The Purpose of a Thermostatic Cooling Fan Switch is to take care of 

Coolant Temp Control in a wide range of driving conditions & demands on

the Eng’ without relying upon the driver having to worry about making the

appropriate decisions ~ There is a Temp’ Range within which any Eng’ is @

It’s most efficient performance wise & that is the Range that Temp Controls

are designed to attempt to maintain ~

        Pg 19.12 in Bently shows the Temp Ranges that the H2OBoxer Gurus

back in the 80s decided would provide best Operating Performance Temps

for our Vanagon Eng’s & this has little if any to do with where You Live or

how You drive aside from the Temp that a particular sensor senses due to

where & how the Vanagon is being driven @ any given time ~

        It Is Interesting to note that the 1.9Ls use a Higher Temp Range than

the 2.1Ls, @ least @ the Rad’ (must keep in mind that the Rad’Fan Switch

is driven by Rad’ Coolant Temp’s & not Eng’ Coolant Temp’s) ~

        All that being said,, My reason for installing a Manual Override to the

Rad’Fan Switch back in 83 was probably mostly due to the fact that My 83.5

had Cooling Issues Out Of The Box & for Me, installing a switch that I could

flip when approaching a hill climb or head wind with 2 70lb Canoes on the

roof & a trailer out back carrying a 150ld raft was an easy comfort source ~

 

> On 24 Aug , 2021, at 9:36 AM, Dan N <dn92610@GMAIL.COM> wrote:
> 
> Depending where you live and how often you drive steep roads. Where I live
> (Oregon) the low temp is not ideal but back then in Southern California
> it's very nice to have. Since you can't control the weather or the road or
> the traffic, it's nice to have a toggle switch to activate the fan manually
> when and where you want it
> 
> On Tue, Aug 24, 2021 at 8:19 AM OlRivrRat <OlRivrRat@comcast.net> wrote:
> 
>>                Jack
>> 
>>        The lower Temp’ Switch Range keeps the Eng Too Cool to be @ It’s
>> Most Efficient Best Performance ~
>> 
>> 
>> 
>>> On 24 Aug , 2021, at 7:13 AM, Jack R <jack007@COMCAST.NET> wrote:
>>> 
>>> Mark,
>>> 
>>> I have an 84 Westy, with working AC, and a 2.1L also.  I put in the
>> "lower temp switch", to help make sure my van runs cool when in traffic, so
>> it turns on earlier.  I haven't had an issue "yet"!?!?
>>> 
>>> Why is the lower temps switch "wrong"?  Should I put in the regular
>> switch?
>>> 
>>> Thanks!
>>> 
>>> Jack
>>> 
>>> -----Original Message-----
>>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>> Of vw_van_fan_Mark
>>> Sent: Monday, August 23, 2021 11:38 AM
>>> To: vanagon@GERRY.VANAGON.COM
>>> Subject: Re: Replacing radiator Fan Thermo switch questions
>>> 
>>> The new switch you have is the standard replacement temp range.
>>> 
>>> The "wrong" switch turns on the fan at lower temps than that.
>>> 
>>> The early watercooled vans used one that turned on at higher temps than
>>> your new one.
>>> 
>>> Bentley page 19.12 shows the original factory temp switch ranges for
>>> waterboxers.
>>> 
>>> After you replace it, look closely at your old one to see what temp
>>> markings are on it.
>>> 
>>> Mark
>>> 
>>> Tom Buese wrote:
>>>> My thermo switch is bad & I have a new spare that is rated 85-93
>> degrees C. I read an old post from Mark Drillock talking about the several
>> different switches that were available 12 years ago & a problem w/ using
>> one that operates at a lower temp thus causing the #7 fuse  to overheat &
>> melt the plastic around the fuse holder!  I dont want to install my new
>> switch if that is the wrong one!
>>>> Do I have the best switch or did I get the wrong one? Inquiring mind
>> needs to know before another 500 mile RT on Friday! TIA!
>>>> 
>>>> Sent from my iPhone
>>>> 
>>>> 
>>>> Sent from my iPhone
>>>> 
>>