Oil leak troubleshooting guide - start to finish?

Joined
Apr 2, 2009
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33
Location
Austin, Texas
Hey folks! I have an oil leak, pretty bad, and want to get down and dirty to figure it out. When I search the threads on "oil leak", I see a ton of different culprits. Is there a good troubleshooting guide or sequence of investigation? Photos to go with it? I'm at a pretty dirty starting point; the underside from the starter area back is pretty caked in oil. This weekend I was planning on degreasing and powerwashing, and then starting the troubleshooting. Any help would be appreciated!

88 FJ62
 

DrRock

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Your thought on degreasing and power washing is a good start. Chasing oil leaks is a pastime of mine based on the cars I’ve owned. starting with a clean engine is the only way to begin to understand where the leak is coming from. Once you have a clean engine, you can isolate the drip better.

cheers, James
 

OSS

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At this point with a 30+ year old vehicle, every gasket and oil seal needs to be replaced. It's up to you, your energy and budget which ones you want to tackle.
 

John Staton

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I had many leaks when I got mine a few years ago. Upgrading to a 5 speed knocks out two of the leading candidates...the rear main seal and the oil pan gasket. I also had one at the cooler, which was just a hose. After pulling the radiator and having it gone through I can say I dont have one drop of any fluid (except water from the AC, which works now) under my truck and have not for a while now. It is a very good feeling to finally get there.
 

OSS

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Before I restored my old cruiser, it was leaking oil everywhere because I had been using synthetic motor oil for 25 years.
When I switched to a "high mileage" motor oil (Mobil 10W-40 High Milesge) the leaks almost completely stopped. So "high mileage" motor oils do condition the seals (swelling them up) to prevent or slow down the leaks.
 

lcolon

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East Bay, SF, CA
Agree with everything above - all the major gaskets probably need replacing - oil pan, timing cover, side cover, oil cooler, valve cover. Once you get it cleaned up, you could start with replacing those that are easily accessible. If you have a rear main seal or transfer case leak, that is more involved.
 

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