Automakers are building vehicles today that are more reliable than ever. They’re also more complex than they were a decade ago. That said, the economy has slipped which means more people are keeping their cars longer. No matter how durable the parts under your hood are, they will fail eventually.
My goal with this column is to help you diagnose car problems as they occur. You may not be able to rebuild your engine or replace your transmission, but you’ll have a head start on knowing what the issues are. In today’s segment, we’re going to help a reader understand why his car is failing his state’s smog test. We’ll also address the “slime” that a reader reports seeing on his radiator cap.
Question: I purchased a 2001 Daewoo Leganza (bought it new) and the engine has a little over 100,000 miles. I live in California, so I need to get my car smog tested. I took it in a couple of weeks ago to have it tested and it failed. I drove it to a local repair garage to have the problem sorted out. The guy at the shop wants to put a new engine in because he says it will fix everything. The problem is, it’s really expensive.
From the beginning, I’ve kept my car in great condition. I get tune-ups, I’ve changed the spark plugs, and I have the oil changed every 5,000 miles. Do I really need to pay for a new engine? Is that the only way I’ll pass the smog test?
Answer: It’s not clear to me whether you need a new engine. However, there are plenty of things you can check if you haven’t already done so. Look at the compression for your car’s cylinders. Also, have your mechanic check the oxygen sensor. Sometimes, replacing it will solve the problem. Finally, check the fault codes on your vehicle’s computer. They may provide hints regarding why you’re not passing the smog check.
Question: I own a 2003 Volkswagen Passat and the mileage is at 84,000. Last week, I had the oil changed. While it was in the shop, the auto technician showed me my radiator cap. It had this light brown slime on it. The guy at the shop said the inside of my Passat’s cooling system is probably like that (slimey). He told me to drive back to the dealer to have their mechanics run a test. I haven’t done it yet, but can you tell me what the slime is from? Does it mean I have to replace the cooling system?
Answer: I’d be willing to bet that the light brown “slime” you’re seeing is due to old coolant sitting in the system. You should change it every couple of years. The good news is that you can probably just flush out your radiator and put a new batch of coolant into it.
That’s the first “slime” problem I’ve addressed. But, both questions make great additions to this regular column. If you’ve been reading since the beginning, you’ll know that we’ve already covered a variety of car parts and issues involving different components. Some of you have let me know that the information is extremely helpful. Next time, we’ll have a new crop of car mysteries to solve. Until then, drive safely.