Oil Pressure

Bigvern · February 13, 2021

I have two GM's. 06 Silverado Crew 4 WD 5.3L LT model FFV 194,000 mi.

06 Suburban 4WD 5.3L FFV 217,****** mi.

Suburban runs 27.5 - 30lbs oil pressure OP. temp (in drive) Foot on brake- Not driving

Silverado runs 38-40lbs op temp (in drive.) Foot on brake- Not driving

I wanted some input if these are acceptable or the oil pump needs replaced? I don't like the Suburbans oil pressure but if its good I can live with it. I feel like I should be able to get 325,****** mi out of the Burban. The Silverado's pressure is more what I would like to see. I wanted to some input if these are OK. 27.5lbs. in gear warm seems low. I don't think these are AFM engines. I had a problem with one of those. I don't want excessive bearing wear, I am trying to get into the 300's as far as miles go on both of my vehicles, thanks in advance. I know a lot of ppl put n here their truck has many miles and runs 45psi warm in gear and off the charts on the gas, that is what is making me ask.. are both my Silverado and Suburban too low? I found a blurb from www.carautoportal.com that says a 5.3L in good working order will run 20psi to 30 psi warm in idle condition ( guessing not in gear Loaded) and 45 psi to 75 psi driving.

Edited February 13, 2021 by Bigvern

CamGTP · February 13, 2021

That's more than enough for at idle and in gear. Being in park or in gear doesn't matter, the rpms typically drop 50rpm when you go from park to drive anyway.

I don't have the sheet in front of me but I recall it being that you only need somewhere around 7-10psi per 1,000rpm. So you are well above that. But even those numbers aren't the bottom line, you can have 40-50psi at full throttle and still have plenty of oil pressure for the bearings. Not seeing 60-70psi isn't the end of the world. The later model trucks max out around 50-55psi because of the oil pressure relief valve in the oil pan.

If your oil pressure is only getting to 30psi at 2,000rpm, it's a little on the low side for typical engines. I usually see around 40-45psi. If you want to be proactive about this you could get a new OEM oil pump with new pickup tube oil ring. Often the pick up tube oring is the cause for the slightly less oil pressure.

Bigvern · February 13, 2021

Ok, my Burban will run around 30lbs to 37lbs at 3o mph. My Silverado at 30mph would be more like 35lbs 40lbs. I may redo the pump in the suburban then. I want them both to last for way longer than the mileage I have.

CamGTP · February 13, 2021

Sounds silly but sometimes even the oil filter you run and oil weight can change oil pressure.

David03gmc · February 14, 2021

The manual states the following.

My '03 6.0L gives 35-40psi at 700rpm to 50psi when cruising at about 2000 rpm.

Bigvern · February 14, 2021

ok David, this is where I am confused by the charts/ manual. On the above, it looks to me idle in my vehicle is around 750 rpm's. So it runs at lowest 27.5 lbs at idle (750) rpm at op. temp. I am not sure how to use the above scale unless I am driving? I am what I would call a little more advanced than a weekend mechanic or oil changer. I hope this post makes sense. I am not sure how those numbers work for me? Thanks in advance.

Bigvern · February 14, 2021

23 hours ago, CamGTP said:

Sounds silly but sometimes even the oil filter you run and oil weight can change oil pressure.

Ok, the truck says 5/30 I'm sure you know that. I use 5/30, I also run usually a fram or Wix. TG3506 Fram, I use Mobil 1 full syn. I have started using a 1/2 Qt. Lucas oil stabilizer ( standard white bottle). I know when I first started driving I ran 10/30 in everything I owned. As I got older I followed the cap. 5/30 seems pretty thin to me, I know govt. wants more mileage so 5/30 is supposed to pump easier like the whole 0/W20 thing. Is if ok in an 06 to try 10/30 for an oil change? I don't want to tax the system and mess anything up trying to pump thicker oil around. If 10/30 is ok, should I avoid the Lucas in that oil change too? I don't want to go experimenting and mess up something. I do use 5 oz of seafoam every oil change. Typical per directions, pour in amount based on oil (qt's) 5-6 oz, run to op. temp, (Do not drive). Shut off drain. I like seafoam. I use it to clean instead of motor medic or trans fluid. Let me know what you think. Maybe I am just worrying too much. I will here in the next month drop the diff in the suburban and redo the pump and the dip tube seal. I think it couldnt hurt with 217,****** mi. My driving pressure is good, I feel it could be higher at op. temp at idle than 27.5 lbs. thought about high vol. pump, don't want to mess up tho. read recently about difference in high pressure, high vol. High vol seemed way to go, thoughts on that? If it's trouble, I def. wont do it, I'll use standard melling replacement. Thank you again, Bigvern.

CamGTP · February 15, 2021

I ran 10W40 in my 2006 Sierra with 255,000 miles on it, never had a problem.

