Solution for the engine block coolant plug

[wwheeler]

When faced with the prospect of draining old coolant (using the block plug) all over my freshly cleaned engine and subframe, I came up with this idea that I thought I would share.

I took the original 14mm block plug and drill and tapped an 1/8" tapered pipe hole in the middle. To do this, you need both a tap AND a tapered reamer to get the right size hole for the pipe threads. The through hole in the plug is 1/4". Then buy a 1/8" NPT coolant petcock with the hose barb on it. I bought mine at Rock Auto and it is for a 1945-51 Jeep or something. And presto, no more mess.

Now when I go to drain the coolant out of the block, I will simply attach a 3/8" ID hose to the petcock and put the other end of the hose in a bucket. Twist the winged nut, and let the coolant flow. Twist it tight again and you are done. Sure it isn't original, but tucked under the manifolds, no one will notice it.
 

[jacovdw]

Interesting idea Wallace... 

[Naj ✝︎]

Early 127 engines did use such a drain.
Don't know if still available

Naj

[wwheeler]

That is very interesting! I'll check into the availablity. I wonder if it has the same 14mm threads or if it is smaller.
Thanks Naj!

[Naj ✝︎]

Hi, Wallace,

Its DIN 71401

http://www.karcoma.com/pdf/AblassventileUnd-hahnenVonKarcoma.pdf

Now, where to buy one 

Naj

[ja17]

Hello Naj and Wallace,

I believe these nice early brass valves are NLA, Mercedes supplies a newer style replacement similar to the one Wallace has used .Most of the old sedan engines of the era used those nice older style valves in fact the 190SLs also used them.  Used ones should be available.

[Naj ✝︎]

Found this one:

http://www.qwikvalve.com/F316N-14mm-1.5-w-Elbow-Joint.html

Naj

[wwheeler]

Nice find. That looks like a heavy duty unit. It says it is for oil and wonder if it would be compatible with water and coolant. It looks like the ball seals are possibly teflon which would be fine. Because it is a ball valve, it should be able to handle 16 PSI. Certainly worth a try.   

The Karcoma looks as though it has tapered threads similar to pipe. Not sure that would work since the coolant plug uses straight threads and a seal ring.

My coolant drain plug is holding up althought the brass drain I bought is a bit on the cheap side. It would be nice if the heavier duty quik valve would work. I also might give some the salvage yards a call to see if the one Joe is talking about is availalble.

Thanks for the help.

[66andBlue]

Early 127 engines did use such a drain. Don't know if still available ....

Naj,
the p/n is 071401 014200 and it is NLA from Mercedes.
But I wonder why it is not listed in the spare parts list for the M127.II - 127.981  engine. Was it really ever installed in a 230SL 

I believe Dave Gallon still has NOS if someone wants one.

[Naj ✝︎]

Hi, Alfred,

Don't know if it was ever fitted to a 230 SL.

Picture is from an earlier 127 engine. Note the drain plug is on the left 'oil filter' side of the engine.

Most of our engines have the drain on the right, near the starter (as you all know)....

Naj

[wwheeler]

I did go ahead and buy the Quik valve that Naj found and will see how it looks. I'll contact Dave and see what he has.

Thanks for the leads!

[jacovdw]

...But I wonder why it is not listed in the spare parts list for the M127.II - 127.981  engine. Was it really ever installed in a 230SL 

Alfred,

As far as I know, it was never fitted to any 230SL.
Naj is referring to the other variants of the M127 engine that was used in the earlier fintail sedans.

On a side note, my early '64 230SL has the drain on the left side of the engine near the oil filter whereas my '75 W114 has it tucked away under the manifolds on the right side of the engine. Very uncomfortable to flush when the engine is still warm... 

[114015]

On a side note, my early '64 230SL has the drain on the left side of the engine near the oil filter whereas my '75 W114 has it tucked away under the manifolds on the right side of the engine. Very uncomfortable to flush when the engine is still warm...  Sad

Same with mine, mid '64 and late '71.