07 Chev uplander won't start in cold

[derekjj]

When cold(below -10) won't start, clicks once.
Battery is fine and also tried boosting from a large truck(with and without the battery in the van connected).

Also had the block heater plugged in.

Starts no problem and instantly above -10.

[Tech II]

First, I would make sure, that the battery cables are clean(no corrosion) and tight, and also the negative cable to the engine, is clean and tight, and the connections at the starter, are clean and tight......

You also want a a voltmeter across the battery, to see what the actual voltage is.....if it is above 10 volts while attempting to crank, and you have checked all previously mentioned connections, it's either the starter or the battery.......if you are getting above 10 volts at the starter(the large positive battery cable), and at the "S" terminal(purple wire) of the starter solenoid(when key is in the crank position), then it's the starter.....

But BEFORE you condemn the starter, take a long wrench and put it on the crank bolt, and see if you can easily rotate the engine, manually......let's face it, when things are warm, things expand.....and when they are cold, they contract.....see if that engine rotates.....