1970 280 SL Heater Core Leak

[johnm]

 It appears I have a coolent leak where the heater valve fitting attaches to the core. Although its difficult to see through the access hole in the fire wall I can definitely see the seepage below where the valve is. I assume this was a welded connection that has fatigued over the years. This raises two questions
1) Has anyone had any luck with a radiator sealant repair product such as what I've seen offered by Prestone here in Canada. It claims to fix larger leaks in radiators and heater cores.
2) Can someone provide a high level overview of what's involved in changing a core?
Thanks very much
John

[Jonny B]

I have not tried the stop leak/sealant repair.

I have, however, had to remove the heater core (on my car, and a friend's) this is a "rite of passage" kind of thing! It is a pain in the back (and the butt) to do this, however, there is an excellent write up about it in the technical manual. Click over to the "Technical Manual", then to the "Heater" link. There are several different write-ups, but they are all related. Check it out.

When we did this, we also took out the seats and the steering wheel - both are easy to remove. It makes the access MUCH easier. With the 280 SL the access to the heater levers is more difficult as the the dash is one piece, the earlier cars, you could remove the overall radio cover and there was more room for access.

Take photos and some drawings also help, to ensure the orientation of the bolts and washer combinations for the heater box and such.

[johnm]

 Thanks for the advise and direction to the Technical Manual. Will definitely consult with it. In the meantime I've bypassed it until economics and time permit for the replacement.
Cheers...John