Drive it forever

Tag : Clutches And Brakes

Q. I have a 1991 Jeep Cherokee with 228,000 miles. It is equipped witha 4-liter straight six.
It ran hot, so I pulled over to cool it down and filled thecoolant. Now, when it's standing still, it will run hot. I put in anew radiator, thermostat, and electric fan - now it has two. Itwill get about 240 degrees at standing still, but not into the redzone. There is no oil in the water. It has not lost any power, itdoesn't leak oil or water, and I've never had to add oil betweenoil changes. What's causing this problem?
A. Replace the water pump. Sounds like the pump impeller is corrodedaway.
Q. I recently changed the spark plugs and wires in my 1998 Mazda B4000pickup, and now it wants to spit and sputter. I checked the gaptwice before installing them. What could be causing the sputtering?
A. Dollars to doughnuts, you've crossed two of the spark-plug wires.
Q. I recently wrote to you about a problem I was having with my engineafter changing the spark-plug wires.
You were right. I did have two wires crossed, but now I've foundthat the catalytic converter was plugged up as well. And I don'tunderstand what one has to do with the other.
A. I'll bet another dozen doughnuts that the misfire from the crossedplug wires made the catalytic converter fail.
A misfiring cylinder dumps its entire charge of unburned fuel/airmixture into the exhaust. The converter burns this off, which iswhat it is supposed to do, but it's not designed to burn the entireamount of fuel from a misfiring cylinder.
The heat generated by the extra fuel can turn the converter'sprecious-metal catalyst into molten slag in less than a minute.You'll need to replace the converter.
Q. We have a 2006 Chevrolet 5500 Kodiak diesel bus that has thrown aserpentine belt after only 15,000 miles. The dealer says that thisis normal for these units, and to replace it every 10,000 miles orso.
I noticed that all the pulleys are six-groove except the A/Cpulley, which is an eight-groove. The belt is a six-groove. Thedealer tells me that's just the way they are.
Is it reasonable to replace the A.C. clutch pulley? Or do we justlive with it?
A. I can't say if 15,000 miles is normal, but what did the old beltlook like? Was it merely thrown, or was it actually worn out?
A six-groove belt should be fine riding on an eight-groove pulley,which I'm sure was done solely because the A.C. compressor alreadycame from the supplier with an eight-groove pulley.
I'd take a close look at the alignment of the pulleys. It'scritical that they all be in the same plane, and also that all bepointed in exactly the same direction as the crankshaft. Theremight be a misalignment, which could have caused premature wear orhave thrown the belt off.
Needless to say, it's also important that the belt tension bechecked regularly.
Q. I have a 1996 Nissan pickup. The ABS lights in the dash came on,and now I have very little brake pressure.
I've looked over the brake lines and the fittings, and see noleaks. I've also added fluid to the almost-empty reservoir, andstill no pressure. Is there a solution to this problem?
A. You let the level of brake fluid in the reservoir get far too low.When you applied the brakes hard enough, the master cylinder suckedin an air bubble when you released the brake pedal.
You've refilled the reservoir, but the air is still in there.
You'll need to bleed the brakes to remove the air, and I'd flushthe system at the same time.