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How can I fix leak in this place of my car radiator? Answered

Here's the bubbling place:


I think I can fix the leak if I manage to separate these two parts from each others:


Is it doable? 

Does this leak cause an air build up in the system? as the upper pipe became swollen as hell with temp. rise.


That rad is a challenge to fix at home.

The seal between the rad core and the end cap is damaged or loose. You can try pressing the tabs until the leak stops but check for these first.

The first thing that is wrong with your cooling system, you need a new rad cap, the over pressure should go through the cap to the reservoir before it over pressurize the system.

Check your coolant mix if it is to much water it can boil.

If it is to much coolant it can turn to jello when it gets hot.

Check your thermostat valve it may need to be replaced.

After that the next most common cause of overheating or over pressure is the head gasket or a crack in the head or the block.

Other than egg white black pepper is another trick to fix a leak.

Dear Josehf

Thank you for the good info's. Here's the thing my car has an expansion tank I have bought 3 new caps in less than 7 months, and they just keep broken!! :@@.


It has an awfully bad design..

I have putted a part of a plastic bag underneath the cap to block it permanently. The car temperature is always great almost steady at 90 degree, but this swollen pipe is what concerns me. This trick worked fine for me for several months with no overheating/swollen at all. But I guess the over pressure is what damaged my radiator :/, and thus begin the swollen problem.

I am sure that the thermostat works fine. Also no sign of Head gasket problem!.

I want to give it a shot and try pepper, for how long this solution can hold?. What is the quantity of pepper to be used?.

Pepper works for up to a month sometimes more, put about a table spoon in the rad.

90 sounds good for this time of the year did you get that with a thermometer or a gage?

That is the return hose on the bottom of the rad isn't it?

If it is it is, a weaker construct hose.

Yes it is 90 for sure.. actually the swollen hose is the upper one that has the thermostat..

I would wonder if your rad might be partly clogged but you are running on the cool side at 90.

With all the faults combined you describe there must be a serious problem in your system!
A leaking raditr cap is a sign of over pressure.
Same for an expanding hose.
Just saying all is fine without actually really checking it is as good as saying it will rain tomorrow just because the rooster starts making a noise at 4 in the mornig.

Why do you think I suggest an egg white?
Maybe because it works and is no myth?
If you don't want to use an egg use a commercial product or better still get your system checked and ifxed.

Dear Downunder35m

I am not saying this without checking!. I am sure that thermostat opens and close when it should (that about 80 degree), I know the water pump works fine cuz both lower and upper hoses have the same temp.. I know the head gasket is OK as there's no smoke coming out from the exhaust, no oil in the coolant, and no water/white matter in the oil filling place. I know there's no clog in the system as I did opened every connection and made sure the coolant is flowing fine through it...

I think the problem is as you said: the water boils on a lower temp. than it supposed to - due to pressure leak, and air is leaking inside the system. And the cap doesn't do its job and release the air from the system as I block it.

Still leaves the qestion of where the leak is that is causing the problem.
So the best option would be to fix the leak in the radiator to check for a difference.
If the hole is clearly visible from the outside you an also try to drill it out a bit and then fill the entire area with JB weld or similar.
Only once the system is sealed again you can make the proper checks to confirm all is good.

Okay will do that and I'll let you know.. The challenge now is to find a genuine expansion tank cap :S :S

Try Google for a bit, quite often the same parts are used on different models and even throughout different manufacturers.
The part numbers are different but the part is the same ;)
Helped me heaps with my old Ford Probe as a lot of parts where available through my local Saab dealer on the cheap.

hello Vyger

That's the thing, the temp. is very fine it is almost always at 90 degree, and never reach 100!!!.

There's no smoke at all out of the exhaust :O, that's why I was surprised of the mechanic diagnostic :S.


3 years ago

A head gasket that is leaking allows compression gasses to leak into the water jacket. This causes pressure to increase in the cooling system. It might also cause overheating because the pressure will increase on the wrong side of the water pump and the pump will not have enough power to push coolant against the increasing pressure.

It can cause the hose to burst if the gas leaks in faster than the cap can vent.

A final symptom is white smoke coming out the exhaust. When the engine is off coolant gets pushed into the piston. When the car is started the coolant burns and produces steam which come out as white smoke. If the leak is bad enough it can draw water/coolant into the cylinder on the intake stroke. The momentary vacuum is aided by the pressure in the cooling system and water jets into the hot piston. hence steam comming out the tail pipe.

Hello Guys

I just payed the mechanic a visit. Once he saw it he said:

1- The head gasket needs replacement. OR

2- The head needs skimming, but we will never know till we remove the head.

I am just surprised how fast he knew that with only a look and a touch on the swollen hose!!.

I told him about the radiator leak but he didn't give it much importance, he said theis leak doesn't produce this air!!. He also said only the plastic part of the radiator can be changed, while the aluminium part can be kept the same..

Downunder35m thanks for answering. I am sure all the cooling system components are working properly. I think the swollen pipe resulted from the airlock inside the system. I removed air from the system several times, but each time I drive the air is back again, and the pipe become extremely swollen. Could this leak in the radiator cause an air leak to the inside of the system?. About the white egg trick what is the way exactly?.

If you have a leak the pressure will always cause air to get back into the system.
Also the system is unable to pressurise which in return will cause the water to boil at normal temps.

With the egg white the trick is quite simple:
In the cold water the white stays as a liquid.
So once the system warms up water and white will be forced out of any leaks.
With the system reaching normal operating temps the surfaces are hot enough to boil the egg white - it becomes a solid.
The hotter it gets the more the white hardens until it is a solid - sealing the leak.
For a head gasket you can use "waterglass", sodium silicate and it will become a rock hard solid wherever it can exit the cooling system.

I really would like to give it a shot and separate these two parts before I buy a new radiator as the egg solution will not hold for long. But what material is used to seal them together? is this a good one to be used:


You can not seperate the parts without having it leak even more after that.
The "clamps" holding them together are fixed in a special press, you won't be able to get a proper seal at home.
The only real fix is a new radiator.
For a short term fix an egg white does real wonders in terms of sealing.
Add it to the cold water and drive around until the temp is levelled out - the leak will be gone.
And unlike some commercial products there is no chance to harm the engine.
But if your pipes also swell up it is a sign of overheating, maybe a faulty temp sensor in the cooling system - they love to fail after many years of service.
Big pressure means boiling water, which means the coolant is getting too hot.
I assume you do use some proper coolant and not just water from the tap?