Getting ready to tackle my first LB7 injector install. My question is do most people pull all the injector cups / sleeves and re-seal them? Or do most let them be, if they stay in the head after the injector is removed? Does anyone know GM's recommendation? Thanks
General consensus on injector cups???
- Thread starter rfinn04
- Start date
GM states to re-seal them
I highly highly suggest resealing each injector cup that you pull an injector from regardless if the cup came with the injector or not. it doesnt take much to crack the sealant and then you are pressurizing the cooling system after putting injectors in wondering wtf happened.
ive argued with guys that work at shops and guys on duramax forum till i was blue in the face to do not reseal cups and they claim they NEVER got a come back truck for coolant issues. ill call bs on all accounts for that. properly cleaning the surface area, inspecting the cups and installing with either the 272 loctite or green loctite with new o-rings on the cups will give you the absolute highest possibility of 0 cup sealing failure
I highly highly suggest resealing each injector cup that you pull an injector from regardless if the cup came with the injector or not. it doesnt take much to crack the sealant and then you are pressurizing the cooling system after putting injectors in wondering wtf happened.
ive argued with guys that work at shops and guys on duramax forum till i was blue in the face to do not reseal cups and they claim they NEVER got a come back truck for coolant issues. ill call bs on all accounts for that. properly cleaning the surface area, inspecting the cups and installing with either the 272 loctite or green loctite with new o-rings on the cups will give you the absolute highest possibility of 0 cup sealing failure
I have never had an issue in my personal truck nor friends trucks or customers trucks with the 272. I make very sure the sealing surface is clean and the cup is in good shape. And if I can, I'll wait a few hours for the loctite to setup before putting coolant in.
I prefer the loctite over the permatex stuff. That said, I have no issues against loctite 272 or the green sleeve sealer
I was on the fence about resealing cups and James talked me into it. So glad he did, all but two fell right out when I started to pull them so who knows if u would have had an issue or nut but I feel way better about it now.
So what do you guys recommend? it appears that loctite 620 is very thick and has good holding strength and high temps.
The 272 seems pretty thick, I haven't had any problems with the dozen or so jobs I've done. I'm going to look into the green stuff when my bottle runs out though. As stated before CLEAN that chit! I like to use a 3/4 bristle brush like plumbers use to clean copper fittings.
I used what LDS sent me with the injectors it was in a small red tube unmarked but smelled and looked just like 272 loctite. Guessing they get it in bulk and send out just enough for the cup re-seal. Both the red and green are the same consistency I use both daily at work. Green is considered "high strength retaining compound" by Caterpillar. Either one will work fine.
620 will work, even good for larger gaps also. I've used green 620 , 648, and the classic red 262. Never had any leak. Do a good job cleaning and you shouldn't have any trouble.
I'm one of the lucky SOBs who doesn't reseal the cups that don't come out with the injectors, and I've never had an issue. I don't recommend other people do that, though. I'm not afraid to go back in and re-seal a cup if I have to, and I have a backup vehicle.
I have also used nothing but the red 272 loctite, and never had a problem. I kept toying with the idea of the green loctite, but having used that before, I am not so sure I could ever get a cup back out after using that, even if I wanted to. Then again, why would I want to?
I have also used nothing but the red 272 loctite, and never had a problem. I kept toying with the idea of the green loctite, but having used that before, I am not so sure I could ever get a cup back out after using that, even if I wanted to. Then again, why would I want to?
Though I'm sure its better to reseal them I'm a full time diesel tech and have done tons of them and have NEVER had a comeback and i only reseal the ones that come out....
Btw im not trying to say that my way is the right or proper way. Im just sharing my experience in the last 8 years as a tech....
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I've had enough trucks come to me from shops that don't reseal each cup that an injector was pulled from to know its not worth the trouble. Maybe it's the fact things are hotter out here and trucks can hit 240 towing hills in a heart beat and that expansion is enough to finish a weaken cup off or maybe it's for other reasons but it takes all of 10 extra min a side on a job that takes 6 or so hours (not flat rate hours) depending on what's done to the truck. So to me, it's not worth saving the little bit of time to make sure the customer has no issues.