Technical Bubbling Knocking noise

[Kerim]

When mines was bubbling etc; it was doing it when the engine was warm not when it was cool, not to sure about if it would be the HG if your hearing a bubbling noise when cold though. I'm sure but im sure one of the more experienced members will tell you though.

If you want to check the turn the engine over and take the radiator cap off and if it boils/bubbles out of the coolant tank then most likely HG.

Craig

P.s Did you open both bleed nipples when bleeding the system ?

Theres 2 bleed nipples? ive got an MK 2 1.2 8v only assumed there was 1 bleed valve. illl have ago at testing the HG tommorow. Hopefully it aint my HG. Otherwise thats it for the 8v.

 

[scottishpunto]

yeah mate same as mine, theres one on top of radiator and one on the pipe round beside the engine.

Try bleeding it again and see if that helps. Think theres a guide on here for bleeding the system.

Craig

 

[MadMan0]

Crap when I start my car for the first time of the day usaly in the morning when its cool I get a bubbly noise i rev it tiny bit and it makes the noise again wait 30-60 secounds and it wont do it? So strong chance my head Gasget is gone? I changed my coolent 2 weeks ago I did let air out of it via the nipple. So do i need to tunrn the engine on and take the coolent lid off and it it bubbles I got a HG problem?

Sounds like air in the heater matrix mine has this also, i found a small leak leading into heat matrix so i get a bubbling noise there aswell as this strange bubbling knocking noise, might just need rebleeding. there should be a bleed point at the heater aswell as radatior

 

[Kerim]

OK VERY URGENT

I tried to losen the back bleed nipple near the engine and its snapped off all i have is a flat lump i need the part number as its held by Heavy duty water restent tape atm. Anyone can help me with it ASAP

52 plate MK 2 8v the hole nipple is snaped and i cant take it out so im going to have to change the whole thing!

 

[MadMan0]

another update. there is now a tapping/knocking noise present almost all the time. The bubbling/knocking noise hasn't happerned for a week now but i do get a bubbling noise - sounds like heater - every time i start it up.

The coolent level seems to drop worse when heater is set to 50:50 hot:cold

Hoping the cold weather doesn't frezze the coolent but cant work on the car until mid - end December

 

[MadMan0]

Car engine power is all over the place!

One min its pulling gr8, next its slowly down.
came to a hill, normally dont have to change down, but this time i did, however when i did ther was no change in pulling power.... i went from 5th to 2nd and it still struggled to accerate up a slight hill. Who knows what would have happened if it was steep hill like the one i would have had to go up if i took the main roads home

On top of this there is now also a quite knocking noise, differcult to hear over engine noise + road noise but it is there...

Any more ideas

 

[MadMan0]

I found my missing coolent!

Put heater on full heat instead of 50/50 and the coolent level in the expansion tank went back up to max marker

This odd problem keeps throwing up surprises

 

[DaveMcT]

Air bubbles in the cooling system. Bleed it properly.