I have a friend that likes to suffer, so in order to expedite his suffering he owns two BMW’s. One of the BMW’s was $700. Do you have any idea how many problems you’ll have with a $700 German ultimate driving machine? Lots. Anyway, this friend has another friend who he has somehow suckered into fixing this $700 BMW. It started with a clutch (nothing like starting small). The car developed an intermittent starting problem and somehow friend two got suckered into fixing that. I wanted to meet the man rumored to have a cool shop and foolish enough to fix that horrible money pit not once but twice.
I dug out the FireTurd and headed towards the address given to me. I was just tooling along–the smokeshow was scheduled for later that evening after I checked out this shop and made fun of this poor fool. The temps climbed up to an indicated 245* (220* on the ECU). I wheeled the car around and headed for the shed. In my haste to get back to safety without having to put the car on the hotrod shop flatbed I pulled out in front of someone. I gave it a bit of gas and to my surprise the temps dropped right before my very eyes. Like–you could watch it dropping, it was noticeable. It went down to an indicated 190* in seconds. I decided the thermostat was stuck shut and now it had popped open. I pulled a u-turn again–the smokeshow was back on schedule.
Except it wasn’t, the temps crept right back up to an indicated 240*. I did notice that rolling on the gas dropped the temps and coasting increased the temps. This behavior seemed to be the exact opposite of what should be happening–although it matched the behavior of a car with low coolant. Before pulling it into my garage I laid newspaper out on my floor so I could see where my coolant leak was. I pulled the car in on top of the newspaper and popped the hood, expecting to see steam everywhere. There was nothing. No drips, no steam, nothing. My overflow tank was almost overflowing as it was when I filled it the first time. Odd. But it must be leaking coolant somewhere–I was always adding coolant every time I drove the car. And if it’s leaking coolant somewhere then it can’t build pressure, right? Right.
So I grabbed a welding glove and a rag and slowly cracked the pressure cap on the surge tank. Immediately I can hear what I incorrectly assumed was water surging out through the overflow pipe and burbling up through the overflow tank. I’d never opened a hot radiator cap before (it’s always a bad idea kids, don’t try this at home) so when it started making noise I immediately clamped it shut. I evaluated what happened, realized I didn’t boil the skin off my hand or otherwise almost die, so I gently cracked the cap again and let the pressure spurt out through the overflow tank. I’m intently watching the overflow tank and listening carefully to the sound of the pressure going through the line. I’m extra careful because the sound suddenly changed–what did this mean? Why was it different? I was still pondering those things when my leg caught on fire.
My leg turned out to not be on fire but to actually be wet. Hot water was spraying from a nick on the overflow hose. I used a piece of leftover fuel line as overflow and nicked it with the right angle grinder when I was prepping to weld the hood latch supports on the car. Fuel line is super thick so I knew I hadn’t cut through or anything. Except I had cut through, and so for the last 300 miles or so driving the car I’d push water into the overflow tank when I got hot but when it cooled off it would suck air through the nicked hose. Mystery solved. I cut the nicked part of the hose off, reconnected everything and topped it off. I ran the car up to temp and let it cool and noticed that for the first time ever the overflow tank went down. Mystery solved and on to the next one.
And if anyone was wondering about the guy with cool shop who is easily suckered into fixing money pits? He was all of that and more–an awesome standalone shop with two post lift, eating area, wet bar, giant wood stove, 1928 Dodge project in the corner, and more swear words and racy jokes than you can shake a stick at. I think I’m in love.