99v 70 Temp and Oil Change

RB3 · Post by **RB3** » 10 Aug 2026, 12:06

okay, change the oil over the weekend. I went from 5W30 to 5W40 as we've had a lot of heat and the car is getting up in mileage. got in this morning drove A very short distance and when I got back in the car it did not want to start. It started on the second or third try but check engine light will not turn off after driving . ran codes at local auto parts store indicates coolant temp sensor and thermostat. both of these were replaced back in March. any correlation with the oil change? vehicle is running ok and at normal temp. fluids are okay. inspected for any oil leaks after the oil change and a couple of times since including now. Help!

V50M66 · Post by **V50M66** » 12 Aug 2026, 15:30

5W-40 Euro spec (ACEA A3/B4) is the correct oil, and what you should be running in these. 5W-30 is too thin, especially in the summer months, if you drive aggressively, or frequently tow or haul things. Your issues are unrelated.

Post by **scot850** » 12 Aug 2026, 17:44

The only engine that I know of in the P80 that is spec's for 5W-40 is my 00 V70R. The others have 10W-30 summer and 5W-30 winter.

But!

If the car is starting to burn the thinner oils, then step up to the 5W-40.

WELL, I just found a Volvo owners manual for a 2000 Volvo and it seems to suggest 5W-40 is the oil that works over all the temperature ranges from -40 to + 104. 5W-30 from -40 to 86F and 10W-30 from around -4 to 104F. Wow, you learn something new every day!

Neil.

RB3 · Post by **RB3** » 13 Aug 2026, 16:00

Appreciate the input. Felt like it needed a change. I'll keep an eye on it.

Post by **abscate** » 14 Aug 2026, 06:40

We run straight 10W-30 year round in NYC in all our Volvos. We dont get to 104F , ever - and if we did I would stay home or during the peak. Volvo even says brief periods outside the range isnt harmful, so 10W-30 or 40 fine.

These cars are well lubed, cooled, and strong bottom end engines - regular changes of good quality synthetic oil.