If the pressure test is inconclusive, there are other tests he can do. He can carefully monitor your coolant for a very slow leak. Or he can do a dye test that looks for combustion gases in the coolant.
I’d say a bad head gasket is the most likely cause of your SOBS, Art. But if your mechanic really investigates it, and concludes that the head gasket and cylinder head are fine, then you go on to weirder explanations – like the brakes.
Now, I’m sure you’re wondering, “How the heck can my brakes send voluminous plumes of white smoke out my tailpipe?” I’m wondering that myself.
Actually, what we’ve seen happen in rare instances is that the brake master cylinder can leak, and brake fluid can drip into the power-brake booster. The power-brake booster is vacuum-operated. The vacuum comes from a hose that’s connected to the engine’s intake manifold. So if you get enough brake fluid in the power-brake booster, some of it can get sucked up into the manifold and sent into the cylinders.
Maybe you go over a bump, or make a turn or stop, and a couple of thimblefuls of the fluid get sucked into that vacuum hose and delivered to the cylinders. That would create plumes of white smoke, diminished performance and possibly even a desperate letter to some idiot car columnist.
Your mechanic can check for that by pulling the master cylinder away from the power-brake booster and seeing if it’s wet back there. Of course, he won’t be able to do this while he’s eating lunch – unless he’s got three hands.
If there’s moisture back there, your master cylinder is leaking. And for a few hundred bucks, you could get a new master cylinder and be back in business. But unfortunately, it’s more likely to be the head gasket that’s starting to fail. And when you find out what that costs to fix, you might decide to just order personalized “J-BOND” license plates and embrace the smoke screen for a while. Best of luck to you, Art.
Is engine noise in brand-new car normal?
Dear Car Talk:
I have a 2016 Ford Escape 1.6-liter EcoBoost. When started (with the engine cold), I hear a noise coming from the back center of the engine near the firewall that lasts for 15 to 20 seconds. It sounds like a fan belt or an alternator bearing noise, but the dealer says it isn't. The dealer thinks it could be the EcoBoost. The car has only 4,700 miles on it. Any ideas would be helpful. – Mary Lou
RAY: "EcoBoost" is the name of the engine family, Mary Lou – it's not a specific part. It's a collection of technologies (like turbo-charging and gasoline direct injection) that Ford calls "EcoBoost" for advertising purposes.
So if your dealer thinks it’s “your EcoBoost,” he thinks it’s “your engine.”
It’s hard for me to know what it is without actually hearing it and trying to pinpoint it. It could be lifters or a timing-chain tensioner that is slow to get full oil pressure. It could be that there’s a space where the exhaust manifold meets the exhaust pipe that quickly heats up and expands then quiets down. Or it could be something else entirely.
My first suggestion is to leave the car at the dealership overnight. Then, in the morning, go back and have the service manager and a mechanic listen to it when you start it up. They may be guessing because they haven’t heard the noise and had a chance to pinpoint its location when the engine is really cold.
If they hear the noise and brush it off by saying, “They all do that,” then ask the dealer to go out to the lot with you and start a few other brand-new Escapes with the 1.6-liter engine.
If none of the other Escapes makes the noise, then they have to look harder and figure out what’s wrong with yours and fix it. Good luck, Mary Lou.