Oil questions

Hey all,
I have a 94 4.0 with 258k on it. I recently purchased the Jeep thinking it would soon need an engine and it was priced accordingly.

After driving it and noticing how good it ran, I decided to see how much more use I can get out of it before dropping coin for a replacement. When I first got it home, the exhaust stunk something fierce and when I changed the oil it appeared that the PO didn't maintain it very well. The oil itself smelled horrible. Also it would smoke if left at idle for any amount of time like in a drive through or similar situation.
I know that to mean that it needs valve seals and will address that when I replace or rebuild the engine obviously.
Anyway, I have driven it about 7k miles since I got it and it seems to get better the more I use it.

It passed the Colorado emissions test.
It doesn't stink anywhere near as bad unless maybe I am getting used to it.
It doesn't smoke as quickly or as bad.
I have changed the oil 3 times in 3 months.
It does burn some oil. I haven't tracked it but it seems to be a quart or so for 3 fill ups. Using Valvoline 10-30.

Now for the questions finally.:sad1:

The oil still stinks (not as bad as before) everytime I change it. Is this due to all the gunk in the motor from the previously poor maintainence? Or could it be due to the age and mileage or the way it is tuned, ie running rich? Would it be worthwile to try an additive to clean it out?

Also the oil seems to break down quickly. It seems very thin right now after only about 1000 miles.

Would there be any benefit to switching to a synthetic or a blend? I have heard that the synthetics don't burn the same therefore they don't smoke as much. (I need to learn more about oil)

Sorry for the long, drawn out post but I wanted to give you all the info to help me with these questions.

Cheers and Thanks in advance,

Scott

Consider changing to a diesel motor oil, I like the Dino Rotella 10w30. All diesel motor oils are highly detergent and will really clean the guts of your engine.

Check your CCV system. They are famous for plugging up, then the engine becomes pressurized and oil is forced past seals and puked up into the air filter.

2x checking vent system as Joe suggests.

Just a thought, theory--

weather permitting-- I would get two loads of Wally's house brand oil (tech?) and a couple of good oil filters (NOT Fram.) get Jeep warmed up at Least 20 minutes and change immediately while HOT. Then have set up for 2nd change ready and go on highway drive say 2 or 300 miles , NO stops (or less than 5 minutes), returning to 2nd change immediately while HOT. Then run no more than 1000 miles and change to that oil Joe suggests. Run that only 1000-1500 first couple of changes, Watching the color as you check oil regularly. Oil usually cleans best first 1000 then gets weaker till it really stops cleaning. (Gets 'Black" change it) As it gets caught up on engine cleaning there will be less gunk so it will run longer till it gets dark.

Avoid "Flushes", Kerosene, ATF, etc.

Good Luck,
Orange

P.S. Eyeball in the oil fill hole to see how much gunk is changing as it goes.

If the engine was not maintained (ie: oil changes), then it may take quite a few changes to clean the engine. Would be interesting to pull the valve cover and see how much "sludge" you see on the top end; always a good indicator of abuse.

I'd just keep changing the oil frequently but start to extend the mileage interval between changes. Don't be too concerned with the smell of the oil and also with burning a bit....hey, it's got 258k on it.

I'd use oil that was a little heavier, say 15-40. I'd also run a quart of ATF if doing frequent changes to clean it out. ATF isn't a solvent like "motor flush" (kerosene), it's a lubricating oil with a high detergent content. It's just a little too light weight for engines, so use heavier dino oil to make up for it when running the ATF.

This would clean it out quicker, but what you're doing now should work fine eventually. I wouldn't run synthetic at this point. I think cheap oil changed frequently will clean it out better than expensive oil changed less frequently.

x2 on thwe 15-40 Rotella, it's cheap too, a gallon is usually 9.99 on sale. Ive been running it in my jeep for the last couple months. I grabbed Bosh filters and my engine is loving the combination, it runs a lot smoother in high load situations (like going up step hills).

What is the fuel MPG running ?


If the oil is thinning in a 1000 mi. something is not right.

Might run a compression test, too.

you may want to run the over size oil filter also.

like the Mobil 1 - M1-301

Thanks everyone. I am running FRAM filters. Unfortunately I purchased two of them before I heard to stay away from them.

I am getting oil up in the tube going to the air filter box so I'll check into the CCV system. I will have to do a search as I don't know what all the components are.

My gas mileage is about 17 mpg on 32s.

I like the idea of the Diesel oil, I will have to put some thought into that but it sounds like it would work.

flingshot said:

Thanks everyone. I am running FRAM filters. Unfortunately I purchased two of them before I heard to stay away from them.

I am getting oil up in the tube going to the air filter box so I'll check into the CCV system. I will have to do a search as I don't know what all the components are.

My gas mileage is about 17 mpg on 32s.

I like the idea of the Diesel oil, I will have to put some thought into that but it sounds like it would work.

Click to expand...

http://www.teamgrandwagoneer.com/parts/Detailed/1273.html

you won't find the parts at the parts store

http://www.teamcherokee.com/Emissions/index.html

I bought my jeep with 197xxx miles. it's a 98. I put 1000 miles on it and did an oil change. Then at 200xxx i switched to full synthetic. After 1000 miles with full synthetic it is black from cleaning out the engine. X2 on ATF and also look into seafoam. I've used it in all my jeeps. Noticed improvement.

NAPA emissions hoses:

http://www.napaonline.com/NOLPPSE/(...sions&Nty=1&N=599001+101994+50038&Ntk=Keyword

i didn't know that the CCV hoses were so notorious for gumming up. i noticed a bit of oil in my air filter recently, i will have to check that real quick.

by the way Joe, your link died out.

I hate when that happens!

Napa part numbers:

BK 7151364

BK 7151362

$6.49 each.

And if you have an O'reilly's near you 5.29. http://www.oreillyauto.com/site/c/detail/WIX0/51515.oap?keyword=51515

better price than i paid for the purolator pureone. (7$ after tax).