5.3L LS OIL PSI / TYPE

Joined
Dec 19, 2024
Messages
6
I have another 2001 2 wheel drive, and when I got it, it idled around 30 PSI cold, and 25-30 hot, and under load 39 PSI. I have been delivering for a company packages 3x a week for several weeks, the truck has been running 8-12 hour days, 80 miles a day and idling with limited start and stops. The oil, when cooled and dropped to the pan is a bit tacky, but not dirty. I maybe burned off at most half a quart since I changed the oil about 1500-1800 miles ago. Just last night my oil PSI seemed to be warm fighting 20-25 PSI sometimes not going past 20-22 PSI, and under load various pressures between 32-39 PSI approximately. Noticing a drop here.

I am getting ready to change the oil, and I did some research and shows that Royal Purple HPS has the most zinc at 1275, most oils are more more than 950. Apparently RP is not API standard, so they can add whatever they want, and their film strength is also superior, as I have seen in several test videos. Im looking for a bit more zinc and some extra film strength to keep it going longer. I was hoping to increase some pressure by having a thicker oil. I was thinking of adding some lucas to my current oil brand. But then I seen the natural lucas thickness, and I said what if I just use that and increased to 5w40 instead of 5w30? I heard a lot of people allege lucas made their bearing tolerances worse, so it improved temporarily, but just made the inevitable happen with just straight weight oil. I ahve been using Valvoline MAXlife high mileage for over a decade, but I feel in this engine maybe its not appropriate.

My plan was to use RP 5w40 and a good quality filter, possible replace the oil sending unit. And then say in 1,000 miles run some marvel mystery through it for another 500 miles, and then do a complete straight RP 5w40 swap until I have to change the pump out. Sound like a good idea?
 
Actually, no, that sounds like a whole bunch of wasted money.

Look, the “film strength” of any oil is gonna be fine in your engine. As long as the oil doesn’t allow metal to metal contact, then they have performed equally.

You’re in search of some magical “film strength “ that won’t make any difference in a daily driver. Further, if you’re gonna put Marvel mystery oil in your engine oil, you’re gonna reduce the “film strength”. You’re working at cross purposes here.

Worse, if you’re gonna put some Lucas in there, you’re adding a bunch of non-synthetic ingredients - mostly group 2 thick oil. Also, working completely at cross purposes. It’s like buying a bottle of really good small batch bourbon, then adding a little bit of Everclear. You didn’t make it better, you took something really good, and made it worse.

Also, why do you think you need more zinc than average? Your engine doesn’t need a lot of extra zinc. More specifically, the zinc exists in ZDDP, which you don’t really need in excess.

The oil you have in there, has lost some of its original viscosity. It has sheared down.

Change it.

But change it with a regular oil. You don’t need anything exotic in this truck.
 
The LS Engines have an issue with some seal on the Oil Pickup tube that goes bad, this needs to be looked at. Take care of this issue 1st and then see what your Oil Pressure is.

If you get a new O-Ring on your Oil Pickup Tube you should be ok, from my limited memory, I seem to remember there was an issue with the Oil Pickup Tube kind of coming loose for whatever reason, and the fix was a new o ring and a bracket to hold the pickup tube.
 
I remember from the old days Engines love ZINC, cats and emissions equipment do not, hence why its been toned down. I'd like to preserve at least 5 more years of use in this engine before having to swap and oil pump or engine. I figure if I change it now with something of quality, remove some deposits, increase some PSI, make it happy... and then after 1500 miles maybe add the marvel mystery to clean it up, and change oil and filter again. I know its an old 5.3L chevy engine....... but a little more help goes a long way, I dont mind spending an extra $25 on RP to save it. Will the 5w40 increase PSI?
 
No problem with RP HPS 5w-30. Their more common oils are nothing special to me so don't see the reason to spend extra on them. I've heard of their synerlec additive that's believed to be a sulfurized ester which is no longer in their regular API oils. I also wouldn't waste the money on the mystery oil.

But I've been using whatever 15w-40 in my 5.3 and 6.0 for many years one burns a lot less and the other one almost none and they're very quiet at hot idle with hot psi never going below 35 and normal driving almost never going over 45-50. You can also use whatever 0/5w-40 you want in it if it gets very cold where you're at. Many off the shelf options at walmart or online with free shipping.
 
I remember from the old days Engines love ZINC, cats and emissions equipment do not, hence why its been toned down. I'd like to preserve at least 5 more years of use in this engine before having to swap and oil pump or engine. I figure if I change it now with something of quality, remove some deposits, increase some PSI, make it happy... and then after 1500 miles maybe add the marvel mystery to clean it up, and change oil and filter again. I know its an old 5.3L chevy engine....... but a little more help goes a long way, I dont mind spending an extra $25 on RP to save it. Will the 5w40 increase PSI?
Your LS has a roller cam, it doesn’t need extra zinc. Your oil pressure doesn’t sound that bad, the 3 6.0 LS vans I drive all seem to run ~20 PSI hot idle in D (5W30 Dexos synthetic), no codes or rattling lifters yet… Got a bunch of M1 TDT 5W40 left over from my departed Cummins, might try some of that if necessary.
 
Actually, no, that sounds like a whole bunch of wasted money.

Look, the “film strength” of any oil is gonna be fine in your engine. As long as the oil doesn’t allow metal to metal contact, then they have performed equally.

You’re in search of some magical “film strength “ that won’t make any difference in a daily driver. Further, if you’re gonna put Marvel mystery oil in your engine oil, you’re gonna reduce the “film strength”. You’re working at cross purposes here.

Worse, if you’re gonna put some Lucas in there, you’re adding a bunch of non-synthetic ingredients - mostly group 2 thick oil. Also, working completely at cross purposes. It’s like buying a bottle of really good small batch bourbon, then adding a little bit of Everclear. You didn’t make it better, you took something really good, and made it worse.

Also, why do you think you need more zinc than average? Your engine doesn’t need a lot of extra zinc. More specifically, the zinc exists in ZDDP, which you don’t really need in excess.

The oil you have in there, has lost some of its original viscosity. It has sheared down.

Change it.

But change it with a regular oil. You don’t need anything exotic in this truck.
True.
 
Just get a jug of M1 0w-40 at Wally World for $28 and be done with it. It has all the vitamins and minerals that your 5.3 need and will raise oil pressure slightly to boot.

As mentioned, no need to worry about zinc levels beyond what’s already in any off the shelf oil.
 
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