1

I have a '94 Honda VFR and two of the coolant hoses are 18 mm ID.

18 mm is a very unusual ID, and it would be easier to for me to go to the auto parts store and get a size they have in stock, which is 3/4" or 5/8".

Is it at all possible to successfully replace the hoses with a readily available ID?

| improve this question | |
  • If you can get the hose on there, yes. Too small can be stretched over or too large (a little bit) can be pinched with a good hose clamp. If it fits, it ships. I don't know what the difference between 18mm and a 3/4" or 5/8" would be ... I think a 3/4" should be pretty close (just checked, it's a shade large at +.041"). You should be able to take that up with a hose clamp ... use some grease on it (inside) to help it seal. – Pᴀᴜʟsᴛᴇʀ2♦ Jun 6 '19 at 1:00
  • That's an answer @Pᴀᴜʟsᴛᴇʀ2, but I'm not sure the math is right. 3/4" in mm is 19mm. – GdD Jun 6 '19 at 7:58
  • 3/4" = 19.05mm (exactly) so in practice it is identical to 19mm. Or equivalently 19mm = 0.748." But 18mm = 0.709 which is significantly smaller than 3/4." – alephzero Jun 6 '19 at 9:05
  • 39 thousands of an inch is significant? Not when it comes to rubber hoses. – Moab Jun 6 '19 at 15:48
  • @GdD - A 3/4" is .750". 18mm equates to ~.709". That's only a difference of .041", as I stated. Divide that in 1/2 to get the difference (0.0205") between the hose and the fitting around the circumference. That's a difference of a little over 0.5mm ... that can EASILY be taken up with a hose clamp while using a rubber hose. As Moab stated, not sure that's significant. – Pᴀᴜʟsᴛᴇʀ2♦ Jun 6 '19 at 20:32
0

18 mm is closer to 3/4 inch (roughly 19mm), 5/8 of an inch is closer to 15.5 mm. 1 mm is .03937 inches you can't beat that. Go for the 3/4 inch.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.