311 sprinter coolant ???????

[norcosight2]

Hi i have a 2005 311 sprinter it has now developed a strange coolant problem i am loosing coolant it is been returned tru the header tank and im catching it in a bottle and replacing it everyday or so.
There is no oil contamination in the oil cap and i dropped the oil last week replaced thefilters ect ,no sign of head gasket failure as i can see i do get heating in the cab but does go cooler then hot again .
Any help would be really appreciated

 

[Benza750]

If its coming out the cap you may have a cap fault - not holding pressure
Or
It's pressurising too much - most likely head gasket gone between cylinder & water jacket

 

[norcosight2]

hru the overflow There is always some pressure in the system its not coming thru the cap but thru the overflow

 

[Benza750]

Try a new cap

 

[norcosight2]

will get one tomorrow if i can obtain one locally im not sure or if will be a n ebay job

 

[Benza750]

Get a new 1 then you know it is right, the dealers should keep them instock, even a good motor factor may be able to get 1. Just price check as sometimes smaller items like them are cheaper from the dealer

 

[norcosight2]

will call them tomorrow any other suggestions i just do not understand the head gasket issue when there is no oil contamination

 

[Benza750]

You do not always get oil contamination.

Only if it goes between oil & coolant part of gasket,
If it goes between combustion chamber side & coolant it can cause it go pressurise.
Head gaskets can fail in several different ways

 

[norcosight2]

I did not realise that could happen i did think thermostat but seems more to it than that