what motor?
First question, broken serpentine belt means temps rise very fast, has anybody done a check for combustion gases in the coolant, i.e. cylinder head gasket failure? head crack or god forbid, cracked block.
This is very common if the belt breaks. This would account for all your symptoms, especially if the head gaskets leaking.

next silly question, is the thermostat actually in the right way round? these ones are in the return hose.
is it actually the correct heat range thermostat? the 2 degrees C difference between the OEM and common aftermarket ones on the 2.4's can result in overheating.

it is possible theres something in there blocking things, was it fully flushed when the pump was replaced, and before you changed coolant? some coolants don't intermix and form a jelly in the block restricting flow as well.

just things to consider and look at.

 

2.4L 4 cylinder

I made sure to use universal coolant,
I had it flushed now 3 times. Mechanic stated a pressure test was done but I’m not sure if they checked for combustion gassed and assume since they didn’t notice the leak in my radiator they didn’t actually test anything. There is no sign of coolant in the oil.

The belt broke several months prior to my overheating. I replaced with a belt from auto parts store. I believed it broke because the tension idler assembly was failing. That was replaced by me after the new belt slipped off about a month later and after the first overheating incident and radiator flush. I replaced the thermostat and water pump at the same time. Then the thermostat a second time because it overheated and I had placed a thermostat that locks open after overheating, I believed at the time the overheating was caused by trapped air. Thermostat was placed correctly by me, however the mechanic replaced it recently and I’d have to open the housing up to be sure they placed it correctly and what thermostat they placed.. I’ll do this if my problems persist.

Since replacing the radiator I did not check the coolant level consistently first thing in the morning and sometimes didn’t check prior to overheating.. perhaps there was still air? I checked first thing in AM and was about a pint low (trapped air vs evaporation from overheating) second time much less needed replaced then I drove a few hundred miles with no issues. I haven’t driven it or checked it since...tbd
Hoping to see my problem disappear ?Thank you for the thoughts.

 

Hey, i read all your story, now i'm thinking what could be the issue in your car.

If it is useful, i had some similarly problems on my GV 2008, 2.0 engine. My belt broke up while going on highway, and my coolant fell down to the ground, while the temperature was very high (reaching H on dashboard), i managed to fill up with new coolant and change the belt, then continued my trip. Sadly the temperature seems to reach high enough to boil, and the coolant fell again, Finally the radiator cap was broken, and couldn't keep the system pressure, so the coolant came out by the expansion cap.

So, even if you already changed the radiator cap, take a look.


Tell us more about it.

Alexis

 

First - if the system is actually developing enough pressure to blow the cap off, then the cap is not fitting correctly - either the cap itself is damaged, or possibly the neck where the cap mounts - depending on which engine you have, the cap may fit on a plastic pipe that connects to the radiator hoses - have a close look at that.

Second - the gauge bouncing around and cold air out of the heater both suggest pockets of either air or steam - the coolant sensor will only measure the temperature of coolant, if it's surrounded by air or steam, it will not give an accurate reading - it's also normal for the a/c to shutdown if the sensor indicates that the engine is hot. A loss of system pressure, possibly caused by a defective or loose cap (see the paragraph above) may allow hot spots to flash into steam, which will force coolant out to the overflow.

Third - a constant stream of bubbles is not a good sign - especially if the engine is not up to operating temperature - that points to a possible head gasket issue, or worse a cracked head/block both of which have been know to happen on the J24 engines, although I believe the problem may have been fixed prior to the 2013 model year.

One last thing - running the heater makes no difference when "bleeding air" on most modern vehicles, this one included - heater temperature control is no longer done by restricting flow through the heater core using a tap - the heater core gets full flow all the time, temperature control is now done by mixing hot & cold air in the heater plenum.

 

Third - a constant stream of bubbles is not a good sign - especially if the engine is not up to operating temperature - that points to a possible head gasket issue, or worse a cracked head/block both of which have been know to happen on the J24 engines, although I believe the problem may have been fixed prior to the 2013 model year.

It was an issue on the 2008 to 2009 model years only (according to Suzukis TSB anyway), was a faulty head casting cracking around the water jacket access plugs due to incorrect stress relief from the original casting process. Was corrected mid 2009 so I would agree, unlikely to be that issue affecting him, unless its a random faulty head.

In this case, the o/p has mentioned he lost a serpentine belt, these things almost grenade heat wise if the belt breaks at speed and a head gasket failure is common. They are a "floating" bore and it doesn't take much to pop the sealing ring and let combustion pressure into the water jacket.
I'm wondering if he does in fact have a head gasket issue which is why i asked if he has had a test done to confirm or deny this.

This would certainly account for all his symptoms would it not? bubbles, air pockets and bouncy gauge and blowing the cap off.

 

when you take the coolant cap of any gunk around the lid, does the coolant look milky?

if so then it a 100% gasket problem blown head .....

is the water pump working correctly or thermostat working correctly.

this is usually from coolant not cheeked or changed or squeak noise from water pump as months go by and not chaged.

get a head die test, and get a cylinder pressure test.

all sounds like a blown or cracked head or block.