What oil do you guys use on your 4.0s?

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Rubirob

Rubirob

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I use black stuff..lol
I always thought that the 4.0L were pretty much bullet proof so I run Castrol Magnatec 10w 30...works great.

I agree there bulletproof, my family has a 90 Cherokee with the 4.0 and that thing raised me lol.. I have always just thrown in it whatever I can get that’s decent.. it’s always Dino too.. but this wrangler I bought has half the miles that does and I wanted to make sure I used the right stuff.. I was getting a few different answers from each place I looked figured I would ask here.. plus even tho there bulletproof does not give excuse to knowingly abusing them [emoji13].. I mostly use synthetic now for convenience.. less changes haha


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UpperMI

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I just had to go to dealer to get the left Column multi switch.. Napa one didn’t work.. asked the guy behind parts desk and he said 10w-30 just for everyone’s info lol


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I replaced my multi function switch this past summer. When it comes to sensors or anything electrical, always choose Mopar parts. The off brand ones may work for a while, but most guys end up replacing the off brand within a year or so. For the multi function switch replacement, I watched the following you tube video:

Replacement was a breeze.

For the oil, 10W-30 dino oil. cheap and easy.
 
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Rubirob

Rubirob

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I replaced my multi function switch this past summer. When it comes to sensors or anything electrical, always choose Mopar parts. The off brand ones may work for a while, but most guys end up replacing the off brand within a year or so. For the multi function switch replacement, I watched the following you tube video:
It was a breeze.

For the oil, 10W-30 dino oil. cheap and easy.

Yea it was a easy swap, even tho mopar was twice as much I agree it normally last much longer.. plus the aftermarket one felt “off” so having the original equipment was nice for that reason too.. feels better..


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Rubirob

Rubirob

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Yep, I run 10W-30. I'd only run 5W-30 in the Winter months if you lived somewhere where it got really, really cold!

But other than that, any brand works. These 4.0 engines are not high performance engines that require synthetic or anything fancy. You can get 600k plus miles on just regular, conventional oil.

I like the sound of 600k miles haha, hope both of mine make it that far!!


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Chris

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I like the sound of 600k miles haha, hope both of mine make it that far!!


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There's a guy on here who sold his TJ with 600k miles on it. Never did any internal engine work at all, just regular maintenance and 3 transmission rebuilds (which is to be expected). But never once had to open the engine!
 

Phil Younger

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I generally use royal purple 10W-30 because I just do not want to take chances with the OPDA in this '06 4.0L.
One thing I will not do again--cut corners on filters next time. The one in there right I discovered was the cause of cold start tapping lifters (would tap for almost 4 minutes) for the first 500 miles. It started right after an oil change and I was suspecting the extremely rare case of wrong oil viscosity on the oil bottling line when suddenly it stopped. A chat with our shop foreman (who is a certified GM and Chrysler tech) led to the point that the valve in the filter had not been seating--the funny thing was that when I asked him to take a look it quit and has not come back. It tapped every time before and has not since the day I asked him to look at a condition that dis not happen for him nor since. Yes- don't do what I did this time- buy the right filter and buy quality. I am just going to go back to the OEM filter which I did not have problem with in the past.
 
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Rubirob

Rubirob

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There's a guy on here who sold his TJ with 600k miles on it. Never did any internal engine work at all, just regular maintenance and 3 transmission rebuilds (which is to be expected). But never once had to open the engine!

That is awesome! My 1990 4.0 has had a head gasket replacement.. but that was due to a bad radiator that caused bad overheating.. it overheated a few times actually.. but it drove just fine haha just had coolant vapor coming out of the tailpipe when it started up haha.. they are really good engines, they take the abuse haha


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Rubirob

Rubirob

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I generally use royal purple 10W-30 because I just do not want to take chances with the OPDA in this '06 4.0L.
One thing I will not do again--cut corners on filters next time. The one in there right I discovered was the cause of cold start tapping lifters (would tap for almost 4 minutes) for the first 500 miles. It started right after an oil change and I was suspecting the extremely rare case of wrong oil viscosity on the oil bottling line when suddenly it stopped. A chat with our shop foreman (who is a certified GM and Chrysler tech) led to the point that the valve in the filter had not been seating--the funny thing was that when I asked him to take a look it quit and has not come back. It tapped every time before and has not since the day I asked him to look at a condition that dis not happen for him nor since. Yes- don't do what I did this time- buy the right filter and buy quality. I am just going to go back to the OEM filter which I did not have problem with in the past.

