The LB7 Duramax is a 32-valve V8 diesel engine produced from 2001-2004.

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Repairing the injectors - clean or replace

Motor has 250,000 + miles and is emitting smoke at idle. Is there a way to clean the injectors or do they need to be replaced?

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mayer, I've never had much luck with cleaning injectors. I would suggest to either rebuild or replace. Rebuild kits are available at places like this. They also have a decent video on here.

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Thanks, I'll forward this to my son.


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I had a similar issue with my 2002 Duramax. Smoke on idle, little bit of a puff upon acceleration and then no problems when cruising along.

I solved my problem by:

1) Running the engine to operating temperature.

2) Removing the fuel filter and putting in a new one.

3) Filling the reservoir with "Sea Foam" (a cleaner you can buy at any auto parts shop)

4) Re-installing the fuel filter housing.

5) Idle the engine for 3 minutes.

6) Let it sit for 20 minutes.

7) Run for 3 minutes.

8) Let it sit for 20 minutes.

9) Run the truck hard (up hills / tow a trailer) for 20 minutes.

This Sea Foam was able to hot soak my injectors twice and broke up whatever was clogging one (or more) of my injectors.


$10 for Sea Foam

$35 for new diesel filter.

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Hate to say it, tried it all. Seafoam, and every other additive made, I mean every single one, they all failed in spades. My injectors were replaced once at 90 k for bad smoke at idle. Smoked very badly at idle again at 185 k. I was not ever convinced my injectors needed replacement again, simply because after a road trip the smoking went away for about a week. I had an epiphany, it is my usage causing the injectors to foul. I took a 1500k road trip with a three horse trailer loaded with 5000lb of horses. I did not go easy on my truck in the mountains. What I did was put a quart of walmart tranny fluid in each tank, high detergent I heard might help. That was two months ago, no smoke folks. I keep the truck in tow haul mode, and drive it like a truck, I drive it hard, I use it hard, it gets hot. I think the issue is using this particular series as a car, not a truck. It was never intended to be coddled. It was the first series, and made to be used hot. My balance rate is now text book perfect, my truck runs perfectly now at 210 k. Truck is bone stock. Try it.

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mayer will be eternally grateful.
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