Does driving in PWR mode increase chances of blowing head gasket?

No
.

 

The engine and its ECM don't even know whether you are in PWR mode or not. The ECM just gets requests (give me yea much power please) from the power management control ECU, and that ECU knows which mode you've selected and how far you're pressing the pedal, and sends a request to the engine based on both.

 

we don't know why some cars blow their tops, and some don't. there are theories though

 

Look, if you already have high mileage and ya haven't cleaned your EGR, intake manifold, and throttle body. Just drive slowly and easy on that gas pedal. Don't put stress on your engine.

 

Going 150k miles without Exhaust Gas Recirculation clean out will do it reliably.

 

Except when it doesn't.

 

Hey i need your professional opinion, so prius are known to have bad head gasket, but i read online that my year and up, they revised so made it better i guess, but sometimes especially cold starts the engine shakes and rattles like it’s knocking for a few secs and goes away, half of the people say it’s just the egr valve and the intake manifold it connects to just needs to be cleaned out of all the black carbon build up, the other half says it’s a bad head gasket leaking coolant into the combustion chamber and my engine is trying to get rid of it, but my coolant level is full and only goes down a lil when it’s warmed up after driving, and i also opened the cap and ran the car for a few mins and there’s no bubbling, it’s just calm, i check the dipstick and the oil is yellow but when i flip it to the other side, it has some dark red residue on it and sometimes it’s in pieces, it’s not sludgy or white or brown like i see in pics, I believe it’s the lucas oil additive the guy added into my oil, that’s why i see that stuff,But there is also condensation at the top of the coolant resevoir, like drops sticking to the top of the resevoir inside but i think that’s normal no?Also no codes or check engine or misfires, so what do you think?

 

exactly

 

insurance is often helpful, but not always necessary

 

My 2 cents: the head gasket failure causes the shakes at start-up, and the EGR clogging causes the head gasket failure.

 

There's probably a relationship between frequent power button use and an increased number of head gasket failures, but I'm thinking that it's not the power button itself.

 

Try Liquimoly oil saver additive. But clean your EGR, intake manifold, and throttle body.

 

Using the power mode might affect the inverter, since there have been several recalls of software upgrades to the the ecu to detune the power feed to the inverter.

Actually, I would be more concerned about the condition of the coolant for the engine. If it is degraded and acidic, it will actually "eat" away at the integrity of the head gasket. The 100k or 10 years change interval of the SLL coolant is actually too long in my opinion/ A 5 years interval might insure a longer head gasket life.

 

At least after first change the interval is halved. Yeah maybe just go straight to the halved interval.

 

I bought a head gasket kit and getting the egr system cleaned out also but how do I know for sure I don't have any bent rods? My car hasn't hydro locked and I don't see any symptoms of a bent rod, I probably won't know till I see the top of the cylinders

 

Will try that out! Thank you!

 

All I've heard is to check all the pistons at TDC, look for any that are slightly lower. You might be able to do this just dropping a dowel down each spark plug hole, cranking the engine by hand. Get the dowel as perpendicular as possible, bring the piston up, and mark the dowel with a very flat knife blade, while pressed against the valve cover. Hopefully you can eliminate vagaries enough to make it meaningful. Or: check with the cylinder head off, with the depth gauge on a caliper if need. Though I believe the top face of piston is virtually flush with the top of block, if ok.

 

Weren't numerous cases of start-up "shakes" being reported here when the cars were nearly new, before head gasket failure was likely? There must be some additional, less ominous, cause.

My recent anecdote for someone to explain:
My Prius has only rarely exhibited the start-up "shakes," maybe 3 or 4 times in the ~87k miles I've owned it. Two days after a 415-mile trip, I was asked to move my car a very short distance in a driveway. Aware of the infamous tendency of Prius engines to misfire and shake on the following start after starting the engine without allowing it to warm up, I tried to make that move without starting the engine. However, the temperature was slightly too low for the EV mode button to work, and I wasn't quite quick enough, so the engine started and ran normally roughly two seconds before I could shut it off. I hoped such a very brief run time wouldn't provoke the issue. Wrong!! The next time I started it, the following day, it had the worst case of shakes ever. Since then (about 2 weeks, maybe ten cold starts) no more start-up shakes.

 

Yeah cold-start and quickly shut down was also implicated. I did get knock on start-up after doing that, one time. Maybe that scenario AND failing head gasket both tend to leave (uncompressible) liquid in the combustion chamber?

I really wish Toyota had increased the roughly 15 second lag on engine start-up, to say 60 seconds, make driveway shuffles (without engine start-up) a lot less stressful.