Going to a 10W30 isn't going to change anything, it's still a "30" at operating temp and just makes it pump harder at cold temps because it's a 10W now. If anything go to a 5W40.

I never run any of that Lucas stuff or Seafoam in the oil. If you change your oil on time and use good quality oil there is no need for any of that stuff. If I suspect I have sludge build up or carbon build up on a new to me vehicle or a customer car I will use a product to help clean things out. A good way to tell on LS engines is just pull the drivers side valve cover, if the rockers are clean as can be then there is no problems.

No high volume pumps. Either a standard replacements or a standard/high pressure pump.

Edited February 15, 2021 by CamGTP

Estm8r85 · February 15, 2021

I had the same, my diesel shop said it was OK, then when towing under heavy/hot conditions I got "Low Oil Pressure" warnings. I drop gears when I;m towint heavy/hot(100deg.+) and I upgraded my motor oil (and filtration).

Bigvern · February 17, 2021

On 2/14/2021 at 9:31 PM, CamGTP said:

I ran 10W40 in my 2006 Sierra with 255,000 miles on it, never had a problem.

Going to a 10W30 isn't going to change anything, it's still a "30" at operating temp and just makes it pump harder at cold temps because it's a 10W now. If anything go to a 5W40.

I never run any of that Lucas stuff or Seafoam in the oil. If you change your oil on time and use good quality oil there is no need for any of that stuff. If I suspect I have sludge build up or carbon build up on a new to me vehicle or a customer car I will use a product to help clean things out. A good way to tell on LS engines is just pull the drivers side valve cover, if the rockers are clean as can be then there is no problems.

No high volume pumps. Either a standard replacements or a standard/high pressure pump.

Ok, Well everyone seems to agree my pressure is good at op temp with 217,****** mi. I use seafoam as a rinse. I use mobil 1, everyone has an opinion on it, lotta ppl say its bad. What is good oil then, I aint running royal purple. I guess I am just going to leave it, change oil, clean air filter and hope for the best.

Grumpy Bear · February 17, 2021

12 minutes ago, Bigvern said:

Ok, Well everyone seems to agree my pressure is good at op temp with 217,****** mi. I use seafoam as a rinse. I use mobil 1, everyone has an opinion on it, lotta ppl say its bad. What is good oil then, I aint running royal purple. I guess I am just going to leave it, change oil, clean air filter and hope for the best.

When a fella makes a stand like this it gets simple. It's less about the oil you use and more about how often you change it. Most newer motors from GM, all perhaps, have low tension oil ring sets and as such very sensitive to gum, varnish and sludge. I'm fighting one right now that was a QSUD DEXOS2 user on 5K OCI's and frankly, I wasn't changing it often enough. Rings stuck and oil usage got as high as a quart per tank of fuel!

Anything that is DEXOS 2 approved is a 'full synthetic which also means it is at best a Group III + oil. At worst a Group II/III blend. The DEXOS license does not allow for a Group IV or V base oil. So...as all of them have to meet minimums for either chemistry or performance then it becomes a game of price and OCI. In a case such as yours where you refuse to use a boutique oil then a short OCI on a really cheap oil with a really good filter WILL give you a good bang for the buck. For me in my problem child that has meant COSTCO Kirkland at $21 to $25 for 10 quarts and 2,500-3,000 mile oil changes. Same thing will drive you broke using a oil twice as expensive...such as your beloved Mobil 1.

BTW my problem child is, after the fight back now using oil at a rate of a quart per 10,000 + miles or a few ounces between 2,500 mile oil changes. That is a rare save....

Bigvern · February 17, 2021

Im not locked in as far as oil? Suggestions, I have used all major brands and didnt think Mobil was a fufu oil. Its literally within $2 of all other major Dexos approved oils in my town. I have followed GM's BS advice after seeing what you wrote. I use the oli life monitor, they claim that is fine. I used to do every 3,****** religiously. Any input?

Grumpy Bear · February 17, 2021

12 hours ago, Bigvern said:

Im not locked in as far as oil? Suggestions, I have used all major brands and didnt think Mobil was a fufu oil. Its literally within $2 of all other major Dexos approved oils in my town. I have followed GM's BS advice after seeing what you wrote. I use the oli life monitor, they claim that is fine. I used to do every 3,****** religiously. Any input?

Mobil 1 for the most part is a very successful exercise in marketing. ALL Dexos 2 oils have to meet the exact same specifications so anytime you're paying extra...you're just paying extra.

You already have allot of miles on both these motors so it would seem your 3K program was quite successful, don't you think? At that OCI the money play would be COSTCO Kirkland, Walmart Super Tech, or Amazon Basics and a good filter changed every time. I buy Kirkland on sale cases at a time for $21 per two five quart jug cartons. $2.10 a quart. Cheaper than conventional oil.

My AFM equipped motors get AMSOIL on 5K mile OCI's as does everything I buy new.