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I have a likely rear main seal leak on my 2000, ES300 Platinum Series
It has only 50000 miles, the oil has been changed meticulously by the dealer for first 15 years, and then by me Mobil 1 5W 30 full synthetic, every 3-4000 miles
Only last time I used Valvoline full synthetic 5W 30, and all of a sudden noticed a leak, started with a big spill and then slowed down, not totally sure if Valvoline use and leak are correlated. Changed oil back to Mobil 1 5W 30 synthetic but still see seepage, few drops on every 10-15 miles.
Also I changed the PCV valve as a precaution but the old one looked clear without any dirt. The new recommended part has a different OEM number and is red compared to the black, not sure whether the new one is improved to protect from sludging.
Need advice, whether I should use a particular oil brand synthetic or conventional. Also curious to know if anybody lately used the Auto RX plus, Blue Devil, AT-205, Lucas, Bar's or similar products?
Leak area
?
Thanks a lot.
Last edited by tbis; 03-22-18 at 11:38 PM.
Reason: Clearer information
Thank you so much, I truly appreciate your input. After reading all the threads and getting more informed, I purchased a Mobil1 Super Conventional 10W30 (from Walmart) yesterday,
I see that you suggest Pennzoil, should I prefer that over Mobil 1 conventional (I can return and get the Pennzoil)
Also, it is not leaking when seating in the garage, so is there any advantage for getting 10W30 over 5W30, I am in Southern California, so perhaps no point to worry about 10W30.
Thanks again.
Thanks,
Unlikely, there is absolutely no oil coming from top. It appears to be coming from behind the Flywheel housing under cover, and accumulates at times on Exhaust pipe support stay. I am not knowledgeable enough, but the leak has to be somewhere in between the engine and the transmission, even if it is not the rotary seal (reading threads, it appears that there are other possibilities). It is easy to track the external leak site since the car is quite clean but I have not been able to check it extremely carefully in broad day light yet.
area of leak, coming behind the plate
Last edited by tbis; 03-22-18 at 11:43 PM.
Reason: correct information
Auto RX is mainly used for sludge removal you want a specialized liquid designed to address the rear main seal. I've used Rislone Rear Seal Fix with decent success, it is not a permanent solution though. I think that product may be a Canada only thing not sure. But look for something similar.
I would be REALLY hesitant to label this a rear main seal leak. It has a superficial appearance, but it is a less likely source and other more likely ones can present that way.
That is just the low point where many leaks on the rear portion of an engine will get to when it seeps. The ribbed panel you showed is, I think, the transmission flex plate access panel. You open that to access the flex plate bolts that bind the torque converter to the engine flex plate when separating the powertrain units. I had a leak like that on my SUV for aa while and was sure it was a rear main seal. It was not - I discovered that when I opened the panel to access the flex plate bolts to remove the transmission and rebuild it. Also, the color of the oil indicates that oil has been traveling a while on the exterior of the engine, not just the short distance down from the RMS (that is my hunch, not a guarantee).
At that engine age, independent of mileage, you need to be treating it as a high mileage engine WRT to belts, seals, etc. If you have not opened that MS5K oil you bought, take it back to Walmart and swap it for some M1 10w30 High Mileage. It is also on rebate right now I think and you can get a $12 discount on the jug, making it darn cheap. This is about the thickest 30wt oil you can get outside of Redline and Amsoil (3.5 HTHS at test temp vs 3.0~3.2 for most all commercial 5w30 or 10w30 oils). It will also have the most real oil in it and a low amount of rubbery, huge, fragile viscosity improvers in it blended in to make the oil extreme cold-weather capable, which you totally don't need and have drawbacks to them. Your climate supports using this oil and not inferior 5w30 very easily. It will have conditioners for the seals, and you can fortify this by adding a 10oz bottle of Lubegard Biotech, which is an ester-based additive that is magic on seals (the ester oil base component). This is one reason (the old formula at least) Redline was so good - an ester-based oil that is super-healthy for seals. As to oil usage wrt that, I typically get about 16ozs of usage with this oil (m1 10w30 HM) in a 7.5k mi oil change interval. That is compared to about a quart with all other good quality 5w30 and 10w30 oils (Pennzoil platinum and Ultra Platinum, Valvoling full syn HM, etc.)
My last OCI was with Havoline Pro DS (a full syn, non-HM oil - I got it for like $0.89/qt on a silly sale last summer) in 5w-30. I added some Lubegard blue/biotech to it and I got the absolute lowest oil usage I have seen in the last 150k miles - about 8~10 ounces in 7,400 miles). Yes, less oil usage/leakage now at near 300k vs. at 150k on the engine! Full disclousre, I did re-do the valve cover gaskets a year or two ago, so that of course helped. Last week I switched back to my "regular" M1 10-30HM and also added 10ozs Lubegard Biotech; I am curious to see the usage over the next interval.
I would also inspect the torque on all the valve cover bolts.
this just 1 opinion based on personal experience
do not waist money on auto rx
Thank you for letting me/us know the personal experience. Strangely, it appears that quite a few Lexus owners have used the auto Rx (in context of apparent rear main seal leak), but difficult to figure out the outcome they had.
I would be REALLY hesitant to label this a rear main seal leak. It has a superficial appearance, but it is a less likely source and other more likely ones can present that way.
