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99 GMC suburban k2500 motor rebuild with a 96 base

6.5 BUILD 
14K views 124 replies 5 participants last post by  OkDually 
#1 ·
I'm new to diesel and I'm making the jump in with both feet. I got a 99 diesel suburban which had a spun bearing (currently unknown if it is a rod or main) but I also bought a second 6.5 motor 1996 so I wouldn't need to concern with obd 1 or 2 swap also.
The 96 motor was said to be running before it was pulled, albeit with some blow-by. The seller recommended a hone and rings, but assured me the block& crank are good candidates for a rebuild.
Assuming it is rebuildable, should I hit any issues from the accessories from the 99 motor going on the 96 motor then into the 99 body? (Short of having to work under a carport in winter)

So, I'm waiting on the weather to break then I'm gonna start dismantling the motor to get the block to a machine shop (got one local with good reputation and moderately low prices) but having no experience with diesel I wanted the forum's help picking what parts to buy, change out or refresh.

My goal for the burb is a reliable daily driver that can run on diesel, biodiesel, and veggie oil. Occasionally tow a 30 ft camper (up to 8k lbs). I think stock plus as far as power, I dunno what a powerful vehicle drives like as I'm currently in an s10, and previously several minivans and hatchbacks, so I'm certain I'm upgrading enough for my entry.

What are things I should get& upgrade? And what brands are worth the loot in gaskets and bearings? I know arp headstuds and a fluidamper HB and I've heard of lift pumps and injectors, but I'm feeling a lil overwhelmed at the variety of things out there, and haven't found a comprehensive list of considerations for a rebuild, just some focus points that oem tends to fail at.

The 96 motor has no accessories with it except the turbo, and the 99 motor is complete and currently in vehicle.

Here's a quick pic of the burb and donor motor
Engine Auto part Automotive engine part Vehicle Machine


Vehicle Car


My first actions will be to prep the block for the machine shop, and while that's there go over the heads myself for a refresh.
Also am I correct in thinking the 99 heads are straight up compatible with the 96?

I guess that's it for my first post. Thanx in advance.
808 out
 
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#2 ·
I'm new to diesel and I'm making the jump in with both feet. I got a 99 diesel suburban which had a spun bearing (currently unknown if it is a rod or main) but I also bought a second 6.5 motor 1996 so I wouldn't need to concern with obd 1 or 2 swap also.
The 96 motor was said to be running before it was pulled, albeit with some blow-by. The seller recommended a hone and rings, but assured me the block& crank are good candidates for a rebuild.
Assuming it is rebuildable, should I hit any issues from the accessories from the 99 motor going on the 96 motor then into the 99 body? (Short of having to work under a carport in winter)

So, I'm waiting on the weather to break then I'm gonna start dismantling the motor to get the block to a machine shop (got one local with good reputation and moderately low prices) but having no experience with diesel I wanted the forum's help picking what parts to buy, change out or refresh.

My goal for the burb is a reliable daily driver that can run on diesel, biodiesel, and veggie oil. Occasionally tow a 30 ft camper (up to 8k lbs). I think stock plus as far as power, I dunno what a powerful vehicle drives like as I'm currently in an s10, and previously several minivans and hatchbacks, so I'm certain I'm upgrading enough for my entry.

What are things I should get& upgrade? And what brands are worth the loot in gaskets and bearings? I know arp headstuds and a fluidamper HB and I've heard of lift pumps and injectors, but I'm feeling a lil overwhelmed at the variety of things out there, and haven't found a comprehensive list of considerations for a rebuild, just some focus points that oem tends to fail at.

The 96 motor has no accessories with it except the turbo, and the 99 motor is complete and currently in vehicle.

Here's a quick pic of the burb and donor motor


My first actions will be to prep the block for the machine shop, and while that's there go over the heads myself for a refresh.
Also am I correct in thinking the 99 heads are straight up compatible with the 96?

I guess that's it for my first post. Thanx in advance.
808 out

Everything from the 96' should transfer with no issues.
 
