Jump to content
READ ME - iOS Notifications - How To Enable - Guide

Coolant pressurising

Steveyboy
 Share

Recommended Posts

ahenners Experienced

ahenners

Posted
Posted

Dumping out of the coolant cap? Can you clarify what you mean here? If the cap is correctly screwed on it shouldn't be able to escape from there.

Link to comment
Share on other sites
  • 2 weeks later...
Steveyboy Enthusiast

Steveyboy

Posted
  • Author
Posted
On 14/05/2019 at 18:46, TaxiB said:

Have you found out what's wrong?

Mines also doing the same after I've had a new genuine water pump n timing belt fitted! Never did it before I had the work done! 

 

 

No still trying to find out what's going on. It only happens after a good few hundred miles so surely if it was something serious it would happin far more regular??

 

 

Link to comment
Share on other sites
Steveyboy Enthusiast

Steveyboy

Posted
  • Author
Posted (edited)
On 26/05/2019 at 07:48, ScoutCJB said:

Sorry - so what actually is happening, read the thread a few times but don't understand

 

The problem only happens every few hundred miles.

 

Drive the car

 

Park up

 

Come back to the car, start up and low coolant light is on.

 

Lift bonnet and you can see that coolant has come out of the pressure relief cap.

 

Refill and as I say wont happin for another good few hundred miles.

 

Temperture gauge never goes above 90°

 

Pressure test and new pump has been fitted.

 

 

Edited by Steveyboy
Link to comment
Share on other sites
bigbluevRS Newbie

bigbluevRS

Posted
Posted

I have this issue and have just had EGR cooler replaced (£990!) but not solved it...

 

Once discovering this  expensive repair didn’t work, I tried some controlled conditions to test when the pressurisation of coolant system happens... I suspect it is a head gasket issue leaking combustion gas into coolant system, but I’m no mechanic!!

 

Control test - drive under minimum engine load:

I drove 400 miles (4x 100mile) on motor way not exceeding 2,000 rpm and the symptoms did not show...

 

Control test - drive under heavier engine load:

I then drove 50 miles putting engine under more load - accelerating up to 4,000 rpm through gears when needed and cruising in 4th to keep engine load a bit higher.

 

This then replicated the symptom of pressurised coolant expansion tank. I allowed to cool overnight and there was still pressure in the system and the expansion tank completely empty.

 

no signs of external leak and no signs of coolant contamination in engine oil.

 

only done 87,500 miles, mostly motorway cruising.

 

Absolutely gutted at the moment...

 

Anyone with ideas or knowledge of a good VAG mechanic in Hampshire would be greatly appreciated as I need the car to live for another 18mths!

Link to comment
Share on other sites
bigbluevRS Newbie

bigbluevRS

Posted
Posted
Just now, bigbluevRS said:

I have this issue and have just had EGR cooler replaced (£990!) but not solved it...

 

Once discovering this  expensive repair didn’t work, I tried some controlled conditions to test when the pressurisation of coolant system happens... I suspect it is a head gasket issue leaking combustion gas into coolant system, but I’m no mechanic!!

 

Control test - drive under minimum engine load:

I drove 400 miles (4x 100mile) on motor way not exceeding 2,000 rpm and the symptoms did not show...

 

Control test - drive under heavier engine load:

I then drove 50 miles putting engine under more load - accelerating up to 4,000 rpm through gears when needed and cruising in 4th to keep engine load a bit higher.

 

This then replicated the symptom of pressurised coolant expansion tank. I allowed to cool overnight and there was still pressure in the system and the expansion tank completely empty.

 

no signs of external leak and no signs of coolant contamination in engine oil.

 

only done 87,500 miles, mostly motorway cruising.

 

Absolutely gutted at the moment...

 

Anyone with ideas or knowledge of a good VAG mechanic in Hampshire would be greatly appreciated as I need the car to live for another 18mths!

(She’s a ‘63 Derv VRS)

Link to comment
Share on other sites
Ash007ks Enthusiast

Ash007ks

Posted
Posted

Just a thought have your heaters been working when on warm ? When you guys filled it will coolant did you leave the cap off to allow any air trapped in the system to escape, I have only ever know this happen on two applications. One was a blow head gasket, but that had oil in the coolant also and the other was air expanding in the expansion from unbled coolant system.

Link to comment
Share on other sites
Steveyboy Enthusiast

Steveyboy

Posted
  • Author
Posted
On 31/05/2019 at 23:24, Ash007ks said:

Just a thought have your heaters been working when on warm ? When you guys filled it will coolant did you leave the cap off to allow any air trapped in the system to escape, I have only ever know this happen on two applications. One was a blow head gasket, but that had oil in the coolant also and the other was air expanding in the expansion from unbled coolant system.

 

Yea the heater is warm when at hi setting but not hot! 

Is there a procedure to follow now when the system is filled to remove any trapped air?

Link to comment
Share on other sites
Ash007ks Enthusiast

Ash007ks

Posted
Posted (edited)

I start with the engine off, fill to the required height and then have someone turn the engine on with the heater on fully hot and the fan off. It should then purge any air out of the system. It does sound like that's your issue.

 

You will notice the coolant level dropping and see air coming out. Just keep it topped up.

Edited by Ash007ks
  • Like 2
Link to comment
Share on other sites
ords Experienced

ords

Posted
Posted
4 hours ago, Gti Jazz Blue said:

JKM in Portsmouth have a good reputation when it comes to VAG Servicing and Maintenance, I've used them on previous cars and always been happy with the work carried out. http://www.jkm.org.uk/

Driving from Yorkshire to Portsmouth should get rid of any air trapped in the system🙂

Link to comment
Share on other sites
Gti Jazz Blue Experienced

Gti Jazz Blue

Posted
Posted
2 minutes ago, ords said:

Driving from Yorkshire to Portsmouth should get rid of any air trapped in the system🙂

LOL - sorry that was aimed at bigblueVRS who is in Hampshire 🤣

  • Like 1
Link to comment
Share on other sites
bigbluevRS Newbie

bigbluevRS

Posted
Posted
On 04/06/2019 at 15:21, Gti Jazz Blue said:

LOL - sorry that was aimed at bigblueVRS who is in Hampshire 🤣

Cheers - JKM were an option - its being taken in this morning for Cylinder head rebuild.

 

I’ll let you know how I get on!

 

🚙💷💨💷💨

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Community Partner

×
×
  • Create New...

Important Information

Welcome to BRISKODA. Please note the following important links Terms of Use. We have a comprehensive Privacy Policy. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.