That is just the low point where many leaks on the rear portion of an engine will get to when it seeps. The ribbed panel you showed is, I think, the transmission flex plate access panel. You open that to access the flex plate bolts that bind the torque converter to the engine flex plate when separating the powertrain units. I had a leak like that on my SUV for aa while and was sure it was a rear main seal. It was not - I discovered that when I opened the panel to access the flex plate bolts to remove the transmission and rebuild it. Also, the color of the oil indicates that oil has been traveling a while on the exterior of the engine, not just the short distance down from the RMS (that is my hunch, not a guarantee).
At that engine age, independent of mileage, you need to be treating it as a high mileage engine WRT to belts, seals, etc. If you have not opened that MS5K oil you bought, take it back to Walmart and swap it for some M1 10w30 High Mileage. It is also on rebate right now I think and you can get a $12 discount on the jug, making it darn cheap. This is about the thickest 30wt oil you can get outside of Redline and Amsoil (3.5 HTHS at test temp vs 3.0~3.2 for most all commercial 5w30 or 10w30 oils). It will also have the most real oil in it and a low amount of rubbery, huge, fragile viscosity improvers in it blended in to make the oil extreme cold-weather capable, which you totally don't need and have drawbacks to them. Your climate supports using this oil and not inferior 5w30 very easily. It will have conditioners for the seals, and you can fortify this by adding a 10oz bottle of Lubegard Biotech, which is an ester-based additive that is magic on seals (the ester oil base component). This is one reason (the old formula at least) Redline was so good - an ester-based oil that is super-healthy for seals. As to oil usage wrt that, I typically get about 16ozs of usage with this oil (m1 10w30 HM) in a 7.5k mi oil change interval. That is compared to about a quart with all other good quality 5w30 and 10w30 oils (Pennzoil platinum and Ultra Platinum, Valvoline full syn HM, etc.)
My last OCI was with Havoline Pro DS (a full syn, non-HM oil - I got it for like $0.89/qt on a silly sale last summer) in 5w-30. I added some Lubegard blue/biotech to it and I got the absolute lowest oil usage I have seen in the last 150k miles - about 8~10 ounces in 7,400 miles). Yes, less oil usage/leakage now at near 300k vs. at 150k on the engine! Full disclosure, I did re-do the valve cover gaskets a year or two ago, so that of course helped. Last week I switched back to my "regular" M1 10-30HM and also added 10ozs Lubegard Biotech; I am curious to see the usage over the next interval.
I would also inspect the torque on all the valve cover bolts.
Thank you for your thoughtful and informative reply, and of course taking the time to respond.
First, I will recheck the area of oil seepage more carefully since I am also not totally sure about rear main seal yet. Also, I will check the valve cover bolt torques. But, I might have confused you with the second picture, it was after I cleaned up the area with pure ethanol, just to see where the seepage will happen on the next drive. The seepage truly appears to be coming from behind Flywheel housing under cover, which is secured with 2 bolts, and that is just a guard that is pushed in a rubber slot. Will update in a day or two when I have time to do the thorough investigation.
And thank you for the details on the engine oil, I spent quite a bit of time researching the data sheet for all these oils, came to the same conclusion with M1 10W30 HM. I will try the Liquid Wax Ester containing Lubehuard with it as you suggested.
Just a note: Before all these started, I have never had any leak from anywhere, and did not observe any noticeable oil usage over 3000 miles, did not measure it that critically so could have lost a few ounces at most.
Last edited by tbis; 03-22-18 at 11:48 PM.
Reason: more info
I just changed my oil with the same Valvoline full synthetic 5W-30 and now suddenly both of my valve covers are leaking. It's been 80,000 miles since they've been done but it sucks (actually just started a thread about it). I know in my case it leaks all the way down onto the exhaust an gets all over everything below. You could easily think the rear seal or oil pan is leaking as well.
I just changed my oil with the same Valvoline full synthetic 5W-30 and now suddenly both of my valve covers are leaking. It's been 80,000 miles since they've been done but it sucks (actually just started a thread about it). I know in my case it leaks all the way down onto the exhaust an gets all over everything below. You could easily think the rear seal or oil pan is leaking as well.
Sorry to hear that, at least it is not too terrible a job if it it is the valve cover. It is very well possible that additives in the Valvoline synthetic oil caused it. I am unhappy that I tried.
In my case however, I am quite certain that it is the rear main seal, I see no oil from top or side. Although unlikely, it is possible that the one of the oil pan gasket (which is in proximity to the protection plate covering the crankshaft) is leaking. I will update with more once I have some time, and try different things, in the meantime, perhaps best to change back to Conventional Mobil 1 Super 5/10W30 or Pennzoil 5/10W30.
Update:
Now that I have looked at it carefully, the oil definitely comes from behind the Flywheel housing under cover.
Even after changing back to 10W30 conventional the leak did not stop or reduce in 100 miles driving.
I just added AT-205 (8 oz in 5 qt of 10W30), and drove another 60 miles, so far no sign of reduction in seepage.
2nd Update:
None of the additives with regular or synthetic 5W30 that I used, showed any sign or helped reduce the leak upon driving 500-1000 miles,
Pennzoil conventional oil did not do any good either.
Fortunately, Mobil 1 10W30 Conventional High Mileage oil (by far the cheapest oil, about $16 for 5 quarts) definitely reduced the leak to the point that I do not see any oil drops in 2 or more days, and I have driven only about 700 miles with it.
Earlier, every time I parked in the garage, there will be 2-3 drops overnight, slowly dripping from behind the Flywheel housing under cover.
One thing I noticed that the oil discoloration (turning towards black) is definitely faster than what I observed with Mobil advanced full synthetic 5W30.
Hope it stays that way, and thanks to gemigniani and oro.
03-15-18, 10:28 PM
Auto RX plus and Rear main Seal leak
