2011 5.3 and the infamous P0521 code

[gealzonwheelz]

Hello folks,

 

This is my first post to the site and yes I have searched google many times for an answer to this but my problem seems to be somewhat unique also sorry for my punctuation, i tend to just type and rant sometimes

 

My truck is a 2011 Silverado Crew Cab LT with the 5.3, 4x4, locking rear and tow package, the truck was a one owner, bought new at Serpentini Chevrolet in Tallmadge, Ohio, serviced at that dealer, traded in at that dealer and then sold to me used from that dealer, all sounded pretty good, right? I brought the truck home on December 4th, 2016 with somewhere around 55,500 miles and I have put almost 10,000 miles on it in 4 months so as you read below, you can see where 4,000 mile oil change intervals will quickly become a nuisance if I do not get this issue resolved

 

somewhere around 59,000 miles, the truck threw engine code P0521, oil pressure sensor out of range, is what my scanner tells me, clear the code, it comes back on fairly quickly, I then replaced the oil pressure sensor and screen with AC delco parts, no change

 

I then took the truck to the dealer that i bought it from, was charged $98 for the "diagnostic" test at which point I was told to replace the sensor and clean the screen, after telling them that I already did, they wanted to run more tests, at my expense or recommended an oil change

 

At this point, I changed the oil myself, followed GM specs and used an AC delco filter, at this point I realized that the oil pressure before the oil change at 1500 RPM cruising down the highway was about 22 PSI, after the oil change at 1500 RPM, the pressure is now at 36-38 PSI, cleared the CEL and everything was happy

 

4,000 miles later, I start to notice the oil pressure looks a little low again, back around 22 PSI while cruising and the CEL comes back on, P0521, this time I take the truck back to the dealer to let them change the oil, CEL is still on, I tell them to make note of the PSI before and after the oil change because the truck was sold to me with a 2 year power train warranty and I'm hoping that all of this well help support my case in a warranty claim if there is problems later

 

They change the oil, did note that the pressure went up after the change but blamed it on old, hot oil versus new, cold oil, fact of the matter is, once the truck is at operating temps and i have driven the truck 20+ miles, the PSI remains at the 36-38 PSI range while cruising, I got home and cleared the CEL because I was not going to pay the dealer $98 to do it again and the light has stayed off for the last 100 miles or so

 

So basically, the dealership blew me off and said everything is normal, I would like to know why the CEL continues come on and appears to trigger around 4000 miles after each oil change, i am now plotting the oil pressure every 100 miles to see if it gradually decreases over time or if it drops fast around 4000 miles, my theory is something is clogging the oil filter, creating a loss in pressure and triggering the CEL, the oil looks good, no milkiness and no odd smells, i have not cut open any filters yet to see what they look like on the inside and I am worried that there is a bigger issue buried in the motor that is causing excessive build up in the filter

 

Also my pressure gauge has never acted funny, never dropped to 0 and I have never gotten any engine warnings like you typically would get with a bad sensor

 

So, does anyone have any thoughts or opinions on my problem? Thank you in advance

[Coby7]

My manual says to change oil and filter at 3000 miles. If you suspect the filter is going into bypass change it without changing the oil and this will eliminate one or the other. Are you using synthetic with a synthetic oil filter ?

[KARNUT]

I've always go with the manual during the warranty period and let the dealer do the service. After that I go extended with synthetic oil. I typically drove around 50K miles a year and changed oil twice. In 40 years no problems. Maybe the original owner never change the oil at all, if you have sludge, or your engine never warms up. Hard to imagine new oil of any brand going bad that soon.

 

 

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[Nanotech Environmental]

My manual says to change oil and filter at 3000 miles. If you suspect the filter is going into bypass change it without changing the oil and this will eliminate one or the other. Are you using synthetic with a synthetic oil filter ?

Can you verify this? I'm pretty sure all late model GM trucks have recommended oil change intervals of somewhere around 8-10,000 miles.

My 06 is 12,500km, or when the OLM says. I do it when the OLM says, which is sometimes as high as 14 or 15,000 km. I always use Mobil 1 synthetic.

 

To the OP. You may want to spend a few bux on a scan to see if it indicates anything.

[Coby7]

Yes if you use synthetic, but you never said you did or I missed it. I would never go over 12000 Kms but it's your truck. When my OLM reads 55% ( ≈ 6000Kms , ≈ 4000Miles )I change the filter and when it reads 10% ( ≈ 12000Kms , ≈ 7500Miles )I change oil and filter. I use Valvoline full synthetic.

