Chevy C-5500 Kodiak Duramax potential safety issue!

[bob-kir]

I was recently returning home after spending the winter in Mexico in our 08 Seneca Duramax with 65,000 miles on it when I had an unexpected engine shut down!
I was driving about 63mph in the right lane in heavy traffic coming into St. Louis towing a car when a very loud continuous warning buzzer sounded and a couple of dash warning lights came on. I couldn’t tell what the icons on the warning lights represented but all of the gauges read normal. I was reducing my speed when the engine shut down, maybe 10 seconds after the alarm started sounding. Now I had no power steering or brakes. Luckily, I was right at the exit for a weigh station. I wrestled it over and got it stopped in the station truck parking area. Had to sit for a couple of minutes to calm down. It took considerable effort to just make the slight steering correction to enter the exit lane. Had I been on a curvy 2 lane road I don't know if you would be able to keep it on the road.
After stopping and checking the manual the warning lights indicated “low coolant” even though the dash temperature gauge was reading normal. I opened the hood and saw that the coolant reservoir was below the minimum level. Then I noticed coolant dripping from under the reservoir and saw that the hose that exists the bottom of the reservoir was about ready to fall off. It had slid down about 2 inches and was within a 1/4 inch of falling off completely. The clamp that holds it on is a steel compression ring with no way to tighten it. I slid the hose back to its original position and put on an additional hose clamp to secure it and added a gallon of water and we were go to go.
Before we leave Mexico I always do pretty thorough engine check , belts, hoses, fluid levels but never looked under the coolant reservoir to check the position of that hose. My guess is that the very rough Mexican roads were a factor in the hose coming loose.
I will always check that hose from now on!

[bob-kir]

It was a long straight run to the truck parking area so I didn’t apply the brakes vert hard. When I did use them the brake pedal felt mushy and it took more effort but they worked.

[DrewE]

You should have power brakes for at least one or two actuations even with the engine stopped. If you didn't, then there's a problem with the brake system--the pressure accumulator (or associated valves etc.) if it's hydroboost braking, or the vacuum reservoir, etc. if vacuum powered, or the air tank if they're air brakes. I'd guess you probably have hyrdoboost brakes, but don't know for sure.

Hydraulic power steering, it is true, is unboosted pretty much immediately.