Coolant Seal Groove Corrosion
 

Is this S4 6 port front plate useable? I saw a couple other threads with chips like this only much smaller. They mentioned being very generous with the Hylomar upon reassembly. I can't make up my mind, so I'd appreciate your advice. This engine burnt coolant upon startup, so I wonder if grooves like these are the culprit.

Thanks!

Attachment 673275

it's fine. and hylomar only really holds the seals in place, it doesn't do shit to help the seals actually seal, so i'm not sure why these other builders really think it does. pitting in the channel is fine, some small pitting on the rotor housing seal face is also fine. major pitting in the rotor housing seal face is going to possibly cause issues though.

Thanks, makes sense. Why would there be large chips like this on the top inside edge of the groove in the first place? Is it corrosion from coolant leaking past bad seals?

just curious but were you using oem style square shaped coolant seals or one of the rounder shaped aftermarket ones.

probably just due to age, corrosion and aggressive cleaning.

This engine was never rebuilt, so it just had the stock seals. Why, are there seals you'd recommend?

All right. I'm quickly learning that S4s aren't ideal rebuild platforms.

they usually have to most imperfections but the irons aren't the problem on the S4 but more the wear that the rotor housings take. these are just blemishes that really won't hurt the integrity of the engine.

that dark stripe just to the inside of those small chips are where the rotor housing abuts against the irons, so you can see how little this makes a difference in the grand scheme of things.