# bubbling sound from water pipes after engine is switched off?



## jabran200 (Sep 5, 2005)

I can feel/hear bubbles in the water about 5 mins after the engine is switched off.

Is this normal, I don't recall this ever happening before.

I've bled it, flushed etc.

Thanks

Jabran.


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## cleethorpes (Sep 30, 2008)

never noticed it on mine, but a few..cough cough...years ago a blown headgasket caused bubbling when I had a gt turbo....... thats a worse case kinda scenario........but you would see high water temps........???and the cloud behind may also be a clue....


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## n600hks (Aug 20, 2008)

are you sure water is ciculating around everywhere as it should seems to me theres a blockage somewhere i would try the thermostat might not be opening or closing on time take it out fill a pan with water put thermostat in and let it boil then pick it up with pliers and see the spring should be opened up


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## jabran200 (Sep 5, 2005)

The thermostat was faulty so I removed for diagnostic purpose.

I don't think its H/G as I done a leakdown test to confirm and it was under 4% on every cylinder.

The bubbling only occurs AFTER the car has been switched off for 3-5 minutes.

The water pump is fine, I did find that the heater matrix was blocked so I bypassed that too but this bubbling sound is still there.

Another thing to note is that when the engine is switched off after a drive the water temps climbs on the greddy gauge but not the nissan one, this is around the same time bubbleing sound starts.

My greddy gauge sensor is located at the top outlet of the radiator


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## freakazoid3 (Jan 19, 2008)

Mine's seems to make the bubbling noises aswell sometimes.
Although I think it's normal because when switching the engine of the water circulation stops and you get "hot spots" in the engine's coolant jacket which may cause some bubbles. Nothing to be worried about if you ask me


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## jabran200 (Sep 5, 2005)

Thats what I have been thinking that its just heat soak from the engine causing it to boil. I don't have any antifreeze in it either so I don't think that helps since antifreeze increases the waters boiling point.

I've read some of this over on sxoc as well and they are also have conlcuded that its just heatsoak. 

can anyone confirm these theories though? as some people I know still need convincing since

@freakazoid

any news on the calipers?


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## FanatiC (Feb 25, 2008)

My r32gtr does the same sound after a hard drive, does't sound good but i can't find anything wrong on mine engine


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## Mech 257 (Mar 31, 2009)

I know its a bit late but i would say the rad cap is not sealing, this causes the water to boil at about 100 deg c, if the cap seals the water is under pressure and therefore go well over 100 without boiling.

Regards, Kim


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## jabran200 (Sep 5, 2005)

The temp of the water goes up AFTER the engine has been turned off (heat soak) to about 110 after a hard drive from about 70-80 on the greddy gauge, the stock one stays in the middle.

I've got a cusco 1.3 bar, The bubbling starts around the time the cap opens I think but I only observed it doing that only once, Need to keep my eye on it and see the correlation between the 2.

Jabran.


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## Mech 257 (Mar 31, 2009)

I think you need to pressure test the cap, you say it lets go at 1.3 bar but do you know it does go to 1.3.
BMW run to 2 bar and so alows higher temps without boiling!

Kim


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## Mech 257 (Mar 31, 2009)

Just thought of another thing, it is normal for an engine to get hotter after switching off and other vehicles have had other methods used to combat this, like electric water pumps that run on a timer after shut down or rad fans that run on timers.

Kim


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## hissingsyd (Nov 4, 2003)

use a high spec or race coolant to overcome this problem.


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## HenrikE (Mar 23, 2006)

My 32gtr did the same and so did Perra's r34.
The water is boiling at the turbos after engine is turned of pushing the water forward between the top water pipe and the radiator. 
Feel the top water hose and you'll understand i think.
Nothing to worry about! Atleast my engine did'nt break down and as far as i know Perra's r34 is still going strong 
It's just the rb26 begging for more abuse


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## mambastu (Feb 13, 2002)

jabran200 said:


> Thats what I have been thinking that its just heat soak from the engine causing it to boil. I don't have any antifreeze in it either so I don't think that helps since antifreeze increases the waters boiling point.
> 
> I've read some of this over on sxoc as well and they are also have conlcuded that its just heatsoak.
> 
> can anyone confirm these theories though? as some people I know still need convincing since


Is this in a 200SX ? Mine used to bubble in the same way after switching off, its just heat soak and normal in a 200SX with a RB.
I found the Nissan temperature gauge to be pretty useless. When it showed halfway on the gauge it could actually be any temperature between 70 and 110 degrees C. Cooling an RB is pretty tricky in a RS13, you have a lot less grille area.


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## jabran200 (Sep 5, 2005)

no its in an r32. I think I may try using a race coolant.


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## roadie (Feb 6, 2006)

Yep, boiling water/coolant at the turbo. Get some glycol in there and don't worry....


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## DAN00H (Jul 14, 2004)

*GTR boiling solution*

it is the Rad cap. I had the same in mine and the rubber on the inside of the cap had slight cracks. 

replace your cap and ensure you remove the bleed screw near the injectors when cool to purge the air (need to start the car)


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## [email protected] M/S (Feb 16, 2002)

When you turn the motor off , the water that is in the turbo,s is boiled due to the lack of flow of the water through the turbo,s so causing spot boiling , this causes the bubbling in the cooling system, it can cause air locks if the cooling system isnt bleed properly, normal thing cool the car off before switching off will help.

Also use some Water wetter like Syd said will help as well. 

But 1 more thing is the rad in good condition , they seem to block up with slit when they get a little old, this will also cause them same problem.


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## andysGTR (Jan 20, 2014)

Bit of a bump but noticed my mates r32 gtr after a hard drive makes a bubbling noise from the rad and engine after a hard drive once switched off for 4-5 minutes but the guage doesent show overheating :s is this genuinley normal as never heard of a car doing this before unless overheating!


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## gtr mart (Mar 29, 2004)

Bit of a bump.... 

Understatement of the year... I dont believe It is right. There is pleny of info in this thread and my thoughts are ensure appropriate coolant and well bled. Ensure the cap is sealing and make sure the car is cooled down before turning it off.

You don't want it boiling as it will put air In the system and mean that localised area (normally the tubs) are not being cooled effectively.

The standard garage is useless. By the time it's showing your overheating - it's too late and you have cooked your lump.


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