1994 Chevy S-10 fan clutch/radiator air temp

JMICHAEL8888

MECHANIC
1994 CHEVROLET S-10
6 CYL
2WD
AUTOMATIC
165,000 MILES

My engine runs about 210 degrees on a 195 thermostat. At idle it will ease up to about 220.
my fan was not engaging so I replaced the fan clutch. It still does not engage. So I drilled a hole in the shroud between the fan and radiator and placed a digital thermometer. At full temp the air temp only got to be 115 degrees max.
after research I found out they usually engage at 170 degrees air temp (about 30 degreees less than coolant temp). So I figured mine would come on around 200 or so. It never engages.
lastly, my radiator is rust corroded. Ive flushed it several times, until the coolant remained green.
(my question)would the rust corrossion prevent the heat from escaping the radiator thus not engaging the clutch?

3 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

No, corrosion wont do that, but a slight blockage would make it get a little hot in the engine while idling and when the coolant sits in the radiator longer it gets cooled more, that may explain the cooler air temp at the radiator, while engine temp is higher

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Sunday, December 28th, 2008 AT 4:00 PM

JMICHAEL8888

MECHANIC
45 POSTS

You dont think there could be blockage in the engine cooling ports, do you, causing bad flow because my heater blows just warm unstead of hot?

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Sunday, December 28th, 2008 AT 5:23 PM

2CARPRO JACK

MECHANIC
11,533 POSTS

Odds are the blockages are in the radiator and the heater core. Low flow will cause exactly what you describe. You can try a backflush to push some of it out, especially with the heater core, it isnt too easy to replace so if you can get it flowing you will be saving alot of time/money. The radiator can always be taken to a shop and given a "rod out" which gets them like new inside.

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Sunday, December 28th, 2008 AT 5:33 PM