Mark-87-951

My first attempt didn't work out so well. I tried at the expansion tank overflow tube but of course the radiator cap blocks that. I could clearly get some vaccum as more coolant was being pulled into the tank but before it could make into the hose it would lose the vacuum and the coolant would drain back to it's normal level. I got a bit going when I released the cap just a little but it wouldn't hold very long.

I removed the bleed screw and put the hose down into the tube pretty far. That worked except it seems to have only drained the expansion tank and not much more.

I'm hoping that it just requires running the car to open up the thermostat. I wasn't finished putting things back together so didn't do that.

Any suggestions?

bearone

pull the bottom hose, open heater valve, run water thru exp tank until it's clear out the bottom.

87951

Mark-87-951

Thanks, but that doesn't add to my knowledge or answer the actual question.

ehall

You asked for suggestions. He gave you a great one...that WORKS.

Mark-87-951

Because the topic title or the context of my asking for suggestions don't exist?

I know how to drain the coolant by regular means so I don't need more suggestions on that matter, been through the threads about that already. That's why I titled the thread so specifically and explained what I was trying to do.

I know others have done it by applying pressure and modifying the cap but I'm trying to get some ideas with what I have, you know, the part mentioned in the title.

bearone

well when you figure it out, if you do, please post how you did it, as you're the 1st i've heard of using a mighty vac to drain the cooling system.

87951

Mark-87-951

Oh I will.

Another idea i had was to modify an expansion tank cap by drilling holes in the sealing/rubber part but I'm not sure the cap itself maintains enough of seal so that will work.

Once I get the car back together again, I'm going to try running it till the thermostat opens and try from the bleed screw hole again. I thought some time ago I read about someone putting a speed bleeder screw there for doing something with the coolant. I wonder if that would work. I could have the hose already connected, get the car warmed up so the thermostat opens, apply vacuum, then open the speed bleeder. I'm just not sure what size to get.

Bri Bro

The Mityvac Plus is a vacuum pump. The only way it will work is to place the hose from the vacuum pump at the lowest point in the cooling system. Then you need to open up the top of the cooling system to atmosphere so that it can draw the fluid into the canister. If you don't do this, it will pull some fluid out until the cooling system reaches the Mityvac max vacuum level, then it will just sit there pulling no more fluid. If you want all the fluid out, you will need to open the drains on the block and open the heater control valve.

BTW, I have used a similar pump to remove oil from the pan in a boat by sticking it down the dipstick sleeve. You can't get a pan under the drain plug because the plug sits right next to the bottom of the boat. I have never used it to drain a cooling system.

Mark-87-951

This looks like a good idea, once it's installed

http://www.lindseyracing.com/LR/Parts/944RADDRAIN.html