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Injector cups and Loc-Tite

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We all are familiar with the use of Loc-Tite to seal injector cups to the cylinder heads. It seems as though my shop has had issues with the last three remanufactured engines we have installed in the last year with regard to injector failures - the kind that allow combustion gasses into the fuel rail but without any failures with the copper gaskets at the injector tips or the condition of the cups themselves. This points to an internal failure with the injector.

 

The most recent FAR engine sits in my bay with a second injector failure on one cylinder head. I noticed nothing on the first injector I replaced 100 miles ago. It's back dropping cylinders on the same side. This time I pulled all three of the remaining injectors. In two of the bores I noticed an odd green ring around the top of the injector cups accompanied by a light colored drip mark inside the cup. I scraped some off and though solid, it was softish. It occurred t me that whomever installed the cups was overly liberal with the Loc-Tite and never cleaned up the bore after installing them. There was also evidence of Loc-Tite on the lower fuel o-ring.

 

The truck has a new fuel tank, fuel pump and of course new filters so negative fuel pressure or fuel contamination from the source is not high on my list of possibilities here. The failure TO ME seems to point toward possible contamination from the Loc-Tite. I ran this by the Hot-Lone and they seemed to be quick to dismiss it as a possibility of being the root cause of injector(s) failure.

 

I have my doubts. Contamination is contamination. Opinions or thoughts?

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It's funny you brought it up because I just did one yesterday and I think I may have used a little too much. I cleaned most of it up but in the back of my mind I am wondering if it could cause an issue with the injector or not.

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I agree but did I not mention there was crap on the lower o-rings which is right in that flat area where they seal? That would be a boat load wouldn't you say? Eh, maybe I am wrong. It just looks like a really sloppy job and there was a bit of clean up to do. I wish I could know for sure.

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