Hi all! First time making a post here so bare with me for my lack of knowledge on some things I currently have a 2017 Prius Prime Premium with almost 75k miles on it. I went to the dealer about a week ago for them to do an oil change, get new tires and an alignment, run a fuel injector cleaning service, and do a full inspection around and under the car. the technician said that everything looked great. I don’t have too many concerns with my car on my end either, but as I have been looking at threads on Reddit and on here, and I’ve noticed that people keep talking about something regarding a heat exchanger bypass service or “fix”. My coolant system hasn’t shown any issues as of yet, but I regularly keep an eye on it with a OBD-II reader with live data whenever I have longer drive. i’m going to be taking a road trip next month that’s going to be just over 1000 miles one way and I wanted to know if I should keep an eye on my cooling system and have that heat exchanger bypass service in mind, or if I should wait to do that later down the line at a higher mileage or wait until it becomes a problem. lmk. As always, feedback appreciated. Thanks!
Wait until it becomes a problem. When you do the bypass it will increase the time to warm the cabin because the coolant is not being heated by the exhaust anymore. Also, the easiest way to keep an eye on the coolant levels is visual inspection of the reservoirs under the hood. The engine coolant reservoir is the bigger one on the left side. The smaller one on the right side is for the inverter. Both should be kept at level MIN or higher.
they don't all develop the leak, but keep your eye on the coolant frequently. may worth bringing the repair parts and tools with you? idk. depends on your risk tolerance
wonderful. I will make sure to also keep a spare bottle of coolant just in case. I haven’t had a problem thus far; she’s been a tank through and through especially with harsher weather so it’s good to know to just keep an eye on it I think I will keep an eye on both the temperatures and levels frequently, checking the levels when I stop off at rest stops or fillups. I’m not sure if I’ll have access to the tools needed but I think my risk tolerance is pretty good considering I have AAA too ♀️
It does not take a long drive to blow a head gasket if the heat exchanger goes out. You should have an alarming obd2 monitor on it at all times and understand its stop and tow if it goes off. No alarm and you may miss it. I set my obd2 P10 to alarm at 215f - the car light comes on around 248f with no sound. If it were mine I would do the no parts required under the hood bypass and forget about the potential problem.
Help educate me a little bit if you are able to. The no parts required bypass? What goes into all of that?
It's just one data point of course, but when my 2017 went bad, there was a sloshing sound I ignored for several week when the coolant was slowly leaking.
You have to remove the wiper cowl assembly to access the hoses under the hood. Or you do from underneath but have to rig a bypass hose. Gen4 Cooling system (Does not apply to Gen3) When done from above you end up with two hoses going down to the heat exchanger not connected. Some would plug, others do not. Gasketmasters Video with Gen4 bypass last half. Starts with Wiper assembly removed. Read the comments but realize some are gen3 questions. The secondary cooling loop is different and would not work as shown above.
It really isn't an issue on all cars. If you simply pop the hood and eyeball the coolant tank on the passenger side of the car - just make sure it doesn't get low. Those leaks start out very small and you'll notice your coolant level going down; slowly. Those who don't bother to check under the hood at every fill-up; usually get a rude awaking. It's a routine for me since I started driving. Hope this helps.... FWIW; if Toyota equivalent coolant isn't available, distilled water will work. Just make sure you get the coolant concentration rebalanced before the next hard freeze.
I have heard of that so I will keep that in mind in case I can’t come across Toyota specific coolant thankfully, I like to open up my hood and make sure everything is still looking good and working properly every week because I’m very much a clean freak and like to keep even the engine very nice and neat so I guess I will take the time to check the coolant levels when I do that too! Thanks for your help. I appreciate it! Both of these resources help a tremendous amount! I’ll keep these bookmarked and make sure to have them on hand in case I run into this issue at higher mileage. Honestly, doesn’t seem too hard from what I see here so I’m pretty sure I can confidently do it If the time ever comes If you don’t mind me asking, what OBD2 reader do you use that has an alarm? I used a Fixd one and I just eye the temps and other measurements while driving with my phone mounted
Keep in mind that these cars don't have an audio alarm when the temperature parameter is violated - it just flashes the over temperature warning lamp; which in NOT logged in your CEL. You can set an audio alarm violation on the P10 unit. Hope this helps....
That can be difficult in practice, due to the specd Toyota coolant being pre-diluted 50/50 with water. You’d need to find a compatible alternative that’s full-strength. Toyota Long Life Coolant would do I think, but hard to find, maybe phased out? Simplest expedient would to score a bottle of Toyota Super Long Life Coolant (the specd, pre-mixed coolant), stick with that. It’s readily available at dealerships, about $24 CDN per US gallon. Up here (in the “great white north”), they mix it 55% coolant . Too, you’ve yet to see any coolant loss?
Not just yet thankfully! I tend to check under the hood regularly and when I took it into the dealer they said that all of the fluids looked good so nothing so far! I’ll definitely keep an eye out tho!
