Stainless v Zinc plated

[Dodge]

I am replacing some of the allen bolts. The M6 engine cover bolts seem to be all "8.8" zinc plated. Is there any reason not to replace them with stainless?

Roger

[Duccout]

I don't think so! I have been replacing all my fasteners with stainless for years (except for brake caliper bolts).

[blethermaskite]

Been using stainless steel engine screws for years, there is a small chance of galvanic corrosion between aluminium and stainless steel in contact with water so just coat the threads with a waterproof grease,I believe you should not use copper grease which may increase the possibility of galvanic corrosion rather than help stop it.......but I am not an expert in this....just got this advice from the marine guys years ago.
Cheers,
George

[Jordan]

I also have had no issues with using S/S screws for engine side covers and elsewhere.
The only problem is its tendency to gall (cold weld) when used against itself.
That is for example with a stainless nut on a stainless bolt.
Some anti-seize grease and moderate tightening is what I use in this case, seems to work OK.