What should I get my Jeep Wrangler with High Mileage?

Messages
1
Location
Chapel Hill, NC
I just bought a 1992 Jeep Wrangler 4cyl 2.5 liter with 113,000 miles on it. I've heard about high mileage oils actually hurting the seals in the engine in the long run and also about the dangers of switching to a synthetic. I also have 32" tires to pull with factory gear ratios and moderate blow-by in the engine. Anyone have any recommendations?
 
Messages
2,569
Location
College Dorm...
This issue with synthetics in this engine will be with them cleaning off old dried up seals that are now covered in varnish/deposits. Once this happens, the seals are expected to perform, well, like seals, and with them now being dryed-up and non-operative, you can expect some degree of either leaking or burning...maybe both. I STRONGLY FEEL that your best bet, at least at this point until late fall, is to run a HDEO 15w-40 such as Delvac, Delo, or Pennzoil Long-Life. You state you are experiencing blow-by, and the Long-Life does have the good dose of molybdenum in it (that significantly helps in regards to blowby), so I'll have to recommend that. Running Long-Life from now until then will get the engines lubrication system back to running/operating like it should, and then, when the colder weather sets in, you can switch over to a 5w-40 of some sort. So, I recommend Pennzoil Long-Life 15w-40 and a nice high-quality oil filter.
 
Messages
22,188
Location
Colorado Springs
What is this talk of High Mileage oils hurting seals? Is there any truth to that? I thought it was just a small does of ester in the base stock mix to help swell seals and stop them from leaking? How is that bad? If it truely is bad, then diester based top of the line synthetics do not hurt a thing obviously. [I dont know]
 
Messages
700
Location
USA
Anytime you swell a seal that has a rotating or sliding shaft or part thru it, it will seal and also wear because it is tight again. The minute you don't use the swelling agent (seal swell, HM oil ect) the seal will return to it previous size and thus leak mmore than before because it has been worn from the rotating or sliding action when it was swelled.
 
Messages
700
Location
USA
quote:
Originally posted by TallPaul: My understanding, at least with the Valvoline Maxlife high mileage oil, is that it does not swell seals, but conditions them. That is, it makes old hardened seals more pliable.
I called Valvoline when i used Max life A few years ago (SJ) and they said it has "seal swell" additives in it. He said it was also a group 3 base oil. The group 3 base oil thing was told to me 2 different times from 2 different guys at the tech line at Valvoline.
 
Messages
2,602
Location
The Tropics of Antartica
quote:
Originally posted by Tripper521: I just bought a 1992 Jeep Wrangler 4cyl 2.5 liter with 113,000 miles on it.
Welcome to the forum ! You'll get alot of advice and mine is with your 12 year old engine relatively light on power for what it's asked to do I'd let modern technology brewed into a high mileage oil work for you and use Pennzoil , Quaker State , Castrol or Valvoline 10w-30 and not let the seal thing bother you in your particular case given the miles you have . They are nearing the end of their life cycle anyway and these oils will probably extend their usefull life . These oils typically have higher levels of additives than the plane jane oils as well and you'll be getting your moneys worth . Enjoy your stay here [Smile]
 
Messages
742
Location
Lake Anna, VA
I have a 2000 2.5L TJ. Although underpowered and rough the 2.5L will last forever with proper maintenance. I would switch to a 15W-40 as stated before year round as it doesn't get to cold in NC. I recently switched mine over to a 40W and it's alot quieter and smoother than with a 30W.
 
Messages
4,868
Location
Lakeville, MN
So far the diesel/fleet oils in xw40 grades are showing some nice numbers in this series of motors (The 4.0 is actually based on some of the architecture of the 2.5, which is loosely based on the old 4.2). Based on similar properties of these motors, the xw40 (a 15w40 would be fine in NC) is a good bet. If you are worried about running a thicker oil than 10w30, the older versions of this motor recommended the use of up to a 20w50 as long outside temps were above 32F. Otherwsie, any quality 10w30 would work fine too!
 
Messages
13,132
Location
By Detroit
My understanding, at least with the Valvoline Maxlife high mileage oil, is that it does not swell seals, but conditions them. That is, it makes old hardened seals more pliable.
 
Messages
2,768
Location
Tn
quote:
Originally posted by TallPaul: My understanding, at least with the Valvoline Maxlife high mileage oil, is that it does not swell seals, but conditions them. That is, it makes old hardened seals more pliable.
Somewhere on here, Bob did a basic test and concluded that most don't actually swell seals. Castrol and Mobil both indicated to me that it's not a problem and this issue has no validity with their product.
 

tpi

Messages
200
Location
So. CA
I have a '95 2.5 and use Delo 400 15W-40 in it (4000 mile changes). The engine is spotlessly clean inside, very little blowby and lifter noise. I have the same situation, has trouble pulling top gear with oversized tires, and frequently run in 4th on anything other than ruler flat terrain. I agree these engines are rugged workhorses, but a little slow :)
 
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