Frankly I can't agree with Desert Dog , boostjunkie or Rambler .You say the interior smells like dead fish and they suggest checking your shorts ? Now how dumb is that ? I ask you ...Anyone knows that you should start by checking your girlfriends shorts first. Then and only then would I look to my cars interior ,especially the heater core .That is where most often some jerk, under the guise of friendship ,spreads Limburger cheese .Although I've never had either of those situstions happen to me ..it is possible .I'll tell you what has happened to me that created a similar stink. I have found at different times ,since living here in Florida a 4' balck snake,a squirrel and a Pametto rat dead under the hood of my car. The further I drove and the hotter my engine got ,the greater the stink. I is positivly strong enough to penetrate the cabin's interior. I suggest that you raise the hood ( bonnet) while the engine is hot and check there for the smell. The snake I found dead was wpapped around the heater and looked like a part of the hose work .The rat was down between the engine and Battery .The squirrel was in plain sight on top the engine void of and body hair .But in any event I wishing you a sweet smelling Christams.