2007 Tahoe 5.3l AFM DOD delete thread

[Geotrash]

I did reuse the old pressure relief valve. Would this be a good place to start or change the pump first to the M10295?

If you're going to drop the pan, you might as well replace the relief valve with a new one and do the pump at the same time. If you were deleting AFM you could plug the valve orifice. That way you can be sure you've covered all of your bases.

 

[wsteele]

Yep.

 

[Taheezy_88]

If you're going to drop the pan, you might as well replace the relief valve with a new one and do the pump at the same time. If you were deleting AFM you could plug the valve orifice. That way you can be sure you've covered all of your bases.

AFM already deleted. I'll probably just plug the pressure relief valve.

On one start up today I let the low oil pressure light come on and then revd the engine up and immediately oil pressure went above 50psi and stayed. So I wonder if your pressure relief valve theory being stuck open could be the issue.

Would leaving the M355 pump be good or no?

 

[Taheezy_88]

Found someone with similar issue

"Installed on 2007 Tahoe 5.3 Flex. Had the hard o-ring issue on the oil pump pickup which caused low oil pressure for the first 10 minutes after cold start. In my slanted driveway idle pressure would drop to just above 0. Once the oil was nice and hot the o-ring swelled up enough and oil pressure returns to normal. Very weird issue. 156k miles by the way.

Since I had to drop pan anyway to replace the o-ring I did the oil pump as well. Left in the high pressure spring. Works great! Hot idle pressure with 5w-30 at about 38lbs is very reassuring all is well. I thought I had a little lifter noise at idle. If I did I don't now, very quiet. 55lbs or so on the highway."

 

[wsteele]

Found someone with similar issue

"Installed on 2007 Tahoe 5.3 Flex. Had the hard o-ring issue on the oil pump pickup which caused low oil pressure for the first 10 minutes after cold start. In my slanted driveway idle pressure would drop to just above 0. Once the oil was nice and hot the o-ring swelled up enough and oil pressure returns to normal. Very weird issue. 156k miles by the way.

Since I had to drop pan anyway to replace the o-ring I did the oil pump as well. Left in the high pressure spring. Works great! Hot idle pressure with 5w-30 at about 38lbs is very reassuring all is well. I thought I had a little lifter noise at idle. If I did I don't now, very quiet. 55lbs or so on the highway."

I think he is talking about an old O-Ring that hardened over time? The symptoms sound similar, but you have a new O-Ring.

I know you can remove and plug the AFM Pressure relief valve successfully as Chris @iamdub did that very thing on his delete.

On leaving the pump you have, honestly, I can't imagine why it shouldn't work. On the other hand, you do have some kind of issue and dropping that pan is a pain. If it were me, I would drop back to what is called out by Melling (I probably would just buy the OP and pickup tube bundle, just to be sure, all in an attempt to be done with that oil pan and gasket, once and for all).

I do think I would go with Melling's "High Performance" option though. You can always lower the pressure relief.

 

[iamdub]

I don't see why an engine that has been AFM-deleted would need any oil pump other than what was in it or it's equivalent replacement. If the factory pump in an AFM engine is a higher-volume design than what a non-AFM engine has, then it should create higher pressures once that engine is made to be like the non-AFM variant.

First off- have you verified that you actually have odd pressures or are you relying on the oil pressure sensor and factory gauge?

Beyond verifying your actual pressures, my guess is something is leaking. Maybe a seal(s) expands when heated and seals off something in the oil circuit.

Did you plug off the AFM towers or just relying on the valley cover O-rings to seal them? It's rare, but there has been reports of the O-rings leaking. It's cheap insurance to plug them.

Since you have no AFM, there's no reason to keep the relief valve in the oil pan. Plug off the port to eliminate any doubt that it may be a leak point.

 

[Taheezy_88]

I will replace the pump with OP and get a new pickup tube with oring and also block the pressure relief valve deal.

