Hey everyone,
this is a great forum, it helped me several times before.
I've searched this forum for answer, but could not find anything relevant, so I am posting here for my first time.

I have 1997 S500 and previous owner used green antifreeze fluid.
I've looked in my Star DVD and it said to remove drain plug on radiator and two drain plugs on block, which I've accomplished.
The tricky part is with refill:
On the DVD it just says fill the overflow tank and worm the car with cup removed, easy.
When taking car for a spin, no heat at all. Than I've heared a lot of bubbles behind the dash - heat come.
I've checked the overflow, but it was OK (no light on dash came on neither).
After a 3 miles car was at 120 and no heat. I let it cool off and was able to put another gallon in.
Still a little bubble noise heat was weak.
When I got home I start looking around the engine bay and found "mystery" hose, that goes from top of the overflow above fan and curves back to the termostat housing (cca 0.5 inch diameter).
There is a T connection on this hose with a small hose (6in) heading forward (next to the air intake). However there was screw at the end of the 6in...
I've removed this screw and stem start to come out T.
I've let it cool off.
Finally stem was gone and I put over a gallon in the expansion tank, until water started to come out of the small T hose. I could hear bubbles
Is this T hose designed for getting air out of the cooling system?
Remove the screw or keep in place?
How to get rid of all the air trapped in the system for good?

I'll be doing the flush several times, so it will be a good practice...

Thank you in advance for all your ideas and help in this matter.
M#.

need to remove the small hose where it attaches to the overflow bottle. There's (I think) a valve inside the nipple on the bottle that prevents the air from burping out.

Fill the coolant with the line detached until the proper level is reached in the tank.

Seems to me when I've done this before that I left the vent line off of the tank and started the car and allowed it to warm up before replacing the line - but I'm not sure about that.

I do know that when I didn't take the vent line off, I had a horrible time getting the air bubbles out of the system.

Be sure to turn the climate control on, and set temp to maximum to make sure the aux pump runs. You may also have to run the motor at an elevated idle for a bit to force the air to purge out of the heater.

Does anybody else have any experience?
I've replaced the line with a regular hose for a quick test and was able to blow and suck to the tank, desto no valve in the nipple.
I'm still curios about the screw at the end of 6in hose from the T...
Does it belong there?
Take it off just for the air bleeding process?
Seems like it's the highest point of the system, perfect for getting air out, but a screw from factory?

Thank you again.
M#.

Could that screw be intended as a bleeder? I am about to pick up my "new" '94 S320 and want to perform this repair before driving the car from IN to CT.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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David, the '94 S320 you speak of has an in-line 6 cyl engine, not the V-8 engine previous posters are talking about.
The in-line 6 Cyl does not have the same 'plumbing' as the V-8 engine. Both of my S320's (a '94, and a '96) have never given any problems when changing the coolant. Just 'empty the old' (at the radiator and on the passenger side of the engine block), and refill with new coolant in the overflow tank in the right-front part of the engine bay. It gurgles and such, but it fills just fine with no air-locks. Just be a little patient. It usually takes between 10 and 11 quarts of coolant to refill, if it has been fully drained.

Questions, Comments, Corrections?

Farrell

Farrell, it's nice to see such an informational post from a first-time poster. Firstly, welcome to the board. Secondly, thank you for the information. That is very helpful.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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