so ive noticed small oil spots on my drive way that have dried, something told me to look under the car and sure enough its leaking where the tranny meets the engine (rear main seal). Not much but its not a great feeling to know its slowly leaking and my dad sure is not happy about the spots on the drive way and the lecture about buying an old car. Anyways i put in Bi-tron engine additive which also slightly overfilled my oil above the fill line by a quarter inch im guessing a combo of the two did it. It started leaking after i changed the oil to 10w30 from 5w30 both castrol high mileage. Anyone know of any oil additives to stop the leak?, i dont have 1200 to fix it and i really love this car.

 

Aside from the leaking...how much oil consumption do you notice in a month?
How many miles on car?

The good old days one might be suggested a heavier dino based oil but that isn't going to stop a RMS leak. Any signs of leaks on the topside of the motor?

 

well i just changed the oil a few weeks ago and i just noticed the spots on the driveway, so far there are under 10 small drops around 2 inches squared. Its not the consumption its the fact that im a perfectionist and it bothers me, taking the enjoyment from the driving that car. You know that feeling you get when you fix something or finally get something fixed or even clean the car, you feel like a million bucks driving it.

 

Same problem here after switching from dyno oil to Mobil 1 synthetic 5w-30. It was suggested by a generous poster here recently who had the same problem to try Valvoline Max Life Synthetic Blend 5w-30. I have yet to do it, but I will give this a try at my next oil change. This seemed to work perfectly for the gentleman who posted this solution originally.

 

I had the same problem and it was my oil pan and my lexus tech just replace the silicon on the oil pan and no more licks it cost $150.00 and works great. hope this helps

 

Update:::I def Know that this is a the Rear main seal as i had the car on ramps and checked everything plus im a DIY when possible type of guy. I drained a bit of oil out and the dipstick was showing in the middle between the fill and emty line. I poured in Kleen-Flo stop leak or something like that, napa recommended it. There are better products on the market but appearently they are only sold in the states (auto-rx, bars main seal). Anyways the car so far doesnt seem to be leaking after several hours which is usually when it would but ill check in the morning. I should add that the seal is abour $1200 to replace and is a waste of money. I can buy a newer engine on ebay for $500, 500 to ship and less than 800 to install, at which point it wont cost much more to replace the rear main seal and you have a new engine.

 

yeah, but there's no performance advantage there, and you're just out a ton of extra cash. these motors will last hundreds of thousands of miles without fail when maintained properly. either just live with the leak and stop trying to use snake oil on it, or pay to fix it properly/buy tools and bribe a more experienced friend and fix it yourself for cheap. the OEM parts needed arent bad at all, and the bulk of this fix is just sheer labor.

 

First post I have seen on a rear main seal for the LS - 2 factors most likely contribute to this issue - oil change intervals way too far apart, and or both overheating of the engine.

the oil passages throughout the engine are designed to distribute the oil in some of the most tight tolerances of engine parts. some of these "snake oil" products will do more harm than good in these Lexus engines - these products are not specified for them and even though it may stop your leak for a time, it will also stop or slow oil from getting to critical parts of your engine and cause scorching and scouring. It's not going to lock up your engine by any means, but it will for sure reduce your performance and efficiency.

take what these auto parts store clerks tell you about thier products with a grain of salt....

 

I don't know how many miles you have on your current engine, but if its running good other than the main seal, I think you need to rethink your risk mitigation strategy of buying another engine.

The $ numbers you're talking about for a replacement are the tip of the iceberg. If I was going to throw in a new / used engine, I'd be replacing every seal and gasket on the new one prior to installation. In addition, I'd be replacing the timing belt, water pump, thermostat, temp sensor, plugs, ignition coils, wires, serpentine belt, etc... Maybe even the starter. Even then, you could install it and it might be a piece of junk.

I'd check around and get some pricing from a local transmission shop to replace the seal. I got an estimate before of 6hrs labor and $100 in parts.

I'm the guy referenced who switched from dino oil to Mobil1 (leak) then to Valvoline Max Life and had the leak disappear (knock on wood) for now anyways...

 

Yes, that's right, it was Jim with the Valvoline suggestion.

Quick follow up question (since our cars are almost identical in age and mileage): After two oil changes with Mobil 1, did you go the full change interval (presumably 5,000 miles) on the second Mobil 1, and then change to the Valvoline? Or did you switch over to the Valvoline ASAP when you saw the leak again?

 

I believe I put around 1500 miles on the second Mobil1 oil change before switching to the Valvoline.

 

My rear main seal was leaking as well. Everything that you add to it is only a temp fix. If you absolutely love the car, it's worth getting it fixed right, and also replacing the front trans seal as well along with it to knock two birds with one stone. I got mine done for $250 from a buddy just cuz he had a lift and could get it done way faster than I can lying on my back... find someone who has a lift and is willing to hook it up, or shop around...

 

It looks like a trip to Pep Boys is in my near future.

 

You should take a close look at the condition of the EGR pipe when the tranny is dropped. Perfect time to change it out.

 

Just switched to synthetic and have developed a leak in the front of the motor above the filter. I'll let you guys know what the outcome is. Also switching back to dino oil.