Chrysler oil spec for 2002 Jeep 4.0 litre

[Tikka]

10w30 was fairly common in the UK until ACEA oils came onto the scene.

any a3 oil will be more than enough

Hi.
I looked on the site of one of the big lubricant suppliers here in the UK. Out of the hundreds of engine oils, they offer just the one 10w/30. Very odd.

The Jeep belongs to an acquaintance of mine. I will advise a good quality 10w/40 semi synthetic. If he really wants to use fully synthetic then a 5w/30 or 5w/40.

If the Jeep has been run on semi synthetic, will a change to fully synthetic cause leaks? Is this an urban myth?

 

[Graham Piccinini]

Synthetic oil doesn't cause leaks. What it does is clean the engine. Including cleaning out the crud and sludge from conventional oils, that used to cover up already existing leak spots. But if said leak is minor, then a switch to high mileage synthetic will help to reduce it, until you're able to replace the bad seal/gasket.

 

[CT Rob]

Jeep dealer i used to work at only used 10/40 in the 4.0 jeeps.Prob still do for the few they are on the road still

 

[IcarusLSC]

I ran Mobil 1 10W30 in my TJ the whole time I owned it. I did run 5W30 Mobil 1 in the winter a couple times, but it didn't seem to make any difference.

 

[Bighorn2500]

My old TJ ran 10w30 in the summer months then 5w30 in the winter.