Last episode I talked about how valuable a well-written tutorial can be. Two weekends ago, supported by an excellent write-up, I dug deeper into the innards of an automobile than I have since I drove an Alfa Romeo. Which isn’t that deep, but you get the idea. The operation was a qualified success, and I saved myself several hundred dollars.
A qualified success. The qualification: I broke a different bit. I didn’t even know the name of the part (1974 Alfas didn’t have them), but it turns out it was the Positive Crankcase Ventilation Valve. The good news: PCV valves are inexpensive and butt-simple to replace. On this car at least, you don’t even need a wrench. The PCV valve is mushed into the top of the valve cover and sealed in place with a rubber grommet. Yank the old one out, mash the new one in, you’re good to go.
But… on a 14-year-old car, the grommet that seals the PCV valve in place can get hard. Not a biggie, but the grommet is cheap and in the long run could be a point of failure. May as well change it, too.
This reasoning is perfectly valid, unless you’re an idiot. In this case, “idiot” is defined as “a guy who might push the old grommet into the valve cover, rather than pull it out.”
I stood, looking at the empty hole that the little rubber donut had just leapt down. I don’t even think I swore. Sometimes words give out. I stepped back from the car and spiked the screwdriver I’d been using to pry at the grommet, hard, into the concrete floor of the garage.
My quick ‘n’ easy repair job had just become considerably more complicated.
Oh, I considered the consequences of just leaving the grommet in there. Could a piece of rubber really damage the camshafts? Yeah, dumb question. I was going to have to remove the valve cover and take out the little rubber donut.
In fact, that’s not a terribly difficult operation. The catch is that the same logic that applied to the grommet applied to the valve cover gasket. Fourteen-year-old rubber might not reseal properly. Off to AutoZone I went, and got a new gasket. It was surprisingly affordable. I also got a torque wrench, because you have to be really careful not to overtighten the bolts when you put the cover back on.
Back in the garage, with laptop propped up with the instructions for the upcoming operation, I snapped my 10mm socket onto the extender and dove in. Things went smoothly, and before long I had the valve cover off. I set it carefully aside and looked down between the valve stems, expecting to find the offending bit of rubber.
It wasn’t there.
I probed in the pooled motor oil with a screwdriver. Nothing. Nic. Nada.
Perplexed, I turned my attention to the valve cover I had removed. Where the grommet had been pushed in, there was a chamber sealed by a flat plate. Seven screws held the plate in place, and they were a bitch to get out. I peeled the plate free, breaking some sort of sealer.
There was the goddam grommet. I removed it, cursed myself, and then considered how I would put everything back together. The plate had been sealed with a dark substance; I went back online to find out what product I needed to restore the seal.
This was when I found a question on a Miata forum by a guy who had, in his words, “idiotically pushed the grommet into the motor”. Like me, he had pulled the valve cover, but he had yet to open the chamber.
“Just leave the grommet there,” was the advice. “It can’t hurt anything.” The chamber exists, you see, to keep oil from shooting straight into the PCV valve. The grommet would be just another obstacle. This would have been really good to read before I tried to fix my blunder. Too late now, though; the chamber is open and must be resealed. Happily in that same discussion was advice that addressed my condition. The right sealant to use (probably unimportant since the chamber is open on one end anyway), and a strong caution about the seven screws. If one of those works free it could destroy the engine. The proper adhesives are called for.
So, another trip to the friendly and knowledgeable guys at my local AutoZone later, I began the reassembly. It went well, with only a (hopefully) minor hitch. My car has a big stiffener bar that reaches across the engine compartment. (The bar was part of Mazda’s “dominate autocross” package.) That bar makes it really hard to slide the valve cover into place without disrupting the complex, 3-d gasket. By now I was cursing freely, but finally I got it into place with (as far as I can tell) the gasket properly seated. Then I discovered that the torque wrench I had bought really couldn’t measure bolts as loose as these are spec’d to be. But I got pretty close, I think, and it really felt like I was compressing the gasket gradually as I turned the bolts.
So in the end my clumsiness cost me about fifty bucks and three hours of stress-filled life. Unless I have an oil leak now. One deep breath later, I’ve still saved a lot of money compared to having the original problem repaired by a mechanic. But it could have been so much easier.