After reading about major engine damage in a Prius Prime caused by low coolant, I checked the levels in my 2018 Prius prime. The engine coolant was low. I went to my trusted local auto repair shop and was told that I shouldn't add fluid because there was a leak. They are thinking it's going to be a minute one in a hose connection. They told me there's no reason why coolant levels should be low. I'm set up to do a pressure test tomorrow. Just wanted to see if anybody else had any input.
I'd reduce the trust level a bit. For starters, even with no leaks, the coolant level can very slowly drop. That aside, early years of Gen 4 have had chronic issues with coolant leaks in the Exhaust Heat Recovery system, whch circulates coolant through a radiator within the exhaust system, to speed up engine warm-up. Toyota USA has issued a Technical Service Bulletin on this. There's numerous threads here on the subject, one for example. Coolant detected in exhaust | PriusChat The required replacement part is quite expensive, and often in short supply, which is convenient for Toyota USA. Also, dealerships will often misdiagnose the issue, and/or "forget" there's a Technical Service Bulletin. The coolant loss is sometimes misdiagnosed as a head gasket failure. FWIW, if the leak is neglected long enough, it can lead to engine overheat and head gasket failure.
Thank you so much Mendel! I will cancel that appointment for now and and just add coolant so that it is no longer low. As soon as I can I'm going to look into that technical bulletin you mentioned.
Asked, and answered expertly. There's a ton of info out there on this condition and I encourage you to read it all, but in the meantime it's ALWAYS a good idea to monitor your fluids and filters. If you're losing coolant and you do not know the cause that's exactly WHEN you would keep the reservoir topped off!! Remember. An over-temp condition in a car is an emergency that can trash your engine in seconds - NOT minutes. If a human with a hidden bleed shows up in an ER they do NOT wait to replace blood volume until they figure out where the leak is!!!! Get another mechanic.....or? Show them this thread and invite them to elaborate on their advice. They might have a good reason based on what you told them at the time. Me? I would NOT reward Toyota's refusal to issue a recall for this issue. There are 'other fixes' for this condition. Just sayin.... Good Luck!
it's important to know how fast the coolant is dropping. keep a supply on hand and check it daily until solved. if you travel, take some with you.
Get a 4 quart bottle of Toyota Super Long Life Coolant from the dealership. While Toyota USA does not say you HAVE to use it, the laundry list of specs they list for the coolant had me thinking, hey just use the stuff they recommend. It comes pre-mixed 50/50 with water, you don't dilute it.
In the USA, where could I find some one to do the fixes you mentioned? I am guessing you mean bypassing the heat exchanger? Thanks for your help! In
I plan to get to the dealership sometime tomorrow. I'm hoping they're open on Labor Day. Probably a stupid question but, is this something that only affects the car when it's running in hybrid mode using gas? If I am able to run only using electric, the engine coolant isn't involved?
. The low coolant level light has not come on on the car. I just lifted the hood and noticed that it registered low on the bottle.
Yeah, if you’re in electric-only, low coolant is not an issue. AFAIK there isn’t a low coolant light, only an overheat warning. Which you really don’t want to see, keep a close eye on the reservoir. also, how low is it, and what’s the miles? It’s not unusual to have a minor drop in reservoir coolant level, as car ages, say an inch every 50k miles. Say maybe due to air pockets working themselves.
My Prius experience was with the G3.....so others will have more experience. BUT(!) I would bring the coolant level back up to the mark and monitor it for a while as a good first step. Your car is at least 7 years old and as mentioned above you may not have any problem at all.
there are youtube videos showing the bypass and threads here with pics. any mech can do it if they are willing. tampa hybrids would probably do it, but that's a haul, and you don't want to use the engine if the overheating light came on. i hope your head gasket is ok!
