Water Boiling!!?
Discussion
Ok this is the situation.
Take the car for a good long ride with no traffic and all is fine but in slow traffic etc I have water spurting from the expansion tank. Had the car on the laptop and the first fan comes on at 92 and cools things down to 88 before back upto 92 and down again. We have looked at an airlock etc and after two hours of fiddling all seemed ok but its back and I'm frustrated! Anybody out there got a clue what it could be and for godsake dont say I'm pumping air into the water via pistons or I will cry.
Mick
Take the car for a good long ride with no traffic and all is fine but in slow traffic etc I have water spurting from the expansion tank. Had the car on the laptop and the first fan comes on at 92 and cools things down to 88 before back upto 92 and down again. We have looked at an airlock etc and after two hours of fiddling all seemed ok but its back and I'm frustrated! Anybody out there got a clue what it could be and for godsake dont say I'm pumping air into the water via pistons or I will cry.
Mick
Make sure you're not overfilling the expansion tank. As long as you can see some in the very bottom, then that's ok. Any more and it can boil out afer a hard run. Otherwise, you have a leak which means your coolant isn't running through your Rad and being cooled. The cheap jubilees do break, so check them all.
JensenA said:
If water is spurting from the Expansion tank, then you have a leak. Where is it leaking from, the Cap? It's a standard VW part (off a Golf I think) s replace it. The system is pressurised so a 'leak' from a failed component is normal.
Spot on analysis.If there is an escape route, then the water will find it and spurt out when the car is hot...
MB
Changed the cap a week ago when we went through all the obvious but yes there could be a small leak in there somewhere, so its hunt the bugger down time. Car is running really well and with a few things coming up in October is making my blood boil that I might be missing something else as I did FT.
C3BER said:
Changed the cap a week ago when we went through all the obvious but yes there could be a small leak in there somewhere, so its hunt the bugger down time. Car is running really well and with a few things coming up in October is making my blood boil that I might be missing something else as I did FT.
Check the pipe underneath the expansion tank.thegreengoblet said:
Not teaching to suck eggs, but the cap needs to be on tight as well.
I've made this mistake, as well as overfilling the expansion tank. Doh!
Any clue helps, sucking eggs or not. Tried the cap as I did wonder if it was loose but nope not that. I have a feeling its a leak somewhere which is pulling air in but why it bubbles when I drive slow and not fast I have no idea as the laptop tells me its only ever hitting 92.I've made this mistake, as well as overfilling the expansion tank. Doh!
what does the gauge say? is it the customary 8 odd degrees above what the laptop tells you? has this only just started happening or is it since any work been done on the car? Also what is your tickover speed? too low a tickover and the water pump just doesnt shift any coolant round the system .. raising the revs actualy imprives circulation and cooling. let us know what you find 
It happened before I had the work done on the car and at first I thought it was linked with the alternator problems I had. When it blew its water today it did it in good style with water bloody everywhere. I'm hoping its only air being pulled into the system by a pipe leak etc but I'm puzzled to why it should do it only when I have to slow down.
If the gauge is bouncing all over then there is definitely air getting into the system.
I seem to have a small leak from somewhere. I open the bleed bolt thing on the radiator each weekend (obviously when its cool). There is always a small amount of air in there. I suspect rusty swan neck pipes or old rubber hose giving up the ghost. Its all coming off this winter for a major overhaul so I'm not bothering to try to find out where it is leaking.
I had a leak a couple of years ago with the same symptoms - air in the system every weekend. Couldn't find it despite crawling around the engine bay looking. Trackcar eventually found it - tiny leak from the welded seam on the top of the radiator. It was so small the coolant evaporated as soon as it appeared. He used a neat gadget to pressurise the coolant system via expansion tank. It only showed up because the rad had cooled down and the pressurisation of the system with the engine off forced the water to leak but it didn't evaporate. I wouldn't have found it until the whole seam had rusted away
I had a new radiator fitted and its been fine for 18 months. Its a bit irritating bleeding the rad every week again but no more of a chore than checking the oil and tyre pressures.
I seem to have a small leak from somewhere. I open the bleed bolt thing on the radiator each weekend (obviously when its cool). There is always a small amount of air in there. I suspect rusty swan neck pipes or old rubber hose giving up the ghost. Its all coming off this winter for a major overhaul so I'm not bothering to try to find out where it is leaking.
I had a leak a couple of years ago with the same symptoms - air in the system every weekend. Couldn't find it despite crawling around the engine bay looking. Trackcar eventually found it - tiny leak from the welded seam on the top of the radiator. It was so small the coolant evaporated as soon as it appeared. He used a neat gadget to pressurise the coolant system via expansion tank. It only showed up because the rad had cooled down and the pressurisation of the system with the engine off forced the water to leak but it didn't evaporate. I wouldn't have found it until the whole seam had rusted away
I had a new radiator fitted and its been fine for 18 months. Its a bit irritating bleeding the rad every week again but no more of a chore than checking the oil and tyre pressures.
Filled as much water as I could with the bleed screw open and went to open the two silver t-bar screws but one will not move and the other just spins round totally free. So until I get those open it will be impossible to clear the air from the system? Anyhow, started the car and the bugger boiled with the fans not coming on. Will let you know how it goes.
Hmm, the water rails are much higher than the radiator. I doubt if bleeding the radiator is going to help with the rails.
It sounds like you have an airlock in the rails which expands with temp and pushes water out the expansion tank.
I had a similar problem which I diagnosed with a infrared thermometer. It showed that the rails varied temp alone their length and incidently in my car heated up the capillary tube for the dash water temp which then overread.
I personally think you need to free those water rail taps and preferably add water wetter as well.
It sounds like you have an airlock in the rails which expands with temp and pushes water out the expansion tank.
I had a similar problem which I diagnosed with a infrared thermometer. It showed that the rails varied temp alone their length and incidently in my car heated up the capillary tube for the dash water temp which then overread.
I personally think you need to free those water rail taps and preferably add water wetter as well.
Julian, Paul.
I've the car booked in for the whole system to be looked at but in the mean time I'm having a good look at it being an airlock problem. Was able to release the passenger side tap today and on refilling and running the car was able to release air from the system, I will be looking at the drivers side tap tomorrow.
Because my temp gauge is up the spout I cut the engine before the fans came on.
I've the car booked in for the whole system to be looked at but in the mean time I'm having a good look at it being an airlock problem. Was able to release the passenger side tap today and on refilling and running the car was able to release air from the system, I will be looking at the drivers side tap tomorrow.
Because my temp gauge is up the spout I cut the engine before the fans came on.
C3BER said:
Jasper Gilder said:
I had this on my cerb - turned out to be a corroded up sensor which wasn't always telling the fans to kick in. Check all the electrical connectiosn to the cooling system
Do you know where all the connections are so I can work through them bit by bit?Gassing Station | Cerbera | Top of Page | What's New | My Stuff