Help: 2019 prius 155k - 1-2 second shake when starting up

if the coolant hasn't been changed yet, it could be a normal level for 155k.

ifit were mine, i would do all the standard maintenance for time and miles, and throw in engine items that aren't on the list, like throttle body cleaning.

if it is still rattling, then a head gasket check is appropriate. you can find methods on youtube, like boroscope.
top up the coolant, and keep an eye on it.

 

any car with 155k is a possible head gasket issue, but unlikely

 

Get all the maintenance up to date and change both coolants. Pay special attention to the old spark plug condition and keep track of where each plug comes from. Post pictures of the ends of each plugs.
It may just be condensation in the combustion chamber, but 15K mile oil changes is really pushing it - especially if you use cheap oil. IMHO.
Get that coolant level topped off right away, because that's a sure way to blow a head gasket - since the dummy lamp doesn't go off until 248+F, NO beeps or alarms; you just need to notice it lit!!!

 

Let me correct that for you. In a Gen 3 Prius, the high temperature light goes on at 248F. I am guessing that a Gen 4 is similar.

 

Sorry; typing that while my coffee was brewing. Already corrected it once - had typed 485F and caught it before posting - still didn't feel right; just thought it was because I hadn't had my coffee yet.

@Brian1954 Thanks for the correction

 

Good Grief...
What a design decision to Not ALERT the driver with a loud warning that the Engine is Over Heating..

I at least get a gentle beep when the fuel light comes on.
I guess that's more important than letting you know your engine is about to self-destruct.

 

Worse; I don't believe it's logged either, when you do a history search of the OBD2 error codes

If that 'design feature' wasn't incorporated - How would they sell you another car?
IMHO; anyone with >150K miles should either monitor their ECT, with a real gauge or preemptively replace that electronic coolant pump; if they want to side-step a head gasket issue.

 

Were 2019's out of the production period where the Exhaust Heat Recovery system was springing coolant leaks? I think so, but not sure.

 

I believe they were, but Toyota is one of those companies that does mid-year changes - so an early 2019 may actually be assembled in 2018. Only the vin or door tag would clarify that, but I would still test for that failure.