Preventive radiator hose replacement is a thing of the past

Dear Car Talk:

I bought a Kia Spectra EX new in 2006, and it’s been a highly reliable small sedan. I’ve always driven the car carefully for its 70,000 miles. A couple of years ago, I took it to the local Kia dealership and had them change all of the fluids and belts in order to keep it running well. Unfortunately, the dealership did not replace the two radiator hoses, saying they seemed fine. But now, at age 12, I’m very concerned that the old hoses could blow out at any time, possibly damaging an overheated engine. How long will hoses last, and can they be accurately predicted by mechanics as “good to go” before failures occur? – Iggy

RAY: It’s an interesting question, Iggy. We used to replace hoses all the time, as preventive maintenance. And we made a pile of money doing it. Ahh, the good old days! Back then, hoses typically would last four, maybe five years, before the rubber would harden up and be susceptible to failure. But something has changed. It may be that with engines running hotter, and everything crammed into smaller engine compartments, manufacturers had to improve the rubber compounds to withstand the extra heat. Whatever they did worked, because we almost never replace hoses anymore.

In fact, recently, a customer with a Honda Accord came in to the shop and asked us to change all of his hoses. Like you, Iggy, he was raised during the Hose Changing Era. So I called our local Honda parts guy, and he said he didn’t even have all the hoses. He said they don’t stock them all anymore, because they rarely fail. The only time they need to be replaced now is when the car is in an accident and a hose gets physically damaged. Rodents may be a bigger threat to hoses these days than heat and time.

So if you were a customer of mine, and I saw no signs of brittle rubber, cracking or impending failure, I’d tell you not to bother changing the hoses, and just plan to check them next time you were in for service. But since we mechanics are also amateur psychologists, if I knew you were going to be up at night, pacing the floor or waking up screaming from a blown-head-gasket nightmare, I’d order the hoses for you and encourage you to spend a couple hundred bucks to buy yourself a little peace of mind, Iggy. You certainly won’t do any harm by changing them.

One or more weak motor mounts could be cause of clunking

Dear Car Talk:

Five years ago, I bought a 2012 Volvo S60 demo with only 4,000 miles on it. It has been a great car and now has just 58,000 miles on it. But over the past few months, the car has developed a loud clunking sound and slight jerking of the car when I go from park to drive, or park to reverse. The issue comes and goes. Of course, when I took it to the dealership, the problem disappeared. – David

RAY: Sounds like a classic case of a bad motor mount, David. What you’re hearing is the engine shifting position when you change gears.

Motor mounts serve three purposes. The first is to hold the engine in place. Obviously, you don’t want it to fall out onto the street while you’re driving. But you also don’t want it to move around inside the engine compartment. There are lots of counter-forces acting on the engine when it sends power to the wheels. And without the mounts, the engine would be doing the Macarena under the hood.

The second purpose of the engine mounts is to damp the engine’s vibrations. So there are rubber bushings in each mount that are there to absorb the vibrations, so you’re not doing the Macarena in the driver’s seat whenever the engine’s running. And the third purpose of the motor mounts is to fail when your mechanic has a college tuition payment coming up for one of his kids.

I believe there are four motor mounts in this car. The most common culprit is the one that goes from the firewall to the top of the cylinder head. If your mount was broken completely, you’d get the clunk every single time. So it’s not gone yet. Though it might be by the time you read this. That actually would be good. Because when it’s completely broken, it’s easy to see the engine moving back and forth when you shift from drive to reverse. It’ll move a lot, and your mechanic will have no trouble diagnosing it then. So ask him to check all of your motor mounts, David. More than one may be weak and getting ready to fail.

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