Q: Will it hurt my motor to switch from synthetic oil to conventional oil?

asked by on

Will it hurt my motor to switch from synthetic oil to conventional oil. The mechanic who replaced my main seal said it wouldn't hurt but now my car smokes at cranking and slow idle it had no problems prior to the seal replacement

My car has 200000 miles.
My car has an automatic transmission.

Hi there. There are varied opinions about switching from synthetic oil to conventional oil. I am old school and believe you stick with the manufacturer’s recommendation for oil type. Nowadays, most conventional oils are a synthetic-blend. I believe BMW recommends synthetic oil.

Given your vehicle has 200,000 miles, it could be the engine’s oil consumption is somewhat normal. Replacing the rear main seal or switching oil type should not have caused the engine to start smoking.

If the smoke is black, it could be excessive fuel consumption. If the smoke is white with a bluish tint, it could be oil smoke. If the smoke is white and dissipates quickly, it could be condensation (cold) or coolant/antifreeze (warm). Switching back to synthetic oil may or may not help. If you would like to have another technician give the vehicle a second opinion, a certified professional from YourMechanic can come to your car’s location to inspect the smoking and idling problems so that this is properly resolved.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Will it hurt my motor to switch from synthetic oil to conventional oil?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Car slipping out of gear

Hello! With the transmission slipping, this vehicle is not safe to drive until this issue is resolved. The most common causes of the transmission slipping is low or improper transmission fluid level, or internal failures in the transmission. A qualified...

Q: Q: Car burning oil

Hi there, thanks for writing in about your 2006 BMW 750Li. The two causes of an engine to burn oil are faulty piston rings and faulty valve guides or seals. If the piston rings are faulty, this will allow oil...

Q: Nissan March 14e.Starts ,shakes and stalls.I have to support it by pressing the gas. Stalls too when I brake in drive or reverse

Hi There, It sounds like your car may have a dirty or faulty idle air control valve causing it to stall at low speeds or when decelerating as you describe. The idle air control valve is a small valve on...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.