Oil Pressure

[Rttoys]

Hmm. That’s odd. I only had one do something like that and it was because of the wrong o ring I used, that’s why I said to “get the right one”. Not saying you did or didn’t, just saying that’s the only problem I have had.

there’s the OPSU and the screen under it, that could be messing with the reading, as stated before, plus a “barbell” on the back of the engine that can fail, but I have never jacked with one of those before. The o ring has always been the cure for my trucks.

and F DOD

 

[Rennat_2006]

what valve body are you talking about?

 

[PAE]

Do DOD engines use the same block or just different valve train ?

F DOD

 

[FleshEater]

Hmm. That’s odd. I only had one do something like that and it was because of the wrong o ring I used, that’s why I said to “get the right one”. Not saying you did or didn’t, just saying that’s the only problem I have had.

there’s the OPSU and the screen under it, that could be messing with the reading, as stated before, plus a “barbell” on the back of the engine that can fail, but I have never jacked with one of those before. The o ring has always been the cure for my trucks.

and F DOD

I went to the dealer and used my VIN for the o ring. I’m going to do the oil sending unit tonight. I noticed when I sat and just watched the oil pressure gauge that it would fluctuate 2-3psi constantly. Hopingthis does the trick.

 

[FleshEater]

what valve body are you talking about?

This: https://m.youtube.com/watch?v=nfhmddqWROE

 

[Rttoys]

Do DOD engines use the same block or just different valve train ?

That’s how I understand it, but I’m not 100% on that, because I don’t deal with them very much. Almost everything I deal with at work is non-dod 6.0l work trucks and vans. I do know, most people will have the programming deleted, go back with a normal cam and that seems to be the trick.

 

[FleshEater]

That’s how I understand it, but I’m not 100% on that, because I don’t deal with them very much. Almost everything I deal with at work is non-dod 6.0l work trucks and vans. I do know, most people will have the programming deleted, go back with a normal cam and that seems to be the trick.

Yeah, if these bodies hold up, the next motor in them will be deleted entirely. Of course, I keep finding nice, clean GMT 800’s on Autotrader. Just need the spare cash set aside for one. I’ve given up on CL. Too many scammers.

 

[FleshEater]

I changed the OPSU tonight and the screen. No idea what the old screen looked like, because I lost it somewhere. No change in pressure. Last try is that valve body on top of the motor, whatever that part is called. After that fuck it, and I’ll run until it blows up.

 

[crispins]

I have a Nissan Pathfinder.

180k miles on it.

Motor purrs, no noises, plenty of power.

damn thing has 5 lbs of pressure when hot at idle

At first I worried about it, tried different oils and filters.

Did lots of research and it seems like it could be a blown gasket behind the timing set.

Well fuck that.

I don't let it idle unnecessarily (turn it off whenever not driving it) and just let it ride.

The fix isn't worth the effort to me and odds are it might run for years like this.

YMMV

 

[FleshEater]

I have a Nissan Pathfinder.

180k miles on it.

Motor purrs, no noises, plenty of power.

damn thing has 5 lbs of pressure when hot at idle

At first I worried about it, tried different oils and filters.

Did lots of research and it seems like it could be a blown gasket behind the timing set.

Well fuck that.

I don't let it idle unnecessarily (turn it off whenever not driving it) and just let it ride.

The fix isn't worth the effort to me and odds are it might run for years like this.

YMMV

As of right now this is our vacation vehicle. I've put 24,000 miles on it since owning it, and it has always been at 20 psi pressure. My dad said his 2011 or 2012 GMC Savanna always had 20 psi, and the motor went at 248,000 miles. This Tahoe has made three or four tows to southern WV, and the whole way out to South Dakota and back. I'm just hoping it can make it out to Utah and back next year...

An outrageous car payment doesn't sound very pleasant right now, so trying to make what we got last.

 

[Gravy]

Thought 20psi was normal for idle? fresh oil change it might shoot up 10-15psi. Probably won't help but could thicker weight oil help with towing.

