2013 Prius, 160K miles - daily driver, never had any issues upon startup. Started it up today and heard this wild noise. Car was shaking so I don't let the car/recorded video run too long. Any thoughts on what might cause this?
Blown head gasket. It tends to allow coolant to leak into combustion chambers overnight, create compression havoc at morning start up. If you stick with it be sure to clean EGR system and intake manifold, and repeat cleaning at least every 50k miles. see my signature for some head gasket and EGR links, plus last link is full engine section from repair manual. (On a phone turn it landscape to see signatures.)
How many miles on the car? Has the temp been hot during the day and then cooler at night? It might be condensation, it's happend a lot with the Prius. Check the coolant tank, is it low? If it is, you could have a head gasket failure. DO NOT PUT ANY SO CALLED HEAD GASKET SEALER IN THE COOLING SYSTEM! It will just cause you huge headaches and cost you a LOT more money and work when you replace the head gasket. If it is the head gasket, change it now. You caught it before it causes worst issues.
Check the coolant level, Prius owner usually never top up the coolant since it is practically sealed until the overflow reservoir reaching certain pressure and the valve opened. In California, You have Head Gasket Master, a Mobile mechanics who can do it on your parking lot for quick, cheap, and right. Gasket masters - YouTube If your car already consumes a lot of oil, say 1 quarts every 1000 miles Autobahn/Interstate drive, just get a used 2015 engine instead. It solved both the head gasket and oil consumptions. Otherwise, do he head gasket repair properly but check if it is not an stuck open EGR valve. It happened to me 4 years ago when I open the black plastic cap on the EGR. I install the screw-in rotor not all way down before installing the black magnetic cap in. That cause the EGR valve open at zero position. It rattles and shakes violently. I stopped and fixed it right away.I was just curious if the EGR is not clogged and move freely on the plunger.
Do you have any links for the full EGR system/intake manifold cleaning you'd recommend as a pre-emptive measure? I just asked a couple of reputable shops in the Bay Area whether they'd do it for my 2012 Lexus CT200h while that head gasket is still kicking, and I was met with a few troubling responses: "That car doesn't have an EGR!" "You don't need to clean the EGR, if it got clogged you'd just get a check engine light. Not going to save your head gasket"
DO NOT ALLOW THEM NEAR YOUR CAR! Nutzaboutboltz has some videos. Plus you do a search on duck-duck-go and come up with several videos
Here’s a Cole’s Notes workflow, excluding the intake manifold: Professional EGR Cleaning Resources | Page 9 | PriusChat also see top two links in my signature (on a phone turn it landscape to see signatures).
