I am an old fellow (77), but not yet senile, I think. Every time I take my 2007 Mercedes Benz ML350 to the dealer, I am amazed by the high maintenance cost. The first time I got an oil change, I was charged for two oil filters, both of which were “fleece” filters. I pointed out what I thought was an error for charging me for two filters, but they told me that my engine has two. This past week I took the car in, and they said one shock absorber was leaking and needed replacing, but both should be replaced at the same time. The cost for replacing two rear shocks was an astronomical $1,200. About half was labor and the other half parts. Why does this cost so much? The car has only about 21,000 miles, and as you can see, my cost per mile (3,000 miles per year) is really high. I hope, as a senior citizen, I am not getting “fleeced.”

No more than other Mercedes owners.

When you buy a “luxury” car, part of the deal is that you’re going to pay luxury prices for maintenance and repair — especially at the dealership. Who else do you think is going to pay for all those guys in white lab coats and the wide-screen TV in the waiting room?

If you had, say, a Ford Explorer, your bill for two shocks would have been $600. But, of course, then you wouldn’t have the prestige of paying twice as much for the Mercedes shocks.

At this point, since you’re no longer under warranty, your best option might be to find an independent mechanic for routine service and repairs. While you still might want to go to the dealer for anything unusual or complicated — since the dealer knows these cars better than anybody — there’s no reason that Dieter and Fritz down at German Auto and Hummel Figurine Emporium can’t do your oil and filter changes, scheduled maintenance, basic repairs, and brakes, tires and shocks. And they’ll do it cheaper than the dealer will.

They’ll still have to buy certain Mercedes parts from a nearby dealer. But they may also have experience with aftermarket parts that they feel are just as good and are a lot cheaper.

If you need help finding a trustworthy mechanic, try checking out our Mechanics Files (www.mechanicsfiles.com). That’s a database of mechanics who have been personally recommended by other readers of the column and listeners to the radio show. Put in your ZIP code and look for a highly recommended shop that specializes in German cars, and see what comes up near where you live.

You might not get free schnitzel in the waiting room like you’re used to at the dealership, but your American Express card won’t be smoking quite so much after you pay your bill.

I have a 2006 GMC Envoy XL with 227,000 miles. After sitting in the garage overnight, when I start it, the oil pressure gauge will drop, and the oil warning lights come on. If I leave it in park and keep the engine revved up, then the oil pressure will go up. Two blocks from the house is a stoplight, and I have to put it in neutral and rev the engine, or the oil pressure drops and warning lights come on. After about 10 minutes of driving, the oil pressure still drops some at stoplights, but not low enough to cause warning lights to come on. Am I damaging the engine by continuing to drive? Why does it have oil pressure after it’s warmed up but not after sitting overnight?

Beats me. Normally, oil pressure is higher when you first start your car, because the oil is cold and more viscous. So why the pressure would start low and then improve as you drive is a mystery.

Yeah, I know, that’s why you wrote to me.

If the reading on your gauge is accurate, then yes, you are damaging the engine by driving it with low oil pressure. So the first thing you need to do is find out if your oil pressure really is low, or if you’re getting an incorrect reading. You do that by taking the gauge out of the equation.

Your mechanic can do that for you. You’ll leave the truck with him overnight. In the morning, he’ll put his own oil gauge on it, and start it up. If his gauge tells him that your oil pressure is exactly what it’s supposed to be, then he’ll know that either your truck’s oil gauge or your oil pressure sending unit is no good.

It’s more likely to be the sending unit. That’s a little sensor that plugs into the side of the engine, reads the pressure and sends that information to the gauge and the idiot lights on the dashboard. A bad sending unit would be the best-case scenario; a sending unit is cheap, and very easy to replace.

So that would be good news for both of us: Good for you, because it means you haven’t been harming your truck all this time, and you’ll have a nice, easy, cheap fix. Good for me, because then you won’t write back again and make me hurt myself by thinking harder. I’ll keep my fingers crossed for us.

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