Coolant overflow

[OBEEWON]

When the engine over heats shouldnt the coolant overflow bottle fill up and spit out some coolant or boil or something?

Ive been trouble shooting a intermitting overheating issue. I have NO leaks that I can see or hear. Sometimes I get the FAINTEST smell of coolant at stop and go (so faint it could be in my mind), or if I stick my head in the engine bay right after it starts running hot then it goes away.

But the coolant level in my overflow bottle never changes. Only if I open the rad cap to bleed off some pressure do I get steam or anything out of the tank, but it never fills to the point it runs out of the tank.

Im suspecting this KOYO rad for some reason.

S13 Blacktop SR

Cooling mods.

New rad cap
Koyo
Power Enterprise Head Gasket
New Thermistor
New Thermistat
Taka oil/coolant lines to turbo
Rad Breather tank on the way

I repeat. I never see any coolant on the ground and my coolant level never changes in my rad, at least to the human eye.

[g6civcx]

When the engine over heats shouldnt the coolant overflow bottle fill up and spit out some coolant or boil or something?

Question: how do you know you're overheating?

[OBEEWON]

Temp gauge. Engine bay is hotter than normal, air in coolant system.

[g6civcx]

Temp gauge. Engine bay is hotter than normal, air in coolant system.

What temp gauge are you using?

[S-Nation S13]

theres your problem you know you have air in system already thats most likely human error..try bleeding cooling system the way ive been doing it i have the car posted parked up hill the uncap radiator as the car is running i message the upper radiator hose typically air will travel to tha highest point so since tha car it already angled tha only way out would be through that radiator neck hope this helps

[OBEEWON]

Mos def not. There is air in the coolant system but not for lack of bleeding. The water in the overflow tank is cold even when the car is overheating.

Ive bled the system countless times with the front jacked up, car on a hill, waffles in my pocket, but air finds its way back in.

[g6civcx]

What temp gauge are you using?

Please answer this question.

[OBEEWON]

Stock in conjunction with a Autometer.

[opponheimer]

Having the same damn problem man... All it takes is a pinhole leak somewhere... Heater hoses seem to be the most probable location... Fuck... who the hell wants to redo their heater hoses on an sr?

Ill work on my car, you work on yours..

Does it overheat all the time? Or just under load?

[OBEEWON]

I'm thinking the rad cap isn't opening enough to relieve pressure into the overflow tank. I never had cooling issues till I went to a KOYO.

[OBEEWON]

Having the same damn problem man... All it takes is a pinhole leak somewhere... Heater hoses seem to be the most probable location... Fuck... who the hell wants to redo their heater hoses on an sr?

Ill work on my car, you work on yours..

Does it overheat all the time? Or just under load?

Sucks right?

It happens with extreme stop and go in heat. Especially if I go uphill. The pressure in my system seems to have no where to go. If I crack the rad cap while its over heating, it steams and bubles out through the coolant tank then starts to cool down. Im thinking about going back to a stock rad.

[Darius]

So you have air in your coolant system? How much?

Try starting the car cold with the radiator cap off. If you see bubbles, the HG is stuffed. Good luck.

[singlecamslam]

try using the breather screw when you bleed your system? And lots of people have problems with the Koyo and overheating for some reason. Thermostat working properly? I would try using the stock radiator.

[OBEEWON]

Really? I think it has something to do with the neck design. Yes I have bled the system according to the FSM with the bleeder screw. However. I believe it is more effective to bleed it with the rad cap and squeezing the hoses. You get more air out that way.

What do you mean the HG is stuffed? Im not actually losing any coolant, nor are there any signs that the HG is causing this. It is a 3 layer Power Enterprise Metal Head Gasket.

I think I will try the stock Rad.

[Darius]

I highly doubt your stock radiator is going to be the issue.

The coolant overflow tank is there to account for the expansion/contraction of the fluid when it heats up it expands and bleeds past the pressure regulating valve (aka the radiator cap). When the coolant cools, it contracts and "sucks" back into the cooling system to keep air from entering instead. That is why there is a minimum water level mark on the reservoir. Overheating has nothing to do with the coolant reservoir unless it is empty.

By stuffed I mean f**ked. I'm not saying the hg is damaged, but it might not be sealing the coolant passages from the cylinders and allowing exhaust gases into the cooling system. What did you do for block and head prep before installing the PE gasket?

And if you take the radiator cap off when the coolant is hot, of course it is going to bubble up and boil out because the pressure is what is keeping the coolant in liquid form. Remember the science experiment in HS where your teacher made water boil at room temp in a vacuum chamber? Same principle applies here. When the pressure is reduced, the coolant wants to boil.

[Bigsyke]

The issue is from air being sucked in from somewhere after the engine cools down.

[MELLO*SOS]

Hope you're not having problems with the head gasket, do a leakdown test to be sure. You say you're not loosing any coolant; but if there's air in the system then you are loosing coolant somewhere. You can also pressure test your radiator & cooling system to make sure it doesn't have any leaks. They make a tool that attaches like a radiator cap & lets you pressurize with a pump. I believe there is also a test you can do that shows presence of exhaust gasses in the coolant to check for HG leaks.

If the problem only happens in stop and go traffic, you might want to look into the airflow at low speeds. The koyo radiator has a thick fin density that makes it harder for air to pass through at very low speeds. What is your fan setup like?

GL

[OBEEWON]

I highly doubt your stock radiator is going to be the issue.

