Skip the auto shop - Our mechanics make house calls

Q: Motor Oil?

asked by on

Just changed the oil and for the 1st time used a synthetic blend over 75,000 mile 10/30 oil. My oil pressure gauge is running about 10 psi lower than it normally did. Is the synthetic oil ok to run in it?

My car has 113000 miles.
My car has an automatic transmission.

Hi There, Contrary to popular belief, it will not hurt your engine when switching from synthetic to conventional or vice versa. In fact, Synthetic blend oils are actually a mix of conventional oils and synthetic oils. Many synthetic oils are made up of a base oil of approximately 80%, with other additives making up the remaining 20%. The main difference between the molecules in synthetically engineered oils and conventional oils are the uniformity of the molecules. The molecules found in most conventional oils differ in shape, size and impurity. The type of oil that should be used for a specific application depends largely on the driver’s driving habits, the environment in which the car is driven, the mileage on the car’s engine and the limits that the engine may be pushed to. With regard to the lower oil pressure you are currently experiencing, this may be due to the slightly more free flow of the synthetic oil vs the conventional oil previously used. The other thing to consider of course, is the viscosity of the oil. Assuming you are using the same viscosity oil (10/30) as before, this should not impact the change in oil pressure. I would recommend double checking the proper oil level as well by checking the oil via the dipstick to be sure the correct amount of oil is in the motor.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: 95 Ford Explorer, replaces battery and starter relay, no power, just clicking with no key. Smoke from positive cable. What is it?

It sounds like what you are describing may be related to a faulty starter relay or some faulty wiring that may not be producing a proper connection to the starter. The starter relay directs power from the battery to the...

Q: My clutch hits the floor was running fine, then I checked reservoir and it's full

Hello, thanks for writing in. The master cylinder is connected to the clutch pedal and the slave cylinder is connected to the release bearing. When the clutch pedal is pushed down, hydraulic fluid flows from the master cylinder to the...

Q: My car overheats and I have no heat - 2004 impala.

Hi there. Check the radiator and see if its plugged up. A plugged radiator will stop the flow of the coolant to and from the engine and cause the engine to overheat. If the radiator is working fine by having...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...