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Coolant coming out of overflow drain but not overheating

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DSMToretto

10+ Year Contributor
45
0
Aug 31, 2011
dh, D.C.
Hey guys,
Ive looked through a few older threads and found similar post but none that gave me an answer that I haven't tried so i figure ill try.

My problem is coolant is coming out of my over flow drain tube and then when cooling down not all the coolant left in the overflow back into the system as suppose to and only seems to lose coolant when driving because when i idle in the drive way or turn it off i dont show any leaks. Some info of what i have checked so far...

No white smoke out of exhaust under boost and normal driving
Not over heating (checked with data log and laser temp taker)
Fans work fine (in fact i wired the ac fan into the first one and made it so they stay on, just to see if that was the problem)
Replaced the Thermostat with 180 degree
New water pump (done a month ago due to leaking)
all correct lvls and mix before i start it and purged system
No milky colored oil mix
Checked spark plugs to see if it was burning any and they are good
Coolant is not very dirty
No leaks (checked with a pressure tester too)
Have bought 2 radiator caps and tried an old one (tested those too)
Radiator is a year old
And i know for sure it is coming from my overflow drain tube because i set the tube in a place that i could see it was draining and the tube and that area was wet.
I thank in advance for any ideas and i will be on as much as i can to answer any questions but as a heads up i am out of town week days so it is hard, thanks!
 
If everything else is good then you either have too much coolant in the system which isnt a big deal. Or the wetness is from somethimg else. When did this start?
 
Are you topping off the coolant before you drive it? If so it may be too much coolant. When you drive around to see if anymore coolant is coming out are you getting into boost?
 
When the car is cold pop the rad cap off and start it, let it warm up and watch for bubbles through the filler neck. If all is well the coolant should just flow by. You could also check the coolant with an exhaust gas tester from an auto parts store... as you might tell, this is diagnostics for a head gasket failure.... which pushing coolant is a symptom.

The coolant and oil don't have to be affected in color or consistency to have a hg failure. But its at least good to know they aren't mixing.
 
Ya, for a small crack in the HG on the exhaust side could cause this issue and not show up in the oil.

Fill the radiator up to the base of the fill neck, put the cap on and only fill the overfill bottle up to the FULL line and not all the way to the top.
 
I have ran it with the cap off and it did just run by... didnt over flow at all. I have also tried to fill the system all the way up and barely put anything in the over flow and it still doesnt suck all the coolent back in when it cools down... i think like a few of you said I may have to start checking into that hg because i have no other ideas LOL
 
Too much coolant maybe, I used to have the same problem so I left it on the middle, and I noticed when coolant was going out because the steering belt started making noises LOL. Im 420a tho..
 
If you think the head gasket is bad you can do this. The car has to be cold then you remove the radiator cap and put it back on, then start the car put it in drive and then mash the brake pedal and push the gas pedal and run it to 2500rpm for like 30 seconds and shut it off. If there is no pressure when you remove the radiator cap the your good :thumb: if comes flying out, then you need to replace it :toobad: How full is the reservoir?
 
Have you checked the hose that hooks to the underside of the cap and dips down to the bottom of the coolant expanson tank? If its missing or even present and cracked near the top it can't suck the coolant back into the engine. and can cause the coolant to over flow.
 
How old is your radiator cap? I noticed when the gasket on mine started to wear out that the pressure leak it created caused mine to overflow. Cheap easy fix to try before you get all worried your HG is blown.
 
What temp is the correct operating temp for these little motors? I am still fresh on these so I want to check mine as I occasionally smell antifreeze when I am at a stop light or drive thru. Thanks!
 
I just went thru this same shit. My thermostat was opening but not all the way, like it was stuck or something. I replaced the thermostat along with all the coolant hoses in the engine bay and issue resolved.
 
ya i bought straight antifreeze and mixed it myself... the car runs around 180 to 190 degrees... the radiator cap is brand new. and Raizen, that actually doesnt sound like a bad idea but i think it is the head gasket because today when i was driving and got on it, you could see the coolent hitting the groung from my over flow but at idle and parked, not a drop.. if it was a small head gasket crack would it show in a compression test?

What temp is the correct operating temp for these little motors? I am still fresh on these so I want to check mine as I occasionally smell antifreeze when I am at a stop light or drive thru. Thanks!

i run between 180 and 190 but i have a 180 thermostat in it..

Have you checked the hose that hooks to the underside of the cap and dips down to the bottom of the coolant expanson tank? If its missing or even present and cracked near the top it can't suck the coolant back into the engine. and can cause the coolant to over flow.

ya i had checked already but its all good..
 
Last edited:
I have this same issue with mine!
It doesn't overheat either but somehow I'm loosing coolant I have to note tho that I use an aftermarket overflow but modded to fit the OEM cap I have brand new OEM thermostat and a Mishimoto radiator cap! Do you guys really think is a headgasket failure that would suck:notgood:
 
Its your radiator cap.

ive changed out the radiator caps with 2 Mitsubishi caps and 2 advance auto caps and hasnt helped. i have realized the even when the system is down almost half a gallon the top hose will still be pressurized though there is no coolant

is your engine bored over?do you have an after market interCOOLER?

yes 30 over and yes a phantomracing intercooler
 
I would do a leak down test to make sure the head gasket isn't putting pressure in the cooling system .
 
ive changed out the radiator caps with 2 Mitsubishi caps and 2 advance auto caps and hasnt helped. i have realized the even when the system is down almost half a gallon the top hose will still be pressurized though there is no coolant



yes 30 over and yes a phantomracing intercooler

You need to properly put the coolant in and get all the air bubbles out. Turn your heater on full and flush the system. (*disclaimer* of course don't remove the cap unless its cold.)
 
I would do a leak down test to make sure the head gasket isn't putting pressure in the cooling system .

have done and held 18 psi for just over 5 min..

You need to properly put the coolant in and get all the air bubbles out. Turn your heater on full and flush the system. (*disclaimer* of course don't remove the cap unless its cold.)

have also done each time i lose coolant... even invested in one of the cap adaptive funnels LOL
 
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