill with water and run engine to operating temp. Drain water. Refill w/ water, run  to op temp and drain. Repeat this once more. Then fill system with distilled water, run engine to op temp  and drain. Add 1 gallon of straight ELC. (This will mix with distilled water left in system). Finish filling system with 50/50 ELC and distilled water.
Steve

[Mike Shumack]

Rick,
The radiator drain is the only one. To refill you can crack open the hex nut at the thermostat housing to allow trapped air to escape.
Steve

Steve - is this the hex nut your referring to?  it doesn't look like it is threaded on my C-13 (but it may be that the threads are painted over). Or maybe the C-13 and C-12 are different regarding this hex fitting. Thanks.

[Steve Huber Co-Admin]

Yes, on my C9 Dave A advised me to crack it to allow air to escape. I chose to heat the engine up as I had to move the coach and just continued to add coolant to the overflow tanks until level stabilized.
Steve