Buying Used? Smoke & Rust — How Much Is Too Much?

The short answer is that no smoke is acceptable. Expecting no rust anywhere on a vehicle that’s made of metal is pretty unrealistic, especially up north with winter and salty roads. Depending on how much and where, some rust can be OK, as long as… Well, we’ll get to that shortly.

For confidence when purchasing a used car… inspect, inspect, inspect. There’s a visual inspection. An active inspection and the test drive. Even better, have your favorite mechanic give it a look over.

Start with a visual inspection

What does the car look like as you approach it? Does it appear level or does one corner seem to droop? What is the condition of the finish? Are any body panels out of line with those around it? Is there any bubbling paint? Is the trim in good shape?

Rust has disintegrated this shock absorber.

Do a walk-around and look for obvious signs of wear and rust. Rust can eat through body panels. It can also eat up the undercarriage, suspension and corrode metal fuel and brake lines.

If you can see signs that there may have been damage, ask about it. It’s not the end of the world that a car has been in a small wreck. Damage that was professionally repaired also hints at how well the previous owner cared for the vehicle.

A big wreck that bent the frame may never feel or drive right even after completing the other repairs. Carfax and similar services can’t rule out all damage with 100% confidence, because not all damage gets reported to police or insurance.

Check underneath for rust. Check the wheel wells. Open the doors and check the bottom of the doors for obvious rust or a bulging seam. Also, check the floor in the trunk for rust and water damage by lifting up the carpet.

Speaking of water damage, is there a musty smell when you poke your head into the car? That indicates a history of water seepage. Lift up the floor mats and check for water or evidence of it. If the seller had a good detail cleaning done, you might not be able to tell. You can always ask. We hope the seller will be honest.

Is any rust OK?

You’d rather not see any but, at least in Illinois and other northern states, that’s an unrealistic expectation. The question then is: to what extent is there rust and where? If you see a light coating of rust in a few places on the undercarriage, that’s probably OK. If you do buy this vehicle, you’ll want to have that treated to stop the rust and protect it from further corrosion. It’s one of your biggest investments. A little prevention now will make it last longer and help with resale value later. If the entire undercarriage is very rusted with flakes that you can easily dislodge — walk away.

In the same way, some light surface rust on the exposed steering and suspension parts is to be expected. After all, every time the roads are wet or you drive through a puddle, these parts get the worst of it.

Think about it, when was the last time you climbed up under your car to wash and wax them? Probably never — give or take a day. Even a beater for carting projects around, that’s really rusty, is a rust “bomb” just waiting to blow. A worthwhile beater is all about good bones in spite of it’s appearance. So when it comes to rust, a little, light rust, OK. Heavily rusted — leave it.

A final part of the exterior visual is the tires. On your own car, tire wear can tell you something about your steering and suspension. When buying a used car, tires won’t have a story to tell because they are so easy to replace.

The Active inspection

This is where you interact with the vehicle. For example, you can bounce the corners to get an idea of the condition of the suspension. Good shocks or struts should bounce 1 to 1.5 times. When you open and close the doors, does the door drop or sag?

Turn the key on but don’t start the car — is the check engine light on? Any other indicators?

Here’s the part you’ve been waiting for… Smoke.

Start the vehicle — When you turn the key, watch the exhaust for smoke. Smoke, of any kind, is unacceptable. If there’s none, does the engine start right up or does it labor to start? (Suggesting necessary repairs).

What does smoke mean?

· Black smoke tells you there’s a problem with fuel delivery, in this case leaving unburned fuel.

· Blueish smoke tells you the engine is burning oil and indicates big repairs to come.

· White smoke suggests burning antifreeze and also indicates big repair bills to follow.

A billow of smoke followed by nothing still signals a problem but it is less immediate. A constant flow of smoke of any color is bad suggesting major engine repair — Walk away.

Check again for the check engine light too.

Test Drive

Listen and feel — The question to answer at this point is: will the vehicle Run, Go and Stop? Ideally, find a quiet road to you can hear the car you are driving and not everyone else’s. Does the engine run smooth and quiet?

Is there any hesitation when you step on the gas from a stop? Once you are at speed, is there any hesitation or other unexpected feelings when you step on the gas, like trying to pass?

When you make sharp turns, are there any noises? Or are there noises that come and go? These could signal a problem with the suspension, wheel bearings or universal joints.

When you enter or exit a parking area, are there any moans or groans as you cross the raised apron or drive up into a driveway? These noises signal problems with the suspension.

Now that you are moving, what happens when you hit the brakes? Any noise indicates a problem. Do you feel any pulsing in the brake pedal? Do you feel a wobble or shimmy in the steering wheel when you break? Or does the vehicle pull to one side? This indicates problems with the brake pads and brake discs (also known as brake rotors).

Now, find an empty street, get up a little speed and do an emergency stop. Does the vehicle pull or drift to one side? Get out of the car and look at any skid marks. Anti-Lock brakes shouldn’t leave skid marks so that tells you something. If there are skid marks or if only on one side, that tells you there’s a problem with the brakes that needs repair.

If at all possible, take your vehicle to a trusted mechanic for a pre-purchase inspection. It will cost a little something but provides some protection if they can tell you about things you can’t see for yourself. Even the best mechanic can’t tell you if a part or a sensor that shows no wear is going to fail in a month or two.

If you don’t already have a trusted mechanic, stop in to see Xavier and his crew at BenzWorx AutoHaus. They specialize in German and European vehicles but can fix any make or model. Get luxury car service that’s affordable no matter what car you drive. Visit the website at benzworx.com or just give ’em a call at 847–844–0349

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TechWorx Car Care Blog

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TechWorx AutoHaus — BenzWorx had changed its name. Still provides full service auto repair for all makes and models, domestic, pacific and European imports.

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