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Old 01-13-2011, 09:41 PM   #25 (permalink)
bluejoey
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Join Date: Nov 2010
Location: Illinois
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Quote:
Originally Posted by Old Mechanic View Post
Trust me on this one, 60,000 hours experience.

Start the engine cold with the radiator cap off.

You should see virtually no circulation until the thermostat opens.

If you see circulation before the stat opens the stat is bad.

Even with a properly working stat, you still have way too much heat loss through the radiator.

Completely block the radiator with a piece of cardboard. Carry a pair of scissors to trim the size of the cardboard if it actually gets to hot (I doubt it).

Use the block to get the operating temps up as high as you can (without being to hot), before you even mess with the thermostat.

As you get the operating temps up higher you can actually test it by placing your hand on the bottom radiator hose (the one the coolant comes out of the radiator through).
In summertime the bottom hose is usually around 110 degrees. In winter time it is much colder and that same much colder coolant goes into your engine and keeps it to cold.

The more the thermostat restricts the flow of coolant the colder the coolant going from the radiator back into the engine.

It could make a very significant difference in your mileage, especially based on your distance to temperature graph, which shows 5 miles before it even gets close to warm enough. The temp should actually be very close to the thermostat rating.

regards
Mech
Thanks for this advice! A couple of radiator blocks drop my idle iGPH within 5 minutes of driving from >.7 to <.3 in <32F weather, in comparison to >.7 to >.5. Since all of my trips these days are in the city and typically only a couple of miles long at a time, being able to reduce my idle GPH in such a short span of time is really helpful for my MPG, not to mention for my car heating. This is the single most significant mod I've made to my car beyond weight loss.
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