Dear All,

I would need your help in a question to make sure I decide correctly on the planning repair:
I have a T6 (3.0) from 2009. It has 162000 km (100662 miles). My check engine light come up, after reading it out it seems to be a catalytic converter issue. In the past 3 times I loaded 100 octane gasoline.
The first question is this: Can it be related to this check engine light?
Also I experienced a higher oil consumption. After 3000 km I got a low oil level warning, so I had to fill it up. For this I have to mention that during this winter my wife used it for very short distances (~2 km) 2-3 times a day.
The second question is: Should I worry about it?

Thanks for everything!

 

what exactly are the CEL fault codes? The most common is the P0420, ake the cat efficiency code that is reporting the rear O2 sensor shows two much O2 per the ECU's calculator to suggest its not converting any remaining HCs. This can be caused by a intake air leak, exhaust leak, failed or contaminated converter or a bad O2 sensor. When you say you loaded 100 octane gas, are you in the US or where are you getting the fuel (in the US the top available pump gas is Sunoco Ultra 94 (94 octane using R+M/2). Are you saying you are dropping in Aviation gas or a Sunoco racing product (wondering why). So my quick take is, yes its conceivable that too high an octane fuel can set off a check engine line. Racing fuels are more highly oxygenated vs pump gas which can cause the ECU to compensate beyond its abilities. If your reference to 100 octane is based on a different measuring standard than R+M/2 and you are using pump gas, then I wouldn't expect any issues so you may have a borderline issue with the converter possibly due to oil from worn rings or a weak turbo seal. Is the car consuming any oil between oil changes? Any signs of blue/gray exhaust smoke?

 

Hello mt6127,

Unfortunately I don’t have the exact code, the service engineer read that out. I will have possibility to read it again within some days, so I will have that exactly. They told me that the catalytic converter efficiency is reduced.
I’m in Europe, we have 3 kind of gasolines: 95, 95 premium and 100 octane.
Regarding the oil consumption: I don’t see any blue/gray smoke, however in ~4000 kilometres the oil level went from max to min. I don’t know if it’s acceptable or not? :S

 

ok so you are using pump gas - where the 98 or 100 RON is roughly the same as the US 93/94 R+M/2. I'd expect a turbo Volvo to be very happy with premium pump gas so I suspect you may have a converter issue or an air leak that needs to be checked out. Consuming 1L for every 4000 km is higher than normal but not totally out of a normal range since that's roughly 1 quart for every 2500 miles.

 

Hello there,
I'm an owner of a T6 myself for a bit over 3 years now,
Regarding the check engine light - I'm willing to bet it was P0420, I had the same when I got the car, luckily I was introduced to a Volvo expert (who works at a dealership and solely on Volvos) that said he knows what the problem before seeing the car.
He explained to me that the thermostat was designed poorly and tends to break, most of the times - stuck open.
Once the thermostat is always open, coolant flows as soon as you start the engine and it cannot reach good operating temp,
ECU keeps adding fuel to the mix to try to warm it up faster - get a rich mixture - drive O2 sensors mad.

I found it very hard to believe, but it does sounds better than replacing the converters (I think we got 4 of them)

As soon as he unscrewed the thermostat bolts - it shot the cap off and the spring flew away, it was broken exactly how he said it would be,
We replaced it with a brand new one - never had a check engine light come on again.
Check your thermostat, recommended.

Short distances falls under "extreme conditions" which requires shortening service intervals drastically.
Does your engine oil smells like fuel?
If so, must shorten service intervals/

Hope I helped

 

Thank you for your reply and sorry for my delayed answer. I had a chance to take a look at the error code by myself (with a very cheaf obd2 reader). The error code was P0420. I deleted it and was waiting to come back again. Since this action I drove around 250 kms, but it didn’t come back yet. Do you think it was a temporary issue?

Regarding the smell of the oil: honestly, I don’t know. I can believe that the lot of cold start mixed the fuel with the oil to warm the catalytic converter up much faster and that mixed oil “burned”. This is that you think, right?

 

some codes are "averaging" so you may need to drive a few more days to see if it resets. The P0420 code is the "cat efficiency" code. What is going on is the computer is comparing the signal from the front O2 sensor to the signal in the rear sensor and seeing if the O2 level is being reduced by the converter (meaning its using the oxygen to burn off any remaining HCs to lower emissions. This code can be set by a few things. The converter can be bad - which begs the question why it would fail at 100K miles (burning oil or consuming coolant come to mind). It can also be caused by exhaust leaks or intake air leaks (lean running cars don't leave much HCs to convert...) or it can be due to a wonky O2 sensor. If you've ever had any work done, after market O2 sensors and cat converters can cause this code as well (the system is that sensitive).

 

My P0420 wasn't always on, but would come up on long drives, replacing the broken thermostat fix it till now (3 years passed since)

 

Thank you guys for your help! I will update this thread when it comes again and we can continue. (Hope I don't need )