Chaospartners

I just bought a 2000 z28 it has 117,000 on it and i put mobile 1 in it and now the rear main or i think its the rear main is leaking like a bitch.. Has anyone every had this problem? im gona drain the mobile one out and put convential back in it

ULTIMATEORANGESS

iTrader: (4)

i doubt m1 caused this. it mightve made it more noticeable but it was most likely going already.

Chaospartners

yea it was damp around the bellhousing before but now it like pours out..

RedHotG8

iTrader: (1)

Synthetic oil is thinner so if there's a slow leak it will leak faster. Mobil 1 makes a high mileage synthetic oil that contains a seal conditioner to help prevent or control seal leaks in higher mileage vehicles. You can try that if you want to run synthetic oil.

Chaospartners

the motor is getting pulled this winter. so would i be better off to put convential oil back in for now. would that slow the leak back down?

kinglt-1

iTrader: (26)

I would if the engine already had that much mileage running on regular oil.

Mr Incredible

Synthetic oil has better solvency. Any leaks or potential leaks that may be masked by crud can be initiated/greatened by the synthetic washing away the crud. It also has a way of finding its way through a gasket that didn't cause problems with conventional. But not because it's thinner. 30wt is 30wt, and they fall within an accepted viscosity range for 30wts.

If the leak is too large for comfort you can go back to conventional. It may not cure the problem immediately but it will eventually fade. Been there, done that. Sometimes the problem goes away fairly quickly, some times it won't.

RedHotG8

iTrader: (1)

Since you're going to pull the motor just run conventional until then.

Chaospartners

ok ima put some castrol back in it tomorrow.. just to play with it a little more till i pull the motor and tranny. thanks guys.

99FormulaM6r

iTrader: (2)

Yeah, as mentioned, switching from conventional to synthetic can cause leaks on a higher mileage engine. The seals actually can swell up from conventional oil, using synthetic takes this away and you can be left with leaks.

Switching back to conventional will probably stop the leaks.

xxrillixx

iTrader: (118)

I agree with the others.

For people who unsure what to use and have high milage cars... keep with what your using. So many people get pressured into the synthetic oils when its not ALWAYS the best idea. Im not arguing synthetic vs conventional, but for higher milage cars that have always been run on conventional you will get problems like this.

I hope switching back fixes it for ya! But id be ready to replace the rear main.

Chaospartners

ill post back in a couple days and let u guys know if the leak stoped!

Chaospartners

Well i drained the mobile1 out and put castrol back in it and the leak has already almost completly stoped!!

RedHotG8

iTrader: (1)

Evidently it's the thicker state of the conventional oil. Plus it makes the seals swell, where as synthetic oil doesn't. So it has nothing to do with the higher solvency of synthetic oil.