Volvo RWD 700 Forum

1985 745t

Noticed a growing hissing whining type sound that increased as I boosted and decided to investigate. After tracing all the vacuum hoses and pulling the console I finally discovered that the "T" splitter off the vacuum hose from the engine had a slit in the middle of the backside of the T about 0.25" in length (the one that sends one hose to the emergency boost cut-off valve and one to the dash vacuum gauge).

I taped it up securely and plan on replacing it asap. However, I'm wondering if this is indicative of another problem? I don't run anything but stock boost, so I can't imagine the total pressure ever passes 7psi. That being the case that doesn't seem like enough pressure to cause a piece of plastic to split like this. Wouldn't a hose blow before the splitter?

I figured it might have been against something that caused it to weaken, but there's no sign of melting or heat damage to the T splitter. Is there any part whose failure could cause excess pressure in the vacuum system thatw ould cause this kind of damage? My hoses are fairly new (less than a year), so they might have held up to pressure that blew the splitter. Wastegate checks out fine, but I'm still using my original Pierburg CBV.

Thanks in advance.

-rt