Crankshaft oil seal

[Stephen H]

Hi, my Avensis (d4d 2013 MY) has what I believe is a small oil leak which came up on its MOT advisories.  I am pretty sure it's the crankshaft oil seal.  I (think) a replacement part is pretty cheap, but it's a very labour intensive job?  Does anyone have experience of this?  The car does not seem to use any oil really, however there's very occasionally a very small oil mark on the drive after the car has been stood for several days.  Should this seal be replaced ASAP and, if so, is it as bad a job as I am thinking?  Many thanks.

[TonyHSD]

Hi, 

main seal can be a serious issue that needs immediate attention but also can be something that you can live with but you have to keep an eye on your oil level, leak marks and if gets worse to act quickly. If it’s only dripping very little it’s normal and may not be from  the seal itself but from silicone gaskets around or small cap in the block which covers an oil galley. Best if you can have a look under the car with torch to try to determine where exactly the oil coming from. I can also recommend to you a very good oil additive that proof to work on and helped many people https://www.amazon.co.uk/Wynns-50664-325ml-Engine-Stop/dp/B0031ROB36/ref=sr_1_1_sspa?crid=39JK3P2GRSQ1P&keywords=wynns+oil+stop+leak&qid=1645113972&sprefix=Wynns+oil+%2Caps%2C207&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExOE5KTTU5QlZYNTFEJmVuY3J5cHRlZElkPUEwMjk2NTkxM1ZBSk1LMDU5M1g5OSZlbmNyeXB0ZWRBZElkPUEwNzM1NTMxMlJaWlBFSDU5NDE5MyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

1. Buy a can of these 

2. Find exact place where oil comes from 

3. Clean with cloth and brake cleaner 

4. Add the additive and drive the car for at least 300-400 miles, check again if any leak still present. If it’s the same, don’t worry just keep driving until your next oil change and then you may try again. All that if it’s very minor leak, if anything bigger and you are loosing oil a lot most likely this will not help. I also have a small oil leak discovered in 2018 at 60k miles, now the car is 201k miles and the leak still there but has not increased, even mot never mention it. 
Good luck 

[Stephen H]

Thank you Tony for that very comprehensive reply, very helpful.

[TonyHSD]

1 hour ago, Stephen H said:

Thank you Tony for that very comprehensive reply, very helpful.

You are welcome 👍

[Red_Corolla]

I would live with it while you can, the job is quite labour intensive for such a small part because major components have to be removed for access to it. The front one (drivers side) is arguably the easier one to do but still requires removal of the timing chain/belt. The rear one is best left until the clutch needs replacing, unless the leak gets really bad.

[Stephen H]

Thanks Stuart.  The leak appears to be more from the passenger side, so assume to completely sort would require the gearbox to be dropped to gain access?  As you say, that would mean it would be better to wait until clutch/flywheel needed attention.  Thanks again, Steve.

[Red_Corolla]

2 hours ago, Stephen H said:

Thanks Stuart.  The leak appears to be more from the passenger side, so assume to completely sort would require the gearbox to be dropped to gain access?  As you say, that would mean it would be better to wait until clutch/flywheel needed attention.  Thanks again, Steve.

Yes, assuming that it is indeed the crankshaft seal and not just oil leaking down to the bell housing from somewhere higher up. A UV dye + torch kit can sometimes be helpful in tracing the source, especially when access to do a thorough clean of the engine is difficult.

[TonyHSD]

Here we have 3 most common places for oil leaks in Toyota engines, although the example is from 1.8 hybrid the diesel may have similar layout. Main seal, oil galley metal cap, form in place silicone gasket . , either of these will require a big job, the wynns may help if it’s from the seal or gasket. Red arrows indicate 👍

[Stephen H]

Thanks Tony for the supplementary information and diagram.  I think I will clean up what I can and try the Wynn's.  I had a ball park estimate provided by Toyota for replacement of the rear crankshaft oil seal plus fitting whilst they were at it of a new clutch and flywheel (which are fine at the moment) just as I was curious.  In excess of £2k for the parts and labour...

[Stephen H]

Thanks as well Stuart for your further comment.  I will ultimately need to have properly diagnosed whether it is the rear crankshaft oil seal and will look to obtain a second opinion from a knowledgeable garage.