Just got a Mityvac. Want, among other things, to replace my coolant with it. I've never replaced my coolant (i.e. I've had it done for me), but want to add this to the short list of things I'm able to do.

I'm confused by the instructions. They say: "Select the largest diameter dipstick tube and insert the tube into the radiator neck or expansion tank." Full instructions here http://mityvac.com/user_manuals/07201.pdf.

So, since I have an expansion tank, does this mean that I draw all the coolant that I'm able to extract through the expansion tank? And I assume without initially removing the cap from the radiator...or would that matter? And then, once I get all the coolant out, I fill both the radiator and the expansion tank, or do I just fill through expansion tank? It doesn't make sense to me that I'd be able to get the coolant out through the expansion tank.

Thanks for your patience with very basic questions....I have aboslutely no idea what I'm doing but it seems like something I ought to be able to do pretty easily.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I wouldn't think the Mity Vac would work for the cooling system, since it opens and closes as the engine temp goes up or down. I'll be interested to see if you find out how to do it. I have a 8 liter Mity Vac.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

How hard is it to put a pan on the ground and open the radiator drain valve with a penny?

Well, I just use mine for oil changes. I got tired of crawling around under my car and having oil running down my arm. Diesel oil is so nasty I hate to take a chance on getting it all over my driveway. The Mity Vac solved that problem. Besides, that's the way MB mechanics change oil, so that's good enough for me.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

Since my original post, I called Mityvac tech support. I described my situation and they confirmed that, yes, you pull out all the coolant through the expansion tank....and that you'll actually see the hoses collapse as you're doing it because of the vacuum that's created,

So, as I understand it, here's the procedure:

1. Remove expansion tank cap.

2. Insert Mityvac tube into expansion tank and begin extraction until no more coolant comes out.

3. Fill expansion tank.

4. Turn engine on with heat on.

5. Continue feeding coolant into expansion tank as it drains into cooling system. Should take 10 quarts altogether.

Does that sound right? Anyone see any downside to this procedure?

CORRECTION...THIS IS INCORRECT, SEE BELOW

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Sounds like that could take a while.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

Is this tube long enough to reach the bottom of the radiator?

Yes. And that's the way to do it with the Mityvac that I have. What I wrote before was incorrect....I guess the tech support guy and I were just misunderstanding one another.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Why in God's name would anyone ever want to empty their coolant with a MityVac?????? It seems like it would be roughly equivalent to filling the fuel tank with an 8oz measuring cup.
Just follow Forced's instructions, and open up the coolant drain on the radiator.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

You can drain most coolant from a 60x out the radiator petcock but there's a bit that has to drain out the block fitting. I don't see how extracting through the reservoir can empty the block. Will you seal the MityVac against the reservoir cap hole and create enough of a vacuum to vaporize coolant in the block? Otherwise it'll take a lot of cycles and a lot water to dilute the old coolant out of the block.

It might be less work to hang your car upside down

Sixto
87 300D

Does sound like it may be more straightforward just to drain it out the bottom.

One question (again, I've never done this before): can I flush and refill the entire system through the expansion tank or do I need to remove the hose at the top of the radiator and fill the radiator through the neck?

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Manual says you can do it through the reservoir but I find there's less bleeding/burping to do if you fill through the upper hose. Actually fill both ends and wait for bubbling to stop before reconnecting the hose.

There are temp sensors atop the fitting on the engine end of the radiator hose. Remove a temp sensor to let air out as you fill the reservoir.

BTW, I don't think that tank you're referring to is technically an expansion tank. It is part of the main cooling loop. There's an overflow tank at the end of the hose that goes from under the pressure cap and disappears into the fender. In a 126 the overflow tank is behind the right [correction] front wheel. I don't know where this tank is in a 124.

Sixto
87 300D

Sixto,

You're right about the (What Do We Call It) Tank.

The overflow tank on the 124.128s is inside the right front fender,
in back of the wheel.Access is gained by removing the Fender Liner
(and then removing the Vacuum Storage tank).

Shertex,
'Draining the 300D 2.5 is most effectively (And Easily)accomplished
[as mentioned above in earlier replys] by:
First opening the Radiator drain plug.
Second unscrew the Block drain.

Even then there will still be some residual coolant mix in the Heater Core.

A member took his block drain plug and replaced it (Temporarily)with a plumbing adapter fixture that he then hooked up to a garden hose,which he then used to "Flush" his system.(with the Thermostat removed)

Do a search for "Citric Acid" flush
(With the de-oiling procedure with "Shout" first).

__________________
'84 300SD sold
124.128

On my GM car a few years ago, I used the Prestone flush kit which consisted of a T that you insert in the line going to (or maybe it was from) the heater core. The new fitting on the T was a garden hose connection.
You still had to drain the radiator when finished to make room for the coolant.
Any used this type of flush with a MB?

I plan to go with the block nipple method.

__________________
Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

Check out the Procedure...

AND benefits!

__________________
'84 300SD sold
124.128