Vacuum Hose Diameter
#1
Vacuum Hose Diameter
Hi,
I noticed that the vacuum hoses in my engine (228k km) may have "swollen?": they don't fit tightly on the nipples anymore.
Today, I cleaned the VSV for EVAP with isopropyl alcohol. Turns out the VSV was very clean / no need for cleaning. While I expected difficulty pulling the vacuum hoses, they were very easy to pull off.
Perhaps at some point it'll be a good idea to replace at least the easiest ones. [Chart: https://www.amayama.com/en/genuine-c...2/engine/1708]
Anyone knows their size? I think there may be two sizes at least. The EVAP ones seem to be 6mm inside / 10mm outside. There may also be 4mm and 8mm ones?
Thanks
I noticed that the vacuum hoses in my engine (228k km) may have "swollen?": they don't fit tightly on the nipples anymore.
Today, I cleaned the VSV for EVAP with isopropyl alcohol. Turns out the VSV was very clean / no need for cleaning. While I expected difficulty pulling the vacuum hoses, they were very easy to pull off.
Perhaps at some point it'll be a good idea to replace at least the easiest ones. [Chart: https://www.amayama.com/en/genuine-c...2/engine/1708]
Anyone knows their size? I think there may be two sizes at least. The EVAP ones seem to be 6mm inside / 10mm outside. There may also be 4mm and 8mm ones?
Thanks
#4
I've certainly get some 10mm and 8mm ones.
#5
There are a couple of 6mm ID hoses in the emissions system. One being over on the VSV for OBD canister (right side of engine - part of air inlet).
I gave up trying to find all the sizes, and was too cheap to pay dealer rates for hoses so I bought a bundle of silicone hoses from Amazon (4, 6, 8, 10, 12, 14mm - each about 7 feet long). Now I have some left over to use with our other vehicles when those hoses get hard.
I did buy the PCV valve and hose OEM.
I gave up trying to find all the sizes, and was too cheap to pay dealer rates for hoses so I bought a bundle of silicone hoses from Amazon (4, 6, 8, 10, 12, 14mm - each about 7 feet long). Now I have some left over to use with our other vehicles when those hoses get hard.
I did buy the PCV valve and hose OEM.
Last edited by oneround; 10-18-21 at 11:40 AM.
#6
There are a couple of 6mm ID hoses in the emissions system. One being over on the VSV for OBD canister (right side of engine - part of air inlet).
I gave up trying to find all the sizes, and was too cheap to pay dealer rates for hoses so I bought a bundle of silicon hoses from Amazon (4, 6, 8, 10, 12, 14mm - each about 7 feet long). Now I have some left over to use with our other vehicles when those hoses get hard.
I did buy the PCV valve and hose OEM.
I gave up trying to find all the sizes, and was too cheap to pay dealer rates for hoses so I bought a bundle of silicon hoses from Amazon (4, 6, 8, 10, 12, 14mm - each about 7 feet long). Now I have some left over to use with our other vehicles when those hoses get hard.
I did buy the PCV valve and hose OEM.
#8
I used an OEM hose for the PCV line as that line tends to get "oily" (is that a word?), and I prefer not to have that mess collect on the intake under the engine cover..
If an emission vacuum line were to have a dip such that fuel could collect in a pocket, any fuel dripping out could/would become a fire hazard. OEMs can't really afford that. And if I was still a working mechanic I wouldn't use silicone for a customer's car either. For myself, I did for two reasons. 1) The car gets driven enough I'm not worried about fuel vapor collecting in any quantity in a line, and 2) I have the arranged the lines such that there is no dip where condensate could collect.
Last edited by oneround; 10-18-21 at 11:41 AM.
The following users liked this post:
Wilson2000 (10-17-21)
#9
Silicon hoses don't do well in continued contact with fuel or oil as they are permeable to fuel, oil and water vapor (but not liquid water). Hence no fuel lines, oil (engine/transmission, etc.) or radiator hoses should be in silicon without some sort of liner. They may be seen more often in racing engines, but those get so much attention that shortcomings are negligible.
I used an OEM hose for the PCV line as that line tends to get "oily" (is that a word?), and I prefer not to have that mess collect on the intake under the engine cover..
If an emission vacuum line were to have a dip such that fuel could collect in a pocket, any fuel dripping out could/would become a fire hazard. OEMs can't really afford that. And if I was still a working mechanic I wouldn't use silicon for a customer's car either. For myself, I did for two reasons. 1) The car gets driven enough I'm not worried about fuel vapor collecting in any quantity in a line, and 2) I have the arranged the lines such that there is no dip where condensate could collect.
I used an OEM hose for the PCV line as that line tends to get "oily" (is that a word?), and I prefer not to have that mess collect on the intake under the engine cover..
