The Keys to Engine Longevity

[Dibbons]

We have two six cylinder, 4.0 liter, Jeep Cherokee's ('92 and '01) which are both high mileage and still running strong. What is the secret to their long-life? I can think of a couple of things. Number one would be the ratio of main bearings to cylinders-more support and more rigidity. Number two is oil pan capacity at six quarts: more lube means cooler running and much less chance of oil starvation (and more chances to top-off an oil leak before engine damage occurs). Am I forgetting anything?

 

[WileE]

Care and maintenance.

 

[OKDart]

I agree, care and maintenance

 

[JackR]

Yes, two Jeep XJ’ at this address. One heavily modified suspension rock crawler but bone stock 4.0 that still runs great with 280K on it. The other is only 200K but also runs great.

 

[Demonic]

The history of the AMC 4.0 is a long one. Yes, AMC. Chrysler kept it when they bought AMC. Although most will say the 4.0 was debuted in '86, it's engineering goes back to the well-proven AMC 285 six and earlier 232. Other than the run of bad head castings around 2000, they're great motors, well regarded in the Jeep world.

https://en.wikipedia.org/wiki/AMC_straight-6_engine

 

[Sixpactogo]

If there is an engine that lives up to the "bullet proof" image, I can't think of one more deserving than than the 4.0 six. My daughter sold her 95 Grand Cherokee a few years ago with 320K miles on the clock. I still see it running around town once in a while. Body is junk but IMO, Maintenance is everything.

 

[coronet68mx]

Change the oil every 3000 miles and a good quality brand oil.
https://www.google.com/amp/s/wyantgroup.com/remembering-the-three-million-mile-volvo-man/amp/

 

[70chall440]

Yeah not buying the 3000 mile oil change deal, do some research on oil and you will find that the 3000 mile deal was developed by the oil companies to sell more oil. The key is to run good oil but more importantly a great filter (WIX), I run Royal Purple in everything and change it at 10,000 miles. My 01 Ram has 140K on it, my wife's 09 Caliber has almost 300K on it.

 

[Sixpactogo]

Yeah not buying the 3000 mile oil change deal, do some research on oil and you will find that the 3000 mile deal was developed by the oil companies to sell more oil. The key is to run good oil but more importantly a great filter (WIX), I run Royal Purple in everything and change it at 10,000 miles. My 01 Ram has 140K on it, my wife's 09 Caliber has almost 300K on it.

I agree somewhat. The old 3000 mile rule when by the wayside when fuel injection became prevalent. I'm not so sure it was the oil companies as much as it was the manufacturers recommendation mostly because carburetors were not as efficient as the newer computer supervised engines out there these days. Our old iron with Carburetors for sure need need more oil changes because of the impurities they put into the crankcase no matter how good the oil or the filter is.

 

[70chall440]

I agree with that statement, don't know it needs to be 3000 miles but definitely more often than EFI cars.

 

[GMP440]

If there is an engine that lives up to the "bullet proof" image, I can't think of one more deserving than than the 4.0 six. My daughter sold her 95 Grand Cherokee a few years ago with 320K miles on the clock. I still see it running around town once in a while. Body is junk but IMO, Maintenance is everything.

My 68 Coronet with 318 has 348K miles. Original cam , crank bearings, pistons , etc. My oil change intervals have been every 2000 miles since I got the car in 79; driving it every day for 17 years. Since I only take it car events the oil change intervals are less.

 

[GMP440]

Change the oil every 3000 miles and a good quality brand oil.
https://www.google.com/amp/s/wyantgroup.com/remembering-the-three-million-mile-volvo-man/amp/

Just saw the second Irv video and noticed it was a commercial for Castrol GTX. I just mentoned in another post about my 68 Coronet with 348,000 miles. I oil that I have always used has been Castrol GTX.

 

[coronet68mx]

Just saw the second Irv video and noticed it was a commercial for Castrol GTX. I just mentoned in another post about my 68 Coronet with 348,000 miles. I oil that I have always used has been Castrol GTX.

There are engines legendary because of their durability, the slant six Chrysler, the 6 in line AMC, vw boxer, the volvo b 16, b 18, the only new car that my grand pa bought, was a volvo p122/ amazon 1959, car that he still own it, in rough shape tough, and that engine last 27 years until it fail, good oil and a good engine design is the key to a long lasting motor IMO.

 

[Rusty 72]

I've got a 2000 XJ with the AMC 4.0L and a 99 TJ with the tiny AMC 2.5L
Both are amazing engines and still going strong after many miles.

My idea of keeping an engine healthy is doing preventative maintenance before anything becomes a problem.

 

[Ron H]

OIL - black gold...Texas tea...heard this somewhere. Always held by regular oil/filter changes btw 4000-5000 miles. In my old ride it's every year regardless of how many miles I drove it during the warmer months before parking it. One year that was 294 miles btw changes...most years maybe find time to drive it around a 1000 miles.

 

[Moparnocar]

You NEED a quality filter, wix, napa gold etc...frame is paper and cardboard!!! Couldn't believe it until I saw it

 

[fratzog lover]

Modern oil will last 8-10,000 miles. Your filter wont. Especially the teeny ones (like my Forester) so remember to spring for a filter at 4000 miles or so. Its not that much for a new filter(buy em on sale 6 at a time) and 10 ounces of new oil.