Hi all,

I started a coolant flush yesterday and ran out of time to finish before dark. I left the truck sitting without any type of fluid overnight and it got down to 19 degrees last night. I filled the truck back up with water today to finish the flush but had hesitations to start the truck being that it was cold last night and the block had 0 coolant in it (I drained all coolant including coolant in the block because I put a block heater in). It is currently 40 degrees out, should I be concerned with starting the truck right now? I have the new block heater plugged in, I plan on letting it heat the block for a few hours. Any suggestions?

Thanks

 

Do you mean water and no antifreeze or no liquid at all? If you mean no liquid at all then your ok. If you mean water only then plug it up for a few hours then crank it and let it warm up and look for leaks. At this point, if the water froze and cracked something, then the damage has been done

 

Yup. No liquid is fine; it's just water freezing that can be a problem.

 

Well, how well did you flush it? If you cleaned out the radiator and left the rest of the block filled with radiator fluid, then whatever water you added to the system should be diluted with over a gallon of coolant from the previous flush, thus probably ok at 19 degrees.

However, if you pulled one drain plug on the side of the block and drained the radiator, you probably had a half gallon of fluid in the other side of the block. When you drain an IDI, you gotta pull the plugs on both sides of the block PLUS the radiator to get all the coolant out. So, if that leftover fluid in the block was coolant, then you don't have a problem. If that leftover fluid was water, then you probably f'ed something up.

 

Problem is, theres no way to get all the water out. Odds are, you might be okay at 19 though, only way to know is to fill it up and fire in the hole.

 

At this point, what's done is done. Run it and let us know.

Remember that:
1. Water expands when it freezes and turns into ice.
2. Coolant(ethylene glycol/propylene glycol) lowers the freezing point based on it's percentage in water
3. Water when freezing will expand along the path of least resistance when it can.
This is why you can have a glass jar of water, and if you leave some open area at the top, it probably won't break when you freeze it. If you fill it completely and put a lid on it, it /will/ crack.
So, as long as either: A, what liquid was left in the block had a few % of antifreeze in it or B, it was drained far enough that there was some 'headroom' in the galleries on the sides, you'll be fine.
It's only when you have a cooling system totally full of water with nowhere to expand that things break.