1993 Jeep YJ
4.0L Inline 6 - Automatic
180,000 miles
Penzoil 10W30 Synthetic
Hello, I am from the YJ forum. I hope you all don't mind me posting my issue in here. I figured since it is 4.0 related I can get as much insight on this issue as possible.
I have been owning my YJ for about year and have been having an oil leak/burn ever since. I have to refill my oil back to full every two weeks of driving it. It usually takes about a little more of a 1/4 of a quart every time.
I have changed out my valve cover gasket, my oil pan gasket, and my rear main seal. All were done following the steps in the FSM. I use to have an oil leak between the transmission cover and the block where the rear main seal sits.
This is what the leak use to look like:
It no longer leaks since changing the seal, but when I drive and warm up the oil, it will begin to leak (still not as much as it was doing).
I did a dry compression test with an Innova Compression Tester I bought from Autozone. The engine was warm with open full throttle during the test.
Cylinder 1: 155...155...155
Cylinder 2: 155...155...155
Cylinder 3: 155...160...160
Cylinder 4: 150...150...145
Cylinder 5: 150...150...150
Cylinder 6: 110...110...110
Obviously, something is going on with Cylinder 6.
I bought a Maddoxx Leak Down Tester from Harbor Freight. I am confident I did it right. Here is what I did:
1. Turned on compressor
2. Warmed up motor
3. Insert hose into 6 cyl. I used a balloon on the other end to find the compression stroke while manually cranking
4. Remove hose. Here I used a screw driver to find TDC of the piston, while someone else cranked.
5. Attached compressor to the leak down tester. Here I calibrated the gauges to where they both read 100%
6. Attach other end from leak down tester to 6 cyl.
Result:
If I did this right, it looks like I have a 13% leak? I don't know it makes no sense. I figured I would have a bigger leak if my compression was 110.
It was difficult to hear for where the leak was coming from. I heard small vibrations along the pipes while listening to from exhaust. I placed a funnel on the oil dipstick tube. It was loud its all I can say. I didn't hear anything come from the throttle portion. There was no bubbling in the coolant reservoir.
Sound from Dipstick tube:
I didn't do any of the other cylinders. I felt it wasn't necessary since my compression results were good.
Just in case this helps any, photos of my spark plug rom 6 cyl. They are less than a year old.
Thanks, first time I am doing all of this as well. I bought this Jeep as a learning project/hobby.
And in case if you are curious:
4.0L Inline 6 - Automatic
180,000 miles
Penzoil 10W30 Synthetic
Hello, I am from the YJ forum. I hope you all don't mind me posting my issue in here. I figured since it is 4.0 related I can get as much insight on this issue as possible.
I have been owning my YJ for about year and have been having an oil leak/burn ever since. I have to refill my oil back to full every two weeks of driving it. It usually takes about a little more of a 1/4 of a quart every time.
I have changed out my valve cover gasket, my oil pan gasket, and my rear main seal. All were done following the steps in the FSM. I use to have an oil leak between the transmission cover and the block where the rear main seal sits.
This is what the leak use to look like:
It no longer leaks since changing the seal, but when I drive and warm up the oil, it will begin to leak (still not as much as it was doing).
I did a dry compression test with an Innova Compression Tester I bought from Autozone. The engine was warm with open full throttle during the test.
Cylinder 1: 155...155...155
Cylinder 2: 155...155...155
Cylinder 3: 155...160...160
Cylinder 4: 150...150...145
Cylinder 5: 150...150...150
Cylinder 6: 110...110...110
Obviously, something is going on with Cylinder 6.
I bought a Maddoxx Leak Down Tester from Harbor Freight. I am confident I did it right. Here is what I did:
1. Turned on compressor
2. Warmed up motor
3. Insert hose into 6 cyl. I used a balloon on the other end to find the compression stroke while manually cranking
4. Remove hose. Here I used a screw driver to find TDC of the piston, while someone else cranked.
5. Attached compressor to the leak down tester. Here I calibrated the gauges to where they both read 100%
6. Attach other end from leak down tester to 6 cyl.
Result:
If I did this right, it looks like I have a 13% leak? I don't know it makes no sense. I figured I would have a bigger leak if my compression was 110.
It was difficult to hear for where the leak was coming from. I heard small vibrations along the pipes while listening to from exhaust. I placed a funnel on the oil dipstick tube. It was loud its all I can say. I didn't hear anything come from the throttle portion. There was no bubbling in the coolant reservoir.
Sound from Dipstick tube:
I didn't do any of the other cylinders. I felt it wasn't necessary since my compression results were good.
Just in case this helps any, photos of my spark plug rom 6 cyl. They are less than a year old.
Thanks, first time I am doing all of this as well. I bought this Jeep as a learning project/hobby.
And in case if you are curious:
