Hi everyone! Have an Octavia G-TEC -15. Very happy with it. I'm only running it on CNG. On a few occasions I've run out of CNG and had to run on petrol a few km before filling up, but very few. I bought it 1,5 years ago with a full petrol tank, and I still have about 3/4 of the petrol left. Driven about 20 000 km. 

 

Someone over at reddit recommended me to run it on petrol every once in a while, since the petrol degrades over time, and that 1,5 year old petrol definitely is not good for the car. So I filled it up and am currently running it on petrol. Can anyone confirm that you would run it on petrol once in a while? If so, how often? 

Does it start on petrol and then swap over or can you start and run on gas?

 

If your not going to run it on petrol at all I would run it with maybe a 1/4 of a tank and then once every week I would it on the petrol for a bit with the aim of using the 1/4 tank up in a month and filling it up again or maybe even 2-3 months if you find it a faff having to fill up with CNG and petrol.

 

That way your keeping the fuel fresh and using the fuel system.

 

 

Edited 1 September, 20196 yr by SuperbTWM

47 minutes ago, SuperbTWM said:

Does it start on petrol and then swap over or can you start and run on gas?

 

If your not going to run it on petrol at all I would run it with maybe a 1/4 of a tank and then once every week I would it on the petrol for a bit with the aim of using the 1/4 tank up in a month and filling it up again or maybe even 2-3 months if you find it a faff having to fill up with CNG and petrol.

 

That way your keeping the fuel fresh and using the fuel system.

 

 

Honestly I don't know if it starts on petrol or not. Rumor says it does, but if it does it consumes VERY little petrol each start. 

 

Thanks for the advice! What makes us a bit tricky is that I cannot choose what it should run on, if there's CNG then it runs on CNG, if not it runs on petrol. There is no way to manually select petrol. 

So in that case fill the petrol tank up and every so often you will have to run it out of CNG and then just use it on petrol for a few hundred miles (im guessing the unleaded tank is reduced to what a normal octavia would be)

 

Seems a bit silly that you can't manually select, they obviously haven't accounted for people just using the car on CNG only

8 minutes ago, SuperbTWM said:

So in that case fill the petrol tank up and every so often you will have to run it out of CNG and then just use it on petrol for a few hundred miles (im guessing the unleaded tank is reduced to what a normal octavia would be)

 

Seems a bit silly that you can't manually select, they obviously haven't accounted for people just using the car on CNG only

 

True.

 

Actually the fuel tank is the same size as on other Octavias (I think), they've just reduced the size of the trunk to fit the CNG tank. Still a decent size trunk. 

@botze - Well, it's true that modern octane goes off after months, not years.