Hello everyone,
I had a P1447 code on my '97 Maxima (187,xxx) and I was about to go through the whole process of checking all the valves, etc, when I say one of my vacuum lines coming off of the EVAP Purge Cut Valve had broken. I temporarily fixed it, but I don't know what size hose I need to replace it.

I figured it's probably a good time to replace all my vacuum hoses since the car is old and I don't think my hoses have ever been replaced (I'm not the original owner, only had it for 4 years).

Does anyone know all the sizes for the vacuum hoses needed to replace my existing ones?

I tried searching and I could not find a definite answer here on the forums.

Thank you so much!

 

No complete info exists to my knowledge. You'll find that most of the vacuum lines are either one size or another. Take a sample to Autozone, PepBoys, Napa etc and buy new stuff in the same size(s).

 

Alrighty, thank you for clarifying that

 

Many of those hoses are "formed" into particular shapes. Although parts store tubing may have the correct ID, it won't keep the same "formed" shapes.

It's worth considering that generic hose may not make a 90' turn inside a given radius, or clear a heat-producing part of the engine, as well as OEM replacements.

Also - the original hoses may not come off their fittings easily / may break at removal. So be sure you have a game plan if you need to drive that car next day to work.

 

gates makes spring like hose shapers. they fit around the hose, then can be bent into shape. once the shaper is bent, it stays that way.

The plastic nipples on various sensors can get brittle through heat and time.
I often will slice the old hose lengthwise at the sensors with a single edge razor blade. That hose will be replaced with a new one of course. I use spit for a lubricant.

 

What's the easiest way to identify which hoses are vacuum hoses? I saw the diagram under the hood, should I just follow that?

Also, if I replace them and I don't necessarily shape them, they should still be fine as long as they don't collapse right? Are there techniques to keep them from collapsing?

 

the spring like hose shapers prevent collapse.

a lot of the vacuum hoses originate from the center hose on the throttle body. be sure not to kink any of them. or you will be scratching your head, like I did to pass emissions.

I would leave most of the vacuum hoses alone.

I was most concerned about 20 year old coolant hoses. So I put my efforts there instead.