[Vwdiesel] VW Diesel engine running too hot

[LBaird119 at aol.com]

In a message dated 10/5/2006 6:33:56 PM Pacific Daylight Time, 
sherwingoff at yahoo.com writes:

>  I have a very nice 83 Westy with the 1900 engine and a 5 speed; however, 
> it runs with the needle straight up or even a little to the right of top 
> center. This is too hot. I do not like for it to run this hot. (My 82 also did 
> this same thing, and I experienced early engine failure because of it.) 

  What was the failure?  If above center is too hot, generally a cooler 
thermostat will solve that.  Proviing your radiator is clean and clear.

>   
>  Over and over again, I have checked this out at cooler times and in cooler 
> climates. At those times the nettle always stays where it belongs--in the 
> LITTLE BOX on the temperature gauge--to the left. This position is where the 
> engine thermostat should normally keep the engine temperature. The temperature 
> must be controlled by the thermostats--not by the radiator fan.

  Well yeah.  The thermostat controlls the temperature of the engine 
side of the coolant.  That's what it's there for.  The cooling fan is simply 
to increase air flow across the radiator when it's not keeping up with 
the amount of heat generated.  It's also thermostatically controlled.

>   
>  I believe this is an engineering problem. I have had only one Diesel Rabbit 
> that always ran inside the little box on the heater gauge. All of the rest 
> of them have run much hotter than their thermostat. Overheating these engines 
> is a number one cause for early engine failure. 

  First, the temp gauges aren't really calibrated.  4 Rabbits of the same 
year, with the same t-stat, running at the same temp, will generally have 
the needle resting in 3 to 4 different points on the gauge!
  I've seen very few where overheating of itsef was cause of early 
engine failure.  Generally failure is a blown head gasket, worn bore 
(here anyway) broken ring or bad rod bearing.  Most of those are 
pretty easily repairable and don't tend to fall under MY definition of 
failurs.  :-)
  Most of the cases of overheating were preceeded by a lightly blown 
head gasket, leaking water pump, blown hose, low coolant, crudded 
up radiator, etc.

>   
>  Is there a radiator capacity problem here? Is the radiator too small, or 
> does the radiator have fewer fins than it needs? The problem is not the engine 
> nor the thermostat. It has to do with cooling.

  Well, when a head gasket starts leaking, the engine will heat up 
faster.  It puts air into the system which insulates the stat and keeps 
it from opening, air locks the system.  Bad water pumps can cause 
little or slow circulation (slipping or stamped steel impeller.)
  I don't know how the Vanagon system does but I've seen little 
complaint about it being inadequate here on tthe list.

>   
>  My experience with all VW diesels (and I have had many) has been that they 
> are IMPROPERLY ENGINEERED to run as cool as they should--else why do they all 
> run hotter than their thermostat would otherwise allow? 

  Frankly I've NEVER seen one that ran hotter than the thermostat. 
Most of the diesels have a hotter than 180F thermostat.  Most are 
192F or such.  They're supposed to run on the hotter side than a 
gasser and as I said before, the gauges are not calibrated so a 
thermometer in the coolant reservoir is the only way to tell if it's 
right or not.  

>   
>  (Do ya'll understand what I'm trying to explain here?)
>   
>  So now here is my question: 
>   
>  What has been your experience for SOLVING this problem.
>   
>  Thanks to all of you,
>   
>  Sherwin
> 

  First is to find if it's actually a problem or an opinion.  So far 
most of what you stated seems to be more opinion than problem 
since you need numbers.  Feedback from others hasn't 
indicated any widespread problem.  Maybe you do have a 
problem and maybe you don't.  
  Radiator could be less than clean inside, water pump could have 
a stamped steel impeller that's rusted away, just plain less efficient 
to start with or cast ones have been known to slip also.  Possibly an 
air bubble in the system, soft or kinked hose, leaking headd gasket...
  IS it overheating or it just runs a little  hotter in hot weather according 

to the gauge but no known actual temperature or degrees of difference?
    Loren