If an emission vacuum line were to have a dip such that fuel could collect in a pocket, any fuel dripping out could/would become a fire hazard. OEMs can't really afford that. And if I was still a working mechanic I wouldn't use silicon for a customer's car either. For myself, I did for two reasons. 1) The car gets driven enough I'm not worried about fuel vapor collecting in any quantity in a line, and 2) I have the arranged the lines such that there is no dip where condensate could collect.
#10
Silicone vacuum lines don't last worth a damn they dry and crack. The best by far are from Toyota I'm told these are neoprene rubber whatever the material these are they last for decades. They are not affected by motor oil, brake fluid or any chemical that I know of. I use one for brake bleeding it has held up no damage, I use brake cleaner, acetone, lacquer thinner, carb cleaner or whatever chemical I have on hand to clean.
The following users liked this post:
Wilson2000 (10-17-21)
#11
If I ever have to replace vacuum hoses in the future, it will be a tough decision to switch to silicon considering the great experience I've had with OEM.
#12
Thanks LeX2K for Toyota part numbers on the OEM vacuum hose! I've been driving and working on Toyotas since 1980. The only vacuum hoses I've had to replace were on 197X's Celicas. I've never had to replace any of the hoses on my 1985 MR2, not even a coolant hose!
If I ever have to replace vacuum hoses in the future, it will be a tough decision to switch to silicon considering the great experience I've had with OEM.
If I ever have to replace vacuum hoses in the future, it will be a tough decision to switch to silicon considering the great experience I've had with OEM.
But, I'm (hopefully) finishing up an emission/vacuum issue on the 2002 SC430 I recently bought.
I believe my replacement will be the third set of vacuum hoses on the car. First the as built equipment, and second, an OEM replacement set put on in October of 2014. Now maybe the Lexus tech down in Miami lied to the original owner (this was a 1-owner car), but, I have a written copy of the service record. Hence I am going with the silicone hoses in what I consider appropriate spots.
@LEX2K2 I noted the shortcomings I know of for silicone. Under what conditions did you see vacuum lines dry and crack like virtually all the OEM lines do? Silicone has been used for vacuum lines, spark plug cables, etc., for decades. Mercedes and BMW have used silicone vacuum lines. It's been years since I worked as a mechanic (except as a hobbyist), so I can't say if they still do or not.
@lexixel I suppose fuel line would work (at least I can't think of a reason why not), but they are reinforced to withstand internal pressure. As such that they don't bend easily to fit where they need to go, and tend to kink if bent too sharply.
EDIT: I'm wondering if being parked outside with South Florida heat & humidity, plus the heat retention of the engine cover, contributed to premature OEM vacuum line deterioration. Anybody have a good idea?
Last edited by oneround; 10-18-21 at 11:45 AM. Reason: corrected several misspellings of a word
#13
Very interesting information here. Indeed I find the vacuum hoses on my car (228k km) has held up reasonably well. They are still somewhat flexible and haven't thrown any codes.
I'm thinking about replacing some because they don't feel tight on the nipples (possibly swollen). I'll at least have some hoses in handy in case some develop cracks.
I used to see smaller diameter vacuum hoses.
I'm thinking about replacing some because they don't feel tight on the nipples (possibly swollen). I'll at least have some hoses in handy in case some develop cracks.
I used to see smaller diameter vacuum hoses.
#14
@LEX2K2 I noted the shortcomings I know of for silicon. Under what conditions did you see vacuum lines dry and crack like virtually all the OEM lines do? Silicon has been used for vacuum lines, spark plug cables, etc., for decades. Mercedes and BMW have used silicon vacuum lines. It's been years since I worked as a mechanic (except as a hobbyist), so I can't say if they still do or not.
silicone=type of polymer
Just wanted to clear that up.
When I say silicone vacuum lines I'm making a guess, I think that is the material. I know people that bought "silicone" vacuum lines replaced every one under the hood. They lasted a few years. Maybe they were not silicone, they felt and looked like it. What happened is they swelled at the ends and dried out, no more tight fit. The Toyota ones in the image I posted never do this in my experience and are not especially expensive.
#15
silicon=sand
silicone=type of polymer
Just wanted to clear that up.
When I say silicone vacuum lines I'm making a guess, I think that is the material. I know people that bought "silicone" vacuum lines replaced every one under the hood. They lasted a few years. Maybe they were not silicone, they felt and looked like it. What happened is they swelled at the ends and dried out, no more tight fit. The Toyota ones in the image I posted never do this in my experience and are not especially expensive.
silicone=type of polymer
Just wanted to clear that up.
When I say silicone vacuum lines I'm making a guess, I think that is the material. I know people that bought "silicone" vacuum lines replaced every one under the hood. They lasted a few years. Maybe they were not silicone, they felt and looked like it. What happened is they swelled at the ends and dried out, no more tight fit. The Toyota ones in the image I posted never do this in my experience and are not especially expensive.