Synthetic Blend High Mileage Oil?
04-17-2018, 07:35 AM
#16
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
No on full synthetic. It's to expensive to be leaking out. But a synthetic blend is close to a full synthetic oil. My jeeps are always lifted and built so fuel economy is total crap. If your engine was taken care of it shouldn't be gummed up and blocking leaks that would other wise be leaking. Your engine will benefit from a synthetic or a blend either way. Like I said leaks will be caused from higher engine pressures after repairing your pan leak and rear main leak. At least this is my experience
The reason those seals leaked is because they were old and needed replacing. That's all.
And I'll bet some of those seals/gaskets were replaced unnecessarily due to faulty diagnosis........and starting at the bottom instead of the top.
Here's why:
Everybody, who doesn’t own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking. Many mechanics, friends, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don’t jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons:
First off, the engine sits nose-up and any oil will run back to the RMS area.
Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber’s adage apply here: “Crap flows downhill”.
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
04-17-2018, 12:53 PM
#17
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Year: 1989
Model: Cherokee
Engine: 4.0
Friggin valve cover gives me fits. Replaced, re-torqued multiple times. Still can't stop it from leaking and as Cruiser mentioned from the bottom looks like RMS at a quick glance.
04-17-2018, 01:11 PM
#18
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Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Pure coincidence, pal. There is no pressure in the engine.
The reason those seals leaked is because they were old and needed replacing. That's all.
And I'll bet some of those seals/gaskets were replaced unnecessarily due to faulty diagnosis........and starting at the bottom instead of the top.
Here's why:
Everybody, who doesn’t own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking. Many mechanics, friends, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don’t jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons:
First off, the engine sits nose-up and any oil will run back to the RMS area.
Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber’s adage apply here: “Crap flows downhill”.
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
The reason those seals leaked is because they were old and needed replacing. That's all.
And I'll bet some of those seals/gaskets were replaced unnecessarily due to faulty diagnosis........and starting at the bottom instead of the top.
Here's why:
Everybody, who doesn’t own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking. Many mechanics, friends, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don’t jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons:
First off, the engine sits nose-up and any oil will run back to the RMS area.
Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber’s adage apply here: “Crap flows downhill”.
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
04-17-2018, 02:45 PM
#19
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04-18-2018, 09:34 AM
#20
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Year: 2000
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Engine: 4.0L Straight 6
Everybody, who doesn’t own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking. Many mechanics, friends, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it?
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don’t jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons:
First off, the engine sits nose-up and any oil will run back to the RMS area.
Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber’s adage apply here: “Crap flows downhill”.
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don’t jump on the RMS/oil pan gasket bandwagon right off the bat.
Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons:
First off, the engine sits nose-up and any oil will run back to the RMS area.
Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber’s adage apply here: “Crap flows downhill”.
Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
04-18-2018, 09:41 AM
#21
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04-18-2018, 06:56 PM
#23
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My source is from past experiences back in the 70s when all of the synthetics contained esther. The esther would break down the seal material of the day. Even faster on old gaskets that weren't leaking. The new synthetics no longer contain the esther, plus modern seal materials are better. This isn't my first rodeo, I was four-wheeling before many of you were born !!! And who said that there was no pressure in the engine??? I replaced my valve cover gaskets and grommets today. My oil pressure went up from 30 to 40 !!! I have decided to put some faith in new gaskets and seals and switch to a high mileage synthetic blend oil. Getting ready to do my oil pan gasket and the rear main seal if it is necessary? I'm concerned wether or not if I have a groove on the crankshaft at the rear main seal? If so, I probably won't switch. Any body have a better grommet for the valve cover bolts ? I thought that the ones that came with the Fel-Pro sucked. Really chinsy. Couldn't torque to spec on some of the bolts using wrist and two fingers. So I had to put a flat washer on three of them just to get them snug w/o pulling through the grommets!!!
04-18-2018, 09:29 PM
#24
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My source is from past experiences back in the 70s when all of the synthetics contained esther. The esther would break down the seal material of the day. Even faster on old gaskets that weren't leaking. The new synthetics no longer contain the esther, plus modern seal materials are better. This isn't my first rodeo, I was four-wheeling before many of you were born !!! And who said that there was no pressure in the engine??? I replaced my valve cover gaskets and grommets today. My oil pressure went up from 30 to 40 !!! I have decided to put some faith in new gaskets and seals and switch to a high mileage synthetic blend oil. Getting ready to do my oil pan gasket and the rear main seal if it is necessary? I'm concerned wether or not if I have a groove on the crankshaft at the rear main seal? If so, I probably won't switch. Any body have a better grommet for the valve cover bolts ? I thought that the ones that came with the Fel-Pro sucked. Really chinsy. Couldn't torque to spec on some of the bolts using wrist and two fingers. So I had to put a flat washer on three of them just to get them snug w/o pulling through the grommets!!!
What were you smoking back then?
Crankcase pressure and oil pressure are totally unrelated.
04-18-2018, 10:34 PM
#26
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04-18-2018, 10:49 PM
#28
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04-18-2018, 10:55 PM
#29
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Oh, excuse the he'll out of me !!! I wasn't aware that you were a high and mighty moderator with the infinite knowledge of the universe !!! You never answered my question as to why the oil pressure rose ??? Now I see what all of the other jeep websites were talking about JF ... Does it make you feel big to try to belittle others ??? I just read most of your posts,,,, I saw a definite pattern !!! How much did you pay to become a moderator??? No wonder others are leaving jeepforum. Every likes a little a$$, nobody likes a smarta$$ !!! Moderate that!!
04-18-2018, 11:05 PM
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Oh, excuse the he'll out of me !!! I wasn't aware that you were a high and mighty moderator with the infinite knowledge of the universe !!! You never answered my question as to why the oil pressure rose ??? Now I see what all of the other jeep websites were talking about JF ... Does it make you feel big to try to belittle others ??? I just read most of your posts,,,, I saw a definite pattern !!! How much did you pay to become a moderator??? No wonder others are leaving jeepforum. Every likes a little a$$, nobody likes a smarta$$ !!! Moderate that!!