I have a mid-aged 300k 3.6L car. I bought it 3 years ago and was using 20w50 oil (I live in Saudi Arabia where tempartures reaches 50c in summer and below 10c in winter)

The 20w50 was so heavy on my engine even in summer so I refered to the owners manual, they (Chevrolet) recommended 10w30.

The 10w30 was so successful the past year. Winter and summer, the engine gained more power, less fuel consumtion and less heat.

3 months ago I suffered oil leaks due to 1-litre of oil over the required qunaitity that borke some seals in my engine and I fixed them but still suffer oil loss.

I guess it is mostly evaporation through the PCV as I don't notice suspicious smokes from the exhaust.

The question, If I move back to a thicker oil, will that help or should I fix something else?

Thank you,

  • How much loss? 1 litre per 100 miles, 1 litre per 1000 miles... Do you have a patch of oil where you park the car? – Solar Mike Apr 3 '18 at 11:44
  • What is the make/model/engine of the vehicle? How many miles (KMs) are on the car? At this point, I'd suggest you stay with the 10W30 and figure out what's going on with the engine. 20w50 is going to do exactly what you said it was doing and not provide you any better leak protection. – Pᴀᴜʟsᴛᴇʀ2 Apr 3 '18 at 12:05
  • @SolarMike It consumes about 1litre per 1000km approx. and I used to see patchs under the engine untill 3 days before when I fixed the camshaft oil seal leakage. – Aqua Apr 3 '18 at 12:11
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    You can clean your PCV valve and see if that helps with consumption. If you see a lot of oil in the PCV port (where it attaches), this might be the cause. You'd be looking for it to be really wet there. I'm not sure on your specific engine if they are prone to PCV oil consumption issues. You might also completely clean your engine & compartment, then see if there are any leaks you've missed. You could put a dose of UV leak detector into the oil, then flash the area with UV to see if there are any leaks you've missed. – Pᴀᴜʟsᴛᴇʀ2 Apr 3 '18 at 12:51
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    @Bart - The OP states in the question 10W30 is the manufacturer's suggestion. I believe that weight of oil is what is suggested for the climate the vehicle is operated in (cooler climate would most likely be 5w30 or 5w20). Using 10w30 is a step up already ... I definitely wouldn't suggest the OP go any thicker. – Pᴀᴜʟsᴛᴇʀ2 Apr 3 '18 at 19:57

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