04 cobra overheating and leaking coolant out of expansion tank cap

[50hoes]

Well today i was coming back from school and all of a sudden my car started idling weird so i pulled over and popped the hood to check and there was just coolant coming out of the expansion tank even tho the cap was tightened all the way so i waited for it to stop coming out and refilled it. On my way back home it started to over heat and it did the same thing, coolant coming out any suggestions why it might be doing that thanks everyone

 

[4601S/C]

what mods do you have? Have you looked at the engine yet to see if there may be a bad leak somewhere?

 

[50hoes]

Car is a full bolt on and i check the engine but didnt really find no leaks the only place its leaking from is the expansion tank were the cap is

 

[NateDogg]

Could be as easy as the cap going bad.

That happened to me a few months ago. Try there, reburp your system.

 

[50hoes]

Could the cap make the expansion tank leak like that Beacuse whenever i would open the cap the coolant would just start coming like crazy im not talking about a little bit of coolant it would be alot everytime and whenwver i had the cap open to the expansion tank i was revving the car a little bit the coolant would just start coming out

 

[P49Y-CY]

if you only refilled it at the reservoir cap, it will continue to overheat. you shouldn't drive it until you refill the cooling system properly, or you risk engine damage. since it is your first post here, you should probably check out the thread in the how-to section.

 

[50hoes]

Lol i already know how to burp the system and im about to do that rn but the problem isnt the overheating its the coolant coming out any suggestions?

 

[NateDogg]

Well yes. The coolant is going to expand when it heats up..

If you have a leak then its going to spew out because its not pressurized and it will take the path of least resistance to get out.

So if it is leaking out of the cap, I would try that first. Its only 12 bucks to replace. Once you get your new cap. Burp your system and fill from the cross over tube. If that doesn't fix the problem, its possible you have a leak elsewhere.

Is it a stock expansion tank? they have been known to get brittle and crack over time. Also, just for peace of mind, check the oil to make sure everything is good on that end.

 

[50hoes]

Well yes. The coolant is going to expand when it heats up..

If you have a leak then its going to spew out because its not pressurized and it will take the path of least resistance to get out.

So if it is leaking out of the cap, I would try that first. Its only 12 bucks to replace. Once you get your new cap. Burp your system and fill from the cross over tube. If that doesn't fix the problem, its possible you have a leak elsewhere.

Is it a stock expansion tank? they have been known to get brittle and crack over time. Also, just for peace of mind, check the oil to make sure everything is good on that end.

I dont think i have a leak, only place its coming out of is the cap and yes its the stock expansion tank but no worries a new one is on the way no more plastic. Also just checked the oil doesnt look like milkshake so thats a good sign thanks for the help im going to go purchas a new cap any type of cap should work thats 16psi?

 

[NateDogg]

I just got mine from Advanced auto.. I think it was car quest brand.. its been holding up fine.

 

[jrichber]

If your system is not properly burped it will come out the cap. Even if the cap is good. I refilled mine incorrectly went to the store and back and saw a line of antifreeze when I pulled back into the garage. Popped the hood to see antifreeze pouring out from under the cap. Removed the crossover bung and burped/refilled the system properly and all was good, no problems since.

 

[MaxSimoneau]

Headgaskets...same thing happenned to me few weeks ago... Do a Compression and Leak down test

See if it does the same thing as in the video : https://www.youtube.com/watch?v=76Eu3vh-rcI

Coolant shouldn't move at all when giving throttle

 

[50hoes]

Just burped the whole system and im not overheating no more. anybody know what my temp should be on the speedometer?

 

[hotcobra03]

Coming out cap is good...

1st this says car is running hot..

is the fan coming on? Turning ac on will confirm fan is working at least on high speed..

common for fan ring to break causing fan not to spin..

I just had issues on same problem but only with ac on and over 80 outside..

im south Texas. .hot as hell

for me radiator replacement was the fix...

guess age is now starting to play a role...

 

[50hoes]

Coming out cap is good...

1st this says car is running hot..

is the fan coming on? Turning ac on will confirm fan is working at least on high speed..

common for fan ring to break causing fan not to spin..

I just had issues on same problem but only with ac on and over 80 outside..

im south Texas. .hot as hell

for me radiator replacement was the fix...

guess age is now starting to play a role...

Hahaha i know what it feels like i stay in houston. Texas is way to hot but yea the fan turns on. What kind of radiator did you purchase?

 

[jrichber]

Just burped the whole system and im not overheating no more. anybody know what my temp should be on the speedometer?

Factory gauge and factory thermostat your temp should be right in the middle.

 

[50hoes]

Factory gauge and factory thermostat your temp should be right in the middle.

I was talkin about number wise, you hold down the button on the speedometer and then turn the car to the on position. Anybody know what the degree c should be?

 

[big dad]

Radiator caps and the intercooler caps are the same part # and they are notorious for having too small of a spring too hold the correct pressure (16#), and after enough heat cycles will loose their tension. This is why Ford changed the diameter of the spring to a larger one in 2009. I just changed both my caps on my 03 as a precaution although they pressure checked okay, probably because the 03 only has 2200 miles on it and they use the same cap for the diesels, which was my main concern initially because that is a big deal with Powerstrokes, and a cheap preventative.

 

[big dad]

Just a follow up on my previous thread, the intercooler tank cap is rated at 10psi but my parts manager and I checked and it takes the same cap as the radiator which is rated at 16psi, so I installed the higher rated cap.

 

[hotcobra03]

Temp guage is a idiot..

straight up is 180ish..

needle will start to move toward hot at@228ish

red @243ish..

after all my reading and testing. .

Tstat is there to stop coolant flow in radiator ro allow cooling process..

a 180 tstat opens at 180 than cooler water from radiator will lower temp below 180 to close tstat.


as load and outside temps around engine change temp goes up. .

@219ish stick tstat is fully open and anything hotter isn't good..


I had just done my radiator..SVE 3row..

before was 216 plus no ac ..

Ac on car would overheat or just about red line if drive was short..


I have 170 tstat..stock fan set at 186 for low on..

been only testing with ac on now being above 80 most of the time

im now seeing @100plus deg outside. 188-192 basic hwy driving
after 30mins constant as low as 178deg@80-85mph

stop and go traffic 206ish

idle sitting in direct sun after 30min..220ish.


I still have original cap and tank..