Do most mechanic shops have a machine that will flush the entire system in just a few minute? I'm debating doing it myself, and if it's worth the time when they do it so quickly. At least I think they usually have a machine for this.

Also, my coolant appears clean from what I can tell. But is a couple years past due on replacement. If I do it myself I'll probably use a coolant cleaner before flushing it with distilled water. But if I take it to a shop, should I mix in some system cleaner before hand? Not sure if they'll flush it out sufficiently with the machine to get it all out - or if it really matters that much.

Make sure the coolant flush machine uses new coolant. Some places use reclaimed stuff that's a mix of everything that was collected

What's the risk of flushing on a hot engine? Drive to a shop and they replace hot coolant with cold coolant. I would think there would be a risk of cracking the block.

Martin Q. Blank said:

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What's the risk of flushing on a hot engine? Drive to a shop and they replace hot coolant with cold coolant. I would think there would be a risk of cracking the block.

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I'd be more concerned about the coolant exploding in their face as it's pressurized.

They'll likely wait a few minutes before opening the system.

1agswitchin4lanes said:

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Make sure the coolant flush machine uses new coolant. Some places use reclaimed stuff that's a mix of everything that was collected

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Oh wow. That's gross.