My S4 TII is overheating no matter what I do!

my thermostat is brand new
my water pump is newer and in working condition (made sure the bearings dont slip and it spins correctly)
Radiator was flushed.


With everything together and rad caps on, i start the car and within 3 minutes it is blowing water out my overflow or blowing steam out of my upper radiator cap.

with the caps off it blows steam out of the top one heavily and the bottom one some.

i have no idea what the problem is, i dont think its a cracked water jacket or blown seal as the motor still has great compression and it doesnt blow steam out the exhaust...

please help!

 

do you have the plastic panel on the bottom of the car? thermostat in the right direction? is it an OEM thermostat?
What does your water temp gauge show when all of the mayhem occurs?

 

Is the thermostat a Mazda OEM or one from a parts store? You should only use an OEM thermostat. Is your fan clutch not working? Change the radiator caps?

 

New OEM thermo
the temp gauge warms up slowly like normal but it just keeps going... if the caps are off it stays cool as long as i keep the water filled. the caps on, it slowly keeps warming up and overheats.
plastic planel is not on the bottom of the car, but why would that have any effect on this problem?

 

Is your fan working? Do you have the system burbed of all air bubbles?

 

if it is overheating from within 3 minutes of starting up, then dare I say your coolant seals are either gone, or you have mad air bubbles trapped in the system somewhere.

 

Unfortunately, it does sound like a cracked water jacket / blown coolant seal. Been there, done that. The undertray doesn't matter if the car is just sitting at idle. With no fan at all even, the car should not go from completely cold to boiling the coolant in 3 minutes. On an S4, 1/4 of the way up is ~180F, 1/2 way up is about 200-215F. If the system is in good, working condition, you should never see it go past about the 1/2 way mark. Ideally, it would stay around 180F, which is thermostat temp.

 

www.aaroncake.net has a cooling system diagnostic section, including checking the coolant seals. If this just started after the coolant flush and wasn't happening before, it's highly likely that the engine is fine and you just flushed it improperly. Otherwise you may have a problem.

Get the reservoir near empty (for now), because some coolant will move from the radiator to the reservoir when you top it off through the radiator cap. Remove thermostat (for now). Fill the system, put on radiator caps, squeeze an upper hose 50 times, remove caps, add coolant, repeat until you can't add any more coolant. Idle the engine with radiator caps and thermostat removed. This is just fine for temporary testing, even though cooling performance is reduced a little. You can leave the thermostat in, but then that's one more thing to test: make sure it's equally hot on both sides of the thermostat after the car warms up. Keep adding coolant if needed while the engine's idling. Steam doesn't tell you anything; could just be spilled coolant on a hot engine or normal evaporation from exposed hot coolant at the fill neck. Check for bubbles at the fill neck. There may be some air bubbles at first even in a healthy engine, but if they never stop coming even after a few minutes then they might be exhaust gas from blown coolant seals.

 

plastic panel is an essential part to guiding air through the radiator. It may not be that big of a deal just sitting and idling, but it is in no way helping to have it off. This is especially important once you get driving again.

Now it's clear this is not the sole source of your problem, so I have to agree that it sounds like a cracked water jacket.

 

Looks like i'm going to pressure test it and go for a partial rebuild. Any suggestions on must-haves for the rebuild other than the water seal kit, main seals, and maybe oil control o rings?

 

Nevermind on the rebuild. The motor has good compression, and when i pulled the LIM both coolant passage o-rings were demolished, which in essence could cause all of my problems. (overheating/over-pressurizing, Compressor surge, running rich)

Thanks for the help guys, wish me luck