#3 ·
even a 93 will. block, except for a few changes, is the same so obd 1 or 2 is no concern.
before sending to machine shop, check mains for cracks. might same time/money if you locate the first.
heads are interchangeable.
use your 99 dual t-stat and WP.
replace HB and pulley.

bio and veg have been causing issues lately....from another site:
ULSD is more prone to infection of bacteria and fungus than the old diesel of past as
Biodiesel appears to allow this stuff to grow even faster.

After the Water In Fuel light went on he pulled fuel from FFM into a glass jar. It had some water in bottom. 2 days later it had white 1" strings of white cr@p growing off of water to fuel interface. Walbro pump screen was plugged with snot and main filter smelled nasty.

He burned off as much fuel as possible, dropped tank, sucked remaining water/fuel out, used a long pole with washcloth zip tied on end as a giant q-tip to swab tank. Steam cleaning's preferred. Then cleaned lines to first filter. Fuel pickup tube in tank can have a good build up of bug slime. This was round 3 with this stuff, a tank sock just causes trouble: makes draining tank harder in future should bugs come back.

Biocide added to fuel kill bugs. They clump, coat tank bottom making you reach for a new fuel filter. Disposing of 34 gal of fuel may be cheaper than filters. He tossed 7 gal from above issue and 2 filters. Put biocide in after quickly burning as much fuel as possible as they double their numbers in 20 min! Drop tank to clean, change filters, clean out FFM. Biocide in FFM and tank before new fuel. Run biocide through transfer pump used to clean out tank: it's infected now too.

Note: bugs usually ruin fuel level sensors so replace while in there and forget about putting tank sock on again! Will need a strainer before LP that's easy to change, around 40 micron max. LeroyDiesel.com has fuel level sensors that don't get ruined by bugs, build up, acids in contaminated fuel. His sensor has outlived a Walbro under this abuse.

More info on biocide and problems:

Sail Delmarva: Diesel and Biocides
Per Hammonds Biobor website it has the most important requirement : dual phase! Killing the bugs in the fuel because modern ULSD and Bio mixes hold enough water suspended in the fuel for the bugs to grow in fuel. Just like brake fluid adsorbs water.

The second thing to remember is to switch it up now and then to make sure to kill the bugs that get immunity or new bugs. A test kit for infection can confirm the product you overnight shipped is killing bugs. Time is critical in infection to keep the mess down.

Biobor Jf Fuel Additives - Products
Dual Phase - soluble in both water and fuel phases for a more effective kill
 
#4 ·
Thanx for the replies.
It's reassuring that I shouldn't run into compatibility issues.
And thanx for giving advice on potential problems with the wvo conversion. I've mainly just seen overly positive stuff or exceedingly negative comments on that.
Also I watched a vid on Leroy's fuel level sensor. I like the thoughts behind it and was thinking that would be a good idea for the second tank at least, if not both.

I've been working till past dark since my last post, so I've done nothing to progress my burb, cuz I'm being a baby and not wanting to work under a cold carport. But I'm taking this time to read thru more of the noob areas so I can increase my familiarity with the options available for my rebuild.

I'll try to post in here at least once a week or more once I start wrenching, cuz it'll help me stay on point and may also help someone else who is in a similar situation.

I'll try filling out my Sig thru this week so I have a starting point for my build.

The couple upgrades the suburban seems to have currently are pmd relocation, 4" exhaust, and an oil pressure gauge under the hood.

Why is the oil pressure gauge under the hood?

Ok, think that's it for now.
808 out
 
#5 · (Edited)
Please post of pic of the gauge in its location..:HiHi:
 
#6 ·
Here's the oil gauge.

Engine Auto part Vehicle Car Automotive engine part


Also what is this disconnected valve for?

Auto part Engine Fuel line Vehicle Car


And what are all the plumbing fixtures for? I'm not used to seeing that under the hood.

Fuel line Auto part Plumbing Engine Pipe
 
#7 · (Edited)
gauge is there because someone didn't take the time to put it in the cab.
drain is from FFM. to drain water.
plumbing looks like for the heater. where does it lead to? might be for external engine heater that circulates warm fluid.
why is VC for CDR blocked off?
 
#8 · (Edited)
Valve cover is blocked off because the PO removed the original CDR and blocked it off.
Re-routing the blowby and combustion gasses through the blue hose from the oil fill neck to the intake on the turbo.

