Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: IrishKenCJ7 on January 11, 2018, 12:00:47 AM

Title: Jeep tj 4.0 engine oil
Post by: IrishKenCJ7 on January 11, 2018, 12:00:47 AM
Hi all.
So the recommended oil is 10w30. What are ye using. I can't find it online in UK or ireland.  I found some mineral oil but I believe I should be using semi synthetic. Halfords only do motorbikes 4 stroke oil.

Anywhere online I can order 6 litres.

Thanks
Ken
Title: Re: Jeep tj 4.0 engine oil
Post by: gazjeep on January 11, 2018, 07:03:41 AM
Not sure where you have got 10w 30 from mate.

Have a look here http://www.birtydastards.com/frm/index.php?topic=8091.0

Always run our previous 4.0 XJ & our 1998 4.0 TJ on of 12 years on 10w40 Semi synthetic

Plenty of places online do 10w40 semi ;)
Title: Re: Jeep tj 4.0 engine oil
Post by: Brynjaminjones on January 11, 2018, 07:53:22 AM

Not sure where you have got 10w 30 from mate.

10W30 I believe is what's recommended for normal climates in the manual and seems readily available in the US. :001:
I've always had the same trouble finding it over here though so use 10W40 exactly as Gaz says.

I did try 5W30 for some time in both of our 4.0s as it's the other oil mentioned in my owner's manual, but it seemed a bit thin and I'd say they're a bit happier on 10W40.  8-)
Title: Re: Jeep tj 4.0 engine oil
Post by: gordy on January 11, 2018, 02:49:27 PM
I bought and used this in my 99 XJ 4.0, 10-30w mopar engine oil. https://www.tuning-shop.co.uk/voyager-grand-voyager/5931-original-mopar-semi-synthetic-engine-oil-sae-10w-30-maxpro-5l-for-chrysler-dodge-jeep-plymouth-fiat-new-0603803750655.html
Title: Re: Jeep tj 4.0 engine oil
Post by: scrw on January 11, 2018, 03:43:44 PM
only evey used Morris 10-40 semi synth in my I6 enginges, did 350k miles between them all with no issues
Title: Re: Jeep tj 4.0 engine oil
Post by: JamesH on January 19, 2018, 09:22:53 AM
10w40 semi synthetic in every 4.0 and 2.5 I’ve owned has always been spot on
Title: Re: Jeep tj 4.0 engine oil
Post by: bigjeepzj on January 19, 2018, 02:45:05 PM
 :iagree: and 5.2 V8  :icon_biggrin:
Title: Re: Jeep tj 4.0 engine oil
Post by: bonza on January 27, 2018, 11:45:32 PM
Not sure where you have got 10w 30 from mate.

Plenty of places online do 10w40 semi ;)

maybe like mine it has a sticker on the fill cap stating 10W-40. 2005 TJ

having said that I use 15W-40 semi syn and have for the past ten years. not too fussed about brand, usually use what ever's on special alternating between Castrol, Shell and Valvoline.

10W-30 for the first couple of years but the engine sounded a bit ticky, especially during the summer months so went for a slightly heavier viscosity. 200k later still runs well

as far as I can see, Jeep specifying 10w/30 was more trying to reduce internal drag of the mating parts and improve fuel efficiency (theoretically) rather than protecting internal engine parts
Title: Re: Jeep tj 4.0 engine oil
Post by: harleykenn on February 02, 2018, 12:46:17 AM
I've used 20-50 mineral oil in my '97 TJ 4.0 for the last nine years,  and in my YJ  before that
also my Wagoneer  and CJ 5 before that,   never had any problems with any of them,  I don't buy expensive oil either.