turbo coolant boiling
 

I've got a watercooled T3 on my 4runner. I smell that sweet smell of coolant after shutting it down.
Pretty sure it's not a HG issue as I've got no water in the oil and my leak down is fine.
What I *think* is happening is that when I shut the truck down, the turbo is still hot.
Water in the turbo boils off, produces 15psi in my cooling system, and that leaks past the cap into the overflow.
The overflow blows a little vapor and that seems to be what I smell...

Shutting down a hot turbo and having the water boil off has to be fairly common.. comments?

Re: turbo coolant boiling
 

headgasket. Doesnt have to leak coolant into the oil to show signs of a headgasket, if that happens its a really badly blown headgasket. The cylinders are pressurizing the cooling system and its leaking out in the only way it can, through the overflow tank.

Re: turbo coolant boiling
 

im not sure of the exact tepm but becuase the water is under pressure in the radiator, somewhere up around 15psi, that the water will not boil untill way past 250 degrees.
we learned this ---- in gradeschool and and i learned to calculate it in college chem, remember how it takes less heat to boil water in denver apposed to deathvalley? called vapor pressure

Re: turbo coolant boiling
 

What's your mix on the antifreeze you're using? 50/50?

Re: turbo coolant boiling
 

50/50
Guys, I've blown HGs before - and I've got the tools to check. It's not a HG. If you're 100% sure that I'm smoking the pipe, I can pull the water cooling and see if I still have the issue.

Think about it, cool down EGTs are in the 900 degree range, the center section is real close to the turbine. Run it hot, stop the water flow and the water that's in there is going to boil...

No one has ever seen this happen, eh?

Re: turbo coolant boiling
 

try letting the car run for a bit when you get home. That might help bring the temp down.

I would think you have a leak or something.

Re: turbo coolant boiling
 

If you're hitting in the 900 degree mark, you must be pushing that ---- really hard. Are you using a stock radiator fan?

Maybe get a coolant temp gauge to monitor how hot it's getting.

I just spoke with my dad on this issue and he's positive it's the radiator cap itself. Too much boost, getting too hot.

Problem solved would be putting a higher pressure radiator cap on to withstand the pressure, but there's a catch.

The cap bleeds off the pressure; I believe my dad said normally most cars are at 15psi or something, I can't remember, so if you put a higher one on, you may run the risk of blowing hoses or something.

Best advice, drop the boost, and run it a little less harder then where you're at.

Re: turbo coolant boiling
 

highest i've seen is 21lbs for a rad cap. anything more and it's beyond automotive use. ill see if i have one of those super duper caps tomorrow

Re: turbo coolant boiling
 

900 degrees isn't that hot in terms of EGT. Cruise EGTs can be 1350... Course, I'm measuring outside the exhaust port.


Megasquirt. It's not getting hot. No hotter than 198 or so (peak temp).



The cap is new (15psi). Dropping the boost doesn't drop my EGTs under cruise.
Note, if I let the truck idle, I don't have this issue (flowing water). When I shut it down, it starts to boil the water in the turbo.

Re: turbo coolant boiling
 

you need a richer part throttle tune