Truck Time with Twayn: Episode 17 – The Exhaust Gaskets


Jeff Foxworthy says if you have spent more money on your pickup truck than you have on your education, you might be a redneck. I fear I am getting much too close to that marker for comfort.

Faced with the first Sunday in months without any real football to watch and not enough excitement for the pending baseball season to go to Twinsfest, I decided to test a theory with the truck. For a couple of months now it's been running rough and loud. I first thought the problem was the catalytic converter. It was pretty old and it had overheated pretty badly after the first head gasket replacement when I didn't have the head rebuilt and the valve seats and guides were fubar so I had to redo the head gasket and pay the $300 for a full head overhaul. Ben Franklin was right, a stitch in time really does save nine. So I had the converter replaced about a month ago, with only marginal improvement.

So the truck is still running rough and loud after the converter replacement. When I plug the tailpipe I can hear exhaust leaking somewhere up the line, but I can't pinpoint it. I thought maybe the exhaust gaskets had fried from the converter overheating, so I jacked her up and dropped the exhaust pipe. The gaskets, there are two of them, were brittle and crumbly but still intact, not burned down to the metal core like I thought they would be. I replaced them anyway and again saw some marginal improvement, but not as much as I'd hoped. Still, at two bucks apiece for the gaskets it was a cheap way to check something off the possible cause list. A quick look at the exhaust behind the catalytic converter and a few taps on the very rusty muffler now have me thinking that could be the source of the problem, because I know everything from the converter to the manifold is solid as a rock and there's still an exhaust leak somewhere, though not quite as bad as it was before.

But that's not the really good news. The really good news is that while I was tightening the nuts on the exhaust pipe flange, I saw clear signs of an oil leak. Behind the oil pan. Right about where the rear seal is. So I got that going for me, which is nice.

6 thoughts on “Truck Time with Twayn: Episode 17 – The Exhaust Gaskets”

    1. This. But I want to see some sausage-making pictures too. Can't Mrs. Twayn or some neighbor kid be enlisted to take a few pics of assorted parts lying on the garage floor and of your grease-stained hands?

  1. When you say it's running rough, do you mean it's running unevenly or feels like it's dogging when you give it gas? I'd double check your invoice to make sure the rear oxygen sensor was replaced.

    I took our Subaru in for an oil change last week and heard the two words no Subie owner wants to hear - "missing coolant." There's no crack in the reservoir, so that coolant is finding a different way out of the system. I fear we're in for head gaskets in the not too distant future, which unfortunately means pulling the engine since it's a flat-four. I'm hoping the lifetime warranty we purchased will cover it.

    1. I've been looking at used Subarus since the girls are going to need a car this summer if they're both going to work -- and they are both going to work. I've noticed in some of the Subaru forums that the head gaskets on Outbacks tend to go around the 100-150 thousand mile mark, and the first symptom is the coolant loss with no apparent leak that you mention.

      1. Yeah, the head gaskets are the one weak point Subarus seem to have (well, that and gas mileage, but you sign up for that with AWD). We're only at 65,000, so I'm hoping that there's some other explanation, or that this was a freak thing. We bought the car new, and this is the first time it's needed any coolant.

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