Fuel / Gas in oil?

C1ph3r · Post by **C1ph3r** » 22 Mar 2022, 11:20

Hey guys. I did an oil change on my new to me 99 V70 T5 at 178504 miles. I have no idea what type of oil was used or when it was changed before I got it.

Because I an a nervous type person I sent off the oil to Blackstone to get it analyzed. Since it was the first report there wasn't much. Metals are all avg or better, no coolant or dirt in the oil. But they did note that the fuel in the oil was at 3.8% and it should be under 2. In my almost 30 years of cars this is a first for me. At least for the cars I have had analyzed.

I am now at around 179k miles or so. Went out and checked the oil for a gas smell and I don't notice any smell.

The car runs great. I've only filled up 3 times since I bought it and seem to be getting around 19 mpg. Mostly city driving. Not a lot of highway. The one longish road trip I just did the on board computer says I avg 25 mpg. I've done the stage 0: plugs, all 5 coil packs, fuel filter, PCV system, new PTC and a lot of new vacuum lines.

When I change my oil again I will be sending it off for another analysis. Any suggestions on what causes something like this? Bad piston rings? Or is that an extreme? Could it be something much simpler to explain?

454cid · Post by **454cid** » 22 Mar 2022, 12:54

C1ph3r wrote: ↑22 Mar 2022, 11:20 Hey guys. I did an oil change on my new to me 99 V70 T5 at 178504 miles. I have no idea what type of oil was used or when it was changed before I got it.

Because I an a nervous type person I sent off the oil to Blackstone to get it analyzed. Since it was the first report there wasn't much. Metals are all avg or better, no coolant or dirt in the oil. But they did note that the fuel in the oil was at 3.8% and it should be under 2. In my almost 30 years of cars this is a first for me. At least for the cars I have had analyzed.

I am now at around 179k miles or so. Went out and checked the oil for a gas smell and I don't notice any smell.

The car runs great. I've only filled up 3 times since I bought it and seem to be getting around 19 mpg. Mostly city driving. Not a lot of highway. The one longish road trip I just did the on board computer says I avg 25 mpg. I've done the stage 0: plugs, all 5 coil packs, fuel filter, PCV system, new PTC and a lot of new vacuum lines.

When I change my oil again I will be sending it off for another analysis. Any suggestions on what causes something like this? Bad piston rings? Or is that an extreme? Could it be something much simpler to explain?

Was it hard starting when you got it? Maybe several unsuccessful/long starts? Maybe a slightly leaking injector? I'm just guessing with out first hand experience with this.

Hard telling.... monitoring it would not be unreasonable in my mind.

Post by **BlackBart** » 22 Mar 2022, 13:15

Right - if it flooded and washed down the cylinder walls, some fuel might have migrated to the pan...?

Post by **volvolugnut** » 22 Mar 2022, 13:39

I THINK a single event of excess gas in the oil would evaporate when the engine is warm. An ongoing problem, like a leaky injector would be expected to maintain excess fuel in the oil.
Your fuel mileage sounds a bit low to me, but I have no experience with your model.
Expect others to comment here.
volvolugnut

Post by **misha** » 22 Mar 2022, 16:32

Volvo manual says that when you do mostly city driving(stop & go),short distances under 10-15 miles and when engine,most of the time in city driving,is idling....oil change interval is cut to 6 months instead of 12 months.

When you mostly drive short distances in city...this is what you could expect....and it's not strange.
That's why the oil change interval goes under "severe" service and it's cut down to 6 months.

Sincerely....i doubt that any of us change the oil in 6 months interval,especially if mileage limit at around 6-7k miles isn't reached in that time.

C1ph3r · Post by **C1ph3r** » 22 Mar 2022, 18:20

Ok thanks everyone. As for hard starts, none since I’ve owned it. But I’ve only been driving it for a few weeks, I just bought it in December and it’s been under the knife since I got it fixing up all the odds and ends.

I would consider what most of its life to be harsh conditions simply because it’s only driven short distances for the most part. Heck all of my cars are like that.

I will monitor the situation and see how it goes. I will certainly not reach 5k miles on this car in the next year even, so it will be the 6 month time frame for my next oil change. I’ll send that off when I do and see if it’s any different.

Thanks,
A.W.

Post by **scot850** » 22 Mar 2022, 19:22

Several starts and short runs could allow some fuel to leak past the rings and into the oil. It will get trapped there until a longer run gets it burnt off.

The only other thing is a leaking injector possibly.

Neil.

C1ph3r · Post by **C1ph3r** » 23 Mar 2022, 05:10

If it was a leaking injector how would I find that out without changing them? Probably isn’t a good way. If there was too much fuel I assume it would be running very rich if it was a case of so much getting in there that there’s accumulation in the oil.

Post by **scot850** » 23 Mar 2022, 10:09

Monitor your gas mileage once you start using it and let us know. Short runs means the car tends to run richer until warm especially if idling so may lead to more fuel washing down into the oil pan.

Only other thing would be bad coolant temp sensor which could make the engine run rich or bad O2 sensors.

Neil.

C1ph3r · Post by **C1ph3r** » 23 Mar 2022, 10:33

scot850 wrote: ↑23 Mar 2022, 10:09
Only other thing would be bad coolant temp sensor which could make the engine run rich or bad O2 sensors.

I have replaced the coolant temp sensor as well. The O2 sensors however are probably still original.