Car has about 90K on it. I use mobil 1 5w-30 and the oem filter. The previous owner also used synthetic although I doubt it was mobil 1. Anyway my small seepage from the rear main seal turned into a full blown leak within the past couple of weeks. The stealership wants $1K to fix the seal which means that a local shop will probably want 600-800 to fix it. I can't afford that right now. I also can't afford to keep pouring in this expensive synthetic oil only to have it leak out on my driveway. Would changing to a dino oil slow the leak at all? Is there any negative effects from going from synthetic back to dino oil? I have heard that it isn't good to stop using synthetic once you start using it. Is that BS?

 

There are no problems switching back and forth. I don't think anything will help your problem. If dino sludge were to help your problem it would take many thousands of miles. To save money you may want to switch to a cheap, heavy grade dino.

I've used Restore for small leaks and it worked fine. Unless a mechanic can recommend something you may be screwed.

 

So if I use a 5w30 syn now should I switch to a 10w30 dino...or heavier? Or would a 10w30 syn leak more slowly?

 

Try some auto rx with the dino du jour.

http://auto-rx.com/pages/sealleak.htm

This stuff works and if does not then you can get a refund.

 

Why not just fix the problem? Chances are it's the rear valve cover gasket. Buy the gasket set (around $50) and install it.

 

heavier dino oil might help, but after a while it will leak again. fix the problem.

 

Im 99% sure it is the rear main seal. Stealership confirmed that too. I wish it was a valve cover gasket. I would have fixed it already if that was the case. I don't have the money right now to fix the engine seal. Im getting married next month.

 

The dealer was wrong. Im leaking MT fluid not oil. I guess I have bad bearings in the trans. It leaks from where the axle comes out of it, kind of close to the seal I thought was bad. I also thought that because the car does use some engine oil too...like a quart every 3000 miles or so. Anybody had their 4th gen tranny rebuilt? What did it cost and did it last? Not really a fluid/lubricant question but the thread is already here...

 

Using synthetic doesn't make your car leak. It just reveals the problems the car has already. If you car is leaking, get it fixed. Switching back to dino won't help.

 

another vote for auto-rx