DUDE454

Im about to change my oil and i was thinkin if it will hurt anything to run 20w 50 oil. The hot weather is about to come and I thought this oil might be good for keepin things stright when offroading in high revs. Just want to know what you all think

djb383

http://www.bobistheoilguy.com/cms/in...d=84&Itemid=92

The XJ is not a Harley. LOL

HCCAFan

Prolly run OK ... for a while.

DUDE454

I was thinking that sense im going to get 33s soon and keep the stock 3.55 gears that this would do best

89Laredo

yes, it will run fine, and it wont hurt it.
But, youll be fine with 10w30.

If youre really worried, get an oil cooler.

XJ_Libertad

The only vehicles that need the 20w50 are vehicles that are air cooled like a Harley. You will due more harm than good to your 4.0 It is designed to run off 10w30. You need to read the link above, it will explain everything you need to know about oil. If you could go 5w20 that is better than 20w50....sounds weird?? read the article.

Caish

I just changed the oil in ours today, 15w40 I've been using it for years in everything from the KTM 640, to the Big Block Ford.
I would not using it in a modular Ford motor though, tends to hurt MPG in those.

I would only use 20w50 if I knew I had a worn bottom end needed the heavier weight to help extend the bearings.

xjmuddigger

my xj has had 20 50 for most of its life and it has close to 258k miles on it,and i run 20 50 all the time and it does great

SamSissine2

Why are you wanting a thicker oil for the warmer weather? Flow will decrease with this viscosity, that to me sounds bad.

rideordie66

with the higher temp you get from going slowly on a trail the 20 50 will take the heat better. I know of many people out here in Nevada that run only 20 50 and they have no motor problems and tons of miles on there rigs. As for the oil being thicker, I have heard that the thiner oil will drain out of the top of the motor when you shut it off and the thicker oil will stay up there so when you go to start it, the oil wont have to travel up to lube the top end. I run 10 40 because I do lots of highway driving but when my rig becomes the trail only ride I will run 20 50.

89Laredo

thicker oil=more heat

SamSissine2

X2

More heat = not a engines friend

jeep93

Last year I was given a 50 gallon drum of oil for free through the company I work for. It is 5W 50. I knew it wasnt the recommended viscosity for my old XJ but Ive been running it for about 10 months now with no apparent negative effects. One of the mechanics at work (I work in a haulage depot), says that (in his opinion) the 5w rating will keep the oil flowing in the cold winters weather we get here, and protect the engine in cold starting conditions, and the 50 rating will lube the engine well at high rpms (when off roading for example), and will help seal up those old leaky gaskets!. So far so good.

XJ_Libertad

I would think it would be better to change those leaky gaskets than try to use your oil as RTV sealant.

Again if any of you have not read Motor Oil 101 it will tell you everything about oil and the misconceptions one has.
http://www.bobistheoilguy.com/cms/in...=article&id=83

00jeepXJ

Unless you have an air cooled engine or an engine meant to run such thick oil you should stick with what the factory recommend. I have a sbc 400 that I needed to run a 50 weight oil in the engine because it would heat up soo much that regular oil would start to break down right away... I would regularly see temps reach 260 if I had stopped in traffic for longer then 5 minutes. Also the rings were failing so it would eat oil almost faster then I could fill it. Run what the factory recommends as that is what the engine is designed for.