Some Tips

[LandMan]

I am looking at a 98 Sub with the 6.5, could yall give me some tips on what hidden problems the layman may not notice. It has about 150000 miles on it and seems solid.

[DennisG01]

Aside from checking fluids and the normal such, here's a couple of things:

A quick check for general health of the engine is to check for blow-by - good/bad compression. An easy way to do this is to open the oil fill while the engine is running. You should see very, very little, if any smoke. Now, put your hand over the hole for a few seconds. Then look at your palm. There will be a ring of black (where your hand contacted the outer rim of the hole), but the middle of your palm should be clean.

For the turbo system - drive it and mash the throttle. You should only see a quick puff of grey/black smoke. It should clear right up and then you really shouldn't see anything - maybe just a very slight haze.

I assume it's an automatic. While you're driving it, accelerate lightly to about 60mph and count the number of shifts. It's a four speed, so you would expect to count 3 shifts (1-2, 2-3 & 3-4). However, if you take notice, you will actually feel (and see on the tach) a 5th shift. This is the torque converter (TC) locking up and it should happen at around 50 mph. Now, slow down and manually shift into 3rd gear and repeat the procedure. This time as you get to around 60mph, push the throttle all the way down. The TC should stay locked (meaning you won't feel the TC "shift"). You can do this in 4th gear, but you'll need to go a little faster.

Another easy thing for the TC is while it's locked (say 4th gear and highway speeds), lightly touch the brake pedal. You should see the RPM's drop to close to idle speed - this is the TC unlocking.

[Hubert]

Hello is this your first diesel? What's your background with vehicles and your intended usage? What is the history of vehicle owner and maintenance! Most any vehicle will run for 100-150K miles without anything more than oil changes and tires. But a common misconception is a diesel will last forever. They will but only if maintenance is done and a few fairly expensive parts will wear out before the engine. A gasser with same milage may be more economical to operate depending on what has been done.

READ a few pages of the forum and search the following terms PMD (pump mounted driver), FSD (fuel solenoid drive same as PMD), injection pump, injectors, and timing chain. Make sure you know what you are getting into with a diesel with 100K+ miles. Don't get fooled into paying top dollar because its a diesel and they can go longer than a gasser.

Good news almost any problem that has ever come up with these vehicles has already been posted and fixed including this question by the way.

[rustyk]

Good advice, above. But keep in mind any vehicle for sale has been declared "Not Perfect" (or why else would it be for sale?)

I've bought MANY used vehicles, and discovered in most the owner had become frustrated with what was eventually discovered to be a minor issue - but diagnosing and repairing that "minor issue" can be a headache.

My advice would be to view any prospective buy with "jaundiced eye"; what could go wrong, might. Money/time spent in checking it out THOROUGHLY is a sensible investment (I can't count the time a seller was dumfounded because I performed compression and leakage tests on the engine, and took a sample of the motor oil...) My Pappy said, "If yer buying a dog, you don't want to be paying for the fleas..."