Vehicles that are hard to figure

The first Dodge Grand Caravan came in a couple of weeks ago because the transmission had screwball shift patterns. It wasn’t slipping, but it didn’t shift gears consistently. Not only were some shifts erratic and delayed, but there was no recognizable pattern – sometimes the transmission would shift just fine.

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Because we’re doing other things this time of year in my automotive department, this customer took the van to a transmission shop. They had advised him to have a new radiator installed, because there was a bit of water mixed with the transmission fluid (not much), but that shop wasn’t interested in doing work on the transmission nor were they interested in replacing the radiator. Go figure. So the owner asked if we’d have a look at it, and I agreed, because everything my guys can learn on a real world problem will benefit them in the field.

Well, to begin with, there was a bit of water in the fluid, but the cooler is external to the radiator on this Dodge. So where did the water come from? We’ve had quite a lot of rain in these parts lately, and I found myself wondering if he or his wife had forded some high water and maybe the water came in through the transmission vent. How else could it have happened short of somebody pouring water in there through the dipstick tube? One way or another, we yanked a P0700 code and made the decision to do a full fluid exchange followed by a filter change so as to clean the pan and then replace the shift solenoid assembly

There was a little glitter in the pan and some fine fuzz on the magnet, but that’s not so unusual on a transmission with 150K on the clock. After replacing the transmission fluid, the filter, and the shift solenoid, the code was gone and the transmission shifted well. On our final scan, we got a code telling us that the upstream O2 sensor heater was burned out. That was a code we didn’t get the first time around,

but we measured the heater on that sensor and found it wide open. With the customer’s green light, we popped an upstream sensor in that 18mm hole and everything seems fine now. I did inform them of the stuff in the pan and warned that the transmission could fail in the coming months in spite of everything we did. It was a chance they were willing to take.

It’ll be interesting if it comes back with water in the transmission again. How it got there in the first place remains a mystery. We’ll see.

We had replaced the engine in this same van a couple of years ago because it developed a nasty rattling noise I’d swear was lifters (although it was exceptionally loud), even though it had 70 psi of oil pressure when it was at operating temp. Rather than digging for that problem, we simply replaced the engine with another one from LKQ. Seems like this particular van always has a hard to figure problem.

All Over the Road Then there was the high mileage Ford 15 passenger van that was driven by several different people on our other campus, and most of

them suddenly started complaining that it was “all over the road.” During a regular vehicle inspection, we had replaced the ball joints a couple of years earlier, not because of the way it was driving, but because the upper grease boots were in tatters and the joints were dry and squeaky.

Further, I had replaced the steering box with a Ford reman unit about a year after that because it was worn out and couldn’t be adjusted any further. Another year went by. Nobody had complained much about the van after that until the powers-that-be decided to have couple of new tires installed on the rear and move the worn but still good tires to the front. Most steering and suspension gurus know how wrong it is to do that on a van like this one, but the bean counters don’t have that perspective.

The new tires they had installed on the rear seemed softer than they should have been, even with the recommended 80 psi of air pressure (the front tires call for 50 psi on this one). Those new tires caused the van to feel prone to yaw on turns, but after we checked the tire pressures and alignment (both were dead on the money) and moved the older, firmer tires to the rear, the guy who drove it back to the other campus said it drove like a different vehicle.

Then the powers-that-be decided that the two older tires should be replaced with another pair of soft tires like the ones that were now on the front, and the “all over the road” concern returned in spades. The

tire store was consulted and really couldn’t say what the problem might be other than to say, “something doesn’t seem quite right about the steering box.” Other than that somewhat ethereal observation, they offered no insight as to what might be done to satisfy the van’s gaggle of different drivers, some of which were in full whine mode.

The steering box was still under its one-year warranty (just barely), and the Ford dealer sent me another one on request, which we installed. We checked the alignment again and increased the caster angle in hopes of improving things. At this point I drove that van for many miles on the road and in town and couldn’t really see a problem with it, but let’s be real here – a 15-passenger van just doesn’t drive like a Crown Victoria or a Monte Carlo.

Finally, after so many complaints from some (not all) of the drivers, the decision was made to get rid of that particular van. Oh, well. To this day I don’t understand all I know about that situation.

