Blowing coolant out blue cap
Discussion
I have nearly finished my mini project and just ran the car up to temp to double check the fans kick in before thinking about booking in an MOT and driving it on the road.
All was going well and the fans kicked in after what seemed like an eternity at an indicated 95 degrees but then shortly after the car started puking it coolant out the expansion tanks blue cap.
I am hoping it is a case of just not being screwed down tight enough but if I need a new one can anyone remember the part number - it is a VW part?
All was going well and the fans kicked in after what seemed like an eternity at an indicated 95 degrees but then shortly after the car started puking it coolant out the expansion tanks blue cap.
I am hoping it is a case of just not being screwed down tight enough but if I need a new one can anyone remember the part number - it is a VW part?
Cheers.
I think the rubber is starting to perish in the one I have. The only other thing I thought it could be was the thermostat but I did test that - kind of. I took it off, checked I couldn't blow through it at all, put it in a pan of hot water and then I could blow through it. Also, the top hose to the rad gets very hot so I presume the thermostat is opening OK.
I will start with replacing the blue cap as that will be the quickest fix.
I think the rubber is starting to perish in the one I have. The only other thing I thought it could be was the thermostat but I did test that - kind of. I took it off, checked I couldn't blow through it at all, put it in a pan of hot water and then I could blow through it. Also, the top hose to the rad gets very hot so I presume the thermostat is opening OK.
I will start with replacing the blue cap as that will be the quickest fix.
TimJM said:
Cheers.
I think the rubber is starting to perish in the one I have. The only other thing I thought it could be was the thermostat but I did test that - kind of. I took it off, checked I couldn't blow through it at all, put it in a pan of hot water and then I could blow through it. Also, the top hose to the rad gets very hot so I presume the thermostat is opening OK.
I will start with replacing the blue cap as that will be the quickest fix.
Cap sounds threaded from being put on uneven, hopefully not the bottle head too. I did something similar recently. the steam is the water bubbling out and hitting the exhaust. when replacing cap after filling coolant screw the cap on backwards, you'll then hear a click to indicate its located the start and in flat position. Now screw on as normal.I think the rubber is starting to perish in the one I have. The only other thing I thought it could be was the thermostat but I did test that - kind of. I took it off, checked I couldn't blow through it at all, put it in a pan of hot water and then I could blow through it. Also, the top hose to the rad gets very hot so I presume the thermostat is opening OK.
I will start with replacing the blue cap as that will be the quickest fix.
Hope thats of help.
DAVEY DEE said:
Had the same & cacked myself. The cap it was.I replaced the reservoir as well coz it was only £22 from euro car parts.Looks a lot nicer as well being new.
That sudden puff of steam gets worrying when sat in traffic and other car drivers start staring! lolGlad it was just this
My new cap arrived (I went for the genuine part as they are selling new ones on eBay for £3.90) and I managed to fit it on Saturday and re-attempt to bleed my coolant system.
This time it went much better, I bled the radiator and water rails and then ran the car up to temperature. This time everything worked as it should and it didn't blow coolant out the cap. I turned the engine off, let it cool a little and then re-bled the system while warm. A little more air came out but not much. I repeated the process later in the afternoon and no more air came out - just water. I guess the system is now fully bled and I am now finally ready for the MOT.
This time it went much better, I bled the radiator and water rails and then ran the car up to temperature. This time everything worked as it should and it didn't blow coolant out the cap. I turned the engine off, let it cool a little and then re-bled the system while warm. A little more air came out but not much. I repeated the process later in the afternoon and no more air came out - just water. I guess the system is now fully bled and I am now finally ready for the MOT.
Yes I did. I found a post on here that said the ajp used a different design and that turning the heater on would make no difference to this engine but I did it anyway as I have always turned the heater on with other cars (like my griff) if refilling the coolant.
I will run it up to temp once more, let the fans cut in and then let it cool before bleeding again but from the last run yesterday it didn't have anymore air in it at all so I think it is OK.
I will run it up to temp once more, let the fans cut in and then let it cool before bleeding again but from the last run yesterday it didn't have anymore air in it at all so I think it is OK.
Supateg said:
You may find it spits coolant out of the cap until its happy with the level in the expansion tank.
When I foiled mine up half way it did this all the time until I kept the level at a third. Now all is fine
I remember from my first Cerbera that the level of coolant should not be up to the max line so what I have done this time is to fill it to about a third as you said and then run it up to temp. The coolant once hot rose to about the max fill line so I guess this is about right. Last time I did this with the old cap it didn't level out at the max fill line it carried on rising and spat the coolant out so the new cap must be holding the pressure better.When I foiled mine up half way it did this all the time until I kept the level at a third. Now all is fine
Thanks for the info guys - my new cap just arrived from VW Heritage (or whatnot) from the ebay link above - quick dispatch and all in for a fiver.
I've found that if I fill coolant to the "max line" it was spitting out steam, but filling up to approx 1-2cm below line seems OK.
I will try with my new cap and see if pressurises system better. However, in discussions about getting all the coolant hoses replaced, as even though mine is a "late" Cerbera - it's now 12 years old!!! Replacing all coolant hoses for silicone seems to be a good precaution....
I've found that if I fill coolant to the "max line" it was spitting out steam, but filling up to approx 1-2cm below line seems OK.
I will try with my new cap and see if pressurises system better. However, in discussions about getting all the coolant hoses replaced, as even though mine is a "late" Cerbera - it's now 12 years old!!! Replacing all coolant hoses for silicone seems to be a good precaution....
mikeinsheffield said:
Thanks for the info guys - my new cap just arrived from VW Heritage (or whatnot) from the ebay link above - quick dispatch and all in for a fiver.
I've found that if I fill coolant to the "max line" it was spitting out steam, but filling up to approx 1-2cm below line seems OK.
I will try with my new cap and see if pressurises system better. However, in discussions about getting all the coolant hoses replaced, as even though mine is a "late" Cerbera - it's now 12 years old!!! Replacing all coolant hoses for silicone seems to be a good precaution....
Silcone hoses are the way forward mate. Tim at ACT is a great guy and quality products. By choice I'd always go for blue but on Cerb 2 he only had a black pair in stock! Instant peace of mind. Enjoy the upgrade mate I've found that if I fill coolant to the "max line" it was spitting out steam, but filling up to approx 1-2cm below line seems OK.
I will try with my new cap and see if pressurises system better. However, in discussions about getting all the coolant hoses replaced, as even though mine is a "late" Cerbera - it's now 12 years old!!! Replacing all coolant hoses for silicone seems to be a good precaution....
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