With all that oil seepage/leaking, I bet that engine smells wonderful when it gets up to operating temp :Insane:


All I can say is, yikes!:eek:
 
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#9 ·
The valve is to drain water? Why is it on top then? Or should there be a matching bottom valve to let the water out?

I'll trace the plumbing out when it's not raining.

And I dunno what vc is, and looking up cdr, I don't think I quite follow what it is either... If it's like a vacuum thing for the waste gate, I think I've got a mechanical waste gate for the turbo. So I dunno if that answers that or if I'm wrong in my guess.

I've never touched a diesel engine before I got this suburban, so I'm wholly unfamiliar with what's under the hood. Not to mention my ignorance with this burb in particular, as I bought it with dead batteries and a spun bearing, but the body is in decent shape and it has a trans rebuild 80k ago. Tho I noticed the front differential is covered in oils, so I think that will need a rebuild as well. Just mentioning cuz I'm willing to learn, but I'm starting from ground zero.
 
#11 · (Edited)
In the OEM configuration, the CDR is normally located on the valve cover and is a one-way valve.

Using the Turbo for a vacuum source, the CDR pulls combustion by-products and oil vapors up and out of the crankcase and routes it through the turbo and into the intake to be re-burned by the engine.

The CDR also helps to keep a slight negative vacuum on the crankcase seals to keep them from leaking due to the high compression of the diesel engine..

In your specific case, with the CDR removed from the equation, the crankcase ventillation has no valve to regulate the vacuum and I'll just about bet that is causing excess blowby and oil leaks.

Removing the CDR is not a good idea for the 6.5L engine's health.

I couldn't begin to guess why the Previous owner would do that..
 
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#12 ·
Well, it makes me glad I opted to buy a motor for rebuild then, cuz that reroute prolly caused the spun bearing that caused them to sell.
 
#13 · (Edited)
The key to it all is to keep up with the preventative maintenance schedules.

( ie. changing the oil, filters, radiator flush, fluids, etc..).

By the looks of it, the previous owner(s) just ran it into the ground, changing the oil whenever and rigging things as it broke down.

A 6.5L is one of the cheapest Diesel platforms to run/repair on the road today.

Just compare the cost of Injectors of a 6.5L vs. a Duramax :Insane:

A lot of people try and cut corners to keep things going and it's understandable because it's a Diesel but, when you cut corners you end up just costing yourself more in the long run,especially with todays parts quality..
 
#16 ·
0 mile salvage off a carrier wreck
 
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#17 ·
Finally talked to the machine shop and they can get to it soon as I get the block over to them, so I'm just trying to figure out what/where I'm getting my rebuild kit, and I'm a lil stumped.
What's the difference between kits, should I opt for 18:1 pistons, and what else might I should change while it's apart?
I'm thinking a gasket set, main and rod bearings, rings, and that's it for the main thrust of parts.
Also thinking of a new harmonic balancer, injectors, and gauges as part of the must buys. But I'm not sure if I should go with hi output injectors or stock, also I'm wondering what the difference is between fluidamper and cheap HBs.

Should i include timing gears and chain, water pump, oil pump, injector pump, camshaft, or camshaft bearings?
Or would they be needed if they turned out to be bad?

As I also started looking at pricing (finally) I find I need to temper my aspirations with this project to a bit of a realistic bent, so I end up with a reliable ride that is generally fuel efficient but can tow a trailer (8k lbs) about 500 miles once a year or so.
 
#18 ·
Just go Standard rebuild .. Don't waste unnecessary money on things..


Fel-Pro Gasket kit, New Harmonic Balancer and Pulley ( if you can spring for it, go with the Fluidampr).
The Fluidampr is the cure all to the HB problem and will outlast the engine.

Buy Standard Bosch Injectors and return line kit. Buying HO Injectors is a big waste of money.
The IP just cannot produce what the HO Injectors need to do the job.

Standard Timing Chain and gear.

If you plan on doing some heavy towing then Buy an HO water Pump and new AC/Delco Thermostat.
Standard Oil Pump.
Rebuilt IP from a quality shop like Midland Diesel
New Crankshaft
New Cam, Valves, lifters, and Heads.
Rebuilt Turbo Cartridge or.. go with a rebuilt Turbo

All new bearings, Pistons, rods, wrist pins, Rings
 
#19 · (Edited)
before you buy ANYTHING, check here first. like OK said, don't waste your money on something you don't need. also don't cheap out on important stuff (injectors, GP's, IP, etc...).
 
