Coolant, recurring problem

[beejay]

Driving down to Harwich l]st Friday with a heavily laden car, 10 miles later coolant light comes on, pulls over, checked header, no coolant, filled up and all ok for 30 miles light on again, pulled into Shell garage restocked on coolant (not the pink stuff) filled system up and again all ok, got to Harwich with no further problems, sets off home again 78 miles and all ok. Driving around for days since, good. Went a appointment in town and back 5 miles pulled onto drive and coolant just errupted from header through cap, no coolant tank, cap was tight!! nothing came up on message centre and temp was as normal, took 1 and half litres to bring to level, now nervy on taking car out!!. Any ideas as to what it might be??

[YIM YAM]

Have you had any work carried out on the engine recently, cause that's bonkers,

Originally Posted by beejay

Driving down to Harwich l]st Friday with a heavily laden car, 10 miles later coolant light comes on, pulls over, checked header, no coolant, filled up and all ok for 30 miles light on again, pulled into Shell garage restocked on coolant (not the pink stuff) filled system up and again all ok, got to Harwich with no further problems, sets off home again 78 miles and all ok. Driving around for days since, good. Went a appointment in town and back 5 miles pulled onto drive and coolant just errupted from header through cap, no coolant tank, cap was tight!! nothing came up on message centre and temp was as normal, took 1 and half litres to bring to level, now nervy on taking car out!!. Any ideas as to what it might be??

[beejay]

New radiator and bottom hose, header tank and coolant sensor fitted in June

[Parker]

There must be a leak somewhere, start her up and check all hoses etc. see if you can see anything.

[beejay]

I looked as best I could when I filled it up again and nothing was apparent, down to the ruddy garage again tomorrow.

[Thomas]

Moved to technical help forum

[rover54]

I wonder if your pressure cap is defective and buy unscrewing it and then putting it back on again it hold pressure for a while. The only event that is changing is that you are removing and refitting the cap. If the cap fails to hold pressure your coolant will boil, hence the eruption when the cap is removed and when refitted it pressurises the system and then possibly the vaccum valve opens (when coolant cools down) and fails to close. Try a new cap, dont try and fit new o rings to the old cap as the vaccum valve is built into the cap.

[Johnny the Fox]

Leaking water pump??

Had the same on my F, small coolant loss, no sign of leak, hoses was fine, replaced the cap, was still topping up once a week, noticed a small coolant stain on the alternator lower mounting, traced it to a leaking water pump.

The leak was small enough to evaporate away due to the heat from the engine

[beejay]

Originally Posted by rover54

I wonder if your pressure cap is defective and buy unscrewing it and then putting it back on again it hold pressure for a while. The only event that is changing is that you are removing and refitting the cap. If the cap fails to hold pressure your coolant will boil, hence the eruption when the cap is removed and when refitted it pressurises the system and then possibly the vaccum valve opens (when coolant cools down) and fails to close. Try a new cap, dont try and fit new o rings to the old cap as the vaccum valve is built into the cap.

Have just refilled system, stated engine from cold and left to idle in driveway sure enough as soon as it temperature gauge reached normal it spewed coolant out of cap, topped up and ran engine on tick over without cap, in no time at all it pushed coolant out of tank, ideas and possible solutions, can't take it to garage, won't hold coolant????

[Rocket]

Get a new cap. It should not let water past at normal temps. The water overflowing with the cap off is to be expected, as the water heats up it will expand and overflow.

If the same thing happens with a new cap it could be more serious.