Hello, on a 1991 Chevy pickup, 4.3 engine, does anyone know if the thermostat spring faces up or down?? It has reverse flow water pump. Thanks, Tim
Chevy 4.3 thermostat replacement
Dec 20, 2008
3 Replies
Down. As a rule the heat slug gets installed facing the engine. Regardless of where it's mounted. That way as the engine temperature rises it will open. Install it backwards and you will probably overheat long before it opens.
I just did this on my 99 Blazer. Spring is down like every one I've ever seen.
Yep, easy thing to remember on a thermostat. The spring and control go in the water flow coming from the engine. Otherwise they wouldn't operate.
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