Can water crossings crack engine block or head?

[LunarRunner]

I was watching some videos of water crossings trying to learn the correct techniques and kept seeing videos of people getting water up over the hood and I can’t help but think water was getting into the engine bay. Is there any concern when it comes to submerging a hot engine in water when crossing a river that goes up to the wheel wells? My 5th Gen 4Runner has an aluminum block and heads so I’m assuming aluminum is better at thermal shock than iron blocks but still, I would be a littler worried about cracking the block or heads.

 

[Jetboy]

It's probably possible, but I've never seen it heard of it happening. The engines aren't that hot and they don't chill that fast in water. A 200 degree change wouldn't probably crack the aluminum. But I can't say never.

I have run other Toyota engines completely under water. It's a great way to destroy them when water gets into the intake. But with the intake up high, they seem to be just fine with the water temperature.

In my 5th gen I stop when the water reaches the door sill. It's just to messy to clean up if it comes into the cab. In my fj40 - if I can still breath I'm GTG

 

[MDH33]

I had downpipe crack during a deep crossing during a flood a few years ago. Exhaust/header is a lot hotter than the engine though.

 

[Jetboy]

I had downpipe crack during a deep crossing during a flood a few years ago. Exhaust/header is a lot hotter than the engine though.

I imagine turbos would be at a lot of risk too. I'm not sure how they manage to survive in things like snowmobiles so well.

 

[GJMacK3]

If the water crossing is being performed correctly, you're creating a bow wave with the front of the vehicle, and the water is being displaced to the sides of the vehicle. There is very little water intrusion into the engine bay with this technique. If you drop down into the water and just creep along, then yes, you're definitely forcing water through the engine bay. I have done countless water crossing with all of my Toyota's. And even creeping through, I have never had any issues with the engines.

 

[LunarRunner]

If the water crossing is being performed correctly, you're creating a bow wave with the front of the vehicle, and the water is being displaced to the sides of the vehicle. There is very little water intrusion into the engine bay with this technique. If you drop down into the water and just creep along, then yes, you're definitely forcing water through the engine bay. I have done countless water crossing with all of my Toyota's. And even creeping through, I have never had any issues with the engines.

That’s the technique that I have heard referred to but I was worried about worst case scenario if I screwed up my first time crossing water with some significant depth. Sounds like even if water was to get in it would be fine.