Anyone dealt with a cooked head gasket?

Hi everyone, has anyone here dealt with an “engine coolant milkshake” situation?

How can I tell if my cylinder head is warped or needs to be resurfaced? And how would I know if the pistons need repair or replacement?

Also, does anyone know a good shop in the East Valley, Arizona, that can handle this kind of work?

Thanks!

I recently did this on my 2011 gen 3 with 130k miles. I followed a few guides online and took my head to a machine shop. They cleaned it, decked it, and replaced the valve seals for around 80 or 100 dollars (don’t remember exactly). The total cost for me, including a new water pump and some extras, was about $600. It might help to do some of the other work while you’re at it. Good luck.

Use a mechanic’s straight edge and feeler gauges to measure the block and heads. I think the tolerance is .04, but you should double-check. Also, rotate the crank and make sure all the pistons travel the same distance up and down. If you hear any knocking, it could be an issue. Hitting the pistons lightly with a block of wood and a hammer can help you listen for rod knock.

If it wasn’t overheated too badly, it might still be fine. It could be worth asking local shops if they can recommend a trusted machine shop near you.

You might want to save time and effort by swapping in a JDM engine.

vanice said:
You might want to save time and effort by swapping in a JDM engine.

Is Gen 4 a better choice?

vanice said:
You might want to save time and effort by swapping in a JDM engine.

What exactly is a JDM engine? Aren’t all Prius engines technically JDM? I’m trying to understand how this works. Is it like GM LS swaps?

@Shawn
JDM means Japanese Domestic Market. These engines are used in cars in Japan. Once the cars reach around 60k miles, they often get scrapped due to strict regulations, and the engines are exported as low-mileage replacements.

@Tavi
Thanks for the explanation. A lot of people would just say, ‘Google it,’ but the point of forums like this is to have real conversations. Sure, I could search online, but it’s better to learn from someone directly.

@Shawn
Exactly. Half the time when I search for something, I end up adding ‘forum’ to my query because I want real feedback, not just AI-generated summaries or ad-filled articles.

Sully said:
@Shawn
Exactly. Half the time when I search for something, I end up adding ‘forum’ to my query because I want real feedback, not just AI-generated summaries or ad-filled articles.

Totally agree. It’s like comparing a generic repair manual to advice from a mechanic who’s done the job before. Manuals are helpful, but nothing beats firsthand experience.

@Tavi
Why do people in Japan replace their cars so early? Is it because they just prefer new ones?

Lilnim said:
@Tavi
Why do people in Japan replace their cars so early? Is it because they just prefer new ones?

It’s mostly due to their vehicle inspection laws, which make older cars very expensive to maintain.

@Shawn
You can find engines with around 40-50k miles on eBay. Just swap the long block.

vanice said:
@Shawn
You can find engines with around 40-50k miles on eBay. Just swap the long block.

I had a post here, but I deleted it because it wasn’t relevant to this topic. Sorry for the mix-up.

@Rio
What were you going to say?

Junita said:
@Rio
What were you going to say?

It wasn’t really about this. I thought I was on a forum about RX-7s. My mistake, so I deleted it to avoid confusion. Sorry again.

If you’re pulling the head, you might as well replace the coolant temperature sensor. It’s much easier to do it now than later after everything is reassembled.

My gen 3 had about 290k miles. I used a Fel-Pro gasket, cleaned the EGR cooler and intake, replaced the PCV valve, plugs, and coils. After 5k miles, it’s still running great.