 

[Rttoys]

I changed the OPSU tonight and the screen. No idea what the old screen looked like, because I lost it somewhere. No change in pressure. Last try is that valve body on top of the motor, whatever that part is called. After that fuck it, and I’ll run until it blows up.

The valve body thing must be a dod thing, I don’t remember seeing it on my trucks. Worth a shot. The intake comes off very easily.

 

[Rttoys]

Thought 20psi was normal for idle? fresh oil change it might shoot up 10-15psi. Probably won't help but could thicker weight oil help with towing.

“Normal” is just under 40. Minimum specs is something like 7psi. Usually when it gets under about 15 psi, you’ll start to hear lifter tick.

It’s one of those things that when all of them run at 40psi and yours is running 20, better start looking for a problem, before it becomes a real problem.

 

[FleshEater]

“Normal” is just under 40. Minimum specs is something like 7psi. Usually when it gets under about 15 psi, you’ll start to hear lifter tick.

It’s one of those things that when all of them run at 40psi and yours is running 20, better start looking for a problem, before it becomes a real problem.

That's my opinion; fix it NOW.

The valve body is DOD specific. Oil runs through it to shut down the cylinders.

Also, whoever put that OPSU where they did should die from slow dismemberment...piece, by piece.

 

[Rttoys]

Also, whoever put that OPSU where they did should die from slow dismemberment...piece, by piece.

that’s no shit. The 2500/3500 are not too bad because the body is a bit off the engine, but the half tons are a ginormous pain in the ass. Someone needs a donkey punch to the dick on that one, as well as the guy who put the #8 plug up against body on the 1500 too. And don’t get me started on the vans.

 

[FleshEater]

that’s no shit. The 2500/3500 are not too bad because the body is a bit off the engine, but the half tons are a ginormous pain in the ass. Someone needs a donkey punch to the dick on that one, as well as the guy who put the #8 plug up against body on the 1500 too. And don’t get me started on the vans.

When I tore the passenger side fender cover out to do the engine mount, I had full access to #8 spark plug. Definitely the way to get to it.

I'm glad I re-watched that video I posted. While the gasket was bad, they were having their oil pressure drop below 10psi. I watched the end when he was revving up the motor, and it would not go past 60psi.

Reading the comments I found someone who researched the hell out of this, replaced a ton of shit on their vehicle, only to find that GM lowered the pressure to try and eliminate the oil consumption issue. That could very well explain the difference between my truck and my Tahoe, one being an 09' and the latter being a 10'. It might have also been a way to eliminate them catching on fire. The local NAPA just had one of these trucks catch fire and burn in their parking lot. The owner pushed his detail supplies back over the counter and said, "Well, I guess I don't need these anymore."

 

[jeepkevin]

I just sold my 08' Burb with 5.3 and DOD, it had 295k miles. Idle oil pressure was around 20 or slightly below. I stepped up to 10-40, made no difference. I plugged scanner in to see what computer was seeing, same as dash gauge. I replaced pressure sensor, screen, O ring, nothing ever changed. Just a tired motor. I did run the Range Technologies DOD plug in device in OBD2 port. No more 4 cyl mode, cost about $150 on Amazon. I was outside sales and drove the crap out of Burb, only towed regular appx. 4000lbs, but never tried to tow my buggy. Rear coils not so happy with that much weight. typical oil consumption of around a qt between oil changes.

 

[Rttoys]

When I tore the passenger side fender cover out to do the engine mount, I had full access to #8 spark plug. Definitely the way to get to it.

I'm glad I re-watched that video I posted. While the gasket was bad, they were having their oil pressure drop below 10psi. I watched the end when he was revving up the motor, and it would not go past 60psi.

Reading the comments I found someone who researched the hell out of this, replaced a ton of shit on their vehicle, only to find that GM lowered the pressure to try and eliminate the oil consumption issue. That could very well explain the difference between my truck and my Tahoe, one being an 09' and the latter being a 10'. It might have also been a way to eliminate them catching on fire. The local NAPA just had one of these trucks catch fire and burn in their parking lot. The owner pushed his detail supplies back over the counter and said, "Well, I guess I don't need these anymore."

