Overheating, bubbling and hissing coolant. Help!

Been driving a lot in the heat and today I noticed the A/C was acting weird and not blowing cold air. I just replaced the compressor last year so I knew it probably wasn't that. Then some scary engine light went on (the one that shows the whole engine) and I pulled over to find my coolant hissing and bubbling. I let the truck cool down before driving it again, but I didn't make it far with the same issue. Luckily it's parked at home now. Anyone got any ideas?

 

Check the coolant level in the radiator. Obviously only open the radiator when the engine is COOL.

 

Excessively high ambient air temperature with the ac blasting combined with hard driving, as in high rpm could create more heat than the radiator can handle. If you have a code reader, hook it up & see what it says, you can do this without the engine running so it can continue to cool off. Maybe you'll get lucky and only have a overheating code.

 

Get ac checked and cooling system.

Just put out a car fire last week. No bueno.

 

Sure would help to know more about your truck - like year and engine. You know where I'm going with this...

 

Can you not see it in his post? He has a 06 SR5 Sport. Just like I can see you have a 07 prerunner and a 08 4runner listed under yours.

 

No, it's not in "his post." It's in his avatar, and I did not see that. The vast majority of people list the details of their truck in the *post* when they ask for help. Happy, hall monitor?

 

So if the truck starts to over heat, the ac will stop working.

Next time this happens look at your coolant temp, if its over heating, turn off AC, and turn on heat to MAX. This will cool off engine much quicker.

The AC adds heat load to the radiator and will worsen the engine over heating.

You need to see a shop and watch your temp gauge before you do major damage.

 

Yikes please provide an update!

 

Scratching my head and about to pop a gasket thinking about what may be the issue.

 

I think you, I, and others, are probably thinking the same thing as to what the problem is, but I hate creating a false panic.
That’s basically why I suggested what I did.


We should wait and see what OP says about the coolant level.

 

Well I know you were all just about to pop a gasket waiting for an answer, so I'll give it to you!

Found a mechanic. He said my radiator cap didn't look right. It was missing a central piece that seems to have fallen off. He ordered a new one and it came within an hour. He added about 1/3 a container of coolant and let it burp out some air before putting the new cap on. We let the engine run and eventually I turned on the A/C. I saw the "you're fucked" warning was no longer lit, just as a cold breeze came through my vents. Pretty soon I was back doing 85 mph in 90+ degree heat, no issues.

I know you are going to say the aftermarket radiator cap won't last, but I believe in it. And yeah, some little piece is in my radiator, but mechanic said not to worry about it. I believe him too, because he was a heck of a nice man. He didn't even charge labor.

 

Keep an eye on the coolant level over the next few weeks. Make sure it isn't slowly going down