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Looking to swap out a 454 with a diesel engine in a ‘99 GMC Suburban

Barking-Iron

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I have a ‘99 GMC Suburban K2500 with a 454 and I’m really thinking I’d like to swap out the 454 for a diesel engine. I have a travel trailer I pull with it and the GVWR is 8,500 pounds. Not really sure what route would be best. My goal is to have plenty of power for pulling in the mountains and not breaking the bank with a swap. What are some suggestions you all may have? I appreciate any and all feedback. Thank You!!!
 

WarWagon

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I suggest looking for a 6.0 or the rare 8.1L gas engine 2500 Suburban. Or do what everyone else does: get a crew cab pickup with the diesel engine. Some of the crew cabs are roomier in the back seat than Suburbans for adults.

For the money get a new complete GM GASOLINE Crate Engine that has the power you want. You could hop up the 454 some including turbo/supercharger.

Without some real coin thrown at it a 6.5TD will disappoint and is known for a real short life working hard towing in the mountains. A 4L80E towing "stock" is worth 50K miles towing I find. Add a Triple Disc converter for better life.

For a "Budget" you are best just hopping up the current 454. F'K concerns about the 454's single digit low MPG as the 6.5TD stock towing is just as bad MPG-wise with higher TCO in filters, oil, and higher diesel price.

Other more practical/reliable/better MPG Duramax or Cummins swaps will eat a budget quick.
 

Will L.

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Budget and use are the first questions.
Your mechanical and electronic diagnostic capabilities would be next.

warwagon has a point of Some advantages staying with gasoline.

make sure you check with your dmv you can do gas to diesel conversion and that there isn’t problems with older engines in newer trucks or different mfr engine into it. Many don’t expect problems but after a lot of work and money have to sell them for losses to others in different states.
 

Will L.

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The older engines are more simplistic, and can burn different fuels better like diesel, waste motor oil, vegetable oil, etc.
Gm 6.2/6.5 (same engine basically) cummins 6bt, ford 6.9/7.3.

Then is newer options of the newer cummins, powerstroke (which say avoid) and duramax.
More power, more money up front usually, requires more comfort chasing electronic issues.

If you are looking for rolling coal- you are at the wrong place. That nonsense is ruining diesel ownership and we won’t help you in that stuff here.

If you are looking for an answer to do everything very low cost sell the rig and buy one ready to go. Conversion will cost more. And putting in all that work without fixing weak points is just dumb. So do it right or don’t do it because it will only lead to more expense long term and a lot kore heart ache.
 

FellowTraveler

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If you are seriously looking into a diesel conversion first issue to address is EPA converting from gas to diesel on modern vehicles even a 99 is simply not allowed in many states.

Next issue assuming you are converting a diesel vehicle to a different diesel "is using a diesel of the same year or newer with all the emissions components it came with."

There are dozens of diesel conversion sites that also sell conversion parts and give free advice that is where you need to look...some even have converted vehicles of sale too.

Expect to pay $15k to 25k just in labor alone for most conversions unless you have the skill-set tools shop manuals and equipment to DIY...
 

WarWagon

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If I was going to do a gas to diesel conversion, in a GM vehicle, i would go the added expense and do the Cummins swap all the way. Complicated ? YES, but, the MPGs is Definetely there.
You can get a 8.1L 2500 Suburban for $10K or so. You can also find a diesel Suburban preferably with a pre-blown engine and drop an industrial diesel in it. For $15K you can get a 2WD crew cab diesel pickup.

The cost of a 4 BBL TBI injection setup and a supercharger for your 454 to wake it up ain't that high. It's more than the vehicle is worth as is any engine swap.

For the cost of a swap you can buy a Tanker Truck of Premium Gasoline. People do swaps for something rare or unavailable with no real budget to worry about. Like Dropping a Duramax in a 2001+ Suburban that never came with a diesel option.

Not only that but it's a light duty diesel with Heavy Duty emissions 6.5TD vs. a Industrial Cummins 5.9 Diesel with a rated 500K miles TBO. You get 5K miles on a 6.5TD light use and 2500 Miles heavy use on the engine oil. Cummins is 15K miles or 7500 Miles extreme use. I have blown both engines and thus Gasoline engines are simply cheaper. Point of fact a 1993 pickup I am borrowing with a 454 has 180K on the original engine. (The 454 OEM power fing SUCKS over the Hot Rod 6.5 diesel I built.) My 1993 6.5 or 1995 6.5 were both on their 4th and 2nd engines at that miles. There was no rebuild or saving the original 6.5 diesel engines. The 2003 Cummins went through 3 engines at 120K: and one wasn't rebuildable.

Pictures of how Bean Counter Light Duty the 6.5 is vs an Industrial Cummins.

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