My '97 5.9 1500 has had a coolant smell for a long time. The water pump and timing chain were both replaced about 6 years ago, and there has been a smell of coolant for about 10 years. Very tough to tell where the small leak is (never a drip on the garage floor) but I think it's the timing cover gasket. Since the water pump is 6 years old, I think I'll replace it while I'm there. Any particular brand of pump I should look for? Any tips or tricks?

Also, it seems every 2 years I need to replace spark plug wires. I route the wires very carefully (according to the TSB, even going above and beyond). But when I do a WOT acceleration run, it often builds rpm to around 3500 and then begins to misfire. I have a code reader and it's often a multi-cylinder misfire. I replace the wires, and it's all good. That seems t happen approximately every 2 years. But the problem is back, yet again. If I drive nicely, the CEL stays off and the truck runs mint. Is there a consensus on spark plug wires that offer tremendous shielding?

 

I use 8MM Taylor Spiro-core spark cut-to-fit plug wires and haven't encountered any issues with them. I removed the factory spark plug heat shields, too. This may be causing some of your issues with the plug wires, if they are still installed, as they get pretty hot around the plug boots. I also use Autolite platinum plugs and have had great success with them. Be sure to lightly coat the insides of the new spark plug boots with dielectric grease.

As for the coolant smell, do you smell it while inside the truck or under the hood? If you smell coolant inside the truck, you likely have a heater core with a very slow leak. If its under the hood, that could be in several places.

 

There might be a dye you can put in the antifreeze and look for leak with black light. Heater core?

What plug wires are you using now? Spark plugs?

 

I still have the OEM heat shields. Is there any drawbacks to eliminating them? I thought I heard something about its better to leave them in place?

I use the Champion plugs, and they hold up very well. I always put dielectric grease on both ends of the plug wires when I replace them.

The coolant smell is definaitely not the heater core. The smell is most pronounced just above the drivers side wheel, when the engine is 25%-75% warmed up. The coolant leaks onto a warm part of the engine and evaporates off as quickly as it leaks out, so that's what makes tracking the source of the leak so difficult. There was a time a couple years ago that I was able to locate a moisture spot around one of the gaskets (timing cover or water pump- it's so long ago I forget which it was now)

I'm using 7mm Champion wires right now, and my last set was 7mm Accel. Before that, was also Champions

 

Leaving the spark plug heat shields in-place makes for a great place for debris to gather around the spark plug and heat to invade the boot. There is no drawback to removing them. Lots of folks have done that on this forum with no ill effects. Just grab them with some decent pliers and wobble them out.

As for the coolant leak, check the freeze plug in the back of the head (with a mirror). Also, check the heater hoses closely in addition to the pipe that comes off the water pump. Also, check the bypass hose coming off the water pump.

 

Yeah, the bypass hose seems a likely culprit. It is cleverly concealed underneath the bracket for the a/c compressor, and alt.... it can leak right onto the nice flat surface on the top of the timing cover, and pool there...... You may never see it hit the ground.

 

I think it's either the water pump itself, or the pump gasket. It appears to be dripping on the harmonic balancer, and being flung onto the nearby lower rad hose. It was smelling pretty strong when I was uptown, but by the time I got home I guess it warmed up to normal operating temp and then all I can see is a damp harmonic balance and some drops on the lower hose. Guess I'll take it apart and check things out...

How about spark plug wires? What's the best set to eliminate misfires?

 

I have no miss-fire issues with the pre-cut 8MM Taylor Spiro-core spark plug wire set I use. I also changed the cap and rotor when I did the replacement job.

 

Your thoughts-

Brand New Gates pump for $122 or a remanufactured Cardone (OEM Mopar apparently?) for $73.

Both have a lime time warranty. I'm in Canada, so those are prices from my local Piston Ring and Napa stores, respectively. Which would you choose?

And 51,000 miles ago I replaced the original timing chain and sprockets with a cheap aftermarket set (I didn't know At the time that I should spring for the high-end double roller). Would it be wise to replace the timing chain again too? I only put on about 15,000 miles per year, so it was in 2010 that I did the timing chain. Would it easily last another 50,000 miles?

 

The reman pumps are fine. It will last a good long time. Lifetime warranty means you will never pay for another one, even if you end up having to replace it again.

Probably wouldn't hurt to pull the timing cover, and see what you think of the chain. If it looks too sloppy for your tastes, go ahead and replace it. Having one on hand when you do the job would avoid the trip to go get one, and if you decide you don't need it, you can always return it.