Results are in! When I pumped the DeLorean's coolant system up to 14 psi, it dropped 1 psi after 15 minutes, 2 more at 30 minutes, and 4 more at the 90 minute mark.

Thoughts? I think this sounds reasonable.

Even better, when I first pressurized it there was a small leak at the line that connects to the bottle. This might explain where the coolant has been going. A few turns of the worm clamp fixed the leak.

I also tried running the car with the pressure system attached (and not artificially pressurized). The car started with just a little bit of white "smoke" (smelled a bit like fuel) and after idling for about 5-10 minutes the pressure has risen to 2 psi. I don't know the norm, but I didn't want to leave it idling all day so I stopped there. I would imagine a head gasket issue could also drive the pressure up in this case too-- which thankfully didn't happen.

Upon doing some quick research on the internet about how long a car should be able to keep cooling system pressure, I did find an article about hydro-locking an engine and the warnings involved with it. If indeed you're leaking into a cylinder, it's not unheard of to compromise an engine this way.


At this point I'll need to do some serious driving to run this gas through the car. Then it looks like the task will be to see if it's still having trouble starting. If so, it must be the WUR or something like that. I should probably change the fuel filter and take a dwell meter to it as well.