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Diagnosing and repairing high-mileage vehicles

Tuesday, August 1, 2017 - 06:00
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Those of us who have been in this industry a long time can remember when a vehicle was pretty much used up at the 100k mark. Odometers “rolled over” after 99,999. I read somewhere that in the 1930s, most engines needed rebuilding every 10-20K miles. Technology has certainly improved, and there are more than a few brands out there that can rack up some stratospheric odometer numbers with very few debilitating problems along the way.

When I worked at the dealer, we saw more than a few Ford pickups and Jeep Cherokees with 300-400K miles. The folks with Jeep Cherokees would keep the one they had driven hundreds of thousands of miles and buy another one. A few years back, my department was given a 1997 Pontiac Grand Prix with 250k on the clock and it still runs like a new car, even though the interior trim has aged to the point of coming apart in places.

This is one of those stealth problems — one of my guys had replaced the radiator in this high mileage Ranger, and since the lower radiator hose clamp had seemed okay, he re-used it. What he couldn’t see was that this clamp wasn’t quite long enough — the screw was only holding a couple of slots, and they gave way one day about six weeks after the radiator was replaced and dumped the coolant.

Some of the customers’ vehicles we work on in my department are low-mileage cars only a couple of years old, but we spend a fair amount of time on older ones. This time around there are several jobs to discuss; the most recent one we did yesterday. It was a high-mileage 2010 Ford Edge that had developed a serious transmission cooler leak after hitting a dog, and she had driven it until it was six quarts low on fluid before realizing that there was some serious dripping going on. As a side note, while it was on the lift, the lift itself breached a hydraulic hose and started leaking, and we had to fix that too – my contention is that that the transmission leak on the Edge was contagious. That one got a transmission cooler and the six quarts of replacement juice and the lift got $200 worth of new hydraulic hoses. Two crises dealt with in tandem.

Another recent one was a 2004 Trailblazer that rolled in with really high miles, an engine skip and a $450 estimate another shop had given her to fix that skip. They had proposed those $13 apiece Iridium spark plugs and a whole set of new coils. Well, this gal is a single mother and rejected that estimate out of hand. We pulled the codes, found a misfire on the No. 1 hole, did a compression test for good measure, then put a set of platinum plugs in there and a single coil.  For grins, we also polished the headlights, which had taken on the color and cloudy opacity that might be compared to dirty lemon juice. And yeah, we don’t charge labor, but why does a vehicle that old need the most expensive plugs and a whole set of coils? There is such a thing as pricing yourself out of a repair.

The Avalanche

The Avalanche

A lady called me one week while I was off during a break and asked if I’d have a look at a 2003 Mazda B3000 she had sitting on the curb in front of her house. The story on that one was that it was her son’s truck and that it had failed to start one night in a parking lot and they had tried to jump it off with no results. Figuring it was a bad starter, they simply parked it (strange, I know, but that’s what happened). It had been sitting there for three months when I opened the hood, noticed that the battery had been removed, connected my 30-lb. jumper cables, and fired it up. Faux jumper cable connections on crummy battery cables can de-rail a DIY diagnosis of a no-crank in short order. The B3000 ran like brand new and even had cold air, so she washed it and got it ready for a quick sale. A couple of weeks later it failed to start at the car wash, but that turned out to be a tripped inertia switch – somebody must have slammed the door or kicked it or something. But during the three months the Mazda was down, she had sold the boy her 2004 Chevy Avalanche and had bought herself a newer truck.

Now her son reported that the Avalanche, which boasted 268,587 miles, was leaking power steering fluid, and she wanted to know if we could check that out. I agreed, and when the truck arrived, we discovered that it had a dreadful engine oil leak that made the power steering leak look like a minor drip. It was odd that he was more concerned with having to add a half a pint of power steering fluid once a week than he was that the engine was bleeding oil to the point of what could be an early death. When I asked him how much engine oil he was having to add, it turned out to be a quart every two or three days. Yet the first thing on his mind was the power steering leak, probably because it’d whine and get his attention and he was tired of that. Squeaky wheel gets the grease, I suppose.

This cover provides insight into the source of a leak. When we popped it out of there and found oil in the bell housing, it was a no-brainer that the rear main was the biggest leak.

Well, we went after the oil leak first – it was dripping off the bell housing, but since that’s the lowest place, the leak might be coming from the pan gasket, the oil filter adapter or the intake. The bell housing was dry on the outside leading up to the intake, and it didn’t look like the oil pan was leaking (which these love to do). We looked closely at the oil filter housing before popping the small round cover off the underside of the bell housing, and through that hole, we found engine oil puddled in there, pointing to a rear main seal. We would attack that first, proposing the rear main, a torque converter seal and an oil pan gasket just for grins, since GM was kind enough to put a crossmember under the oil pan and make that part of it an easy fix.

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