synthetic oils

[67GTA-FB429]

Did an oil change a few weeks ago and I have noticed increased spotting on my driveway...so my questions is, will using a synthetic oil (Mobil 1) exacberate an oil leak? Should I use a heavy weight synthetic? Or go back to conventional?

The leak seems to be occuring near or around the oil filter (and I already checked, it is on tight). The previous change was done at a dealer and they used conventional and I had noticed that the leak went away...

 

[latamud]

Your oil pressure sender fitting my ght have a leak, its just above the filter, or the oil pan gasket. Or the drain plug, or if you have two oil filter rings on there. I'd use some brake clean and hit the area around the filter and let the engine idle for a few minutes and watch for leaks to pinpoint the source. Good luck.

 

[69Rcode_Mach1]

Yeah like latamud said I would first check and see if the oil filter has been double gasketed youd be surprised how many times these little things occur. But if that is happening it would be a big leak. What also could be is the oil filter was dry gasketed on. Take the oil filter off and dip your finger in oil and rub it on the gasket and the baseplate, Also make sure the stud is tight. And put it back on if that doesn't work try out what latamud said to pinpoint the leak.

 

[Darkhorse845]

Mobil 1 is a great oil to use I highly
recommend it!

 

[Hack]

In answer to your question: yes, a synthetic will exacerbate a leak. Synthetics have a more uniform molecular size - so the really long molecules that won't leak out (or help to prevent the rest from leaking) are missing. At least that's the explanation I've heard before.

As to whether you should quit using the synthetic.. that's your decision. I guess it depends on whether you can live with the leak. IMO it's no big deal. Just monitor your oil level. By all accounts synthetics work better than regular oil. So, even though it's leaking, as long as you keep enough oil in the engine it should protect your engine better.

 

[69 302/351c]

I went to synthetic in my 69/302 a coupla years ago...Mobil 1... and I did notice leaks that I didn't have before. It might be that I have 175k miles on the motor. Went back to conventional oil since I change it every 2000 miles anyway. The motor has been on this schedule since new by previous owner and I just continued for the 10 years I have had it. Inside still looks like a fresh rebuild.

 

[67GTA-FB429]

In answer to your question: yes, a synthetic will exacerbate a leak. Synthetics have a more uniform molecular size - so the really long molecules that won't leak out (or help to prevent the rest from leaking) are missing. At least that's the explanation I've heard before.

As to whether you should quit using the synthetic.. that's your decision. I guess it depends on whether you can live with the leak. IMO it's no big deal. Just monitor your oil level. By all accounts synthetics work better than regular oil. So, even though it's leaking, as long as you keep enough oil in the engine it should protect your engine better.

The part that really bugs me are the little drip marks all over the concrete driveway.

Thank for all of the responses. I knew about the dry gasket and double gasket problems, but the loose stud, I will check. Also, this is not on either of my Mustangs, it is on my wifes Isuzu Rodeo. I just wanted to get some decent advice as the Rodeo forums are all about mudding and how low can you lower you car.

 

[69Rcode_Mach1]

Oh sorry to be the bearer of bad news but i didn't know this was an isuzu. I work the pit at jiffy lube and let me tell you every single isuzu that comes in there leaks, along with the newer chevy 454 pickups. It's inevitable with that car I would change to conventional since you say you change it every 2000 miles anyways. Good luck man.

 

[fastdave]

I spoke to a person at Amsoil and I told him that I heard that sometimes on older cars when you switch to a synethic oil that leaks will develop. His reply was on motors wth a lot of miles on them some buildup may be on the oil seals. The synethic oil will clean them and may expose any minor cracks which the new oil will leak through.

 

[2nd Mustang]

That happened on my old Pathfinder. Switched to synthetic oil and developed a small drip that would never go away, even after switching back to conventional oil. Drip pan under the car helped.