Thanks Shep.... your suggestion might be part of what is actually happening...
I just pulled the thermostat out.... engine runs in a range of 140 to 175 degree's
depending upon speed of travel, stuck at a light or stop and go traffic. The
engine did not pass 175 degrees even once. I also tested the thermostat
it opened at 195 degrees (according to spec) and the opening looked about
normal compared to another thermostat (used as a control).
I might swap out the water pump (although it's only a year old) as they are
inexspensive and relatively easy to change out. If that doesn't make a
difference, I'll try a 185 thermostat rather than the 195 (spec'd by the
manual). I would prefer having less heat, rather than having the engine
run hotter.
Thanks for your suggestion !!
Peter.
On Thu, 18 Nov 2004 19
52 -0500, "Shep" <djsljsrn@capital.net> wrote:
>You might consider a general degradation of cooling system effiency from
>time and mileage, rust and scale build up for example, my 3800 Lumina runs
>at 200 will not build up any real pressure without about 220 on the
>scanner.
>"Peter" <Peter@spamtrap.net> wrote in message
>news:7p1qp0tjb3hbkdte0h3ia09q1jqupov46q@4ax.com.. .
>> Working on a 1992 Chevy Lumina APV. 3.1 L engine
>>
>> The engine was experiencing
>> several problems which have been repaired....but still running hot (not
>> overheating, just running hotter than normal).
>>
>> Engine Temperature is 207.3 degrees (OBD1 tester). Electric Fan
>> does cycle on and off. A radiator thermometer shows antifree temperature
>> to be around 210 or so.
>>
>> But, with the engine running and at 200 plus degrees, the system
>> should be pressurized...but it is not. I can remove the radiator cap
>> without having the coolent spurt all over. And the upper and
>> lower radiator hoses...are hot but can easily be collapsed.
>>
>> When thermostat opens and water begins to flow I get even
>> heat over the surface of the radiator.
>>
>> Cooling System Tester showed the cooling system holding
>> 15 pounds pressure steady for over 30 minutes without losing anything.
>> Also no leaks, or signs of leaks. Radiator Cap tested okay using
>> tester but I swapped in a new one anyway. No change
>>
>> The water pump was replaced about a year ago. Thermostat
>> was replaced (tested before replacement). Radiator is full of
>> coolent. (about a 50% mixture using an antifreeze tester.
>>
>>
>> Is the system failing to pressurize during operation indicative of a
>> failing water
>> pump??? Water pump is not leaking. No bearing noise (far as i can
>> tell).
>>
>> Is the troubleshooting technique okay....what am I overlooking ???
>>
>> Thanks in advance for your help.
>>
>>
>>
>>
>
>
>
>
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