Iamdub
No pressure test and I did not plug AFM towers which I should of done and will get to after I replace pump and pick up tube.

Thanks guys will keep posted

 

[Decker73]

I have an 08 Tahoe LTZ with a 5.3L, similar issue. Cold start I have 25-30 psi, once up to temp 40-50 psi. I was thinking maybe the sensor/screen was possibly the issue. Could this be the start of the o-ring going ? It matches symptoms a little bit.

Sent from my SM-N960U using Tapatalk

 

[Taheezy_88]

What type of plug for pressure relief valve? Could I just find a bolt that matches and plug with that?

 

[Taheezy_88]

I have an 08 Tahoe LTZ with a 5.3L, similar issue. Cold start I have 25-30 psi, once up to temp 40-50 psi. I was thinking maybe the sensor/screen was possibly the issue. Could this be the start of the o-ring going ? It matches symptoms a little bit.

Sent from my SM-N960U using Tapatalk

I would say that pressure seems about right but would let a more experienced person around here confirm that. My problem could be not related to the oring I pulled pan today and tomorrow I pull the timing cover/oil pump to inspect oring and change pump

 

[iamdub]

What type of plug for pressure relief valve? Could I just find a bolt that matches and plug with that?

Growing up doesn't have to suck

I have the high lift version of that cam in my 6.0 and it sounds basically stock even with long tubes and full dual 3" exhaust. Granted it has a massive flopro mufler and "highflow" cats. A buddy has that exact cam in his 2002 5.3 with stock heads and swears hes never driven a more "peppy"...

www.tahoeyukonforum.com

 

[Taheezy_88]

 

[Taheezy_88]

Anyone have the correct torque for the oil pressure relief plug? I keep searching and getting mixed answer from 20ft lbs to 29 ft lbs.

 

[iamdub]

Anyone have the correct torque for the oil pressure relief plug? I keep searching and getting mixed answer from 20ft lbs to 29 ft lbs.

1 1/4 grunts will do. Seriously- it's not a structural item. Aim for the middle with 25 ft. lbs. or just go as tight as you can get it with your hands on that hex wrench. Use red Loctite on the threads and never give it a second thought. For reference, GM's spec for the oil drain plug is 18 ft. lbs. This is about the same but with pressure on it. 20-25 ft. lbs. with thread locker will be plenty.

 

[01FormulaTA]

Anyone have the correct torque for the oil pressure relief plug? I keep searching and getting mixed answer from 20ft lbs to 29 ft lbs.

correct torque spec from GM is 20 lb-ft

 

[Taheezy_88]

I tightened it by hand with some Blue loctite thanks guys. I'll wrap it up Sunday afternoon and give a start to see where the oil pressure it at.

I have a small oil leak shown in the picture below. I assume you pop that lid and replace?

 

[iamdub]

I tightened it by hand with some Blue loctite thanks guys. I'll wrap it up Sunday afternoon and give a start to see where the oil pressure it at.

I have a small oil leak shown in the picture below. I assume you pop that lid and replace?

That's in inspection hole cover. You pop that out to see the flex plate, torque converter and rear main seal. If engine oil is dripping out of that, then you have a rear main seal leak. Red oil would indicate leaking transmission input shaft seal.

 

[Taheezy_88]

That's in inspection hole cover. You pop that out to see the flex plate, torque converter and rear main seal. If engine oil is dripping out of that, then you have a rear main seal leak. Red oil would indicate leaking transmission input shaft seal.

I figured that be the next thing to do that I may have a shop handle. How's the difficulty of that? Would throwing a newer tyranny in be a wise choice also?

 

[Taheezy_88]

So far after replacing oil pump, and installed newer oring(green) my low oil pressure has been solved. So I can finally say this AFM delete was a success and hope this thread can help years to come with my questions and the answers given by you fine gents. Special thanks to Iamdub and Wsteele stayed the whole process with me.

 

[Taheezy_88]

Next repairs will be suspension may go with a RC lift, and rear main seal.