Skip the auto shop - Our mechanics make house calls

Q: Does synthetic oil cause leaks in older vehicles?

asked by on

Hi,

Following link describes that synthetic oil may cause leaks in older model vehicles.

https://www.yourmechanic.com/article/can-you-switch-between-regular-and-synthetic-motor-oil

However, myth vs fact link below addresses exactly the same question and contradicts with what YourMechanic.com explains.

http://www.pennzoil.com/en_us/education/know-your-oil/why-synthetic-oil.html

Which one is true?

Thanks for your help and time.

Opinions vary pretty widely with this topic. For the most part, if a vehicle’s engine has spent most of its life using conventional oil, it should stick with conventional oil. The full synthetic blend has more defined and uniform molecules. So where an older vehicle using conventional oil may have never had an oil leak, you may start to see oil leaks with the more defined, uniform, and "more slippery" full synthetic oil. Conventional oil may leave deposits that can, for lack of a better term, "plug" a small leak where the full synthetic oil with the better detergents will wash away these deposits and the leak becomes more prominent. An older vehicle with newly installed seals may have a good experience with full synthetic oils. If you have a newer vehicle which was engineered to use full synthetic oil, use full synthetic oils.

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: oil pressure light came on shut engine I add pint of oil no light yet

If the oil level is low, oil should be added until the level reaches the full mark on the oil dipstick (no higher though). Adding oil to the full line on the dipstick will give you a safety margin just...

Q: Will it damage my engine if I switch from synthetic blend to regular motor oil to do a oil change being I live in Florida?

It is not snow or ice that will damage an engine but heat and friction. This engine is turbo charged and the turbo bearings are lubricated by the engine oil. When you change the oil you should use only the...

Q: Burns a quart every 1500 miles

Your engine oil usage is considered normal when you ask a dealer or manufacturer. They will tell you that one quart for every 750 miles is considered okay by their standards. Has your Accord always used this much oil,...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...