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Amedee, Former ASE Master Tech
Category: Car
Satisfied Customers: 24150
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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1990 isuzu: 2.3 pu oil lieak at the front seal on crankshaft

Customer Question

1990 isuzu 2.3 Pu oil lieak at the front seal on crankshaft. Have replaced seal 3 times with different brands. HELP
Submitted: 4 years ago.
Category: Car
Expert:  George H. replied 4 years ago.

Hello I will help you with your question,


Is the seal just leaking or does it get pushed out?


Is this a manual transmission?



Customer: replied 4 years ago.

manual trany just leaks

Expert:  George H. replied 4 years ago.

Try measuring the play of the front pulley as someone presses the clutch to see if it moves more than a couple of thousandths of an inch. Each time the clutch is pressed about 800 lbs of forward thrust is placed on the back of the crankshaft and this will wear the thrust surface over time. If you hold the clutch in at lights that pressure is always applied and it wears faster.


If the crank is moving forward and back the seal will leak


The other possibility is that there is excess pressure in the crankcase. If the PCV is plugged or the intake in the valve cover is restricted the blowby from worn cylinders can cause enough pressure that it blows oil out the seal.


Let me know what you find and how I can help you


Thank you



Customer: replied 4 years ago.
I checked the clearance on the inplay of the crank shaft. It is close to specifications. The pcv works fine. No other seals leak. I instaled a speedy sleve on the crank shaft.2 seals back. Any other sugestions? Sorry late getting back to you Gene
Expert:  George H. replied 4 years ago.

If you have a good surface and the thrust is good and there is not excessive blowby in the crankcase I am out of ideas so I will OPT OUT and open your question to all the experts. Maybe someone else has more suggestions for you


Sorry it was not what I sugested.



Expert:  Walt-Mod replied 4 years ago.



I'm a moderator for this topic and I wonder whether you're still waiting for an answer. If you are, please let me know and I will do my best to find a Expert to assist you right away. If not, feel free to let me know and I will cancel this question for you. Thank you!

Customer: replied 4 years ago.
Yes I would like an answer to my problem..Thank you Gene
Expert:  Walt-Mod replied 4 years ago.
Sometimes, finding the right Expert can take a little longer than expected and we thank you greatly for your understanding. We'll be in touch again shortly.
Expert:  Amedee replied 4 years ago.

My name is XXXXX XXXXX I can assist you with your question. The previous expert is correct on the things to check that can cause a new seal to leak.

The only thing I wanted to add that might help is to use some silicone to the outside of the seal after it has been inserted into place. This may help it seal a bit better. Don't use it on the seal surface that contacts the front cover, just put it on the side after the seal has been inserted in place. You can use clear, red or black silicone. Just a small amount will do the trick.

I hope this helps!
Customer: replied 4 years ago.
How long does it take for the silicone to dry.....Gene
Expert:  Amedee replied 4 years ago.
Only a few hours. But if you want, you can let it sit overnight to be sure that it is nice and dry before starting it up.

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Amedee, Former ASE Master Tech
Category: Car
Satisfied Customers: 24150
Experience: ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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