[Vwdiesel] A tale of two coolants or my life and times as a glycol-holic!

Shawn Wright swright at zuiko.sls.bc.ca
Fri Mar 26 09:29:31 EST 2004

On 26 Mar 2004 at 7:57, Hayden Chasteen <dieseltdi at earthlink.net> wrote:

> Ever since I put my Caddy back on the road, I have been concerned with 
> the temperature at which it runs.  Not only was the water temp too high 
> as far as I was concerned but also the oil temp.  At times water temps 
> would rise to just 1 white notch below the red and oil temps would 
> reach 220+ degrees F. Part of this heating I attributed to the turbo 
> engine running hotter but it was too hot for me.   Now you have to 
> understand that I have replaced the water pump, the thermostat (yes I 
> checked it in hot water before I installed it and I drilled two small 
> relief holes), the radiator (with a genuine copper one with metal 
> intakes), most of the hoses, put in a two speed fan and fan switch 
> (with after run) and  yet the  "heating episodes" continued.  I 
> mentioned this in frustration to my son (the "professional" 
> mechanic...thank God he has a job and his own apartment now!) and he 
> asked me which coolant I was using - red or green.  Well, being the 
> convenience enthusiast that I am, I had decided to use the red coolant 
> so that I didn't have to change it so often.  "Well", he almost 
> sarcastically says, "that is your problem. for what ever reason, early 
> water cooled VWs don't seem to cool as well with the red.  My Scirocco 
> and formerly owned Corrado both ran hot with red coolant.  Switch back 
> to green and your heating problem will go away!"  Well not being one to 
> question the word of a professional, I flushed the system AGAIN and 
> used the green coolant.  Guess what?  The car now runs at the correct 
> temp, it never goes above the first mark above the middle and doesn't 
> even reach that unless I really stand on it for a while.  And the oil 
> temps that used to reach 220+ now rarely go above 190!  SOOOO anyone 
> else noticed this strange state of events?  As I pondered how my son 
> could actually be so smart, I remembered that when I put the 1.9TD in 
> to my old 85 Jetta, I used the red coolant in it also and it ran hotter 
> that I liked.  I just put it off at that time to the larger turbo 
> charged engine.  Any chemists in the group could maybe explain this?  
> BTW,  I used the same mixture of green and red with water in the 
> radiators (50/50 or very close) so the variable is only red verses 
> green.  Talk amongst yourselves and make comment.  At this point I am 
> baffled.  Hayden

Interesting... my old TD used to run quite hot also, even after I replaced the rad with 
the larger A/C version. I just assumed it had more to do with the worn int shaft 
bearings and resulting low oil pressure causing more friction under load. I never 
even considered the coolant could have a role, but I did start using orange stuff 
about 5 years ago, after having excellent results with it in my '88 Westy 2.1L wbx. 
The waterboxer engine does well with it - I've never seen the gauge rise about 2/3, 
even on long slow hill climbs.
Shawn Wright
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