2013 Cold Start Shaking - Head Gasket?

Hi everybody, used to be active in the Gen 2 forums, now in NZ with a direct import JDM 2013 (so manufactured in 2013, possibly even 2014 US model) Prius alpha with 133000km, or 80k miles. We've had it for about 7 months now, and I check fluids regularly and everything's perfectly stable, both coolant and oil. The coolant has been at the plastic seam since we bought it.

It's been quite cold recently, but we haven't had any issues other than on cold starts sounding a little rough like you'd expect from a cold start. Until Friday, when it shook badly just like how everyone describes the initial phases of head gasket failure. Since then, it's back to exactly how it's been.

Some people described this happening early on in ownership too without it being concerning, but a lot of the cases recently have been head gaskets. Obviously I'd love for it not to be the head gasket, but I'm getting used to the idea that it could be.

I took the EGR pipe apart to see how bad it is, and here's what I found. It looked quite clean in my opinion. Just a little bit of carbon here and there, although the worst part was the manifold end. I have the experience needed for the EGR cooler/valve cleaning, but I don't have the time, temperature, tools, or level working area I'd need for that unfortunately.

Intake Manifold End:


EGR valve end:


EGR valve pipe itself, which looks amazingly clean:


Again, the coolant hasn't dropped, but I know some people's have suddenly started dropping.

I'm planning to take it to the (independent) dealer garage tomorrow, simply because they specialize in hybrids and EVs, so they'll probably have the most experience with this engine specifically. How long do I likely have before the (likely) head gasket replacement becomes necessary? I have immigration expenses coming up soon, so a major expense is not easy on the wallet, but could be managed with tight spending. What options are there? A rebuilt engine is probably not super likely here in NZ, but possible. Also, it might not be affordable for our current situation.

Any thoughts are welcome, thanks!

 

Reading the oil catch can thread, it sounds like lots of people have experienced the cold start shaking during a real cold soak, so I'm not sure how big of an issue 1 occurrence is in very cold weather. Is this just normal and I shouldn't worry yet until there are more signs of a head gasket issue? Really the only symptom so far is the one cold start shake, and the things leading me away from the head gasket hypothesis are the age (only 80k miles), the lack of coolant level changes, the extreme cold, and the good-looking EGR condition.

 

OK, good news, thank you everybody. I think I'm likely not going to do the EGR valve/cooler myself until spring in a couple months, but from the condition of the pipe I think it's not in dire need within a matter of weeks. I'll keep an eye on the sound and as long as it doesn't happen too commonly I won't worry about it.

 

I'd appreciate constructive comments, thank you. What evidence do you have to indicate that? I know that your personal opinion of the Prius is full of doom and gloom, but many people have had the one symptom I have had and it often means nothing. So please back up your opinion.

 

If the coolant does drop I'm likely to have the HG replaced. I suspect that 80k miles is very early to have HG issues though, especially with what I'd expect Japanese driving cycles to be like (probably easier than American ones).

 

Out of curiosity, what mileage did your HG go out?

 

A little update from today. We did a lot more highway driving today, and it sounded great, even in the cold, and the coolant seemed to stay perfectly stable. I was concerned about a (very slight) lack of power (based on level 100kph cruise control power bars) early on, but I think it was simply because of the cold, because it wasn't an issue on the way back. Plus the drive to the town we headed to seems like a net level journey, but it's actually a slow steady climb.

I booked in for an appointment at the shop just to do leakdown/borescope/hydrocarbon testing to definitely rule out the head gasket. I also asked my friend who has a 2010 Prius whether his engine ever shakes on cold starts, and he said it does sometimes, intermittently, and sounds like it has for a while. That's with an already replaced engine for several years. If the coolant is stable then I'm not going to worry about it, and I'll just make sure to clean the whole EGR circuit and possibly install an OCC.

 

Also, mileage steadily improved with the highway driving since it's mostly been driven in town lately.

 

What is the best procedure for cleaning the manifold passages? I've seen a lot about the cooler/valve, but not a lot about the manifold side. Do you have a thread you point people to?

 

Appreciate it, thanks!