Classic/Antique Car Repair: 1976 MGB Roadster - exhaust fumes..., firewall one, air leaks

Question
Hello Mr Fitzcharles!

My car is a very good example and has been recently serviced, though not by a MG expert.
I cannot find and cure the source/smell of what seems like exhaust leak... Can you give me some ideas?

Kind regards, Michael Jay  

Answer
Hi Michael,
The only way to find an exhaust leak is to put the car on a lift with it running and closely examin the exhaust from front to rear.
Sometimes just the smell of the engine compartment due to an air leak in the firewall or something like a broken shift lever boot or missing transmission dipstick cover can give you normal engine smells inside the car which make you believe you have an exhaust leak. These types of air leaks should be checked by examination of rubber gromets etc. where wires or cables go through the firewall into the cockpit.
What ever you do don't skip the exhaust system examination even if you find an air leak in the firewall.
One other thing to look at is a seal across the rear of the hood which prevents engine air and smells exiting the hood and entering the heater intake vent just in front of the windshield. Also inspect the rubber seal around the battery cover behind the seat.
I hope this helps.
Howard