Please Heeeelpppp me, Engine Problems.

[blood69]

Hi,

Having problems with my polo G40. 

Here it goes,

When engine is cold, dense white to gray smoke comes out of the exhaust pipe. When it reaches normal engine temp, blue smoke is coming out of it but less dense. I have disconnected Oxygen sensor because the idle was erratic and black smoke was coming out of the pipe, witch means bad air/fuel mix. I have in mind changing the blue temp sensor to.

The last time i changed the oil did not found 10W50 so i putted again 10W40 with some oil additive, witch had reduce a little the smokes out of the exhaust.

The engine has 110000km and was stopped for some months (said the older owner), its not drinking water but its obviously drinking oil.

At the beginning i thought it was the PCV ( Positive Crankcase Ventilation) blocked, forcing the oil passing through the piston rings (witch i learned it is a common problem o G's), but my regular mechanic said it was probably the valve sealants.

I meet another mechanic that was recommended to me because he have done nice preparations on Rally G's. It was quite impressive to see he diagnosing the car, after 10min he said it was piston rings. After that i kept wondering, "How the F*** he knows its piston rings without doing a compression test???".

How can i test if it is the PCV valve, my regular mechanic was afraid of braking the thing, its well attached to the engine.

Sorry about my "Engrish", im Portuguese living in Madeira island.

Thanks in advance for any help.

[z3i]

By valve sealants do you mean valve stem seals? if its your valve stem seals then you will get blue smoke at very high engine rpm when being thrashed not at idle so i highly doubt its that

your best bet is to have a mechanic carry out a cylinder leakage test, this can identify if your rings or other seal etc are shot on the engine

like you say the pcv is the best place to start. im pretty sure its on the back of the engine block (like a dome shaped thing) under the inlet manifold i noticed mine the other day whilst doing my clutch. but i was lying down under the engine looking past the driveshaft at the back off the block. im sure this is it as mine is leaking a shed load of oil from it. is worth taking off, giving a clean and checking no gunge has filled any of the pipes
hope this helps
Taylor

[hayesey]

the pcv is pushed into the back of the engine.  Chances are you will damage it by removing it.  I last bought one from VW a few years ago, I dont think it was too expensive.  I'd probably just buy a new one.  Like I say it#s just a press fit so prise the old one out using flat screw drivers and then tap the new one in.  I applied a bit of silicon sealant around it too before putting it in to ensure a good seal.

I'd also do a compression test on the engine.  A tester isn't expensive to buy and is a useful thing to have.

[blood69]

Thanks for your quick reply's.

I looked for the PCV in some parts shop, no one could find on their catalogs even searching by the pcv code that i had given t o them or know about it. Its a  simple one way valve that exists for more than 50 years ffskake.
I'm was stunned when my mechanic scared about taking out that part and quickly recommended the supposed "G40 specialist" mechanic.
Unfortunately i don't have way to proper lift the car in my garage, if i had that would be out for sure breaking it or not.

I have to try the VW parts section here in my tiny island, but every time o look their for parts they say "we don't do that anymore, your car is 20 years old, bla bla bla".

Again, thanks for your advice.

[hayesey]

yeah you'll have to get it from VW.  They should be able to order one in.