Two defective AC Delcos??

[GMBoy]

Ok, I need your guys expert opinion on what the deal is here. I personally think that AC Delco is making some cheap or defective PF46 filters. Here is what happened to me TWICE.

First the basics - the truck is a 2006 GMC Sierra Denali pickup with the 6.0L (345hp) engine. Oil used is always Mobil 1 10w30 and the OCI is between 4500 and 6000 miles. (I change when the oil life monitor reaches 25%). Truck now has 33,000 miles.

I have always used AC filters, but a year ago I had a problem when I started the truck up I had NO OIL PRESSURE on the gauge and the LOW OIL PRESSURE warning message came on. This happened right around 3,000 miles on the oil change. Once it happened, everytime I started the truck warm or cold I had NO oil pressure. Once I revved the engine high - the oil pressure would then come up. So, again - start the truck-no oil pressure. Rev the engine and the pressure would come up. When this happened, I thought maybe an oil filter issue (after of calming down from the no pressure scare) and so I changed the oil filter. I went to autozone and got a Bosch and replaced the filter. Immediately the problem went away! So, than I decided that I must have gotten a bad filter and decided to not buy anymore Delcos.

NOW - flash forward to this week. I take a camping trip, Truck has around 3,000 miles on the oil change - where I had to use a Delco filter (PF46) because that's all they had. I get 2 states away, stop for gas. Restart the truck - you guessed it NO OIL PRESSURE again! I rev the engine - oil pressure is back. It does this at every stop I make. When I get the campground, I unhitch and go over the O-Rielly's and get another oil filter. I change the filter and again the problem is gone!!

So what do you guys think??? Truck does this twice and both times with a Delco PF46 and never with any other filter used. I think the filters are bad and maybe AC/Delco should be contacted. I know my oil pump is good. I have used Mobil 1, Bosch and Napa filters all without issues right thru the oil change life. Both times with the AC Delco - around 3,000 miles the NO OIL pressure issue happens.

 

[Chris142]

Were the lifters ticking? What kind of guage? A stock one?

If they were noisey then you do have a problem. I'd suspect a oil pump losing it's prime.

If they were not noisey I'd suspect a bad oil pressure sender.

 

[kd5byb]

Does the PF46 have an anti-drain back valve? (Wix shows that a 51042 is the a PF46 equivalent and that it does have an anti-drain back valve.)

Seems like the pump is losing prime and it seems like the only thing that could cause this that would be isolated to the filter would be a defective ADBV.

How does the oil pressure behave when you install the new filter? Seems like it would be WORSE with a new, empty filter with no oil in it, yet it seems like when you replace the filter, it instantly has pressure?

Any confirmation of the low oil pressure like ugly engine sounds or lifter tick? A bad sender could be a possibility, but it seems unlikely if the problem is so regular - happening, then repeating, then going away with the new filter. Is the sender near the filter? Possible that you bump it and renew the bad connection when the filter is changed until it loosens up and does it again? Still have the filter? I'd cut it open and look at the ADBV.

Just my few cents...

later,
b

 

[Chris71]

I would say there is something wrong with that design of filter. Why don't you switch over to the Mobil 1 filter since you are already using the oil? It costs a little more but it's a much better filter.

 

[Steve S]

OLM is for dino oil .

 

[GMBoy]

Originally Posted By: Chris142
Were the lifters ticking? What kind of guage? A stock one?

If they were noisey then you do have a problem. I'd suspect a oil pump losing it's prime.

If they were not noisey I'd suspect a bad oil pressure sender.




No engine noise, no ticking etc. First thing I went listening for. Oil pump prime was my thought the first time - but than the problem only happens with the AC filters. Goes away as soon as you change the filter. You can even put a new AC on and the problem will go away until that filter acts up at around 3k. I'd like to run an experiment and run another AC filter until it does it again - but am hestitant to risk my motor, and time.

 

[GMBoy]

Originally Posted By: Steve S
OLM is for dino oil .



