Expansion tank bubbling (found the problem)

[Johnny H 0]

Hi guys

I've noticed that the water in my expansion tank starts bubbling when it gets hot. The fans kick in fine after a bit but I'm sure the water shouldn't get to that point.

There is no water in the oil or oil I the water and the temp ever get to high on the clocks.

Should I be looking at a new Thermostat to kick in sooner??

Thanks Johnny

Edited November 21, 2012 by Johnny H

[captainredeye 0]

Possible there is a leak somewhere the coolant is pressurised to stop it boiling away at 100c.

 

Have you noticed any loss in coolant recently?

[Johnny H 0]

Possible there is a leak somewhere the coolant is pressurised to stop it boiling away at 100c.

 

Have you noticed any loss in coolant recently?

 

Can't say I have mate.

Would make sense thou.

Might be time for some samco hoses??

[captainredeye 0]

Keep track of it each day could be a small amount your loosing, also have found in the past some small leaks are not prominent until pressure builds up when the engine is running, had a pin hole radiator leak did a similar thing to the coolant.

[Johnny H 0]

Keep track of it each day could be a small amount your loosing, also have found in the past some small leaks are not prominent until pressure builds up when the engine is running, had a pin hole radiator leak did a similar thing to the coolant.

 

Thanks will do.

Hope it's not the rad thou :(

[dragon green 5]

i dont want to sound doom and gloom,

but could be a head gasket !

sorry :shrug:

[Johnny H 0]

i dont want to sound doom and gloom,

but could be a head gasket !

sorry :shrug:

 

How can you tell??

[dragon green 5]

Prior to my head gasket going or the 2nd time,(2.0 16v) i noticed my header tank bubbling !

 

But to put your mind at rest,have a read

http://www.google.co.uk/url?sa=t&rct=j&q=coolant+expansion+tank+bubbling+&source=web&cd=2&cad=rja&ved=0CC0QFjAB&url=http%3A%2F%2Fwiki.answers.com%2FQ%2FWhat_does_it_mean_when_the_overflow_tank_is_bubbling_yet_the_car_does_not_overheat&ei=tf-CUPSNF4mV0QX194G4BQ&usg=AFQjCNHBRxCvR1Trxt9Z0c4edu2IhB_TTg

[Johnny H 0]

Thanks buddy.

A good read. I WILL found this fault.

Thanks again guys :)

[Johnny H 0]

Should I start with changing the thermostat?? If so, how easy are they to do.

I see that they are quite cheap

[Peebee 0]

Screw out, screw in i believe , it depends on how easy it is to access on you're engine. Not 100%, please correct me if wrong.

[CazzaVR 0]

Not the easiest job on a VR, but very doable, just fiddly. You'll need to remove the coilpack for better access. Also worth unplugging the fans and removing the plastic rad cover to free up some space.

 

I would only buy a genuine stat from VW + make sure you test it in a pan of boiling water first. I would get new stat bolts/washers + housing and seals. Could also be worth changing the sensors that sit in the housing while you're there. The housing has 3 bolts that secure it to the block + one funny shaped rubber seal. The shortest bolt (on the right as you look from the battery/wing) is a little tricky to get at. So long as you have sockets + hex + different extensions you'll be fine. The danger with the bolts is that they are hex head and sometimes round off. If this happens, you'll need a set of Irwins and they'll come off in seconds. Takes an hour or two. Don't do the bolts up too tightly. Give the opening to the block a really good clean before refitting the housing. Also worth adding a very thing bead of silicone outside the rubber seal.

 

I'm going to do this in a few months, but I'm going to change the rad/hoses/expansion tank/crack pipe/water pump at the same time.

[Johnny H 0]

Think I might do the same as you Andy and do it all at the same time.

Can you get new rads still!?? And everything else new??

[CazzaVR 0]

Don't think you can get the rad anymore, but you can get everything else. Think there are decent rads available. There was a thread recently + the definitive cooling guide that should throw up some info.

[CazzaVR 0]

This looks just the ticket: http://www.mjmautohaus.com/catalog/product_info.php?cPath=2_4_19_241_1357&info=PORTsport_075121113D.PS.80_Thermostat_Housing_Kit_with_Aluminum_Coolant_Pipe_80c&products_id=4760

 

Just depends what shipping would cost.

[Johnny H 0]

This looks just the ticket: http://www.mjmautohaus.com/catalog/product_info.php?cPath=2_4_19_241_1357&info=PORTsport_075121113D.PS.80_Thermostat_Housing_Kit_with_Aluminum_Coolant_Pipe_80c&products_id=4760

 

Just depends what shipping would cost.

 

That does look just the job.

Might be worth asking about shipping. Or a group buy??

[VW_OwneR_85 2]

ah before going to town with buying a new rad stat and bits n bobs for it get the car up to temp and check both rad hoses are getting hot! if the bottom hose is hot when its up to temp then its not the stat, could be your expansion tank cap, so idd start there as there cheap as chips,

[Johnny H 0]

ah before going to town with buying a new rad stat and bits n bobs for it get the car up to temp and check both rad hoses are getting hot! if the bottom hose is hot when its up to temp then its not the stat, could be your expansion tank cap, so idd start there as there cheap as chips,

 

Thanks mate.

Tired a mate cap tonight and it still bubbling.

Will check the hoses tomorrow to see if both get hot.

[Jon_vr6 1]

You sure the fans are coming on at the normal temps, had a similar issue where the yellow temp sensor was at fault, the temp just kept on rising with no fans and then the temp light would come on as the water was bubbling

[Johnny H 0]

I'm not sure If I'm honest, the water is bubbling before it hits temp after a 3 mile drive

[Johnny H 0]

Booked in to my garage next week.

Lets hope they can find out what's wrong.

[Johnny H 0]

Has anyone heard of waterless coolant??

They say it goes down to -40 and up to 170c.

It cost a lot more but you only need to do it once.

[Harrier 1]

They had some on Wheeler Dealers last week,put it into a TR6.Looks like good stuff but i dont think it will sort your issues.

[Johnny H 0]

They had some on Wheeler Dealers last week,put it into a TR6.Looks like good stuff but i dont think it will sort your issues.

 

That's where I seen it lol.

Didn't think it would fix mine but thought might put it in when it is fix.

[Wullie 1]

That's where I seen it lol.

Didn't think it would fix mine but thought might put it in when it is fix.

 

And as soon as it's in a hose will pop and the whole lot trundle down the gutter. Corrado's eh!