How do you tell if the head gasket is shot ? I have noticed some bubbles in the coolant in the header tank at start up ..is that norma ? the engine is lumpy when first started although plugs have been changed recenctly .... but no white smoke or cream around filler cap .....

 

Hiya, no bubbles are normal as the system is always flowing the coolant back into the tank, lumpy idle is normal on certain models (you need to state what year and model you have when you post ) but your biggest givaways are normally the temp guage going through the roof and a film of oil on top of the coolant/gunk around the filler cap, these are not always present though as it depends on where abouts the head gasket has gone.
One of the best ways to tell is on a cold engine, remove the filler cap to the coolant and rev gently, if fluid comes out then you have air in your system (or gas) then you can start looking at other problems
Other options include cracks in the pipes that let air in under expansion or the radiator could be shot.

Tony

 

thanks for the info , its a 98 uk turbo facelift....car drives as it should with no over heating etc ...just has a lumpy idle to start and some bubbles in the header tank , coolant doesn't spurt out all other the place ...no gunk