Hello, my prius started to lose engine coolant and i went to a car shop and they diagnosed that it is leaking at the catalytic, and i got a quote for almost $3,000 for catalytic replacement. I searched the internet and found out about coolant bypass as a fix is it a safe alternative long term? And is there a mechanic here in the bay area that you can recommend that can do a bypass? Thanks!
Welcome... The exhaust gas heat exchanger is part of the emissions control system. Under CARB rules, it's warrantied for 15 years or 150K miles, since it was originally sold as a PZEV. If you meet those specifications, it's a free repair. If your just over 150K miles, you can ask the dealership for a good-faith replacement, since there's a TSB out for this issue. It never hurts to ask; worse they could do is say, NO. California Vehicle and Emissions Warranty Periods | California Air Resources Board I'm looking at your three attachments and concerned about your middle one. The exhaust gas heat exchanger and catalytic converter is a one piece assembly; the $900+ labor dollars seems excessive. Also the heat exchanger is behind the catalytic converter, so leaks isn't going to damage it; but can cause the car to overheat - due to low coolant. I'd probably shop around. According to that estimate, you could buy the OEM part outright and pay any muffler shop a couple hundred to install it. 4-6 screws and gaskets; would take them less than an hour, unless there's a lot of rust on it. https://parts.olathetoyota.com/v-2017-toyota-prius--two-eco--1-8l-l4-electric-gas/exhaust--catalytic-converter FWIW; if you bypass that heat exchanger and the smog stations sees it - They can FAIL you and/or say you were tampering/bypassing emission control device. I don't know of any 'honest' mechanic that would do that, they could lose their license and/or get fined. Hope this helps.....
You could in theory bypass it, then put a catshield up to cover it a bit. Most SMOG stations don't get too busy under there and some don't even check under the hood these days.
It's way safer than what you are doing now by continuing to drive it. Your engine and head gasket are the big concern. I would bypass it as a diagnostic to verify no engine damage has occurred. A bypass will not damage the catalytic converter. A coolant leak can and will ruin your engine. There is a method to bypass it from the top although you have to remove the windshield wiper motor and base to access it. This video starts with the wiper cowl removed which is not hard. A no parts required fix you could do in your driveway. The alternative is replace which could be done later for thousands and not diy. Below Capture from Gasket Masters Gen4 Bypass No Parts Required Video
