Pantera99
TJ Enthusiast
Gonna give Pennzoil a try. I've tried several HM oils & I'd say Valvoline was pretty good, Castrol leaked a bit more, Napa has been decent & I'll probably get flack but so far Fram HM oil seemed to slow the RMS leak the best.
That RMS leak opinion question
- Thread starter Ronutz
- Start date
Gonna give Pennzoil a try. I've tried several HM oils & I'd say Valvoline was pretty good, Castrol leaked a bit more, Napa has been decent & I'll probably get flack but so far Fram HM oil seemed to slow the RMS leak the best.
I'll try the Fram High Mileage oil next, nothing about that brand scares me.
Pantera99
TJ Enthusiast
Hey there Jerry, wanted to get your take on something. So been running the Pennzoil HM as summer is getting started. Not bad, minimal RMS drip, so oil had gotten a bit low & all I had on hand was 10w30 full synthetic super tech. Was supposed to be for my Titan but I added about half a quart. Well it was about 114° here yesterday & barely noticed any drips at all the last few days. What are your thoughts?
joniki
TJ Enthusiast
I'm no @Jerry Bransford but I wouldn't be worried about it. Proof ultimately will be in the leak. I think you can throw about any oil at a 4.0 with few consequences...the seals and leaking issues...well, that's where conventional high mileage (additives to swell seals perhaps at the expense of catalytic converters) helps.
-Mac
egclassic
TJ Enthusiast
I used a bottle of the AT-205 and mine hasn't leaked a drop in over 3 months. (Knock on wood). I'm sure not a permanent fix but it's buying me time.
I drove a 1990 silverado with a RMS leak for like 4 years. Keep a quart or two in the Jeep and check the oil every time you get gas and you'll never have an issue. TJ's have a two piece rear main so many of us ARE leaking, and don't care enough to drop the oil pan to do it.
Now if you're hemorrhaging oil out of the rear main, then yeah get into it. Back in the 70's and 80's cars burned a little bit of oil even when new, and checking the oil was commonplace for all drivers. The 4.0 isn't a "modern" engine... keep oil in it and it will serve you as long as you need it to.
Pantera99
TJ Enthusiast
Yea not too worried about it, just expected it to be worse in the high heat. Tempted to try a full synthetic HM just to see what it would do.
Valve cover can also cause a leak that can drip in the same spot as the rms.
joniki
TJ Enthusiast
If it is the RMS or oil pan gasket then I’d try AT-205. It worked for me.
I’m going to grab some of this today and see if it works. I’m not too concerned of the small leak, it’s just the spots it’s leaving in the driveway
A couple of thoughts from following this today.
1. I had an oil leak. I replaced the valve cover gasket and the leak noticeably decreased. I still have an RMS leak though.
2. I have a bottle of AT-205. I need to put it into the engine at some point soon.
3. Many people say that a high mileage conventional oil does a lot to help small RMS leaks. It is hard to find though.
4. If you do a VCG or RMS, make sure to thoroughly clean off the back of the engine and trans bell housing after you do the change. There will still be a ton of residual oil and you want to make sure you have all of it cleaned off. Get some POR-15 and go to town back there.
1. I had an oil leak. I replaced the valve cover gasket and the leak noticeably decreased. I still have an RMS leak though.
2. I have a bottle of AT-205. I need to put it into the engine at some point soon.
3. Many people say that a high mileage conventional oil does a lot to help small RMS leaks. It is hard to find though.
4. If you do a VCG or RMS, make sure to thoroughly clean off the back of the engine and trans bell housing after you do the change. There will still be a ton of residual oil and you want to make sure you have all of it cleaned off. Get some POR-15 and go to town back there.
Pantera99
TJ Enthusiast
All the valve cover bolts I can easily get to were tight. I'd like to get to the nuts at the very back but I had an injector connector code (#2) that I chased around for months. It turned out to be the wire harness wrapping around the back & was shorting out on a stud. I wrapped the harness with teflon & zip tied & its been fine since so I don't wanna mess around back there. But yes I suspect the valve cover is leaking a bit too.
When I got my TJ last year it had small oil leak few drops per day (RMS plus oil seepage around oil pan gasket towards the rear of pan)
I replaced valve cover gasket to eliminate that possibility and still had a leak.
Changed oil to NAPA high mileage conventional oil. It made the leak little worse.
Added AT-205 and it did not do anything same amount of oil leak
I had some leftover synthetic Rotella 5-40 oil. I still get oil leak but seems less then before.
Eventually will need to do RMS and oil pan gasket.
I replaced valve cover gasket to eliminate that possibility and still had a leak.
Changed oil to NAPA high mileage conventional oil. It made the leak little worse.
Added AT-205 and it did not do anything same amount of oil leak
I had some leftover synthetic Rotella 5-40 oil. I still get oil leak but seems less then before.
Eventually will need to do RMS and oil pan gasket.