Problems with blue smoke exhaust.

[Martin Margerrison]

Greetings one and all.

1996 Audi A3 1.8 petrol. 200,000 miles on the clock.

Problems starting it, takes 3 or 4 attempts. Once running it performs fine but emits blue smoke intermittently approximately once every 8-10 miles.

Fitted replacement throttle body and new spark plugs but no improvement.

Any advice ?

Martin

 

[cliffcoggin]

Martin.

Blue smoke is a good indicator that the engine is burning oil. Intermittent smoke in combination with difficult starting suggests the most likely problem is worn valves and seals, though at 200000 miles it is likely the bores and rings are also very worn. If you can get a compression test done and it confirms low compression I reckon you are facing an expensive repair or replacement of the engine.

[Magnet]

Hello Martin,

Along with Cliff’s reply, I would ask for more information about when this intermittent blue smoke is evident.

There are two basic tests better judge the causes of blue smoke:- 

When the engine is fully up to optimum operation g conditions - i.e. about 5 miles after the coolant temperature reaches normal - allow the engine to idle at say traffic lights, and ask your following accomplice to note any blue smoke when you start to move away. You should also ask for blue smoke assessment immediately after travelling down hill, then accelerating. If blue smoke is evident on these occasions, then it’s likely the oil is passing the valve guides, either via. worn guides or more generally failing valve stem oil seals. 

The second test is to note any blue smoke on enthusiastic acceleration. This is usually attributed to worn piston rings. 

How much oil does this engine use Martin? 

More problematic starting may not be associated with the blue smoke issue, but as Cliff says - it might be. 

If it were mine, I would be wanting to eliminate/investigating any connection between the two, and first looking to other reasons why it’s not starting as well as it did.

Kind regards,

Gareth.