Date:         Thu, 6 Jun 2013 22:03:39 -0700
Reply-To:     Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Poppie Jagersand <poppie.jagersand@YAHOO.CA>
Subject:      Effectiveness of cooling system flush and clean products?
Content-Type: text/plain; charset=us-ascii

On a couple of occasions last summer the motor temp of my 1.9TD crept up to the warning light/buzzer level. These were both on hot days and high loads (going up a backroads rocky mountain pass). With hotter temps again here in ALberta, Canada I'm thinking about what to do.
I'm running the original 30 year old 82D radiator and it seems to be gumming up and restricting flow a bit too much. I know I can get a new rad from e.g. Busdepot, but I'll have to wait for shipping to Canada (while Busdepot radiator is a reasonable $100, ship is another $100 on top of that), and also need to locate an 83+ parts vanagon for various things (fan shroud, radiator mounts, 3 pin thermostat).

Therefore I want to consider the following and wonder what might be useful:

Alternative a: An hour or so of work and some waiting time while running with flushing agent in engine)
1. Flush with a relatively strong cleaner, e.g. Permatex 80032 Aluminum Radiator Flush, or Gunk C2124 Super Heavy Duty Radiator Flush which has the same ingredients according to the MSDS data sheet.
2. Take out the thermostat while flushing to get better flow.
3. Reverse the rad coolant hoses to backflush. (Might rel;ease stuck scales from rad better if flow is reversed)

Alternative b.
Some Mercedes Diesel forums suggest buying food grade citric acid and flush with a strong solution of this. They claim that is what Mercedes dealer service do.

Alternative c. (Probably half a day to a day)
Take out rad and take to a radiator shop for flushing with some stronger cleaning/scale dissolving agent. (If such a service can still be found)

While neither of these will restore the old rad to new, at least they can be tried quicker than ordering and waiting for a new radiator to ship internationally. Therefore I was curious what you would think of the potential effectiveness? Or if you had any other suggestions for what to try let me know. (Other obvious things such as water pump, thermostat, cooling system pressure have been tested).

Thanks for any insights.

Martin (and '82 Westy TD)