Last winter I started a thread - 51317 - about a problem I was having with the heater on my 1985 300TD. The symptom that persists is - I have an odor of coolant when my heater starts up. Coolant leak is slight, maybe a quart every two months. By some irony, my 1979 300D has the same symptoms but with a stronger odor and greater loss of coolant.

I have tried the quick fix - sealant (Bars Leak) to try and repair the heater core from within (with thanks for his tips to Larry Bible). This hasn't worked. I have read up on the threads that recount how much work is involved in removing the dash to replace the core, and understand that many people with much more experience of these cars than me have never had to replace a core.

I read with interest thread replies to The Warden (on his heater problem in thread 65466) in which Rwthomas1 and Ridge describe -

rwthomas1
".... Incidentally I have a very small heater core leak as when I first run the heat I get a whiff of coolant that goes away in a few minutes. No film on the windows though so it must be very small." RT

Ridge
"The one and only time that I had a similar problem, I removed the dash and extracted the heater core. It was weeping slightly around the rubber seal where it is crimped like on the main radiator.
I took it down to a local radiator shop, where they recrimped the seals, pressure tested it and gave it back to me with no charge."

My plan is to remove the core from the 300TD (with the assistance of my good and incredibly generous friend Joe Bauers) and have it checked out, if its bad I'll replace it. If it turns out to be the seals or o-rings then I will have saved some money. Pending the success of this exercise I will tackle the 300D.

I have three questions: -
Has anyone else had a problem like this that has turned out to be seals or o-rings, and if so how did you proceed?

Given the apparent rarity of the need for this operation, is there any way of moving forward here without removing the core?

Any tips for the removal of the dash, except patience...?

Many thanks for all and any replies.

'85 300TD 166K miles
'79 300D 198K miles

You have been here 14 months and have 11 posts... you are the quietest person I have ever seen....

From the pics from those that have taken the dash off I say do what you can without taking it off first...

If you do have to take it off I would suggest :

1. Be sure you have a factory shop manual handy
2. Be sure you have a digital camera handy
3. Be sure you have 'wire ties' and those paper tags with the hole reinforced to apply to everything you unhook.
4. Be sure you have lots of little screw and nut holding jars on hand before you start and a grease pencil to mark on the jars with.

Since this leak does not seem to be enough to effect your running temp of your engine ... perhaps a small hole in the case for spraying Lysol or Fabreez into the area once a week or so would suffice ?

Thanks for the tips about reference materials, documentation, tying and tagging.

Quiet? Well, the 300D is a recent acquisition and the 300TD was my first Mercedes. I haven't had too much trouble with it and I don't feel knowledgeable enough to offer much advice.

As for the air freshener approach, I am more concerned about the toxicity of the air coming out of the leaking heater than I am about the aroma.