What filter caused the tapping? Was it a wrong type completely? Or just a great value brand? Just curious, I do agree tho cutting corners on lots of things just create issues down the road.. a few more bucks for a better filter just seems like no problem.. especially for a Jeep you plan on trusting to take you down some remote trails haha


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Chris

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Well, replacing the head gasket a few times is something I would expect with 600k miles. But the important part is that the engine should be able to go at least 600k without a major overhaul of any kind. That speaks to the longevity of the 4.0!
 
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Jerry Bransford

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... I personally think anything 5wXX is too thin for the 4.0, but I'm also not a professional nor am I a mechanic. I am open to being learned about this.
A 5W-30, for example, only has its 5 viscosity when it is extremely cold which helps it flow through the engine more quickly in uber-cold conditions. Once warmed up it has the same 30 viscosity as a 10W-30.
 
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Rubirob

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A 5W-30, for example, only has its 5 viscosity when it is extremely cold which helps it flow through the engine more quickly in uber-cold conditions. Once warmed up it has the same 30 viscosity as a 10W-30.

That’s true, but that would only help for a very cold start up.. I believe the manual said below 32 degrees. However if it is say 70 degrees outside the 10w-30 should provide better protection on startup.. the 5w-30 might become too thin at that point.. just my option.. as for going too the snow with 10w-30 I think I will just let my Jeep idle a tad longer.. let that needle begin to rise before I take off.. a few times a year shouldn’t hurt anything..


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Phil Younger

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What filter caused the tapping? Was it a wrong type completely? Or just a great value brand? Just curious, I do agree tho cutting corners on lots of things just create issues down the road.. a few more bucks for a better filter just seems like no problem.. especially for a Jeep you plan on trusting to take you down some remote trails haha


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The problem was not that the filter did not meet the specification- the filter is just cheaply made and the drainback/bypass valve was sticking open. I also did not state that I use 10W30 because I do not ever run mine in winter and am old school enough to buy an oil with less viscosity index (VI) improver in it when I do not need it (like I would if I was starting it in cold weather). In the old days more VI improver was a bad thing-especially the old 10W40's but today the VI improvers are very robust and I just have an old habit ;)
 

Head Lice

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The land of 'salmon & grizzlies' ....... BC
Live in a 'cooler' climate here ....
My TJ came equipped with a block heater.
Plugged in with the timer set for 2 hours before departure.
Easy 'warm starts' ..... heat very soon.
All for the price of a cup of coffee.

A large logging company here plugs-in their trucks all year.
Shop costs have gone down considerably.

Thin start-up oil is great ....... plugging-in is better yet.
 
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Jerry Bransford

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That’s true, but that would only help for a very cold start up.. I believe the manual said below 32 degrees. However if it is say 70 degrees outside the 10w-30 should provide better protection on startup.. the 5w-30 might become too thin at that point.. just my option.. as for going too the snow with 10w-30 I think I will just let my Jeep idle a tad longer.. let that needle begin to rise before I take off.. a few times a year shouldn’t hurt anything..
It isn't a 5 viscosity at 70 degrees. At 70 it's going to be more like a 10W-30.
 
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DC0046

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Have posted this before and differing opinions here. I have a 2004 Rubicon. Had 68,000 miles when I bought it. No oil leaks. Changed to Mobil 1 10 w 30 and the rear main started leaking. Ran it 3,000 miles and changed to Castrol 10 w 30 conventional oil and no more leaking rear main. I will stay with conventional oil with mine. I use Wix oil filters in everything I own.
 
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Rubirob

Rubirob

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Have posted this before and differing opinions here. I have a 2004 Rubicon. Had 68,000 miles when I bought it. No oil leaks. Changed to Mobil 1 10 w 30 and the rear main started leaking. Ran it 3,000 miles and changed to Castrol 10 w 30 conventional oil and no more leaking rear main. I will stay with conventional oil with mine. I use Wix oil filters in everything I own.

Interesting, I haven’t changed over to Mobil one synthetic yet.. maybe I will stick with conventional then.. I have no leaks at the moment either..


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