| Re: OEM temp gauge readings [message #366069 is a reply to message #357738] |
Wed, 11 August 2021 09:54  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
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Understand that the fan clutch engage point needs to be at least 10 Deg above the thermostat rating to prevent nuisance engagement. This allows for a bit of creep up before the clutch “engages”. What is important is that above that point it DOES engage and stop the temp rise from creeping further. You should hear it and watch the gauge drop within a minute or 2. Usually the clutch will slightly overshoot on the down side then relax. In severe conditions the temp will then creep up and engage and cycle repeat. C4 Corvettes being bottom feeders would do this at highway cruise with AC on. The gauge would slowly creep up, then at about 220 you would get fan roar and feel the drag, run 60-90 seconds then relax with gauge about 190. This cycle would repeat every 4-5 mins or so as there was not enough ram air cooling on it’s own. On the GMC the theory is the engine room becomes pressurized by air getting in and under, which reduces natural ram air cooling. So one more thing we have in common with Corvette besides fuel separator, SMC body and washer nozzles.
John Lebetski
Woodstock, IL
77 Eleganza II
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