JDM_SOHC

Anyone ever have an overheating problem due to their overflow failing..?? It seems that once my car gets to that point of overheating the first thing it does is start steaming and boiling from the overflow, but my overflow cap never fully tightened down an if u tighten it a spec harder it dethreads and becomes loose and you have to retighten it again to that point right before its to tight... Anyways, has anyone ever had an issue like boiling coolant or w/e and resolved it by replacing the overflow..??

TravisCadello

yes, i had this problem with my new engine. turned out it was because my fan wasn't turning on. so i put a constant power to it and now its good.

driveslow

If you are talking about The overflow resevior is just a plastic container. I would check other things first. If you are talking about the cap, It could be bad. Things to check.

radiator
cap
make sure fan is turning on ( this process could take up to 40 mins)
amount of fluid in the system

JDM_SOHC

yeah dude i just bought new honda cap, new fluid, flushed & bled system, did a radiator pressure test, did a compression test, an all came back good... i did everything but a leak down test... im startin to think its my head gasket but i dont understand how all the other tests could pass with flying colors, and my car still overheats... it doesnt actually overheat until all the coolant boils out but something is makin the coolant boil and i've narrowed it down to air somehow gettin in my system... its either air/exhaust I just cant figure it out, but my guess is exhaust because my car warms up rather fast from a cold start and when the bubbles are poppin up in the radiator they are lil smoke bubbles it seems like... i'd just hate to go through the whole headgasket process an that not be it...

driveslow

what about heat sensor or or thermostat is stuck in the closed poistion and not allowing the coolant to flow.

JDM_SOHC

put brand new thermostat, and what heat sensor are u talking about...?? the heater core..??

driveslow

I beleive Its somewhere on the cooling system, I would have to look it up though. I beleive its like a temp sensor that tells the ecu when you are at operating temperature.


what car, how many miles?

JDM_SOHC

92 dx d15b7 140k miles...

driveslow

anyone else care to chime in? Not sure what else he could try...

driveslow

any updates on this?

sicrx69

I am pretty sure your car is over heating and could be the fan or most likely the thermo is sticking. Any time your coolant boils your car is getting way too hot. Generally it will boil after you turn your car off and stop driving. When you are driving the outside air can generally keep the water cool enough before it circulates through the engine, but after you stop the fan should continue that job. The thermo is very easy and cheap and then you can wire the fan directly to check that problem.
John

donut.

Do you even know what the coolant overflow is for? lol

are you sure your fan is even coming on? did you jump the fan switch? Did you switch out the thermostat?

driveslow

this is what he has done which includes thermo

EL Vap133

I had a slow leak on my head gasket and every so often it would cause those symptoms you mentioned. In the morning though the car would start to shake for a bit when I turned it on and then it would burn off the anti-freeze that had leaked and it would be good. All tests passed also, then one day it overheated again and I just had the headgasket replaced and problem solved. It has been a year since and the car runs like a champ now.

driveslow

what did it run you to have the head gasket replaced. Mine is fine and I dont drive my car hard. But it does have 187k miles on it. I am always affraid of the head gasket going.

Adankid

have you fixed your problem OP?
or at least gotten closer to figuring out the problem?

EL Vap133

It ran me about $450 with parts and labor, a good friend of mine did it for me along with some other replacement parts. Mine seemed fine too but it turned out that was the issue. 187k miles is a lot, has your car actually overheated before? Fan and fan switch work?

driveslow

everything has been fine, never an issue (knock on wood). I am always affraid to push it in fear something might happen to this 187k mile engine.

EL Vap133

Keep it in top shape, never let the needle hit the red zone. If you ever see it get close hit the heater full blast or shut the car off right away.

JDM_SOHC

well i had my z6 sittin in the garage with vitara setup and i just couldnt bare lookin at it any longer, so i threw it in yesterday an took the b7 out... im gonna rip it apart and check to see any leaks or burnt gasket areas and come back with a lil update... possibly throw a vtec head on there an make some cash off sellin a mini-me... thanks for ur input guys, always appreciated..

JDM_SOHC

ok so i sold my semibuilt motor in need of cash, found a local z6 from a friend and put it in my car and the coolant still boils over an leaks from overflow cuz every 2-3 days i can add about 15-20 ounces of coolan... its not leaking from anywhere, it just boils over in the overflow just like my b7 was doing... this motor ran perfect in my friends car now im havin the same problem as before... anyone have any ideas now? i did a pressure test on the radiator and it holds pressure but could it still be bad..? fan is working, even hotwired it few times just to be sure, brand new thermostat, and system was bled.. i constantly get bubbles when bleeding tho just like before.. could this be a leak somewhere else that maybe we've not discussed..?? thanks...

Dasfinc

By-pass your heater core, and see if it still over-heats.

Please be aware that 'boiling over in the over flow' is what happens when your car over-heats, thats the only place for it TO boil over/out of, so this problem is not 'coolant boiling out' it is your car overheating.

With heater core by-passed you are still overheating, borrow a buds radiator and call it a day.

pixelated

sounds like the head gasket, if your getting bubbles in your coolant while the engine is running then its definitely head gasket, it will pass a pressure test beause the cylinder its leaking into can hold the pressure too... check your exhaust, see if you have a whiteish sweet smelling smoke when you start up after it has been sitting for 5-10mins,

Dasfinc

If you read the thread, you would have seen he has had this problem in the same car with 2 or 3 separate motors.

Please read the FULL thread before posting.

JDM_SOHC

Ya kno, I thought of bypassing the heater core or at least thought maybe the heater core had something to do with it "air getting in somehow, ect" If I could only find the thread on bypassing it DIY style lol..