His Subaru Forester Is Burning the Midnight Oil

Dear Car Talk

Dear Car Talk | Jun 07, 2019

Dear Car Talk:

Can you help me identify what is causing a burning oil smell in my car?

We drive a 2011 Subaru Forester X. The engine is leaking oil, and we think it's dripping down on a sensor, which is causing lights to turn on on the dashboard. How can we fix this? -- Mitch



You can fix it by pulling out your credit card, putting a pleading look on your face and handing the card to your mechanic, Mitch.

In our experience, the most common oil leaks on low-to-moderate mileage Foresters come from the valve cover gaskets. The oil leaks down from there onto the front exhaust pipe, which gets very hot. The instant a drop of oil hits that exhaust pipe, it starts to burn, and produces a very strong smell.

That smell wafts into the nearby fresh air vent at the bottom of your windshield, and from there, right into the passenger compartment and up your nostrils, where it causes you to feel lightheaded and seek out brochures for 2019 Subarus. It doesn't take much oil at all to make a lot of smell. A drop or two will do it.

Replacing the valve cover gaskets is not a big deal. It'll cost you a couple of hundred bucks at most. Unfortunately, the higher your mileage, the greater the chance that it's something much worse: the cylinder head gaskets. To replace those gaskets, you have to remove the engine. That's a job that'll cost you over $1,000. Maybe way over.

So, a test is in order. We start by cleaning the whole area because it's always an oil-soaked mess. Then we insert a fluorescent dye into the oil. After running the car for a few hours, we shine a black light on the areas that we suspect are leaking. That usually tells us exactly where the leak is coming from.

If you're lucky, and you've lived a good, clean life, it'll be a valve gasket or two. I've never seen so much oil leak that it shorted out a sensor. So, if you've got dashboard lights coming on, those may be unrelated to the oil leak.

Start by figuring out what's leaking. Then your mechanic can scan the computer and figure out which sensor needs to be replaced.

Once you have the full picture of what it's going to cost to bring this Forester back up to snuff, you can make an informed decision about whether to fix it or grab those 2019 brochures. Good luck, Mitch.


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