VVF

Top coolant pipe! you mean that plastic piece of sh.. err, plastic directly above the exhaust that cracks close to the engine connection and leaks coolant? I recently discovered that on mine, haven't replaced yet. Did you have problems disconnecting the rubber hoses at the back?

jpman

VVF, That same pipe! I was lucky it started to ooze out coolant and I saw it leaking slowly. I just got a gallon of mb coolant and the pipe at my dealer and changed it in about 30 mins? It's pretty easy. Just make sure to use vice grips to move the clamps on those rubber hoses. Piece if cake really. Once off I added a little mobile one synthetic grease on the pipe where the hoses attach to so that a) they wouldn't get stuck, and b) they would slide in easy and not force the rubber hoses.

After that just did my 50/50 mix of distilled water and coolant and added and bled the system. Finished off with cleaning the block and giving her a wash

The new pipe comes with a new temperature sensor and I believe that pipe that attaches to it that always breaks. I might have purchased that on my own though, don't recall.

Once done sit down and grab a cold one.

Edit: I just remembered that what leaks from the tube is actually the connection that goes to the block. There is an o-ring that just goes square. I remember pulling it out and saying I should have just gotten the o-ring and called it a day but it would have been more work going back and forth. I would buy both the tube and the o-ring and see if it's the o-ring that just needs replacement. Then return the tube if it's not needed.

VVF

Do you recall how much coolant you lost? Or did you drain it first?
I kinda don't want to drain it again since I just replaced it about a year ago.

My plan was to wait and observe that pipe. Then next year when I flush the coolant I will also replace the pipe (and the water pump which makes a slight metallic scratching sound - found that when changing the belt/pulleys).

jpman

Id say no more than a liter. I bought the gallon thinking it would leak all out but that wasn't the case. A year later I did the expansion tank and did a full flush with distilled water.

I added something to my previous post, I believe that is usually the problem with that coolant pipe. The pipe itself was not brittle or leaking, it was just the o-ring that got squared off.

VVF

Hmm... that might be the case. When I look at mine, it seems that the coolant is slowly leaking from the plastic flange just a fraction of an inch from where it connects to the block. But it might well be getting past the o-ring and then travelling to the flange.

Now I just need to figure out what's the time frame for part returns at the dealer.
Need to give it at least a couple of weeks to see if replacing the o-ring solves the leak.

Thanks for the heads-up!

polarbexar

ooops i forgot, 2 sets of plugs 3 serp. belts, 3 coolant flushes, 3 tranny flushes, 4 brake flushes, and numerous filters....

I keep an eye on that plastic thing too and sofar no seepage. Mercedes did say they used a new coolant two months ago when I had mine changed. it's a different color too.

VVF

Is it the 'new' blue coolant? Apparently it has the same MBZ approval numbers as the straw-colored one. I think they changed the color so that it's harder to spot the contamination...

polarbexar

Yeah its blue.
I hope it jsut works good.

VVF

Works fine, I've had it for about a year now. But then again it broke the o-ring on that plastic coolant pipe most likely just a coincidence though.