5.3 Overhaul

[PNWMuseumman]

I come to the most knowledgeable place on the interwebs (as far as I'm concerned)... I am gearing up to do some engine fixing / freshening on the 5.3 in my 02 Hoe with 275,000 miles on it. I'm wondering what else you guys think I can / should address while I have it torn apart. Here is my main goal:

Fix my extremely poor oil pressure → Barely registers on the guage when idling at operating temp. gets up to 20-30ish PSI while driving → back to not quite zero at stop lights. I am also suffering from multiple oil leaks. I suspect one of my leaks is higher up on the engine, because when the engine is hot and I'm stopped at a light, you get a faint smell of burning oil, like it is leaking out up above and burning off on the hot block. The exhaust looks alright though, don't see any blue-ish smoke to suspect engine is burning oil. Here is my plan so far.

• Change pick-up tube O-ring
• Change oil pan gasket
• New Oil pump just for good measure
• Replace valve cover gaskets (hopefully to fix upper leak)
• Spark Plugs and Wires (Just because it hasn't been done in a while) Any recommendations?
• I want to throw on an Airraid MIT while I am putting everything back together as well.

What else can you think to address / look at / change while I'm in there?
Oil sending unit maybe? My dad had to change out the knock sensors maybe 5,000 miles ago, he replaced both of them and did the upper intake gasket, so that should be ok.

MY hope is to get this baby running good (She already runs really well, it's just the oil pressure making me nervous) and then do a BB Tune. I don't see Seattle on the schedule anytime soon, so I have a feeling I'll be doing the mail order recording and tuning... Not enough patience to wait and maybe see if they come back to Portland / Seattle.

 

[iamdub]

Remove the oil pressure sensor and the screen behind it. Clean both then reinstall. Your pressure may actually not be low. You could verify with a mechanical pressure gauge if you want and even replace the sensor for good measure since you're already working in such a tight area. For plugs and wires, stock replacement is fine. There's nothing to be gained with the super-ultra-mega-unobtainium-tipped-multi-electroded gimmick plugs on a stock motor. There are two popular high-output oil pumps made by Melling that you may want to consider. One is actually a factory part on other motors (6.2, maybe?). Melling 10295 is the high-pressure pump, 10296 is the high-volume pump. On an older motor with possibly looser bearing clearances, I'd go with the high-volume pump. If your pressure is still low after all of this, then this would indicate that your motor is worn and nothing will fix it except for a rebuild.

 

[rockola1971]

275k? I vote dont even screw with that engine. Its just not economically logical at all. Throw a salvage engine in there (car-parts.com) or if you really plan on keeping the Tahoe then maybe toss a reman long block. There are still plenty of low mileage gen 3 engines in the salvage yards for well under a grand. Your 02 engine is getting very near its end of usable life at 275k. The crosshatch pattern in your cylinders is gone, rings are worn, there will be substantial compression loss when compared to new specs, valvetrain wear especially valve seats, bearings are worn and cam is worn.

All of us Gen 3 Engine owners are getting real close to not being able to get low mile salvage engines because Gen 4 is not a direct fit (electronically) so we will then be limited to rebuilding current engine or reman long block. I believe we still have atleast approximately 3 years before the pickings start to get really expensive and scarce. Whats that saying about getting off the pot? You got 3 years to get up.

 

[Tacky]

Agree with iamdub, go with the high volume pump. The engine probably is a bit worn, but pumping a higher volume of oil should bring the pressure up. I do not believe there is a screen under the sender on a non-AFM engine