I think my Volvo has it in for me...

After the thermostat failing and the starter deciding to stop starting while on vacation in Maine, I had hoped that my little Volvo was done breaking on me for a while, but alas, it was not to be. Driving home this afternoon, I noticed a faint odor that I couldn't immediately identify. There was a lot of traffic, so I foolishly thought it might be another car - nope. Definitive proof emerged as soon as I got off the highway and stopped at the end of the ramp, in the form of steam curling around my hood. The temperature gauge read normal, and I was not in a good spot to stop, so I made the executive decision to run for home, only a mile away, with one traffic light; if the gauge so much as flinched, I would have pulled over, but it stayed steady into the driveway.

I popped the hood and saw a good bit of steam, but also still some coolant in the pressure tank. Looking around, I spotted the problem: a failure-prone plastic coupling that connects the heater hoses had let go. Fortunately, I was aware of this potential issue and had already gotten the preferred solution, a set of brass barbed couplers and new hose clamps. I ripped it apart and had it back together in an hour. I filled it up (it lost a little less than a gallon of coolant) and started it, hoping not to see a cloud of steam out of the exhaust. It ran fine and I saw nothing more than a few wisps of steam from the tailpipes. Unsatisfied, I took it for a test drive, including some highway and a few full-throttle pulls; everything felt normal, and I didn't see any steam while driving.

I have no idea how tolerant Volvo whiteblocks are of coolant loss, but being aluminum, I'm guessing not very. The temp sensor is down low in the thermostat housing, which is not really ideal, but I don't think it got very hot. When it happened I was at light throttle on the highway - not much load, lots of airflow. I don't know exactly when it popped, but the whole drive was only about six miles. Fingers crossed I escaped without further damage, and that this is the last failure for a while.

In reply to 02Pilot :

I'd drive it fingers crossed but I'd drive it till it showed signs of not being OK.

In reply to Tom1200 :

That's my plan. So far, it's behaving normally. I'll be watching coolant levels and checking the oil for signs of contamination, as well as any loss of performance.

A white block Volvo will survive things that will have your Kenworth in the scrap yard.

In almost every situation with coolant, as long as their is still liquid in the passages, you are good.  It's when that liquid turns to a gas, or disappears, that you have trouble.

In reply to Streetwiseguy :

That's reassuring, though I have no way of knowing for sure if the coolant dropped low enough to expose the passages in the head at least. I'll just have to keep an eye on it through a few heat cycles to see if anything shows signs of trouble, but I haven't seen anything yet.

I think an important part of Volvo ownership is recognizing when it's time to separate yourself from any particular Volvo. 

In reply to Woody (Forum Supportum) :

Fair point, but until the last month or two, the car has been fine and I've had no thoughts of getting rid of it. Even now, it hadn't really crossed my mind. I tend to keep my cars for a long time, and I'm probably too inherently stubborn or stupid for it to become a consideration this quickly.

In reply to 02Pilot :

I can respect that. 
 

Volvo wagons do everything very well. Until they don't.  

Second post-repair test drive revealed no symptoms. The system is holding pressure after shutdown, no mixing of fluids, and performance remains normal. I suppose I could scope the cylinders or do a leakdown test, but right now I'm not seeing a need. Stay tuned.

Good to hear. ^That's positive news!

So I acquired all the necessary hoses to do a full replacement, and finally got it done today. The heater hoses use these very annoying Norma Twist II connectors, which are of course plastic, and equally of course don't want to come apart after 18 years. I had already smashed the ones I replaced with brass fittings, but there are two more that connect to the (thankfully aluminum and not more plastic) heater core. They're right on the firewall and seriously inaccessible. I finally ended up cutting them with a Dremel until they gave up. There's no room for hose clamps in there, so I had to install the new hoses with the same stupid plastic, but I don't expect to have this car long enough - 2042 or thereabouts, based on the longevity of the first set - for them to fail again. Some of the new hoses had plastic fittings I didn't need, which I remorselessly smashed with a hammer after they refused to be removed sensibly.

All new hoses now, fresh coolant, new thermostat - hopefully it all behaves, at least until I have to do the timing belt in a couple years.