Rear main seal leak problem

[todelil209]

Asslam o alikum respected members, My mira 2006 (L250V) is having oil leak from rear main seal of engine, presently I am using 5w30 grade engine oil, as the rear main seal leak is a big work to fix as it involves completely dismounting of transmission to replace the seal, now my point is; will changing the engine oil grade i.e using thicker oil like 10w40 will fix the leak and if yes then what will be the impacts on performance of engine with thicker oil, expert guidance needed, else should I necessarily go for seal replacement (kindly suggest some good mechanic as well in rwp/isb), TIA.

[Xulfiqar]

No, it wont work at all

There is no other fix than to replace the seal, make sure the mechanic uses medium threadlocker on the main flywheel/flexplate bolts, that is also a leak point, oil can literally leak through the threads.

The factory installs it too

Ditto for the torque converter bolts if auto and pressure plate bolts if manual.

[todelil209]

My instincts were already yelling nothing else will work, thanks for confirming it, will definitely follow the instructions provided I get some reliable mechanic to do the job one time as to fix the sealing issues commonly mechanics uses hit and trial methods to spoil time money and energy.

[nfssaad]

for such jobs, try to find a service manual for your specific car.

source ALL the parts required before even touching the car.

for work, i would suggest @rajaatta or @dani_kk

[rajaatta]

Yes it's not a big problem for replacement leave the transmission as is and disassembly the engine only it will save the axcel and transmission oil and many less labor hours too

[Xulfiqar]

Yeah, in most toyota products its easier to remove the engine.

[rajaatta]

It saves a lot of labor hours plus if the cvt axcels aee bad opening and re fitting them most of the time fails the cvt trans

[todelil209]

Its AT trans, the idea of removing engine is quite a significant relief my mind was stuck on removal of tranny. @nfssaad sir tried to search service manual of this model but couldn't found it. If Seal dimensions are known before opening the engine it will be another big relief .. anyone who can share relevant service manual will great help, jazakAllah.

[Xulfiqar]

Service manual will not have seal dimensions, you will need to find it against the original part in hand for a car like yours.

Easier would be to find a scrapped engine and have its seal removed for you or take a picture of the seal and read the part numbers or dimension numbers on it. (Original seals dont have dimensions printed on them)

When installing, have mechanic use multipurpose grease on the seal lip so the seal can have a good life (also make sure the crank surface is not scratched or lipped, use a 800 grit polishing sandpaper to polish it back to new look if scratched)

If your engine uses a springless teflon lip seal then follow the directions on the new seal packing exactly as they tell you. It is critical for good install.

[Xulfiqar]

How does removal and install of the cv axles damage the unit? I’ve replaced hundreds of them and never had any issues at all.

[rajaatta]

Boss already depleted transmissions with no oil change and driven 1-3 lakh kms without nay service transmission fails and 80% vehicles are of same condition I inspect