Cheapest version Supertech

[Carlostrece]

He got 410K out of it (mostly highway) with minimal maintenance, but how many miles could it have gone if he'd put more effort into maintenance? We'll never know. He certainly got his money's worth out of it.

 

[CharBaby]

What parts were replaced on the Jeep during his ownership?
Typically it would be suspension, electrical/electronics

 

[burbguy82]

the 4.0 can live with nearly any motor oil, as long is it is changed, so I would say that it has nothing to do with ST oil

 

[addyguy]

I worked with a guy at a WM TLE years ago that had a 4.0 Jeep that he used and abused horribly as a Jeep - went and found the nastiest trails he could get through with his buddies, revved and lugged the heck out it every weekend.
His regime? 10W-30 Super Tech and a Fram filter every 3,750 miles like clock work. Never had a lick of engine trouble; but had to replace other parts all the time. Engine was smooth and quiet, never burned or leaked a drop of oil.

 

[Carlostrece]

What parts were replaced on the Jeep during his ownership?
Typically it would be suspension, electrical/electronics

I don't know. I'm sure as minimal as possible. He's a cheap guy and he is not a car lover. He's also not consciencious, except maybe to do the barest minimum, if that.

 

[Carlostrece]

the 4.0 can live with nearly any motor oil, as long is it is changed, so I would say that it has nothing to do with ST oil

I'm not suggesting Supertec is the best. I'm only suggesting it's more than adequate in a well designed engine such as Jeep 4L. I wonder if he'd have got more than 410K from that engine if he'd used Supertech High Mileage oil.

 

[Carlostrece]

I worked with a guy at a WM TLE years ago that had a 4.0 Jeep that he used and abused horribly as a Jeep - went and found the nastiest trails he could get through with his buddies, revved and lugged the heck out it every weekend.
His regime? 10W-30 Super Tech and a Fram filter every 3,750 miles like clock work. Never had a lick of engine trouble; but had to replace other parts all the time. Engine was smooth and quiet, never burned or leaked a drop of oil.

I think my friend probably changed his oil at 5K or maybe 7K miles. When I owned it (from 30K to 92K miles) I changed Mobil One 10w30 every 5K miles. I wheeled it hard offroad, a lot of short trips in city, and some highway.

He drove it on highway mostly, some city, rarely offroad. He probably changed it around 4.5K to 5.5K.

 

[factorytuned2012]

Engines just want clean oil at the correct viscosity but the 4.0 is a stout engine

 

[burbguy82]

I'm not suggesting Supertec is good. I'm only suggesting it's more than adequate in a well designed engine such as Jeep 4L.

I would say it is just as good as any other of the shelf stuff.

 

[Carlostrece]

I would say it is just as good as any other of the shelf stuff.

Plain ole Supertech is good enough, but I personally prefer Quaker State HM FS because it's better (IMO) and costs approx same as Supertech HM. However, my friend just used plain ole Supertech 10w30. Not the ST HM version.

 

[fen]

I agree on the Supertec and the 4L Jeep engine are awesome. They certainly worked very well with each other on this vehicle.

 

[Carlostrece]

Just out of curiosity... How many miles is normal for a Jeep 4L engine? I've often heard 300K+ is normal with average maintenance.

I beat on this Jeep hard from 30-93K miles on and off road, but I did maintain it well. My friend never beat on it, but his maintenance was minimal and it took him from 93-410K without any major repairs.

I have to wonder how far it could have gone with less beatings from me and better maintenance from him? 500K or more?

 

[pbm]

Wasn’t the Jeep 4.0 an American Motors designed engine? AM made some good engines….the 390 in the Javelin was right up there with GM, Ford and Chrysler V8s of that era (late 60s).

 

[MrWideTires]

Supertech is good oil, and the 4.0 doesn't make enough power to break down.

It's such a dog, it can't get out of its own way, even in a light 2 door Jeep, but it's low stress so I think a lot of the credit it gets is exaggerated (like the Ford 4.6). Yeah they're reliable.. only because they don't make enough power to cause issues.

 

[Carlostrece]

Supertech is good oil, and the 4.0 doesn't make enough power to break down.

It's such a dog, it can't get out of its own way, even in a light 2 door Jeep, but it's low stress so I think a lot of the credit it gets is exaggerated (like the Ford 4.6). Yeah they're reliable.. only because they don't make enough power to cause issues.

How dare you sir!

It was peppy enough up to 60 mph. Then doggish above that, if stock. That's by the standards of 1999 to 2015 when I owned Jeeps.

Back in the day when fuel injected 4L debuted in late 80s or early 90s it was a lot peppier than mosts 80s cars and much more fuel efficient than a full size Cherokee or Wagoneer. It was excellent back in its day and acceptable in modern times. This Jeep lasted 29 years and 410K miles.

I think that's pretty good.