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Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4708
Experience:  Fully qualified / self employed garage technician in the UK
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My citroen relay leaks a lot of water on a journey, it is

Customer Question

my citroen relay leaks a lot of water on a journey, it is not going into the oil, nor out of the exhaust. we have just had a reconditioned engine put in. It does not leak when stood.
Submitted: 1 year ago.
Category: Car
Expert:  Robert replied 1 year ago.


In what way have you checked for leaks?

How quickly does it loose coolant etc? and or how much needs to be topped up?

Customer: replied 1 year ago.
We have looked all around and underneath vehicle, we have had it pressure tested. It does not loose water when stood and not running. It looses the header tank in a 160 mile journey. We wonder if it could be the fans by radiator, or the radiator cap. It does not over heat. The red light comes on when it is short of water.
Customer: replied 1 year ago.
It seems like it is using water to cool, but we are no mechanics
Customer: replied 1 year ago.
Would it be an electrical fault
Expert:  Robert replied 1 year ago.

If its been pressure need to let it sit under pressure for at least 15minutes..if it holds..then the coolant system doesnt have a the pressure test should help ID leaks that can occur if the engine is hot when things expand..but if nothing is seen or the pressure guage doesnt move after 15minutes..then the system is fine...that would leave maybe possible bad expansion tank cap maybe allowing the coolant to boil and you may want replace that and see if that helps....Normally during a engine swap you will need to reconnect coolant pipes thats why is best to recheck those are tight..aswell as the radiator too..but if all these are dry and tight then you can sort of focus i say with the cap as above... The fans or an electrical fault shouldnt coolant loss...

Customer: replied 1 year ago.
Everything is dry, so will get An expansion cap, and try, will let u know outcome
Expert:  Robert replied 1 year ago. problem...In the mean time if you could leave a rating for me before you log out..much appreciated

Customer: replied 1 year ago.
Will wait to see if cap sorts problem, we have come on a journey, after 70 miles red light came on,we put 2and a half litres of water in
Expert:  Robert replied 1 year ago.

Unless the cap is faulty - i cant see how it could loose that amount of coolant but not show any signs of overheating or even a sign of leak somewhere..if the pressure test was done correctly - that will only leave either the system maybe over pressurizing exhaust gas leaking into the system thus forcing the coolant out..a block test would check for that...

Customer: replied 1 year ago.
Could you please explain how a block test is carried out. Just rechecked under vehicle and around expansion tank, no signs of any leaks.
Expert:  Robert replied 1 year ago.

You need a block test kit - it test for combustion leak and can verfiy that the coolant system maybe overpressurising.. in the kit you have tube and suction bulb on the fill the tube with the special it onto the neck of the expansion tank..and squeeze the bulb a few times..then start the engine up..whilst its running watch to see if the dye changes colour to Yellow then you have internal leak..if its stays Blue then you have no leak...Having said that any good garage should have this it maybe worth enquiring locally to have it done than buy the kit yourself.....if its still Loosing coolant then the cap might be your could also be worth making sure the Oil is ok and water not getting into that instead...have you checked the heater matrix and around the floor area just to be sure it not leaking into the cabin

Customer: replied 1 year ago.
Thank you, ***** ***** try cap first
Expert:  Robert replied 1 year ago.

no probs