Hi 

 

Audi A4 1.8T 2003 – Can any help diagnose white smoke from exhaust? 

I have had engine flushed and 54 point service carried out with all levels topped up, garage saying may be catalytic converter so used cleaner twice and no difference. Any ideas?  

Hi Stevee

Is it white white or white blue? could be a cracked head gasket or oil burning too much. does it still smoke when the engine is warm?

Regards

Bradley

Hi Bradley, Thank you for answering me so quickly, The smoke is white white and the car smokes when the engine is warm?

Okay, Like the picture shows really, I'm afraid I cant help with much more than that as I'm not 100% on the issue and don't want to be giving out wrong information, but I hope what is happening gets fixed soon.

Hopefully someone with more knowledge can help you out soon.

Keep us up to date Stevee ;)

Thanks again I'll post up if i get this fixed!

Does the smoke smell of oil or fuel?

If not, then it may be steam and this is coolant being burnt within the engine...if so, this can cause tremendous damage to the pistons and cylinder head so if you are losing coolant then it needs investigating immediately.

It could also be fuel particulates being converted in the Cat and emitting as water vapour in which case it can damage the cat and may indicate that you have a misfire issue.

Hello Stevie,

Personally I wouldn't get too pessimistic about this - in terms of head gasket failure etc- until we have a bit more detail from you. The only comment I would make is to question the possible diagnosis as being due to a faulty catalytic converter! Still..... 

What I would want to know is whether the car is losing coolant or not, and if so how much to return it to its original level when cold and how many miles had been travelled. I would also need to know is if this smoke is still present after a 10 mile run on a fine day with the car at standstill and an assistant holding the revs. at a constant 2000rpm. If it is, and its white (if it was oil burning  it would be blue) then I would agree that it is likely to be water entering the combustion. 

Now I'm pre judging your answers here, but if it is losing coolant, and the white smoke is persisant then my first port of call would be to suspect/eliminate the (water heated) inlet manifold gasket - based on the system being flushed, probably with a caustic additive which might have  attacked an already failing manifold gasket. Please don't get frightened into head gasket issues until all else has been eliminated. 

Hope this helps,

Kind regards,

Gareth.

Thanks for all the replies i have had on this... So i  ran a diagnostic check on the A4 and it came up with Code P0420 which lead me to here http://www.p0420.com..Thoughts please?

Hello Stevie,

While someone interprets the code, perhaps some additional information might help us- such as the questions I asked.

It is also important to know if the car is relatively new to you or not, and if not, how long you have owed it. However long you have owned it, it would be useful for you to confirm, or otherwise whether this problem was there to any degree before you had the coolant system flushed. I feel it is going to be far more difficult for anyone to help you with this without the above information. 

I do have what can only be a theory for what may be the trouble here, but the viability of that theory is very much dependent on the additional information we, or at least I, need to offer any further advice. 

Kind regards,

Gareth. 

Here we go then Stevie. A quick Google shows 0420 is something like catalytic converter low efficiency (or something along that line), which is why the garage convinced you to pour your hard earned into Cataclean or whatever which would have been a miracle cure, since they were not looking at the cause of the cat.being below par - to my guess it is simply the fact that you are pushing high quantities of water vapour ( white smoke) down it at a rate of knots. 

"They don't like it up 'em" as Jonesy would have said.

I think you can forget about the code, and concentrate on why you have the white smoke. To spell it out as simply as I can, it's the white smoke which is causing the problem and not code 0420 (which is an affect of the white smoke).

It's over to you Stevie to give us the full history on this issue. Just read the replies and give us all the answers asked for and I'm sure help will be at hand. I should have put the full of full history in capitals,  and the all of ... all the answers.. but I'm sure you will come up with the information for us.

Kind regards,

Gareth.