My previous daily driver was the 2002 S60 but in Sept 2017 my wife got another car and now I have her 2007 V50. Before the S60 I was driving a (very good condition) 1990 Jaguar XJ40 (also known as an XJ6).

The Volvo had a flat head 4.0 engine.

All the cars mentioned above are driven in my same daily routine which is mostly stop / go around town.

1990 Jaguar MPG was mid 15 (199,000 miles on odometer) non turbo
2002 S60 is sitting at 17.4 (223,000 miles on odometer) turbo
2007 V50 is sitting at 15.4 (103,740 on odometer) turbo

The V50 seems to be running well but last week it dawned on me that the MPG seems low. I use premium and full syn oil.

Last fall I had the PCV system replaced under extended warranty. When I retrieved the car from the dealer they had only replaced the box, nothing else. Volvo USA warranty said that that under the extended warranty the hose was to br replace and the intake O rings, etc.

I called and the dealer said bring the car in and they will take care of it. Retrieved the car and they gave me a $50 gift card to be used at the dealer. Checking the car they forget to tighten the one hose clamp on the big hose that goes over the top of the engine.

So here I am thinking about this mileage thing and I am wondering if they did the O rings correctly, did they pinch one, is there something else at hand, etc?

No CEL.

I can't believe that I am not getting better mileage than the big, 4,000 pound, 1990 Jaguar that was a 4 speed auto without OD.

Maybe this mileage is as good as it gets?

 

Is your V50 FWD or AWD? City / Highway?

In either case, that sounds really low. I have a pretty light foot but my previous V50 T5 FWD auto was pulling 27-28 mpg in 70% highway. My present V50 T5 FWD 6spd is getting 28-30 mpg.

 

It is an automatic AWD.

I live in the suburbs a bit busy but not sitting in traffic jams. For the 30 years I've lived here my daily driving is the same. My office is in my house, I may go out for a cup of coffee, go for groceries, etc. So when I say that my Jag got the same gas mileage, I am comparing the same driving habits.

I am not heavy on the pedal, I don't tailgate means I am not always hitting the brake pedal - then giving gas - hit the brake - give gas, etc.

My wife's Honda CRV takes regular gas and is averaging 23 MPH. She is retired and does the same type of driving.

I like the "it takes regular" gas in the Honda manual. Sure we don't have the turbo boost but when you need it, the darn thing will go. Plus it has a timing chain. The Jag also had a chain and nobody on the forums had any trouble with the guides.

 

Agree it sounds low. Even my wife's Highlander gets 18 in town in suburban driving which is what I'd expect a V50 T5 AWD to get with in town driving. Air leaks can certainly mess with your efficiency but I'd expect to get a code. How does it run at wide open throttle? (if you have a light foot, you may never get to sense if its not making full power). If you had to get work done on the PCV, I'd also look to see if the intake is clean (ie MAF, throttle body etc) since the PCV feeds back into the intake. Also what gas do you run? Try throwing some Techron or similar FI cleaner in the tank and if you tend to run regular do a tank or two of name brand premium (to pick up their detergent additives). See if that helps. Also check tire pressure, inspect the exhaust pipe for any dents, and check the air filter. Does it behave better worse on cold days vs warm or have any wobbles in the temp gauge? Could be an ECT sensor or even a temp sensor that controls the intake preheat airflow...

 

I always use premium gas

WOT it goes fine, turbo kicks in and off ya go (although I really never gave it a true WOT where it would be head jerking off to the moon).

I've been thinking about pulling it off and cleaning the MAF

With OBDII a bad ECT or temp sensor should throw a code. A lazy one might not??

Cold or hot it behaves the same. Except for the poor MPG there really aren't any arrows pointing to a bad running car.

I did notice one oddity the other day. When I was getting on the highway, giving gas to merge, I did smell --- what I always call a carbon smell. The heat was on and it would have been coming through the vents.

The temp gauge doesn't waiver but it does take longer than the S60 to reach operating temp (half way).

 

when I had to replace the temp sensor on my 00 S40 I didn't get a check engine light...

 

Yes I would believe that a CTS that isn't too far out of range would not throw a code. One out of range would be a P0118 ...I think?

Very poor fuel economy
A no start condition Vehicle may start, but run very poorly, blowing black smoke, running very rough
Misfiring
Illumination of MIL

Read more at: https://www.obd-codes.com/p0118
Copyright OBD-Codes.com
Symptoms of a P0118 could include: Very poor fuel economy A no start condition Vehicle may start, but run very poorly, blowing black smoke, running very rough and misfiring Illumination of MIL

Read more at: https://www.obd-codes.com/p0118
Copyright OBD-Codes.com

I have one of the above. Wonder how far and deep they buried the CTS on a V50. What I miss about that Jaguar is working in the engine bay. The CTS was easy to get at and so were many other things on that 1990 flat 4.0 six cylinder.

I know where the thermostat housing is on the S60 but not familiar enough with the 07 V50 to know where it is hiding.

 

to look for the temp sensor, follow the upper radiator hose to the thermostat cover and see if the sensor is right under that on the front side.. I can't imagine Volvo would change the design from the other white blocks