I have a ~5 mile commute right now. I thought I was smelling something while driving this week, but couldn't put my finger on it. A cursory sniff near the hood after my last few drives didn't yield any easy-to-diagnose burny-oily-smells we all know. I figure we all do the 'false-positive' thing when driving behind a big truck or gross polluter. Start smelling some oil burning, the antennae go up, and you're certain the smell is coming from YOUR truck.
Today I smelled it again and decided it couldn't be a coincidence. It was a hot dry stale smell - something between a left-on-handbrake and an oil drip on hot exhaust - but faint, and only when I was driving. Gauges functional and normal. I checked under the hood for any obvious leaks, exhaust manifold is bone-dry. The engine bay smelled normal, tailpipe smelled normal. Engine is responsive, oil cap is on, dipstick is in, I can see nothing amiss. So I closed the hood, and got back on the freeway, feeling like I'm bordering on "paranoid weirdo"
2 minutes later and I hear "POP!"
WTF was that! There is no way I just ran over something! Was that my
suspension?!
Looking for an exit, Gauges are normal, engine still running.....it seems to drive ok...when what looked like smoke began entering the cab through the shift boot and dash.
Immediate "HOLY SHIT I'M ON FIRE!" mode.
Hit the hazards, beelined it for toward a mercifully-placed off ramp, and began the dig for the extinguisher(which will be on a strap in the passenger foot well instead of behind the seat underneath everything from now on)
Opened the hood and got a moist face full of that familiar warm stale-smelling coolant. That faint smell was a bleed from my cooling system! And now there is a ton of steam coming from somewhere near the fire wall. WTF did I do!
I'm learning better than to go poking around with fingers or sticking my face down into hot compartments, but without a mirror I was left sticking my trusty cell phone camera with the dirty work.
Yep, big fucken hole. Not exactly what I expected. Cylinder head freeze plug. View of back of head from driver side looking forward right.
But the engine still runs....I'm less than a mile from home and have only been driving for 5 minutes...temp gauge reads normal. At least it isn't fire! Off we limp!
I suppose it
could be a stuck thermostat, but I view that as unlikely. I have not checked coolant levels in several months, nor have I taken a
hard look around the engine bay for issues lately. I am not sure why the fluid is so low, but I would not be surprised to find a leaking hose or water pump weep hole . I haven't yet investigated that. Nor have I popped the radiator cap to see where I'm at coolant-wise
Given that there was an over-pressurization of some type, I assume that over time, as the volume of air in the system grew, the steam was slowly bleeding off during each drive, torturing that poor radiator cap pressure release valve until it began to stick. Once it stuck, something else had to give. I am a bit surprised the plug was the weakest link, and not some hose. Basic regular maintenance would have prevented this. It feels like a straightforward case of human error. I guess I'm in for a minimum annoying plug press job and radiator cap replacement, and maximum a water pump and everything else that would go along with that.
Lessons: Check fluids regularly. Trust your nose.
Anyone got a freeze plug lying around?
Rock auto makes you buy a pack of 10, so if not, does anyone need some free(+shipping) freeze plugs?
Link:
http://www.rockauto.com/en/catalog/chevrolet,1975,luv,1.8l+111cid+l4,1054291,engine,cylinder+head+plug,11833
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