Not to be a PITA, but that's how all this inaccurate info gets out on the net and how young 'uns get thinking they can pull 400-500 hp out of a 6.5 with an air filter, an exhaust and a "tune"......

You're looking at 250 hp if you put a lot of work into it. 300 hp is a difficult mark to hit even with a lot of cash. 400 is right out there and you're getting into a truck that can't be daily driven. 500 hp is a rare group of 1-2 trucks worldwide. More than 500 are unrealistic claims and "pie in the sky "and not much more. There's only 1 truck in that range that I would half believe is true....



(next part not directed at anyone specific)




The TD 6.5 is a poor design right out of the gate. GM rushed stanadyne into the electronic diesel injection market prior to when stanadyne felt they were ready. GM felt the need to compete (ie: "out do") with the Dodge/Cummins and Ford/International and wanted to be first to market in a couple areas. Chuck a turbo and half breed electronic injection on a 10-ish year old IDI and see what happens.

Looky looky! We gots electronic diesel injection first! We the best! Heartbeat! Like a Rock! Buy our stuff!

Surprise surprise; rampant failures of all types and description followed.

Shot themselves right in the foot.

Then came the endless recalls, "secret" factory replacement policies and finally a "very quietly announced" extended warranty program. Didn't matter, damage done, reputation ruined.

PMD issues, all kinds of electronic failures, failing rotary pumps, wastegate issues (mostly due to the poor solenoid design), cracking main webs, core shifted blocks, severe overheating, tooling clipped cylinder walls, etc, etc, etc.......bad ideas and poorly executed. Maintenance, even religious maintenance, can't mitigate those issues.

That's not just my "opinion", it's been proven out over and over. Don't believe it? Google......

It's not a matter of IF a 6.5 will fail but WHEN. Age and mileage only make it more likely.

High mileage is not an indicator of reliability either.

My truck has 425,000 on it.

But it's had 3 engines (including original), a couple PMD's, two IP, etc, etc, etc.....

Bad design from the get go. That's why GM abandoned the design. Unreliable and incapable of keeping up with the other OE's. And it's not like GM didn't throw a fair bit of engineering at it trying to fix the issues either. Just look at the cooling gymnastics they went through to get it to the point where it was merely "acceptable" in 2000 to keep up with the overheating issues....couple different pump revisions, bypass, crossovers, single or dual starts, several different clutch fans and at least 3 fans redesigns. That dog never did hunt......

Now that I've got an optimizer in there, I'm hoping the block and head problems are at least handled. A Heath PMD will hopefully take care of the PMD issues, although I've always got a spare in the glove box. Spare IP sitting on the shelf in the garage.

I like my truck, but I don't turn my back on it, not even for a second.....I know what it is, and won't ever forget it; a problem waiting to happen and stick it's fingers deep into my wallet again and again.

If the OP intendeds to get a 6.5 truck, you have to be mechanically inclined and able to accept "down time".

Not only because it IS going to break, but because no one knows how to work on these forgotten "half breed" diesels. It's not just that they don't remember, they never really knew...

The price of admission with a GM 6.5 is low because of it's poor reputation (and it earned that rep). They are a good buy in that respect.

However, you pay out on the back end in both time an labor.

Don't get me wrong, I like my old truck but here's the advice I'd offer anyone considering a 6.5:

If it's in decent shape and running; buy it, drive it while it runs, don't expect a lot out of it and get rid of it when it starts costing you 500 bucks at a sitting....

 

I have to agree with No it's not a good engine.

 

Yup, been floating around for a while. Last I heard it blew up on him....


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Coming from a family of truck and tractor pullers you learn that's what they do. You pull for awhile then they blow up, you rebuild them and start the circle over.

A 6.2/6.5 is what it is. There's better stuff out now but when it was first designed there was no diesel in light duty truck's to look to for what worked good and what didn't. What it was built to do in the early 80's was mpg's and it did that very well. The major problems with them are exaggerated to huge proportions. Cracked heads are a surface crack. The deck of the head between the valves is too far from the coolant passage. The surface gets hot and cracks till it gets to cool metal and stops. If your that worried about the cracks don't weld them brass pin them. Busted mains can happen to any of them but 96 1/2 and newer are more prone to it. Main studs also reduces the chance of it happening. Out of the 5 6.5 I have ever owned I have never had a main break and only seen one break in a 97. Cranks can break but the chance can also be reduced by not running one with a bad damper and even more if you go to a fluid damper. Never had one break a crank.

I can only speak from my experience with the 6.5 and every one I have ever owned gave me years of good service and I have never regretted buy any of them.

 

I'll post one last thing and I'm done. Read:

http://www.enginebuildermag.com/Arti...izer_6500.aspx

The OEM gm 6.5 was a poor design right from the get go and to compound matters the manufacturing was poorly executed.

Good idea (mpg meister), poor design (crack master)....


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I have a 1995 Gmc 2500 Turbo Diesel with 304,000 miles on it and no problems

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I owned a 6.5 for about a year it has 304,000 miles on it. i had no problems since i owned it. its a very reliable engine. but it does not compete with the newer diesels tho.

 

Obviously you have had bad luck with yours. GM abandoned the design because it was old technology. So is that the same reason Ford abandoned the 7.3L? Because it was a pile of crap too? Don't think so. There comes a time when they no longer meetb emissions, or they came up with a new design with better power.

And I hate to tell you, but every mechanical thing on earth will fail at some point. If engines never failed they wouldn't sell replacements.

And on the $500 get rid of it. That's up to you. I have 3 friends with powerstrokes, and all of them have spent more money keeping that truck on the road before 170,000, than I have on my 6.5L. Not saying that stuff can't happen to a 6.5L. I have had great luck with mine. But there are other things that can fail and cost you money.

 

I own 3 6.5L diesels currently and have been problem free up until recently with an IP that went out of my 96 crew cab. Unfortunately i attribute some of that to my own fault. Here in illinois, we get our share of salt and rust potential. This truck was an old state truck and my LP had a pin hole which sucked air and then burned the IP up. My 98 suburban is converted to veggie and my 99 suburban was babied by the previous owner and is running great. I like the 6.5L TD but opinions and experiences abound for others.
thanks

 

I bought a 6.5 last year or had 200k miles I replaced the injectors and relocated the pmd it now has over 400k miles and still runs as strong as when I bought it.

 

I'm looking at buying a 1992 chevy 6.5l turbo with 194000 miles what should I look for when I'm looking at it?