NEW!!! Service Bulletin for Engine Knocking at Startup T-SB 0012-10

Here's a video:

 

The p301 I believe is your number one cylinder misfiring If you think that that's not happening by seepage from the head gasket move that coil to number two or number three and the number three or number two coil to the number one if it's a bad coil the mist should move move the plug and the coil from one to three and the coil and plug from 3 to 1 The mist should now be at 3:00 if it's not in fact something quenching the fire in number one. If the miss doesn't move then more than likely something's causing the miss internally in that cylinder usually that's steam from water seeping into that cylinder and trying to put out the fire which is what's happening in the cylinder when it's running correctly.

 

246k miles, that’s unusually long. Was the video with cold engine? If so it smoothed out quite fast. Cylinder one is where head gasket failure usually starts, on the common wall between cylinders one and two. As @Tombukt2 says, swap coils and plugs first, see if code follows. It usually doesn’t. Then boroscope inspection with coolant system pressurized, looking for coolant seeping past head gasket, and/or exceptional clean piston top (due to coolant). Or leak-down test.

has EGR and intake manifold been cleaned, and when?

how’s coolant level in reservoir?

 

Unusually long for what?

Yes, cold. Doesn't do this when it's warmed up. After ~30 minutes of being off, the next time I start it up, it'll sometimes do it again.

Don't believe this has ever been done unless it is part of one of the regular maintenances I have performed by Toyota

Looks low:

 

Head gasket failure.

Doubt it's been done then. Taking off the stainless steel pipe between EGR valve and intake manifold and checking for amount of carbon build-up will get some idea of how the rest will be. Video #16 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

Top it up to full line, then watch for a few weeks. That line is hard to see, it's this:

 

Mid to late stage head gasket fail.

 

Will see what they say Wednesday I guess when I take it in. Thanks!

This is the first (potentially) major issue I've had with the car so really can't complain.

 

My shop removed the plugs, and put a borescope into the cylinder, and pressurized the coolant system. They confirmed that coolant is leaking into Cyl. 1 at the head gasket/engine block interface.

They did not recommend simply replacing the head gasket, and quoted appr. $5k CDN to do this. They recommend engine replacement, and found a used one with 191k km on it, all-in with tax I'd be looking at $7k CDN to go that route. Hard pill to swallow when the car is likely not worth that (2010, 395k km) - but, at the same time... used cars are overpriced, anything new has a long wait list (my dealership is quoting 4+ years for a Prius Prime), and this is the first major repair I've ever been faced with - the worst until this point was brake rotors and wheel bearings!

Lots to think about.

 

How long have you had the cold-start rattle? If it's just started the chances for simpler head gasket replacement are better I think.

There could be several reasons they recommend against head gasket replacement:

Maybe they saw scoring on the cylinder walls.

Or suspect a bent piston arm, though I'm not sure that could be determined with boroscope??

Or could be as simple as they don't want to take on the risk, haven't done them before.

That last one is not entirely frivolous either; it is a gamble. Get a second opinion?

For just head gasket replacement? Or the proposed engine swap? Or either? Ugh, that's bleak. The parts, just round numbers, for just doing head gasket replacement:

Toyota gasket kit, includes head gasket: $300CDN
Replacement head bolts: $150CDN (virtually a guess, haven't checked in a while)
(head bolts "can" be reused if they're within specs (see last link in sig) but new is safer)
Shop supplies: $50CDN (cleaners, form-in-place gasket, etc)
Machine shop inspection of head (if warranted): $500~1000CDN??? (machine may well not be needed, if valves seal, and warpage within specs (see last link in sig))

 

Do they warranty the used engine? How do you know it doesn't have the same issue
you have????
You should find another shop. Are you burning oil? If not, and depending on how much
you drive in a year, do the head gasket. Since you caught it early, the head shouldn't be warped.

 

It's only been doing this for a week - just started out of the blue one day, without warning.

I got the impression it was something like this. They are a big dealership with high throughput, and may not want the headache of having a car sit there for a few days while they completely rip the engine apart, and put it all back together. The advisor and tech I talked to about it did say they had just gone through this with another customer with a Camry - the customer insisted they do the Head Gasket (rather than engine swap), and a week later the issue returned.

