Is this the radiator drain plug?

[Zarniwoop]

Hi all,

Having discovered this morning that my coolant system seems to be mostly water, I felt fresh coolant might be a sensible option.

I've not managed to find anything that details draining the coolant on my particular car, a W209 CLK 270 CDI.

My understanding is that there should be a radiator drain plug and another drain point in the side of the block. As I don't have any sort of pump, I guess I'll be leaving the latter well alone, but it would be nice if I could work out how to drain the system at the radiator.

My question is... Is this the drain plug, and if so, how on earth do I open it?

Thanks in advance!

 

[EmilysDad]

Difficult to see but I doubt it is ... looks like a location mount of some kind. Just release a hose clip from the bottom of the radiator.

 

[Zarniwoop]

Difficult to see but I doubt it is ... looks like a location mount of some kind. Just release a hose clip from the bottom of the radiator.

It's a good thought, and definitely what I'd default to on something older, but access to the bottom hose, on the opposite side of the radiator, looks daunting. I couldn't even see what kind of hose clip was keeping it in place...

Just have this fear that I'd get it off and be totally unable to get it to seal again. That said, you could probably make the same argument about the 20 year old drain plug (if and when I find it).

 

[alexanderfoti]

No, its the mount. The radiator drain is a tap a bit further up, on the side, with a small stud which drains the coolant.


Often like this

 

[Uncle Benz]

No, it was the drain, but some devil has been there before you and has sheared it off. There should be a bit more red plastic there with a screwdriver slot in it. Sadly it has gone.

 

[alexanderfoti]

No, it was the drain, but some devil has been there before you and has sheared it off. There should be a bit more red plastic there with a screwdriver slot in it. Sadly it has gone.

Ah yes! holiday too long ha

 

[Uncle Benz]

Ah yes! holiday too long ha

I’m still away in the Lakes for another week. Can’t help myself though, keep dropping in to keep an eye on you lot

 

[alexanderfoti]

I will pop in one day soon!

 

[V6Matty]

I’m still away in the Lakes for another week. Can’t help myself though, keep dropping in to keep an eye on you lot

Feel free to pop over if you want, more than welcome

 

[Uncle Benz]

Feel free to pop over if you want, more than welcome

Kind offer, thank you! We are at Buttermere for another week. We come here every year at easter for the last 25 odd years, minus one for covid. It used to be a well-kept secret, but it’s got pretty busy now.

 

[mioba]

Is the red plug going into the rad. go to a dealer (order a new one) or look on the online parts lists for your cars rad drain plug.

If thats your old plug, and it may well be as looking at the pic the whiter parts of red show something has sheared, you will be able to get it out with slow persuation. Have a new one ready.

Cooland out is ideal to change the stat and give the sytem a real good clean.

 

[Zarniwoop]

Thanks all - much appreciated.

Yes, now I've Googled 'Mercedes radiator drain plug sheared' I can see some worryingly familiar pictures! That's a shame, but I'm beginning to realise that the car wasn't necessarily looked after as well as I might have hoped.

OK, well I guess then the only option for now then is to get to that bottom hose and drain from there.

And maybe try to replace the drain plug in future? Wonder how possible that would be without damaging the radiator. Looking at pics of a complete drain plug, it doesn't necessarily look like the greatest bit of engineering I've ever seen. And all in lovely breakable plastic. Nice.

 

[V6Matty]

Kind offer, thank you! We are at Buttermere for another week. We come here every year at easter for the last 25 odd years, minus one for covid. It used to be a well-kept secret, but it’s got pretty busy now.

About 20 miles west of me then, yes it’s beautiful there but has got busy in the last few weeks

 

[Jim2]

Hi all,

Having discovered this morning that my coolant system seems to be mostly water, I felt fresh coolant might be a sensible option.

I've not managed to find anything that details draining the coolant on my particular car, a W209 CLK 270 CDI.

My understanding is that there should be a radiator drain plug and another drain point in the side of the block. As I don't have any sort of pump, I guess I'll be leaving the latter well alone, but it would be nice if I could work out how to drain the system at the radiator.

My question is... Is this the drain plug, and if so, how on earth do I open it?

Thanks in advance!

View attachment 76078

There are several ways to remove it...you could get an easy-out, its a tapered left hand threaded drill, and the more. you twist it, the more it enters the hole, and the more it enters, the tighter it gets, until it will unscrew the plastic bung.

 

[mioba]

Since the change interval of MB coolant is every 15 years, it makes no sense in draining from hose, then replacing drain later on (as you will lose a ton of coolant). depends how OCD you are I say,

 

[Jim2]

Plus there's ways to check the mix to see how strong it is. You can buy a meter which measures the specific gravity, If the float reads in the green, its fine, if not, you can siphon out the amount that's in the header tank and replace it with concentrated coolant. This will help.

 

[daibevan]

I can see replacing the tap being a job full of potential danger and grief. I'd pop off the hose, refill and forget about it. when you replace the coolant in 2037 you could do it then if you really want to.

 

[mioba]

You can dremmel into the red plug to make an indent for a screw driver and simply unscrew or simply knock in something sharp to make similar.

 

[Zarniwoop]

Yes, having slept on it, I think the answer is probably to leave well alone, and do my best to drain the system using the bottom hose. If I fail at that I will syphon out of the header tank and replace the missing volume with concentrated coolant. That should at least be better than how it is right now, and will ease my mind until I can work out a safe way to remove the drain plug. But fingers crossed I can figure out a better way to get access to that hose!

Thanks for all the advice - very helpful, as ever!

 

[Jim2]

You can repeat the siphon trick many times, just drive the car between siphons as this will mix the new coolant with the old, making sure of course that it's cold when doing it. Keep account of how much you put in each time, and pretty soon, you'll have it at full strength. .