The head gasket on my 300TD wagon is leaking and my mechanic said you can drive years with this condition. Being a major investment, how important is this to get done? Is there a reasonable chance of serious damage if it's not fixed soon? The mileage hasn't been so good since we got it, don't know if this repair would help that. I think I'm going to replace to injector tips soon to see if that helps mileage a bit.
Thanks for any feedback.