6.5 turbo diesel blues

Here's what caught my eye... oil pressure. 40 at idle is fine, but take a look at the temp gauge too. my stock 6.5 will almost peg the oil pressure gauge at cold idle. Then near the end when he revs it, the oil pressure doesn't rise much at all.

Its possible you lunched a main or rod bearing, but it sounds more like a valve issue. Mains and rods tend to clunk more than tick. If the smoke is blue, its oil. If its white, its diesel. If its diesel, you're in for injectors most likely unless the timing is way off. If its oil, you're in for at least rings.

But, the good news is that the rest of the truck looks nice, the alternator looks brand new, and even if you have to rebuild you still have a really nice truck.

The stock 6.5 has a couple weak spots. First of all, move the injector computer away from the engine. It can't take the heat and likes to die. Many aftermarket companies sell kits to do this, or you can get creative. There is rumor that the block decks and/or head decks are thin on the civilian models, but I've run two of them senseless and never had a head or block failure, nor a head gasket failure. But if you want to remedy that issue, just get a military block to replace it.

Stock HP ratings were 180-200, but don't let that fool you. They make more than enough torque for towing. If you want to up the ante a bit, intake and exhaust FIRST. That should give you a nice boost, but if it isn't enough go with a mild chip and an EGT gauge. With diesels you always improve airflow first, then add fuel. If you do it the other way around, your EGTs will spike and damage the turbo. Keep EGTs 1200 or less and all will be well.

What I would do first is use the screwdriver-to-the-ear trick to narrow down where the noise is. If its up top, pull the valve covers and diagnose what's wrong and fix it. Have spare valve cover gaskets handy since most of them came with cork/rubber gaskets that will leak if you try to reuse them. Then check the injector timing to see if the smoke is from retarded injection. Maybe pull the injectors and have them tested and rebuilt if necessary to get rid of that smoke... unless that's oil smoke in which case you'll need a whole rebuild - the extent of which can be determined between you and your machinist.

I delt with one of these things for a short time and learned a little. First, they have alot of weak points, are expensive to work on, and are short on durability. They are notoriously hard to start if you have a bad set of glow plugs or something is not perfect. Mine never started quickly unless warm. Diesels can make nasty sounds with bad injectors so if you can have them tested cheaply it might be worth a shot. This could also explain the horrid amout of smoke. As mentioned computers can fail and cause all kinds of issues. The comment about checking timing is only valid if this is a 93 back since later are electronic. If the earlier there are timing marks on the pump where it goes in the block. You can see the marks with the cover off looking behind the water neck with a flashlight. The cracked flywheel is also worth looking. When I boat anchored my engine I found a cracked flywheel.

The best thing you can do is go to a 6.5T site and talk to the guys that know and like these engines. Most anyone else is gonna tell you they are junk....I would tend to lean to this side.

When mine broke a pulley and overheated, I yanked it out and replaced it with a cummins. Never looked back.

I agree that 6.5s aren't the greatest diesel, but they are far better than 90% of the gas engines out there. I'd rather have a crappy diesel than a great gas engine. I would rather spend the money to properly address the weaknesses of a diesel than to spend $500 dropping a gas engine in it. Anyone who has used a diesel to tow heavy loads would probably agree. There is just no comparison when you're towing 10k, your foot is to the floor and you top a mountain at 65 mph with the coolant at 180 degrees while getting 16 mpg.

I had my 6.5 (98 1-ton) pulling my 10k travel trailer from Phoenix to Flagstaff. Phoenix is at 1000 ft elevation. Flagstaff is at 7000. That's 6000 ft up and down in 150 miles. This was in July, and the temperature in Phoenix was 115 when we started. The whole trip I could choose whatever speed I wanted, the temp never went over 200, and the A/C was keeping us nice and cool. The bonus was we made that particular leg at 12 mpg. I don't mention this to sensationalize the topic, but when it comes to towing, diesel definitely gets the nod.

... well, I can think of SOME diesels that I don't want 80's BMW diesels come to mind

Good info guys. I am eager to turn wrenches on it. I'm admittedly not a diesel fanatic but since this thing will be the new tow rig, I may change my mind. I like the fact that I darn near stole this truck.

It's a '93 1 ton. Mechanical IP. Interior is nearly perfect. I'll be hotrodding a 6.5TD if a rebuild is needed-(maybe soon ). If I can get lucky and 'make the bad things go away' I'll drive it until I gain the knowledge (and thick skin) to have a 6.5 that will get out it's own smoke. Seems all problems with the 6.5TD is cooling/owner related. At least that's my take as I'm just starting to wrap my head around the whole 6.5TD scene. (that's a lot of wrapping)

The white smoke is pure unburnt diesel. And 40 psi while cold may not be what it needs to be. I can't help but think it's an injector stuck open. Yet it does have a metallic valvetrain sound.

I will be sure to post updates.