Crankshaft oil seal failure

TOYOTALN65

MEMBER
1985 TOYOTA TACOMA
100,000 MILES

Hi.
I have an 1985 Toyota Hilux 4x4 truck.
2L engine, which is 2.4 turbo diesel.
LN65.

Okay. I have replaced the cooling system, new radiator, cleaned hoses, and new heater core. New coolant.
Now last step was a new thermostat.
Which I installed last.
All is new factory parts and to specs.
I idle the truck for five minutes to check if new thermostat is opening and the top radiator hose is warming up. And blam! It happens.
Oil pours out of the crankshaft seal.
No, it did have a mild leak before this but now oil is pumping out like there's no tomorrow.
Can this be related to the new cooling system have too much pressure?
Just a coincidence it happened five minutes are new thermostat.
Do I have a blown head gasket?
Greatly appreciate any advice.
Philip.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

Hi Toyotaln,

I think you are on the right path. The cooing system and oil/lubrication system are meant to be separate so replacing cooling system components would not have any effect on the rear main seal.

If the cooling system was adding pressure to the oil passages then you would also have coolant in the oil. Do you have milky oil?

Also, you can run a compression test to confirm possible head gasket issue. However, if just the oil and coolant passages are the issue, again you will see oil and coolant mixed.

Here are a few links to related information:

https://www.2carpros.com/articles/coolantantifreeze-in-the-engine-oil

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/head-gasket-blown-test

https://www.2carpros.com/articles/crankshaft-main-seal-replacement-rear

If all of this checks out and you don't have fluids mixing and compression is okay, then most likely the seal just failed.

Please tell me if you have any other questions. Thanks