My miata started bellowing white smoke from the engine bay when I came to a stop at a free way exit.
I checked the engine bay and I noticed a vaccum cap was leaking. I attached an video below showing the nipple.
Anyone any experience as to why this coolant leak happened? Is it just that the nipple went bad or could be something else entirely.

 

Do you have a 1.6? That is a common place for the cap to go bad.

 

Nope its a boosted 1.8, bought it fully built by another person.
Just made a diy vaccum tube with an oil hose and a bolt, but its resting up against another coolant pipe. Any chance the hose clamp on my vacuum cap would get hot enough to melt the coolant tube?
https://imgur.com/2UinUM1

 

Previous owner removed that coolant line that goes from that nipple to the oil heater/cooler and replaced it with a cap.

 

Lars, thanks for the explanation. I was trying to understand how a missing vacuum cap could cause overheating.

DNM

 

It definitely won't get to hot, but I'd be worried about the clamp abrading the hose. I would try to get a piece of split loom or something between the two.