Had a check engine light come on for 2 days recently. Was noticing disappearing coolant (gradually increasing over a year). Had the overheat light (red boat icon) come on for 15 seconds once a month, always at the base of a hill. Then go back off at the steepest part of the incline. This also had been going on a year. Since it didn't stay lit very long, I thought it was a fluke of maybe shifting borderline low coolant going on an incline and just triggering it momentarily. The car is a prior salvage 2014 Prius (4H) that just rolled over 100,000 miles. Likely had hit a deer. My first mechanic stop said it was the head gasket. Since I ever noticed any sign of a misfire or milkshake oil, I sought another opinion. 2nd place, the Prius specialists, noticed the fan motors weren't activating, could be enough to overheat the engine, and replaced the sensors. $700 later I had a few good weeks. The red boat icon then returned familiarly for 15 seconds. Took it back in, they couldn't guarantee it wasn't the head gasket, but they didn't think it was because there's no misfire or shake. Very smooth running. They suggested with low confidence replacing the water pump and thermostat. This summer, after an oil change (from neither of the above mentioned places)I went back because I thought they didn't top off fluids, after refilling the coolant, they pointed out some pink cotton candy looking puffs in the frame alongside the radiator, and it was explained this was dried up coolant. They said if coolant keeps disappearing, watch the radiator. The radiator is very clean and we can't find any obvious sign of leaks now. I'm not a fan of process of elimination part replacement. I'm leaning towards just replacing the engine as it's cheaper than a head gasket. But the head scratcher is the only symptom we have for a bad head gasket is the disappearing coolant and absolutely nothing else. Smells kind of hot and burnt in the engine when hood is popped after a drive. Any thoughts? Thanks!
Head gaskets can fail a lot of different ways. If the breach is from coolant passages to the outside world you'd never get contamination in the oil or misfires, just coolant loss.
“Red boat” icon is likely low oil pressure light. How’s oil consumption, level? EGR and intake ever been cleaned?
Keep driving it keep an eye on it when the when you think it's overheating boat or whatever icon you're seeing if you immediately pull over and get out of the car with an electric temp gun and shoot the engine in different places are you seeing wildly different readings of your temperature not so much of the engine but the hoses in and out crossing the inverter at the bottom of the engine at the back of the head all of that we seeing really wild swings of temperature? I'd say keep driving it until it does shake and does the dance and then replace the engine and/or transmission so you have kind of a equal mileage set or whatever your plan will be. That's what we did to our gen 3 it's worked well so far
I would say the place that discussed the 'pink cotton candy' found A problem, not necessarily 'THE' problem. The pink fluff IS residue from a coolant leak. The amazing thing about coolant leaks that only leak when hot is that it often steams off without leaving 'liquid' evidence, but the puffies or crunchies that are left in the area are a solid tattle tale of something happening. Fix the obvious first. Puffies and crunchies fall in that category. Bad head gaskets that cause loss of coolant into a combustion chamber do not leave residue on the car frame next to the radiator. And as a side note, a radiator fan only provides "real" cooling when below 15ish mph. Above that, the vast majority of cooling is done just by wind flow pushing through the radiator. The fan(s) running or not running when above 15mph is of no significant consequence.
Thanks for the replies! Great notes. I'm gonna read again to absorb. Here's a pic of the specific "red sailboat" light. I'm surprised some of the advice is to keep driving it. I would have thought opposite.
Here's the exact icon. Oil level has been fine without any top off last 3 months. As far as I know exhaust/EGR have never been cleaned (didn't that know was a thing). The engine does smell like a burnt exhaust when opening the hood after the red light comes on. But then again it could be the burnt dirt of normal engine collection.
The BT-500 is a good way to test for head gasket failure...sorry to see this happening to your car! Amazon.com: Block Tester BT-500 Combustion Leak Test Kit - Made in USA : Automotive
I appreciate it. Thanks!! Will look into this. Also got two error codes signifying water pump, OverRev at 3000.
So when you start getting these water pump codes you pull your water pump and you take it apart and you'll notice the impeller plastic is peeling off and you can barely turn the impeller and it's bore get a new one another one whatever and check these things first and then plug it up while it's not connected to the car and turn the car on and you'll see it start to rev up and down indicating that it looks pretty good check it out
Was noticing disappearing coolant (gradually increasing over a year) If the pump isn't damaged, it could be that the cooling system is just losing coolant enough that water pump is cavitating or surging instead of providing a steady flow.
Also a new correlation, my heater usually took 20 min to kick in and get heat circulating all of last winter. More sign of water pump?
Ordered the Block Tester from the Amazon link and came next day. Assuming there isn't direct radiator access for the 2014, I did it by the coolant tank (tho directions say not to) this way engine running, then warmed up and revved up, and pumping quite a lot on the bulb, the color remained blue. Probably narrowed to water pump / stat? Thanks.
You definitely have repeated overheating for over a year. Personally I would pull over immediately and have it towed with the first light. No head gasket burning coolant? Then there is a leak. Any decent shop can diagnose a leak with a pressure test. Either way you will have an engine failure if guessing continues.
Did pressure tests at two different mechanics. Wouldn't like to guess, but over the 4 mechanics I've mentioned it to thought it was low coolant. Shouldn't the (red boat) light stay on more steady? In every case it came on for seconds and went away. Doesn't cause for much alarm, if a person even notices it. Biggest thing I noticed was never being able to top more than 40 mpg in nearly 2 years of driving it. Not sure if that's related.
My thoughts… 1. Leave car parked with bottom engine panels removed. Look for puddles. If there are puddles, you have a leak. If no puddles, you could have engine issues. 2. Drain and inspect the oil. If you have a bad gasket in the motor, and the coolant is bleeding into the oil, the color will reflect that. 3. If it takes unusually long to produce heat in winter, possible failed thermostat…forcing the engine to heat ALL the coolant before there’s enough to warm the cabin. Most lock in the open position when they fail. 4. If your coolant pump has failed/is failing most have a weep hole that allows a small amount of coolant to leak out as an indicator of failure. Your system may work well enough to get you around for many days, but you’re always getting inefficient cooling and losing coolant.
I can't believe this is still being tossed around. Let's just keep running the engine until it wrecks itself. If you want to not eventually destroy your car, get the water pump replaced, resolve the leak you have that is causing puffy residue and fill the coolant. Then enjoy the car. Or you can keep dicking around until you DO blow a head gasket or seize the engine from overheating. I find it hard to believe you've been able to find that many mechanics that can't figure this out.