The 2002 Crown Vickie The college also owns a 2002 Crown Vickie that came in with the complaint that “it’s all over the road.” This same car had come in with complaints of a popping noise and brake squeak just a couple of weeks earlier, which we had repaired, but we hadn’t noticed any “all

over the road” problem. That being said, as I drove the car this time around, I could tell the front end was kind of tight; the steering almost wouldn’t return to center unless you helped it, and while it wasn’t actually “all over the road,” I figured that mildly stiff steering was what they must have been talking about.

On the lift with the front wheels clear of the ground I could tell as I turned the steering wheel that the front end was indeed quite a bit stiffer than normal, and when we popped the tie rod ends loose from the spindles, both of the spindles were fairly hard to move by hand. This car has a lot of miles on it (nearly 300,000) and it still runs good, but when that much rubber has met the road, the steering system obviously needs to be monitored with all diligence. We had replaced the idler arm about two years earlier. A pricey set of ball joints and sway bar links and a careful alignment straightened this one out. At least now we can grease the joints, which we couldn’t do before.

Another 2005 Caravan
Caravan No. 2 had a strange rattling noise that was coming from the belt area. It seemed to be tied to changes in engine speed. Things would seem normal until the engine was mildly accelerated in the service bay, and then the noise would come and go abruptly with changes in engine speed. Further, it always exhibited the same pattern.

My initial thought, having heard similar noises before, was to condemn that overrunning generator pulley. This vehicle is equipped with such a pulley, and those things love to make alarming noises when their innards become compromised. These pulleys have a couple of spiral clutch-type springs inside that pulley, a relatively

weak one just inside the pulley drum and a heavier one wrapped around the outer surface of the pulley hub, and it’s these springs that make the pulley special.

The natural tendency of springs to tighten up when torqued in one direction and loosen in the opposite direction gives the generator pulley the ability to grab or release the alternator rotor shaft when load and speed demands are met. One way or another, when those pulleys fail, they make weird noises.

The pulley runs about $70, and I was certain enough that the pulley was the problem that I ordered one and the parts store had it in my hand in about 15 minutes. We yanked the alternator, popped the round cover off the pulley that conceals the 17mm Allen socket, used my dandy homemade tool (a bolt heat brazed into an old socket) to remove the pulley. But when I felt the relationship between the pulley and its hub (you can usually tell when one is bad, and this one didn’t seem to be faulty), it felt just like the new one and I wasn’t about to toss a $70 part at this problem without taking a closer look.

My entire inspection had taken place with the van flat on the ground

with limited access to the problem area, and so I swung the lift arms under it and got it in the air to remove the right front tire and splash shield, where I found the problem. That dandy little water pump flange is Y shaped (three arms with a bolt hole in each arm). The pulley bolts to this Y shaped flange, and there’s a matching hole in the pulley itself so that when you unbolt the pulley, you turn it 120 degrees so that it drops back between the flange and the pump, which grants egress to the bolts.

One of the ears was broken off this flange and that was the source of our noise. I don’t know how common this is, but I hadn’t personally seen it before. t took less than an hour to toss a water pump on it, reinstall the alternator and a new serpentine belt, and get everything bled out.

Conclusion

Just about every busy wrench twister has stumbled into situations that made us better, stronger, faster, and more capable. And it always helps to tell another mechanic about your experience – it seems to deepen our understanding when we do that. I spoke to another veteran tech yesterday who fixed an overheating Pontiac that had been everywhere for an overheating problem and he figured it out when the driver pulled the car up to where he was standing and he saw by the movement of dust on the ground that the fan was pushing air into the radiator instead of pulling it through.

The easy ones are the ones we sometimes forget. A 2002 Trailblazer no-start parked near my shop took about five minutes to troubleshoot with the scan tool (no rpm signal) and five minutes to fix – the crank sensor had died. The customer, who had been beat up and overcharged by other shops and mechanics thought I was some kind of Superman, but nobody can figure out every problem that fast. And the next problem she has might smack us around before we finally win the fight. Some jobs are just harder to figure than others, but that’s what makes things interesting.

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