JK 3.8 Oil leak problem
02-27-2017, 07:13 PM
#11
JK Newbie
Thread Starter
Join Date: Oct 2016
Location: Youngstown, Ohio
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
My 2011 3.8 has lost about 1qt/1k miles of 10w30 on average since new. I carry a 5qt container of 10w30 oil with me and just add about 1 qt every 1000 miles. I now have over 100k miles on my hybrid "diesel/gas" JK, lol. (Yes I have added over 100qts of mobil 1 over the last 6 years, I like that Mobile 1 burns clean lol!)
A few months ago after an aggressive wheeling trip I checked my oil at the 1000 miles mark and it was down about 2 quarts. This is unusual so I started poking around I found a lot of oil under the engine. It was weeping down from the oil pan seems, Upper and lower oil pans. Also above the junction of the tranny and engine block there were drops. Topside looks like the seem where the valve cover met the block also weeping. I started researching...
I found the 3.8 engines are known for lower intake manifold gasket leaks. These drain down the backside of the block and drop off the bottom junction of the bellhousing and block, presenting as a rear main seal leak but rear mains are uncommon leaks on the 3.8 engines not like the older TJ's where this was the main oil leak you see.
So I changed the valve cover gaskets, lower intake manifold gasket, upper and lower oil pan gaskets (lower is actually just RTV sealant), and for good measure the PCV valve. After about 2 months now I have been consistently losing (burning? Who knows?) 1qt/1k miles again.
There is not one drop of oil or any sign of seepage anywhere on my engine now and all is good with my hybrid "gas/diesel" engine once more...
A few months ago after an aggressive wheeling trip I checked my oil at the 1000 miles mark and it was down about 2 quarts. This is unusual so I started poking around I found a lot of oil under the engine. It was weeping down from the oil pan seems, Upper and lower oil pans. Also above the junction of the tranny and engine block there were drops. Topside looks like the seem where the valve cover met the block also weeping. I started researching...
I found the 3.8 engines are known for lower intake manifold gasket leaks. These drain down the backside of the block and drop off the bottom junction of the bellhousing and block, presenting as a rear main seal leak but rear mains are uncommon leaks on the 3.8 engines not like the older TJ's where this was the main oil leak you see.
So I changed the valve cover gaskets, lower intake manifold gasket, upper and lower oil pan gaskets (lower is actually just RTV sealant), and for good measure the PCV valve. After about 2 months now I have been consistently losing (burning? Who knows?) 1qt/1k miles again.
There is not one drop of oil or any sign of seepage anywhere on my engine now and all is good with my hybrid "gas/diesel" engine once more...
