Blue Devil Experience? - Diesel Forum -
6.9L IDI Diesels (Not Power Strokes) Technical discussion of topics related to vehicles powered by the 6.9 Liter In-Direct Injection Navistar engines.

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post #1 of 4 (permalink) Old 04-24-2012, 05:51 PM Thread Starter
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Blue Devil Experience?

I have a 6.9L Diesel, and it's been running kinda rough, and utting out a lot of grey smoke that smells like unburned fuel. I've tried quite a few things, and nothing seems to work.
Someone recommended Blue Devil Head Gasket Sealant to me today.
Has anyone heard of that, and is it effective for a 6.9?
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post #2 of 4 (permalink) Old 04-24-2012, 05:57 PM
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Welcome to the Diesel Stop

If your exhaust smells like unburnt fuel, then a head gasket sealer isn't going to fix the problem. If the head gasket(s) were leaking, the exhaust would have steam/white smoke and smell sweet like anti-freeze.

Your problems are most likely fuel related.

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post #3 of 4 (permalink) Old 04-26-2012, 10:02 AM
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With the engine idling use a flare nut wrench and loosen each injector, listen for changes. If the idle changes move to the next injector, if no change than that is a bad injector. Grey diesel smelling smoke is either bad glow plug or bad injector, if it goes away when the engine warms up then it is a bad plug. You also might have an air locked injector which will not pop off right leading to a miss and grey smoke.

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post #4 of 4 (permalink) Old 04-28-2012, 03:07 AM Thread Starter
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Thanks for the welcome, and for the advice. I was a bit confused when told it was the head gasket, because it didn't smell sweet, and I wasn't getting oil in my anti-freeze or vice versa. I'm just so ready to be done with this problem that I grasped for anything that offered a quick fix.

I'll try checking the injectors like you said this weekend, and report back with the results.
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