Originally Posted by
pizzaguy
Ultra Black RTV is the right stuff. Could your product work? Perhaps. But I KNOW that Ultra Black RTV works because it worked for me and for many others. See, I learned from reading this ENTIRE thread, back four years ago. I read how others had to do the job twice and made up my mind to do it RIGHT and ONCE. Here I am, years later, with NOT ONE DROP of seepage anywhere on the engine.
Just this week, I have told TWO people on Facebook to read this entire thread before proceeding (at least up to my posts, as what I learned was found in the posts up to that point). I prefer to learn from those who went before me, when I saw how some had to do this fix twice in six months, I made up mind to take my time and do it right. "Right" being defined by the likes of MikeR, Maxchion, ALa_Xfire Thorn and others. My mechanical skill is about a 2 of 5; I am only successful by learning directly from those I know can, and have, done the work successfully.
You’re the man.
I think the secret is clean surfaces, a thin even layer of sealant so that it sets up evenly through its thickness along the whole surface, let it skin over a little, apply the two parts together so the faces touch at the same time and slowly torque the screws in an even pattern so they all end up at the final torque more or less together.
Left for the time stated and check the torque again. Wait at least the recommended time before use.
Rapid setting is not what you want at home, it may be OK when assembled by a real expert or a robot.
A rapid set, an uneven layer and a delay in putting it together probably spells a disaster down the line.
Fortunately I have not had a leak and it looks like it never has been fixed. Some sealant surface pictures I have seen on the forum look like the sea with waves on it, not good. Smooth is good, ripples not, you need a steady hand and a sealant gun like that from NeedsWing would help, it is a bit pricey though. Doing the job on a bench with the valve covers off would be the best. And you can replace the valve cover seals while you are at it, if not you may end up with leaks from them.
Do a good job and you will only do it once.
I am sure that Mercedes did a good job, maybe a few errors. Their sealant is not something they would cheap out on, robots are used in many cases to apply the sealant, on these engines we cannot say though.