Oil consumption excessive, worn pistons

15 C3. Had it 4.5 months. driven 9 thou since ive got it and the oil consumption is really high.
engine light came on and i took it back to the dealership.
they told me that my catalatic convertor was torn. £350 to fix.
I get the car back and 3 days later engine light goes on again. Back to the dealership.
They now say that the pistons aren't working properly because of the high oil consumption and that its going to cost 2-3 grand to fix? the warranty covers 1 grand but surely this isn't right????
I dont know how to talk to the dealership and for this to get sorted but not shell out 2 grand for a car i've only had for 4.5 months!!!

Hi

It's not a new car, so they are often sold as seen. You are lucky to even have any warranty, but these are not worth the paper they are written on.

The wrong choice of oil previously used or a lack of oil in the past can easily cause worn pistons rings, combustion chambers and now cause the catalytic converter failure.


This all seems plausible and the cost seems right. You may just be better off getting a replacement engine complete with cat.


Buying used is fraught with problems and a verified full service history can help alleviate those concerns.


The wrong oil or lack of oil in the past may well have caused the problems and you have now inherited them.

The test for worn piston rings or scored cylinder bores is a compression test
(with one of these testers on Amazon).

Do the compression test, note each cylinders pressure, check if it is within spec.

Then add a small quantity of engine oil to each cylinder and retake the tests.

If the pressure rises on the second test, it would indicate the oil has (temporarily) sealed the pistons better, so they were worn.

If the pressure doesn't change for the better then it would point to other problems like valves or head gasket.

louistlindsay wrote: ↑Sun Oct 02, 2022 11:10 am 15 C3. Had it 4.5 months. driven 9 thou since ive got it and the oil consumption is really high.
engine light came on and i took it back to the dealership.
they told me that my catalatic convertor was torn. £350 to fix.
I get the car back and 3 days later engine light goes on again. Back to the dealership.
They now say that the pistons aren't working properly because of the high oil consumption and that its going to cost 2-3 grand to fix? the warranty covers 1 grand but surely this isn't right????
I dont know how to talk to the dealership and for this to get sorted but not shell out 2 grand for a car i've only had for 4.5 months!!!

I would recommend you watch this video to find out what is happening inside your engine;


https://www.youtube.com/watch?v=CZhV0Qv1lps
If this is the case (and it most likely is) then there is no physical damage to the engine. It just needs to be un-gummed up! Now that's easier said than done! As it says in the video they used some very expensive and proprietary chemicals to un-gum that engine. It's not available to the public.
You will need to do some on-line searches to see if there is a company in your area that can perform this service.
I believe the damage to the catalytic converter was done by the excessive oil consumption and replacing the converter without addressing the oil issue will just result in another damaged converter!
All of the damage done to this engine was done before you owned it! This does not happen over night. So the car dealer should be responsible for the repairs. But they will argue to the contrary.
If you find a company that will de-gum the engine, talk to them, see if they can help you with the dealer?