I know that, but still have not been able to bring myself to oil changes beyond 5-6000 miles.

 

[GMBoy]

Originally Posted By: Chris71
I would say there is something wrong with that design of filter. Why don't you switch over to the Mobil 1 filter since you are already using the oil? It costs a little more but it's a much better filter.



I have used the Mobil 1 filter and with no problems. Will go back to it.

 

[JHZR2]

dont GM truck engines use an ADBV in the block rather than the filter???

If so, then who knows... if not, then it sounds like something is wrong. Ive always had good success with the PF52 filters... but perhaps it is time for you to go to a purolator or something else.

Very interesting observations...

JMH

 

[Gary Allan]

Edit: Missed JMH's post while taking a break

I too think that this is an ADBV issue. It does seem curious that it would be magically fixed with a new filter as one would reason that this should simulate the defective ADBV.

I'd save the filter and report it to AC and send it in. Assuming it has nitrile parts, that would be around the mileage that they harden. It usually results in start up rattle.

I'd say that if the ADBV hardened enough, it could do something screwy there.

You've still got an in block bypass valve. That's why there's no lifter noise or rattle. When you rev it, it must trump the in block bypass valve and force the issue, so to speak.

Your engine wasn't at peril ..at least seriously. Your pressure sender must (or so I reason) be on the filter side of your in block bypass valve.

 

[Drew99GT]

I've got a PF-46 on my mom's Impala. I'll cut it open after this next oil change and post results. It'll be interesting how the condition of the ADBV is.

The GMs have the BYPASS VALVE built into the oil filter mount.

Maybe the ADBV is somehow getting stuck/sealed onto the baseplate or stuck nest to the filter can and it's pushing the bypass wide open - but it can't fully handle the flow and the oil pump bypass is opening, hence the low/no oil pressure. But a solid stream of oil at 50 psi could surely push the ADBV open if it got a little bit stuck.

hmmmmmmmmmm.

 

[Drew99GT]

By the way, AC Delcos are made by two vendors I believe - Delphi and Champion Labs.

 

[GMBoy]

Drew99GT is correct, AC's are made by Champ labs and Delphi. When I get off my vacation and return to work (GM factory) I'm going to see if our Delphi rep has any info on what filters they make and maybe she can help me with this issue. You also make a good point (Drew and Gary) about the anti drain by pass valve being nitrile and probably sticking. In any event, I'm not using these filters anymore.

 

[GMBoy]

I checked the online GM manuals from home tonight and it states that a defective oil filter bypass valve is a possible reason. Sells me, I am insistant that the filters were both defective and probably like Gary Allan said that the nitryl rubber gets bad and misbehaves.




--------------------------------------------------------------------------------Document ID: 23360

Oil Pressure Diagnosis and Testing
With the vehicle on a level surface, allow adequate drain down time, 2-3 minutes, and measure for a low engine oil level.
Add the recommended grade engine oil, and fill the crankcase until the oil level measures FULL on the oil level indicator.

Operate the engine and verify low or no oil pressure on the vehicle oil pressure gage or the oil indicator light.
Listen for a noisy valve train or a knocking noise.

Inspect for the following:
• Engine oil diluted by moisture or unburned fuel mixtures

• Improper engine oil viscosity for the expected temperature

• Incorrect or faulty oil pressure gage sensor

• Incorrect or faulty oil pressure gage

• Plugged oil filter

• Malfunctioning oil filter bypass valve

Remove the oil pressure gage sensor or another engine block oil gallery plug.
Install an oil pressure gage.
Start the engine and then allow the engine to reach normal operation temperature.
Measure the engine oil pressure at the following RPM:
Specification

42 kPa (6 psig) minimum, at 1,000 RPM
125 kPa (18 psig) minimum, at 2,000 RPM
166 kPa (24 psig) minimum, at 4,000 RPM
If the engine oil pressure is below minimum specifications, inspect the engine