Re: 85 Rocco overheating

[trnsfrma@ix.netcom.com (Shawn C. Meze)]

At 08:59 AM 6/16/97 -0400, you wrote:
>
>Hi folks,
>
>What is the normal coolant temperature for the 8V (1985) engine ?
>As far as I could tell, my Rocco would run between 100 and 110 C
>(ok, 212F and 230F) in warm to hot weather. I'm also pretty sure that
>the coolant temperature never saw the wrong side of 230F. Over the
>last week, I noticed that continuous cruising at 70mph (3400 rpm)
>or higher speeds gets the temp gauge beyond 230F. In fact, at one
>point, with the AC on,it was approaching 250F and I backed off
>on the throttle until the temps climbed down.


Thats WAY too high for a street machine. Something is definately wrong. 
At highway speeds, your car should run very cool. (about 180-200. Lots 
of air flowing through the radiator) 250?! Yikes!!!


>The oil temp gauge was at the 2nd dot from the top at the same time.

Too hot!

>My first guess was that the radiator wasn't providing adequate cooling
>or that the thermostat wasn't opening. However, this problem doesn't
>manifest itself in stop and go traffic (fan works fine) which
>leads me to believe that the thermostat is opening.


It could be that the radiator ISNT cooling adequately. Maybe a good 
chemical flush is in order?? Couldnt hurt. 


>What confuses me is the following : The thermostat isn't supposed
>to open until the coolant is at 185F, right ? Well, If I start the
>engine from cold and run it for a few minutes (temp approximately
>140-150F), I can feel the upper radiator hose getting hot. This
>means that the thermostat IS open, right ? 


That depends on what temp your thermostat is set to open. (There are 
different temps avialable from 160-195) Heres something that you may or 
may not have realized. Your thermostat may be only partially opening. 
Around town, its flowing enough coolant to keep things cool. On the 
freeway, the same amount of coolant is flowing to the radiator but the 
engine is now working much harder, producing much more heat while most 
of the coolant is recirculating already hot coolant back through the 
engine. From that descriptiion alone, id definately replace the 
thermostat and flush the system. 


>After all this, I detect that the coolant level is about a quart low
>(duh) and topped it off with 50-50 coolant and distilled water. This
>morning, temperatures seemed to stay at 230F, but the ambient 
temperature
>wasn't very high. I'll do some careful observing and report my results
>here. 


Low coolant is probably from the engine basically overheating (Mildly). 
You got it pretty hot there!
HTH!


Shawn
86' Jetta GLi
82' Scirocco GTi
The Fastest, Quickest, Cleanest and
best looking Scirocco in all of San Diego!
http://www2.netcom.com/~trnsfrma/vws.html

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