i have problems with my older 240D starting. Changed glow plugs (used a reamer), changed glow plug relay,starter,fuel filters (have not checked sock in tank yet); question is why would does it start right up some times...then not start later in day after use. When it runs i can drive all over the world no problems (including hills) --somebody said could be valves too tight? i also read some things to suggest i could use a stronger starter than the one that is supposed to be for that car? thoughts?