Edited March 28, 2017 by Coby7

[gealzonwheelz]

I used Mobil 1 full synthetic with dexos1 specs and an AC Delco filter, the dealer said they also were changing it with synthetic

 

My original thought was to only change the filter first to see if that solved my issue but I thought if I let the dealership change the oil, and they took note of the light going out, then that would help me warranty the truck later, but they won't clear the light without the $98 diagnostic fee that I already paid 2 months ago and that told me nothing that I didn't already know

 

I guess i'm going to let it go until either a 7,000 mile oil change or the CEL comes on again at 4,000 miles, then I will change only the filter myself and cut it open to see what the inside looks like

 

Thankfully, the truck runs great, it does have the slightest miss at idle but I don't think I've ever had a vehicle that didn't, so I know I probably due to check the plugs soon too

[Coby7]

Is that ACDelco filter rated for Synthetic? The problem I encountered with regular oil filters used with synthetic is they disintegrate if you leave them in too long. I think the glue holding the paper together dissolves. When I did the first oil change on my wife's G6 ecotec after all the GM free ones, it uses a cartridge. All that was left was the plastic frame there was no paper material left. I hope most of it remained in the base. The oil came out in clumps. I have been using Synthetic filters since, a bit more money but never had a dissolved filter since, of course I change them every ≈ 6000Kms , ≈ 4000Miles . The synthetic filters use a material that looks a lot like a hepa material. When you cut yours open I hope it isn't empty.

 

[Nanotech Environmental]

Yes if you use synthetic, but you never said you did or I missed it. I would never go over 12000 Kms but it's your truck. When my OLM reads 55% ( ≈ 6000Kms , ≈ 4000Miles )I change the filter and when it reads 10% ( ≈ 12000Kms , ≈ 7500Miles )I change oil and filter. I use Valvoline full synthetic.

You're actually doing a lot of un-necessary filter changes. These LS engines run clean enough that you could probably skip a filter change every once in a while, going by the OLM rec'd oil change intervals. Changing them 2x for every oil change, is just a waste of time and $$. But hey, It's your truck and your wallet

 

Edited March 29, 2017 by 3beejay3

[Nanotech Environmental]

Is that ACDelco filter rated for Synthetic? The problem I encountered with regular oil filters used with synthetic is they disintegrate if you leave them in too long. I think the glue holding the paper together dissolves. When I did the first oil change on my wife's G6 ecotec after all the GM free ones, it uses a cartridge. All that was left was the plastic frame there was no paper material left. I hope most of it remained in the base. The oil came out in clumps. I have been using Synthetic filters since, a bit more money but never had a dissolved filter since, of course I change them every ≈ 6000Kms , ≈ 4000Miles . The synthetic filters use a material that looks a lot like a hepa material. When you cut yours open I hope it isn't empty.

 

I think you ended up with a bad filter. It's not possible for synthetic oil to disintegrate a genuine paper filter. There have been a fair bit of fake auto parts showing up out of China for quite some time now. This includes oil filters. I'd suggest the possibility that you unknowingly, accidentally installed a fake filter, which could disintegrate under normal usage.

[Coby7]

I think you ended up with a bad filter. It's not possible for synthetic oil to disintegrate a genuine paper filter. There have been a fair bit of fake auto parts showing up out of China for quite some time now. This includes oil filters. I'd suggest the possibility that you unknowingly, accidentally installed a fake filter, which could disintegrate under normal usage.

It had been installed by my local Pontiac dealership and was an ACDelco according to the invoice.

 

But then again they also did this to my 08 Cobalt, not sure that filter ever filtered anything.

 

Edited March 29, 2017 by Coby7

[Coby7]

 

You're actually doing a lot of un-necessary filter changes. These LS engines run clean enough that you could probably skip a filter change every once in a while, going by the OLM rec'd oil change intervals. Changing them 2x for every oil change, is just a waste of time and $$. But hey, It's your truck and your wallet

 

 

Actually the way my 5.3 goes through oil I would only have to add a quart every thousand miles. Changing the filter to me is an inexpensive preventative maintenance that helps keep oil pressure up an the oil clean.

[diyer2]

IMO

You mentioned this truck was serviced by the dealer where purchased. Ask for the records.

I think you may have a motor that has sludge due to oil. Either do a engine flush or do more frequent oil and filter changes. Changing the oil sooner will eventually clean it out.

[MaverickZ71]

IMO

You mentioned this truck was serviced by the dealer where purchased. Ask for the records.

I think you may have a motor that has sludge due to oil. Either do a engine flush or do more frequent oil and filter changes. Changing the oil sooner will eventually clean it out.

 

+1 Sounds like it's sludged up. Some more oil changes with Mobil1 (I prefer Pennzoil Platinum) will help clean it out, or use a flush or AutoRX to clean it faster. Edited March 29, 2017 by Maverick Z71

[gealzonwheelz]

I may consider doing some more oil changes more often and see what happens, I can ask for the records, I believe all I received before was the "carfax"

 

Its a shame that dealerships can't even be trusted these days and really, really irritates me when they talk down to you about your vehicle, like you know absolutely nothing, which I suppose is 90% of the people who go to a dealer, I'm pretty mechanically inclined, I don't know much about newer cars or much about motors but I know enough, I have a jeep that I wrench on regularly as well as weld and build my own parts, just don't know much about diagnosing problems all the time

 

how do you do an engine flush?

[diyer2]

Google it. Simple to do.