Found a cracked injector cup on an old Detroit 60 series after 4 hours of chasing a miss

I was working on a 2003 Freightliner in our shop lot last Tuesday and it took swapping the whole fuel system before I spotted that hairline crack with a borescope, anyone else had a sneaky one like that on these old engines?

2 comments

2 Comments

tyler_fox411mo agoTop Commenter

First time I ran into that issue was on a 94 Series 60 in a Western Star. I wasted a whole day swapping injectors and checking pop pressure before I finally pulled the valve cover and pressurized the coolant system to see bubbles coming from the number five cup. Ended up renting a proper crack detection kit from the Cat dealer that uses a penetrating dye, made the hairline show up like a neon sign. Now I always borescope the cups first thing on any 60 series miss, saves me a good 6 hours of chasing parts. Did you pull the head to replace just that cup or do the whole set while you were in there?

davis.linda1mo ago

And it's ALWAYS the little crack that laughs last, just like a slow leak in a tire you'd swear was fine.