diesel oil to stop leaks???

[olivedrabcj7]

a guy i talked to the other day said he has run "diesel oil" in his xj and it stopped the leaks in his engine. has anybody heard of this or know anything about it. doesnt sound like a great idea to me but im just curious as to how that would work? he said its so thick it plugs up any leaks. anybody heard of this??

[RichP]

Nope. The one time I ran castrol diesel engine oil in a 66 HP 289 mustang GT it wiped the motor out...rings, bearings and cam. Did it in less than 50 miles too...

[98JeepXJ]

RichP :huh:

Most diesels use 15W40 oil, which is obviously a heavier oil than the 10W30 the 4.0 calls for. The heavier weight oil would thin out less when it gets hot and be less likely to escape past old seals. (It doesn't actually 'plug up' the leaks) There's no harm in it at all, really.

Some good diesel oils to look for are Valvoline Premium Blue and Mobil Delvac 1300.

I say, Go for it...

[Wayne Sihler]

I use Shell Rotella T 15w-40 in the warmer months and my motor has over 200,000 on it .
Wayne

[JoBo]

I have Synthetic Rotella in my 96 XJ. It's 5-40 and is in a blue bottle. Some Wallmarts have it for $12.88 a gallon. My XJ has 142k on it and is a "little" loose.

JoBo

[BigDadys94xj]

I dont know if I would do that only because I firmly believe in using what is recomended and changing at EVERY 3000 miles. I have 3 XJs 2 with close to 200k and my 87' which has 325k . All 3 have never given me any problems all have the original engines (never rebuilt or torn down). I have never even had a seal leak on any of them. If you want a cheap fix to stop oil seapage I would use something like Bars Leak or a seal conditioner that you add to the oil. (personally I would just replace the leaking seal)

[Sarge]

Diesel oils meet or beat every recommendation for the XJ's. I run them in my bikes and my XJ (Delvac 1300) and have never had a problem. Don't see them stopping leaks tho.

Sarge

[creeperjeep]

I use Shell Rotella T 15w-40 in the warmer months and my motor has over 200,000 on it .
Wayne

X2 no problems

[dyna]

I too run shell rotella 15/40 in my XJ and have been at 180k. here recently I did a change with castrol 10/30 and it used oil like there was no tomorrow. switch back and usage is back to normal. Diesel rated oil has more additives than gasser trash. soot control, foaming,detergents,etc. even my bike reccomends an diesel rated oil if no "motorcycle specific" oil is avalible. They reccomend highly against using automotive oil due to it now being shit.Everyone reccomends a super light oil in an attempt to lessen engine drag and boost fuel economy. New ford products reccomend a 0/20 wt in their engines from what I read.

[Matthew Currie]

I usually run 15w-40 diesel oil in my XJ in summer. It leaks just the same. I suppose if the leak is very minor it might slow down a little, but any self-respecting XJ will find a way to leak that too.

[unicorn]

It used to be an old trick back in the days of single weight oils to put in a nondetergent oil to control oil usage in higher mileage vehicles. Now remember that in the days when there wasn't much in an engine compartment except the engine, most vehicles in this area were doing good to have 100,000 miles on them, and if yoou had one with 150 grand, it was pretty well shot. I was told by an experienced mechanic back in the early '70s that in order to get a few more miles out of an engine, he would put in Shell Rotella. Not "T", just Rotella. This was a non-detergent oil, and in the time of manual chokes, slow working chokes, leaded gas, and short trips to take care of your errands, It did not take long to carbon up the rings and sludge up the crankcase. $.02

[hillbilly_jeeper]

What i have heard of is running a quart of ATF through your engine around town before an oil change. supose to soften old seals. never tried it though, although, ATF will make fadded paint nice and shiney, till you wash it a few times....

[TroyAndEddie]

Many, many, many Cherokee owners use Delvac -- including my dad who is a trucker and a Cherokee owner. Stuff works like any other oil, the only difference is there are more detergents in diesel oil. Stopping leaks depends on where and how bad, but it certainly won't hurt your straight six in any way.

[casm]

What i have heard of is running a quart of ATF through your engine around town before an oil change. supose to soften old seals.

The other one that works well is diesel fuel. Let your dipstick get down to the low mark, throw enough diesel in to bring it back up to the high line, then idle (DO *NOT* DRIVE) for five or six minutes, no longer. Kill the ignition and drain and change the oil as normal (be ready for a fast deluge instead of slowish run when you remove the sump plug) and tons of buildup will be sluiced out.

[Woodstock]

Diesel oil has fitting additives for a Diesel engine. Every engine is producing a lot of chemical stuff which is bound by the additives in the oil. These additives try to help to keep the lubrication (which is more important in the higher compressing modern engines), the cooling effect, the long time lasting of the oil itself and a lot of other things too.
So I don't think that diesel oil is sealing leaks. Just take care of synthetic oil in older engines because synthetic oil is "washing out" the oil channels and also the oil sludge which is sealing the seals a liitle bit.
Here in europe we have alot of diesel engines in cars and we just use the proper oil for the engine. So use the right type of oil for your engine (diesel or gas) and then decide if you use synthetic or not (in older engines it is better not to use it - aside you want to rebuild your car and engine. Then you can "wash out" the oil sludge with synthetic). :lecture: :laugh3:

greetings from Austria
Rainer :wave:

[fire325]

Pennzoil 10w40, add a quart of Lucas oil treatment in place of a quart of oil, each oil change. Lucas products are very good to use in your Diffs, TC's, Tranny and fuel systems. My XJ has 211,000 miles on it. Uses 1 quart of oil between changes due to rear main seal leak.