I discovered that my bimetal vacuum switching valve (BSVS-1), the violet one on the thermostat housing, is leaking antifreeze. I think that the plastic is shot because there was some antifreeze in the vacuum line when I pulled it off. I do not think it is the threads, but the plastic. Has anyone seen this before? Can I do a JB Weld ghetto fix and still have an operational valve or should I suck it up and order new? Did not see this particular subject in the 3 1/2 page search function.
violet BVSV leaking antifreeze
- Thread starter Heartworm
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
Suck it up and replace it. Failure in the field could cause overheating.
I'd kick myself if I spotted an easy fix and ghetto/cobbled it and
blew a headgasket. My 2 cents.
I'd kick myself if I spotted an easy fix and ghetto/cobbled it and
blew a headgasket. My 2 cents.
Don't know if ya can buy a used one; it would fall apart during removal from the donor....
Yea, I agree about hate to spend money on plastic: wait till ya see how much
Maybe a brass allen heat pipe plug & just bridge the vac lines ( smog stuff & vac advance would work 'too soon' relative to engine temp). Oops, noticed you are desomgged; well, then vac advance would work when engine cold (rather than not work until engine warmed up) If yalive in south, no problem
Peter ( with bypassed plastic BSVS BS)
Yea, I agree about hate to spend money on plastic: wait till ya see how much
Maybe a brass allen heat pipe plug & just bridge the vac lines ( smog stuff & vac advance would work 'too soon' relative to engine temp). Oops, noticed you are desomgged; well, then vac advance would work when engine cold (rather than not work until engine warmed up) If yalive in south, no problem
Peter ( with bypassed plastic BSVS BS)
Used ones are often not too bad. I would look there first.
Butt Ugly Chuck
Fish Biologist, DOGE-retired. S#iT!
When you replace the BVSV, put some loops in the the vacuum hose to reduce the liklihood of re-breaking them on install.
Butt
Butt
I have a pink on that I just took off yesterday. It is the bottom one. I'm not sure of the difference, but if you want this one, let me know. I believe that there is a difference in the opening temps, but not sure.
never heard of one leaking... I know the vac nipples break easy 
maybe it's loose, see if you can snug it.
maybe it's loose, see if you can snug it.
- Thread starter
- #9
Thanks for the replies. Both our rigs are desmogged. The violet BVSV-1 receives vacuum from the carb at the EGR R Port and switches it to the "S" port on the VCV for EVAP. Thus, I want to keep my BVSV-1 because my charcoal canister was not removed. I did away with the steel tube "spaghetti junction" during the desmog so the vacuum hoses mentioned above are straight shots. The pink BVSV-2 is plugged although it remains in place. It is my understanding that the BVSV-1 and BVSV-2 open at different temperatures, and thus, are not interchangeable.
vtcruiser60
SILVER Star
pretty sure I have this valve sitting on the shelf If I can help you out. I think they are 22-27 bucks at the dealer.
I don't see how it could leak.. it's brass plug (kind of like a cup with threads on the outside) a part inside of it reacts to temperatures and moves letting air pass or not pass through it. I would think IF it was leaking coolant into the vac line it would be under pressure and be pushed (by the coolant system) and pulled (by engine vacuum) into your carb... but anything is possible with old stuff
- Thread starter
- #14
OK, I have never had one out so it could be as you say. I will check it out when I receive the new one that I ordered from Cruiser Dan (~$30 plus the ride). It will be interesting to see what is going on. I could have sworn that the antifreeze was coming out of the tubing when I pulled it off but it may have just seeped around the edges of the tubing.
