Coolant leaks when it's really cold

[Redland1]

(09-26-2023 )Hamish Wrote:  This is a problem common to any engine with a plastic rear water pump cover that sits outside in the cold up north. Happens lots up here. The real solution is to have a steel rear cover machined before you install a new water pump. Plastic contracts way more than steel and the shrinkage allows, sometimes, ALL coolant to be lost over night. After this a couple of times I took the water pump off, had a steel ring machined and fitted inside the lip of the plastic insert. This was a cheaper fix than machining an entire steel piece. The fit needs to be an interference fit at room temp, where the steel ring just slips in when the assembly is placed in recently boiled water. I have some great pictures of this mod which has worked flawlessly so far down to -42 Deg C



This fix means I can actually just turn on my engine heater and start the truck, whereas if all coolant is lost, and adding more just runs out the bottom, the options are limited. By the way, let the air out of your coolant heater before firing it up if you'd like your heat chamber to not crack... (there is a small purge screw on top of mine).

You should have a bunch of them made and sell them.