Super Tech 20w-50 in my 500,000 mi. Jeep 4.0.Bad?

[cog]

My 89 Cherokee has 508,000 miles with mostly Castrol 20w-50 used.

The last few years have been the Super Tech 20w-50 at 3000 to 5000 change intervals.

Do you guys think im harming the old mill and does the ST have the Zinc that my motor needs?

 

[Dominic]

At 508,000 the main objective is just keeping it full of oil. I would probably run a 10W-40 if it were mine, but I doubt the 20W-50 is harming anything. It made it this far!

 

[Nick1994]

Why such thick oil? Have you done a compression test and checked the oil pressure? If it's fine I'd go down to 10w30 or a 5w40.

But then again if 20w50 brought you this far it obviously isn't hurting anything.

 

[cog]

Im in So. CA so it never gets too cold. But I bet I would get better mileage with a thinner oil.

I probably have an old school way of thinking that the thicker oil lubes better and wont leak out the seals as quick

I use to add Slick 50 once in a while but havnt in a 100,000 mi.

Thanks for the replies, think I will try a 10w-40 ST.

 

[aquariuscsm]

I'd keep on using the Castrol 20W50.

 

[heynow]

If 20w50 got you that far, I see no reason to change!
I wouldn't hesitate to use the ST over Castrol.

 

[cog]

Ok, im sticking with the tried and true ST 20w-50!

Thanks for your insights.

 

[umungus1122]

How about ST 15w-40?

 

[nwjones18]

Only on BITOG would someone say "I've gone 500k on this weight oil" and get suggestions to try something else... lol

 

[askani79705]

Originally Posted By: umungus1122
How about ST 15w-40?

QFT

 

[Kuato]

Originally Posted By: heynow
If 20w50 got you that far, I see no reason to change!
I wouldn't hesitate to use the ST over Castrol.


Exactly right! At over 500k miles your engine is loving what you put into it. Don't change a thing...

 

[expat]

Funny, I bet if he had 50k miles and planed using 20w-50 people would be screaming "stop! You will kill the engine"

 

[CT8]

We should be asking you for advice.

 

[CT8]

Originally Posted By: expat
Funny, I bet if he had 50k miles and planed using 20w-50 people would be screaming "stop! You will kill the engine"
I know better than to say such a thing.

 

[yvon_la]

Just make sure you let the coolant needle move before going and let it cool 5 minute before shutting it off and keep using your oil (2050)if it was doing harm you wouldn't be asking it you would have lived it

 

[TeddyVelvet]

What a champ! I only made it past 100k before I spun a connecting rod bearing in my RSX. May you and your Jeep have many miles ahead together!

 

[FCD]

Well if it's running ok on it why change

 

[OneEyeJack]

A salesman here has a Jeep Cherokee (purchased new) with that same 4.0 engine. He uses Castrol 20w-50 as well and has just over 500K miles on the clock without going inside the engine.

He also has an older Ford pickup (purchased new) with a Y-block engine that has over 700K miles on the same Castrol 20w-50 oil, driven by his wife, son and daughter. They tow a horse trailer quite often. The engine has been worked on, valves, timing gears and water pump but the bottom end has never been touched.

They also have a 59 Ford wagon (purchased new by his father) with a V8 using the same oil but they have no idea what the total miles might be. It's gone around the clock too many times.

He stated with conventional Castrol 20w-50 and now uses Castrol Syntec 20w-50.

You could tell this guy he should use thinner oil but I don't think he'll listen. They do 5-7K oil change intervals with NAPA filters.

 

[Nick1994]

Originally Posted By: OneEyeJack
A salesman here has a Jeep Cherokee (purchased new) with that same 4.0 engine. He uses Castrol 20w-50 as well and has just over 500K miles on the clock without going inside the engine.


The OP is in California. Maybe you know him?

 

[Ducked]

Originally Posted By: OneEyeJack
A salesman here has a Jeep Cherokee (purchased new) with that same 4.0 engine. He uses Castrol 20w-50 as well and has just over 500K miles on the clock....You could tell this guy he should use thinner oil...


They would, too. Don't encourage them.