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#20 ·
Hey all, another delayed update, I finally started wrenching the other night, to get the block from the motor to the machine shop, I pulled the turbo,t stat housing, timing cover, flex plate, water pump,intake and exhaust manifolds, and valve covers off.

Engine Auto part Vehicle Automotive engine part Fictional character


Engine Auto part Automotive engine part Compact car


Engine Auto part Automotive engine part Vehicle Transmission part

Tonight I plan on removing heads and oil pan.
Then I have to decide if I'm pulling the timing chain off or leaving that for the machine shop too, as I was gonna leave the cam shaft for them.

Also I saw b'laster 1 gal parts solvent for $15 at depot clearance, should I get the 3 tubs that they have or is there a better/cheaper solution?

And I'll definitely ask y'all before I buy any parts, thanx for being eager to help.
 
#21 ·
.......Also I saw b'laster 1 gal parts solvent for $15 at depot clearance, should I get the 3 tubs that they have or is there a better/cheaper solution?....
is that for the engine compartment? sounds like a good price if it works. ever used it?
 
#23 ·
I ended up getting 6 one gallon containers, so I'll let you know how it works for me.
But the block is all wrapped and loaded for machine shop before work

Waste Scrap Plastic Litter


And all the parts off it are filling my freezer. I figured it's a decent weather proof storage area.



This weekend I'm going to work on the heads, clean them up& reseat the valves and prep the burb for the swap.
Also prep my wallet for the hit its gonna take from the machine shop and parts places.

That's it for now.
 
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#24 ·
Started cleaning the head, and noticed cracks all around the injector ports, should I bother continuing, or check the heads on the suburban motor?
Auto part Metal


Auto part Metal Steel
 
#26 ·
The solvent seems ok, but there's allot of scrubbing still and it doesn't seem to be good on gasket material. But it seems to do good on the oil and carbon buildup.
 
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#27 ·
when you say injector ports, are you referring to the precups? i didn't notice any. can you get a better pic of the area?
 
#28 ·
Auto part Metal


2 or 3 cylinders have cracks between the valves, but all 4 have 2 cracks at the hole.

I was guessing that's where fuel enters the cylinder.
Precup you call it?
 
#29 ·
#30 ·
Also the valves. Not sure which is which, but the smaller ones have a T on them,
and they were rather dry, the shine around the big valves is large corrosion& deposits, I'll pop out some valves to look at the seats tomorrow, but they look chewed to me, but it just looks like staining in the pics.
 
#31 ·
Hey just a quick update, I finally heard from the machine shop. The block seems sound as does the cam & crankshaft. The cylinders will need a bore rather than just hone. He said about 30 over. Which means new pistons for me.
Due to family issues he's moving slow, just got the thing broken down not all cleaned off yet. but the preliminary checks are favorable, so I'm excited. And I'm starting to wrench up the suburban now.

I am trying to pull the engine by next weekend so I can compare heads to see which I'm gonna use.

You guys have any advise for that? It seems it's not a front clip situation, more like remove everything piece by piece. (Grill, rad, bumper, etc)
Basically just move systematically thru, separating and labeling?
 
#32 ·
Also, which gasket/rebuild kits should I look for?
It's a 96 block with dual t stat housing and possibly heads from a 99.
Should I be looking at 99 kits with larger pistons or a 96 kit and get the housing gaskets separate.

I'm thinking get 99 rebuild kit, but just want to check.
I think the tolerances and clearances should be the same, but I want to verify.
Also I know not to order till I get the full measurement list from the shop. I'm just looking to be ready when I get them.
 
#33 ·
Also engine is out of suburban.
Wow,I have the best friends.
I'll have the heads separated again by Wed, to check their condition.
808 out
 
#34 ·
engines are the same, whether sub or truck. GVWR changes some of the emissions though. 99 and 96 gaskets are gonna be the same.
pulling front end parts off is easy. get some cans and put all the same areas screws/nuts/bolts in the same can.
good luck on it. not sure i helped. there was a lot of info to sort.
 
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