The coolant overflow tank is there to account for the expansion/contraction of the fluid when it heats up it expands and bleeds past the pressure regulating valve (aka the radiator cap). When the coolant cools, it contracts and "sucks" back into the cooling system to keep air from entering instead. That is why there is a minimum water level mark on the reservoir. Overheating has nothing to do with the coolant reservoir unless it is empty.

By stuffed I mean f**ked. I'm not saying the hg is damaged, but it might not be sealing the coolant passages from the cylinders and allowing exhaust gases into the cooling system. What did you do for block and head prep before installing the PE gasket?

And if you take the radiator cap off when the coolant is hot, of course it is going to bubble up and boil out because the pressure is what is keeping the coolant in liquid form. Remember the science experiment in HS where your teacher made water boil at room temp in a vacuum chamber? Same principle applies here. When the pressure is reduced, the coolant wants to boil.


I was saying the fact that the level never changes indicates the coolant tank isnt getting to do its job. The coolant never passes the cap to go into the bottle. Meaning the pressure in the system keeps building and at no point passes the cap.

[WhiteTE72GT]

Have you tried another radiator cap? I think pressure testing would be good as MELLO*SOS mentioned.

[Bigsyke]

This means coolant/pressure is excaping elsewhere if the cap is good. After you park the car, pop hood- wait 45 minutes, open up the radiator cap. If the fluid inside the radiator is low, then you have a leak in the system, which probably is below the IM. Or IMO the bleeder screw, which doesnt seal for S**t

[s15specR]

This means coolant/pressure is excaping elsewhere if the cap is good. After you park the car, pop hood- wait 45 minutes, open up the radiator cap. If the fluid inside the radiator is low, then you have a leak in the system, which probably is below the IM. Or IMO the bleeder screw, which doesnt seal for S**t

This seems to make the most sense other than the rad cap

[Brentbohn]

dude change your cap. its not releasing pressure or building pressure right. make sure it seats fully inside the neck of radiator. also if its a koyo radiatior then you need koyo cap. make sure its 1.1 bar

[OBEEWON]

I believe I found the culprit. Im seeing some fresh coolant underneath the water pump. I had to climb into the engine bay to see it. Ill be changing the water pump as well as going back to a stock radiator. I don't like this Koyo anyway.

[shmiddy]

:aw:

when installing the new thermistate are you making sure the jiggle valve if pointing upwards?? this allows air thats in the system to leave.

http://www.autozone.com/images/cds/jpg/small/0900823d8013e995.jpg


you bleed the system countless times and you still get air.... from nowhere?...... maybe head gasket :bite:

[OBEEWON]

For anyone who searches and finds this epic thread. I changed everything that has to do with overheating/cooling aside from the headgasket because I KNEW I did that right.

I went back to stock rad. End of story. Two events in the bag with stock rad and the car has never ran cooler.

Moral of the story:
Koyo will ruin your life and eat your children. Copper>Aluminum I dont care what you think you know, and flip what you heard.

That is all...Im going skrimshawing....

[Addicted2Kouki]

I still think you didn't bleed right.

[Bigsyke]

That is all...Im going skrimshawing....

You saw that on conan last night huh?


And yes, the filler neck on those radiators sometimes dont seal right, thus the more you drive the more air gets in.

[smelly240]

if obee and i didnt look so much alike i would agree with him... but since we're virtually twins - he has to die (plus his radiator issues made him eat a baby)

[OBEEWON]

I still think you didn't bleed right.


Yes you know what??? Now that I think about it you are right...

wait no...no...thats silly.

[OBEEWON]

if obee and i didnt look so much alike i would agree with him... but since we're virtually twins - he has to die (plus his radiator issues made him eat a baby)


That baby gave me food poisoning/bubble guts.

Stop stealing my womens with you good looks and cunning wit. Just cuz u muh evul twin gives you no right.


Everyone was wrong. Deal with it. Nissan techs knew what they were doing. Koyo can lick my toe jam, maybe ill try thier copper rad.

[OBEEWON]

You saw that on conan last night huh?


And yes, the filler neck on those radiators sometimes dont seal right, thus the more you drive the more air gets in.


Actually I got it from that episode on the Simpsons when Homer was predicting the rapture. But Conan wrote that episode so yeah, his.

Dont take it personal, I just love to scrimshaw.

[MudRacer]

Stupid Koyo radiator!
Ive had the same damn problem as you forever. Nismo Thermostat, bled several times.

I think the cap just doesnt let any coolant out. or in for that matter.

But I'm sure alot of other people use KOYO radiators, and I mean ALOT of them, and they dont necessarily have the same problem. Or do they?

WTF is this intermitten overheating. I sometimes reach high temperatures on the fwy. This is really annoying.

[OBEEWON]

Make sure you have a KOYO cap. But still I say get rid of it. I had a KOYO cap and the rad get WAYY hotter than my stock cap ever did.

3 hours straight BEATING on the car and I could lay my hand on the cap and not get burned.

2 runs on the koyo and I can burn my hand without touching the rad.

You be the judge.

Oh yeah and Im running the stock E fan, and nothing else. Did this for 3 years before with no issues. If it aint broke then fix something else.

George Bush is our king... don't sleep...

[MudRacer]

yea the cap gets pretty hot. It always feels like it wants to blow up. Im going to do a flush and see if i can resolve this.

Im thinking its the heater hoses that are going in circles trying to make it to the firewall. Might have air in them. I will attach a chain in the front of my car and suspend it in the air, then run the car with the heater on full. If the air still doesnt get out, then i dont kno what im going to do.

[s14sport]

it was your radiator???

[smelly240]

Lol - toe jam with juice!

[OBEEWON]

Fresh squeezed.

Yup Im suing KOYO and Japan.