Shell Rotella T Syn 5w40, 4192 Miles, '88 Jeep Cherokee 4.0l

[MNgopher]

Vehicle: '88 Jeep Cherokee
Engine: 4.0l Inline Six
Tranny: 4 Speed Auto

Oil Filter: Wix 51626
Air Filter: Carquest Premium (Wix)
Oil Used: None
Makeup Oil: None

40%City/60%Freeway Mileage.

Period was from 6/04-9/04 in Minnesota weather.
I have not broken down temp details yet.

Rot 5w40= Shell Rotella T 5w40 Synthetic
Valv AC 10w30 = Valvoline All Climate 10w30
Valv 5w30 DB = Valavoline Durablend 5w30

code:

---

Oil Rot Rot Valv AC Valv DB Universal

5w40 5w40 10w30 5w30 Average

Mi on Oil 4192 4103 3515 3455

Mi on Unit64995 60803 52963 49448

Date 9/04 6/04 10/03 5/03

Aluminum 2 2 3 3 4

Chromium 0 1 1 1 1

Iron 15 32 17 31 29

Copper 3 3 5 3 6

Lead 8 17 6 3 5

Tin 1 3 0 3 1

Moly 4 6 4 5 33

Nickel 1 1 1 1 1

Manganese 0 1 0 1 1

Silver 0 0 0 0 0

Titanium 0 0 0 0 0

Potassium 1 2 1 3 2

Boron 0 1 1 3 42

Silicon 9 11 9 13 12

Sodium 10 13 15 26 7

Calcium 3153 2929 1939 1949 1927

Magnesium 8 10 10 24 287

Phosphorous897 818 738 766 753

Zinc 1022 984 890 900 912

Barium 2 1 0 1 0

TBN 2.9 2.3 1.9 2.5

Vis@100C 13.3 11.4 8.4 9.5

Flashpoint345 365 350 395

Fuel 2.3% 1.2% 1.3% 0

Antifreeze0 0 0 0

Water 0 0 0 0

Insolubles0.4 0.4 0.4 0.4

---

My comments:

The good: All wear is down from the previous interval. Also generally lower than observed values on shorter intervals.

The Bad: Lead wear is still higher than I'd like to see, but improving. Fuel dilution has unfortunately gotten worse, though the vicosity didn't take such a hit this time (but look at the flashpoint!). Obviously, Techron Concentrate applied several times has not improved that problem, and the Jeep was driven more on the highway and long trips than before since I fixed the cruise control a few months ago...

My conclusions: The oil is doing its job just fine, and should be AOK for using over the next interval (which is good since that's what I put in!). I have to find the source of the fuel dilution though. Thoughts?

 

[Al]

quote:

---

Originally posted by MNgopher:
Thoughts?

---

Fuel dilution..fuel dilution..fuel dilution.........

But you already know that. Interesting how much worse the wear was last time and the dilution wasn't quite as bad.

 

[friendly_jacek]

quote:

---

Originally posted by Al:

quote:

---

Originally posted by MNgopher:
Thoughts?

---

Fuel dilution..fuel dilution..fuel dilution.........

But you already know that. Interesting how much worse the wear was last time and the dilution wasn't quite as bad.

---

Simple: winter interval vs. summer interval.
Live and learn...

 

[SSDude]

The fuel dilution has affected your TBN. Otherwise you would be able to do longer OCIs.

 

[427Z06]

quote:

---

Originally posted by MNgopher:
I have to find the source of the fuel dilution though. Thoughts?

---

What condition are the spark plugs in? How about the rest of the ignition system?

Is that engine FI or carbureted? Attached pressure gauge to fuel rail and see if it leaks down if FI or check float level in carburetor if carbureted (i.e. get rebuild kit and rebuild it).

 

[MNgopher]

quote:

---

Originally posted by 427Z06:

quote:

---

Originally posted by MNgopher:
I have to find the source of the fuel dilution though. Thoughts?

---

What condition are the spark plugs in? How about the rest of the ignition system?

Is that engine FI or carbureted? Attached pressure gauge to fuel rail and see if it leaks down if FI or check float level in carburetor if carbureted (i.e. get rebuild kit and rebuild it).

---

Spark Plug check is next on the list. They are about due anyways, so no big deal to pull them.

Th 4.0 is Fuel injected, though the '87-90 Cherokee's get a Renix fuel injection system versus the Chrysler system '91 and later.

Fuel pressure checks OK, no problems there.

After I pull the plugs, I'll see if one or all of the Cylinders are running rich and deal with it from there...

 

[Jay]

So, was it the combination of winter + fuel dilution that caused the lead to spike in the last interval? I notice that lead looked OK for the Valv DB 5w-30 interval which was winter also.

Silicon seems a bit elevated for the miles. Do you drive in dusty conditions?

 

[MNgopher]

Honestly, I'm not sure what the cause of the lead spike was in the previous interval. At this point, I will wait for the next interval that will likely be changed in January to see what the lead numbers look like. If they are elevated again, more or less it could be chalked up to too thick of oil in coild weather. I'm not confident enough to say that based on one data point though. Two, and I'll believe.

As far as silicon goes, these are perfectly normal, if not lower than normal values for the the 4.0l. It ain't exactly the tightest motor ever produced

The Univeral average values from Bstone are around a 4300 mile average run, IIRC. In any event, the Jeep gets a fair amount of gravel road driving, but not so much I'd call it "a lot".

FWIW, some have theorized the Carquest Premium (Wix) air filter I am using is part of my fuel problem - ie: too restrictive. While it filters well, it may be too well!

I still haven;t had a chance to pull the plugs to see if one or two cynlinders are running rich yet...

 

[Bror Jace]

MNGopher, I'd keep using this oil.

As for the spike in wear indicators, it looks like classic cleaning of the motor by a switch to a gas/diesel oil ... followed by a drop off in wear. Surprised at how low the wear is given the fuel.

What are the cold weather numbers for this oil? Might be a good deal for modest intervals as long as the price is around $3.50 per quart and its cold weather performance is good.

--- Bror Jace

 

[MNgopher]

I pulled the plugs (well, 3's 1-5, need a swivel to get to sixv or pull the cruise control servo), and they all look perfect, with a very light grey coloration. I will look at #6 soon, but based on the other 5, it is not a cylinder specific problem and doesn't appear to be running rich overall either. If #6 comes up clean, I'm at a loss...

I ran the oil all last winter, and she starts and runs fine on it.

I too was generally pleased with the wear numbers, especially given the fuel load...