silicone hoses
 

im starting to rebuild my motor and of course all the vacuum lines are old and brittle and need to be replaced. Are silicone hoses a good replacement?

yes

Thanks

its good but do you need them.

Just make sure you get good silicon hoses and not the cheap ones. Basically you want the walls of the hose to be pretty thick so that they don't collapse once the vacuum starts.

I can't see any reason that silicone hoses would be preferable to regular ole rubber except maybe color.

wouldn't they hold up to the heat better?

yes and no.

good thing about OE-kind of rubber hose is that its cheaper, easy to get, usually fits easy, and you can get them almost anywhere.

bad thing about rubber hose is that, its rubber, due to heat, over certain period of time it will deteriorate, the outside will crack, that's fine. but the inside when it deteriorate, it will start chipping and it runs around as containments in your cooling system. also it expands when heated, not cool for a pressurized system.

Good thing about Silicone hose (a good REAL one that is), it last a lot longer (usually) it does not expand when heated (compare to rubber hose), and its looks great.

Bad thing about silicone hose is that they cost a lot more than rubber hose, it will still break and when it does, unlike rubber hose which probably just a crack somewhere, it usually just "shattered" into pieces, so instead of losing coolant slowly, you will lose almost all coolant right away. but that usually won't happen until like 5-10 years later. obviously it cost more. and its a bitch to fit some of them(don't ask me how I know)

^In large part, same argument for using silicone hoses for vacume lines as you asked. It would be a good idea to use small zip ties to "clamp" each end of the replacement silicone hose.

what size for regualr hoses? 4.5, 5.5 mm or?

Simple answer, just order a quantity of silicone hose from mazdatrix. take all the guess work out of this.