XC90 trouble starting

JAL42 · Post by **JAL42** » 05 Apr 2020, 12:45

Hello folks. So have a 2010 XC90 3.2 and havent had any issues for 10 years up until a month ago. Got my oil changed at a chain place (I know that's my first problem) and within that 30-40 min of changing the oil they had to jump start the car. Ever since then I've had to jump the car in the morning.

All the electrics and lights come on but when trying to start the car I get an almost clunking sound but no turnover. I've tested the battery and alternator plus had the pros check them as well and both are good. I had a bad fuel rail sensor thinking that could have been the issue and after replacing it started right away. After sitting overnight it started right way the next morning but the following morning back to the same issue. I did manage to start the car on the third try without jumping it though.

My battery reads 12v but I suppose it could still be the battery. Just dont want to throw down $$ on one and still have the issue. The clock does blank out each time which sounds like a battery issue but as I mentioned it tests fine. I also attempted a parasitic battery drain test but not sure if I did it it correctly as I didnt get any readings.

Any help would be appreciated before I throw in the towel and head to a mechanic.

Post by **RickHaleParker** » 05 Apr 2020, 17:37

JAL42 wrote: ↑05 Apr 2020, 12:45 My battery reads 12v but I suppose it could still be the battery.

You need to list the exact voltage to the nearest 0.1V and the conditions when the measurement was taken.
12.0V would be a very dead battery ? Full charge at rest is ~ 12.7V .

Do you do a lot of short trips? If so the your battery may of been running low when you took it on. When they did the oil service they pushed it over the edge. No fault on anybodies part. Get some more precise measurements and do tell under what conditions, Example: 12.3V before start in the morning.

If it is a battery issue. Leaving the battery on a charger for several days may bring it back to life. The parts stores will bench test the battery for free but I recommend charging it for a couple of days before you take it in.

Post by **RickHaleParker** » 05 Apr 2020, 17:55

With everybody staying at home, expect to see a rash of battery issues. If you are not using a car much, a float charger will keep the battery in good condition.

Post by **SuperHerman** » 05 Apr 2020, 19:47

Yup - my cars have been sitting unused and I hooked up the charger and the all showed low voltage. The systems are running at a limited draw, but a draw never the less. Put a charger on your battery and see how it reads. You should have more than 12V - that is a sign of a battery near end of life.

JAL42 · Post by **JAL42** » 06 Apr 2020, 08:30

Thanks for the quick reply. So details: Resting battery tested in the morning was 12.45V. Running I got 14.75V and after driving 40min I tested the battery and got 12.90V. It took 3 tries this morning to start. I disconnected the battery to see what happens the next morning. So maybe a dying battery?

My schedule really hasn't changed much with the current situation. I have a 25 min drive each way, 4-5 days a week. Unfortunately don't have a way to charge the battery but might be able to take it in somewhere and have them charge for a few days.

JAL42 · Post by **JAL42** » 07 Apr 2020, 06:49

Update: After disconnecting the battery I tested it this morning and got 12.80V. Hooked it up, test again and watched as the voltage dropped on the meter. Car wouldn't turn over. I assume there is some draw from computers and what not but am I looking at a parasitic draw or really just a shot battery?

Post by **ggleavitt** » 07 Apr 2020, 10:11

This post reminded me to put a float charger on my '08 yesterday, battery is just a couple years old but the vehicle has been sitting in the garage for a few weeks and won't be driven anytime soon.

If this is an original Volvo battery, you'll see a date code stamped on one of the posts. And if this is an original battery, it's a 10 year old battery so entirely possible it needs to be swapped out.

Not sure if you have the Group 48 (6xx CCA) or the Group 49 (8xx CCA) battery in the vehicle, it can take either size by relocating the bracket on the bottom. Might be worth considering moving up in capacity if you have the smaller battery (did this on my '05).

Post by **RickHaleParker** » 08 Apr 2020, 04:30

JAL42 wrote: ↑06 Apr 2020, 08:30 Resting battery tested in the morning was 12.45V. Running I got 14.75V and after driving 40min I tested the battery and got 12.90V.

I think the Alternator's voltage regulator is defective and it cooked the battery.

12.45 is 60 - 70% charge.

14.75 is charging but it is high. Running 14.7V too much will boil the battery.

12.90V right after shut down does not tell much, surface charge will produce a false reading. It takes 20 - 30 minutes for a surface charge to dissipate.

12.80 V Open circuit voltage is always higher. The quick drop in voltage after hookup a strong indicator the bulk resistance is high.

If you are getting low voltages constantly after waiting for the surface charge to dissipate. The battery is not taking a full charge or it self discharging at a very high rate.

You need to check out both the battery and the Alternator's voltage regulator.

JAL42 · Post by **JAL42** » 11 Apr 2020, 15:55

Update: Welp, it was the battery. After 10 years, it finally had enough (great run for a German made battery) and three days after replacing its starting like a champ. I appreciate everyone who helped.