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what causes this oil leak

wildcat-xj

NAXJA Forum User
Location
Kingwood, Texas
when i run straight up oil...10w30, i have very little leakage. when i add a little atf or marvel, it spits out of everywhere. spits oil on underside of hood. blows on firewall. this time i only added about 1/4 of a quart of atf and its doing it.:soapbox:

why? does it thin it out too much?
 
1. Why are you adding atf to your oil and then running the engine UNDER LOAD--you like damaging bearings?

2. Check your CCV system.
 
so is adding one quarter of one quart going to damage stuff? does it break down the oil? guess i will be changing oil tomorrow. doh!
 
MMO, no problem. How much atf to effect the pressure properties in 5/6 quarts of oil? I don't know.

Are running the atf to clean the engine? If so, run a diesel motor oil, it will clean the crap out of it and stand up to any use you could put it to.
 
I buy 10w30 Shell Rotella dino at Walmart here locally, about $8 a gallon jug.

Hit your truck stops, they usually have oils on sale weekly.
 
I beleive diesel oil is something like 20 50, its just thicker weight, if I remember right

Diesel motor oil is available in a wide variety of weights, both multi-viscosity and single-weight. 10w30 and 15w40 for the Rotella multi-viscosity Triple T.
 
okay. thanks.

i just need to leave it alone. it runs fine. i need to quit messing with it but i just can't keep my hands off it. got to always be doing something to the heep. im gonna change this oil and quit worrying about it.
 
okay. thanks.

i just need to leave it alone. it runs fine. i need to quit messing with it but i just can't keep my hands off it. got to always be doing something to the heep. im gonna change this oil and quit worrying about it.

Ok, but please do check the CCV, when it isn't functioning you will start to find oil getting pushed out.

Front of valve cover is a filtered air fresh air intake, rear has a metered orifice in the valve cover, it likes to plug up, the vacuum line likes to plug up, and the orifice in the intake manifold for supplying the vacuum likes to clog too.

If you have a Renix--87-90, there is a valve cover mod Cruiser54 has posted that helps with oil control.
 
I beleive diesel oil is something like 20 50, its just thicker weight, if I remember right
It's got a very different chemical makeup too - lots more detergents and some other stuff as well.

I would not run ATF in the engine under load, it contains extra detergents (what you were after) but also friction modifiers to help the wet clutches in a transmission do their job. Friction modifiers + bearings + pressure = bearings take a beating.
 
Diesel motor oils are highly detergent. They work extremely well in severe service, and are recommended for off road vehicles.

Newer XJ, lots of highway miles, I wouldn't see a particular benefit, but personally I would still run Rotella.

For off road, older engines, lots of short trips (under 20 minutes operation), then I would definitely recommend diesel motor oil.
 
ive been runnin 15-40 rotella for awhile and the old heep couldnt be happier. now she purrs like a kitten and i think it even brought it back tolife a little. takes awhile to get used to the smell but the shell is better for our motors than this newer oil formula. i couldnt be happier with the switch. i think it even stopped the bleeding a lil too :greensmok
 
Question, are the diesel oils better for non roller valve train? I know a lot of older engines (like SBC) use flat tapet cams and newer oils took the zinc out and they tend to flatten the cam lobes. Does the diesel oils have zinc in them?
 
Question, are the diesel oils better for non roller valve train? I know a lot of older engines (like SBC) use flat tapet cams and newer oils took the zinc out and they tend to flatten the cam lobes. Does the diesel oils have zinc in them?

i know that shell rotella t does contain zinc, but i have heard the government is going to put an end to that too, just like they did with the regular gasoline engine oil.
 
hmm tempted to do the 5th oil change ive done in just over 2 months of having the xj in only about 1k miles. i kept having to switch the oil due to ironing out previous owners tardations and oddities i came across. but the diesel oil sounds nice to run in my 90 renix motor
 
I don't know about the zinc content but I started using the diesel oils in my vehicles about 18 years ago when I had a fleet of diesel trucks. I figured if those oils were made to withstand the punishment of 14:1 compression with 30 pounds of turbo boost added to it, not to mention the acids created as a by-product of diesel combustion, and oil change intervals of over 7500 miles, then they would be just fine for my cars. Rotella is a preferred oil in the trucking industry BTW.
 
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