For what it's worth, I've always taken it to the same Toyota dealership since the car was new and they have always treated me fairly, so I do have some loyalty and trust there. They know me and the car has been well taken care of and is in very good condition. So I am leaning toward keeping it, vs. ditching it and trying to find something used (although I have always wanted a Prius V).

 

Dealers around here won’t do a head gasket alone. Too many warranty reworks which the mechanic has to do free.

The dealers also know the piston and ring problem only gets fixed by them with a new short block and a rebuilt head. You do get a warranty but you are out at least $7500.

If you push them they will do a used engine swap, usually a JDM engine. No warranty.

Obviously the dealer would much rather sell you another car and will give you $1500 as a trade.

 

I've contacted a few local shops in the area which might do a head gasket replacement. The more I think about it, the more I want to do that and keep going. I think it's the right choice.

Out of curiosity - at least one video I watched online mentioned one of the symptoms of this is "water sound, sloshing around behind the dash on startup or when first driving off". I did notice that, starting a few weeks ago, but couldn't put my finger on what I was hearing. How is that related to this, and what exactly is going on there?

Thanks everyone for all the feedback and suggestions.

 

If you do get the head gasket replaced, make sure you also replace the engine water pump.

 

So I've collected (3) quotes for Head Gasket Replacement:

• Toyota, $5400 CDN after tax, incl. Coolant Pump Replacement
• Shop 1, $5200 CDN after tax, incl. Timing Chain (no Coolant pump)
• Shop 2, $7125-$8000 CDN before tax, no Coolant Pump or other work

Toyota also quoted $7100 CDN after tax for a used engine with 190k km on it. Makes it kind of seem stupid not to do the engine swap for just a bit more. My pride makes me wanna just do the head gasket and keep going but the numbers on paper sure are pointing me toward engine swap.

If I had a week off work and a garage I'd love to tackle this myself.

 

You won't need a timing chain. WHY would they try to sell you a timing chain??????
Go for the coolant pump replacement.

 

$3900-$5200 US ($7100 Canadian) is ridiculous for a head gasket job in the US except at a Toyota dealer who usually won’t do a head gasket job due to the risk of failure.

In fact we can get a quality rebuilt engine with revised pistons and rings shipped to our independent shop for less than your lowest hg price. I assume US to Canadian shipping is more than the $500 US we would pay, but I might ask about local independent rebuilders (a specialist rather than a general mechanic).



Assuming you can’t get rebuilt at a reasonable price, I would look for a JDM used engine (used engine from Japanese Domestic Market). There are resellers in major US cities and probably in Canada.

 

Are you burning any oil? Can you do another borescope of all cylinders to check for any scoring in the cylinder walls? You want to rule those 2 things out before doing just the head gasket.

If you are halfway through a head gasket job and take off the head and notice any scoring or worn down cylinder walls it may turn into a full engine replacement. Also used engine is not enough without doing an inspection for the same issues and at least installing the updated 2015 piston and piston rings.

The full video is worth watching but this section shows what I'm talking about:

Another video for checking worn cylinder wall with borescope camera: YjsUsXc3TPU;t=609

Another thing to consider if engine replacement is worth it is the rest of the car. Any rust? Heath of the hybrid battery? Have you had the ABS pump/manifold issues yet? The hybrid battery and ABS could be another $2k - $4K issues. But that point if the body is good you have a "new" car mechanically.

Also how far are you from Chicago, it may be worth it to reach out to the YouTube guy's shop and see what your options are. Probably the most honest mechanic you can find to do this type of job or tell you if it is worth it or not. Its called "TCCN Automotive Inc."

 

Thanks for all the suggestions and advice. I'm leaving it with the independent shop which has a lot of experience with Prius', and they're going to replace the head gasket, machine the top part/valve assembly, and replace the timing chain. I asked about the water (coolant) pump, and they said not worth bothering replacing it.

 

"replace the timing chain. I asked about the water (coolant) pump, and they said not worth bothering replacing it."
Well, that's a mistake. And he's got it backwards!
It's YOUR car. Sounds like he's just making sure you're a repeat customer.