bigbadon

It is under normal conditions but I live in the south and Jeep stays in heated garage. Any dino oil is going to be too thick at startup to flow adequately but that is part of the norm unless you use synthetic. It is just a uncontrollable sacrifice engines have always lived with UNTIL synthetic. With engines achieving 300k miles on conventional oil I can't justify a panic to switch.

CCKen

Panic?

cruiser54

Nah. It's fine. We see single digits here with no issues.

JohnEP

I think it's an STP oil filter (blue filter, blue box). Less than $4 at autozone.

The real question I have: is high-zinc oil really needed to help "break-in" these used (junk-yard) mis-matched rockers and pivots?

cruiser54

STP filters suck. Get a Napa "Silver" at Napa since you're probably gonna change it in less than 3,500 miles. Inexpensive but good quality.

The Rotella is a heck of a lubricant and cleaner. Use it.

bigbadon

When I bought my Jeep the oil was black as tar. After about six routine oil changes (high zinc 15-40) the oil progressively got cleaner. The rockers and top of cylinder head now look brand new. A motor flush IMO is too agressive, lifters need clean oil. All it takes is a little debris to get under a lifter's check ball,or worse yet,to plug the oil inlet hole. Diesel engines get dirty fast, and because of high compression they need a oil with a higher shear point and that is what Rotella is designed for.

cruiser54

Yep. My sentiments and experience exactly.

JohnEP

I've got 200+ miles on the odometer now since my "cracked head replacement." At idle, dash gauges still read: 650 RPM; 205 deg F; 20 PSI after driving home from work (9 miles). Getting 16MPG per engine computer.

Do we all agree that my lower bearings are "fine," based on the 20 PSI dash gauge reading alone? Any OTHER 'tests' to do for the lower bearings that do not involve removing the oil pan? Rev and listen?

cruiser54

No strange noises? 20 PSI at idle hot?

Keep peeking into the oil filler hole and watch the progress. Refresh my memory. What oil combo and what oil filter?

JohnEP

Got 400+ miles on it now. Still 4 quarts 10w-40 and 2 quarts 5w-30. Still STP oil filter. After my 50 mile drive today, idle settles at 700 RMP, 205 deg F, 18 PSI. Got about 21 mpg highway at about 70 mph, windy conditions.

What I started it this morning, I heard a bit of ticking (like usual) at cold idle. After the 50 mile drive, I hear none at all at hot idle.

I normally see 20 PSI at "hot idle", but my usual commute is only 10 miles, so maybe that's not enough to be "fully hot" in winter. Or maybe my pressure is lower today b/c my torn-up lower bearings are getting "work polished" into their new positions... heh heh.

I've been monitoring oil via dipstick and white paper. Looks good to me. What should I be looking for in the filler hole?

cruiser54

Wasn't it rather sludgy in there? Just to see the progress of the oil dissolving the sludge.

Why not replace the filter with a good one and see what happens to the oil pressure? STP is pure junk.

JohnEP

Nahhh. I ran 2-quarts kerosene to 4-quarts oil "flush" through it before I even tested the PSI with normal oil before deciding to replace the "head only". There was very little sludge on disassembly, and the "new" junk-yard pivots and rockers came with ZERO sludge, and a nice petina instead.

Point taken. The relative oil pressure drop across any 2 points in the system depends ONLY on the resistance to flow across those 2 points. So, let me ask: does my dash gauge read pressure BEFORE, or AFTER the oil filter?

cruiser54

I THINK it's after. The FSM isn't clear.

bigbadon

After. A dirty filter can cause lower pressure. Your filter has a spring-loaded bypass to allow SOME flow in case it was to get severely clogged.

cruiser54

Change the filter for giggles. You can get the cheaper Wix at Napa. Ask for the Silver line of Napa filters if you wanna save a coupla bucks. Good quality but not for extended intervals.