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Oil type

Tom and Ray, I have a 2002 Ford Taurus with 24v V6 engine with 95000 mi. My car has developed a slow oil leak that I’m told is coming from the gasket between the upper and lower engine block, which apparently would be quite expensive to fix. I am wondering since the car requires 5w20 weight oil, could this have been brought on by changing the oil with the incorrect weight oil, such as 10w30 or 10w40. I usually have the oil changed at a local garage and have been assured they use the correct stuff. Over a period of time what is the consequece of incorrect oil?

The 5W20 is a fuel saving trick by Ford to meet CAFE standards. Your car will be perfectly happy with 5W30, which I would use. If you live in Florida or S. California, 10W30 would do, but I would not use it in winter in the rest of the country.

Not likely your leaks are due to the type of oil used. Using 5W30 is better than 5W20 if you want to minimize leaks. If the leak is small just top it up and put a cookie sheet with cat litter under the leak on your garage floor. Most 9 year old cars have some leaks, and fixing them would probaly buy 10 year supply of oil.

“could this have been brought on by changing the oil with the incorrect weight oil, such as 10w30 or 10w40”

The opposite actually. 10w30 or 10w40 are thicker than 5w20 and would slow the leak if anything.

The weight of the oil has nothing whatsoever to do with the leak.

Stick with the recommended oil and check the level on a regular basis. Keep it topped up and you’ll be fine.

The oil would not have caused the leak. But you should use the correct oil for other reasons. Engines today have tighter cleraances (although not at 95,000 miles) and some manufacturers use the oil almost as a hydraulic fluid to operate the various “variable valvetrains”.

A bit of oil seepage on a 9 year old vehicle is nothing to be concerned about as long as the oil level is monitored as per normal practices and kept from dropping too low. The lubrication system doesn’t know what level the oil pool is at, it only knows that the level is either above the pickup tube (good) or below the pickup tube (bad).

Thanks for the quick answers guys! I just wondered if some type of “pressure” could have developed from overweight oil useage in the crankcase and compromised the gasket. I definitely take above averaqe care of my car and am disappointed to see such developements. Thanks again!

I would get a second opinion on the REAL source of your oil leak…