Opti Vacuum Harness?
Opti Vacuum Harness? Back in 2022 I had an engine fire and burned up one of the valves in my opti harness. 2023 and 2024 saw me having opti issues. Last year I took apart the first "failed" unit, cleaned/reassembled and it ran fine. I'm convinced that blowby was getting in and causing issues, so would like to get a filter, check valve, orifice, whatever GM used instead of dropping $100 on an aftermarket harness. Does anyone know what components I'm after?
Launching!
Joined: Oct 2014
Posts: 220
Likes: 36
I was pretty much in the same boat you are. Swapped a 96 engine into my 93 and didn't get the vacuum hose to vent it, thought the atmosphere would be enough like the older style. Well it wasn't. The opti corroded within a few thousand miles. Realized I needed the hose but couldn't find a way to make one. After a week of looking I ended up buying the GM $100 vacuum harness. I foresight I didn't want to end up doing another opti clean because some aftermarket valve didn't work enough. Here's my money GM.
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
without the vacuum harness, the opti will quickly get condensation in it (500-1k mi)
These may work to make your own harness. Confirm you have the flow orientation correct
These may work to make your own harness. Confirm you have the flow orientation correct
I still have the harness, all I need is to make sure I get the correct orifice and/or valves. It's not open to atmosphere, rather blowby from the engine is finding its way in.