Ya. A lot of times it’s on the lift and I just do everything from the sides. Spark plug socket and wrench (not ratchet) seem to be the way to go.

I dont know when it started, but now there are now dual stage (electrically controlled) oil pumps. Nothing can go wrong here. :rolleyes:

 

[FleshEater]

I just sold my 08' Burb with 5.3 and DOD, it had 295k miles. Idle oil pressure was around 20 or slightly below. I stepped up to 10-40, made no difference. I plugged scanner in to see what computer was seeing, same as dash gauge. I replaced pressure sensor, screen, O ring, nothing ever changed. Just a tired motor. I did run the Range Technologies DOD plug in device in OBD2 port. No more 4 cyl mode, cost about $150 on Amazon. I was outside sales and drove the crap out of Burb, only towed regular appx. 4000lbs, but never tried to tow my buggy. Rear coils not so happy with that much weight. typical oil consumption of around a qt between oil changes.

Well, this is good to know. I've got quite a few miles before I get anywhere near 295,000 miles! Ha-ha! Thanks for this information.

I'm also running the Range Technologies. However, I'm going to schedule an appointment to get a custom tune before my next trip. It's the same guy who rebuilt my 4l60 on my Silverado. He said he wants to try locking up the TCC on these 6-speeds to see how they shift. He did a damn good job tuning my 09' Silverado...thing runs great now.

 

[FleshEater]

Ya. A lot of times it’s on the lift and I just do everything from the sides. Spark plug socket and wrench (not ratchet) seem to be the way to go.

I dont know when it started, but now there are now dual stage (electrically controlled) oil pumps. Nothing can go wrong here. :rolleyes:

My gosh...I need to buy 2 or 3 older vehicles NOW, before they become impossible to find.

 

[Rttoys]

My gosh...I need to buy 2 or 3 older vehicles NOW, before they become impossible to find.

Lol.

Ya. It’s a little disturbing. A coworker brought me his wife’s 2018 suburban for a CEL. It’s warranty, but he wanted to know the code before he took it in. It had a P06DD “engine oil pressure control circuit stuck off”

ya, because old mechanical isn’t good enough anymore. :rolleyes:

 

[FleshEater]

Lol.

Ya. It’s a little disturbing. A coworker brought me his wife’s 2018 suburban for a CEL. It’s warranty, but he wanted to know the code before he took it in. It had a P06DD “engine oil pressure control circuit stuck off”

ya, because old mechanical isn’t good enough anymore. :rolleyes:

Should be great when a relay or something stupid goes while the car is idling with no one in it.

 

[FleshEater]

Well guess what...now my 2009 Chevy Silverado with 107,629 miles on the clock is creeping below the 30 psi mark at hot idle and almost down to 20 psi. Just 1,000 miles ago it would hot idle at about 35-38 psi.

I’ve owned this truck since it had about 46k miles on it and changed oil and cared for it religiously. I’ll do the screen, sending unit, and drop the pan, but I have a feeling nothing will fix it.

Note: this happened after changing to Amsoil last oil change and running their engine cleaner before doing so.

I’m going to hunt down a 2500 GMT800. These GMT900’s can eat a dick.

 

[FleshEater]

This was ticking in warm weather. When I switched to Amsoil the ticking stopped. Safe to assume this is a cam issue on both Chevys?

 

[PAE]

 

[Tin Roof]

The GMT800 8.1L with 111k miles I had hot idled at 20, ran down the road at about 40. My GMT900 6.0L has 83k miles and hot idles at about 20 and is between 35-40 when driving. i want to check my 6.0 wirh a mechanical gauge and depending on what that reads might start tossing some parts at it. I’m really not overly concerned with those numbers as long as they stay consistent which they have so far.

 

[Mikel]

I've been driving a rental new Chevy Malibu. Through the screen menus I can see the oil pressure readings. Which do not follow at all what a mechanical gauge would do, temperature and rev-wise.

I know that a lot of modern oil pressure gauges have strange algorithms to show "normal", rather than the real pressure, which might confuse some people, but would the digital read out be programmed to do the same??

 

[SHARPMACHINE]

While being an old thread, this post has a lot of great information. I think I need to check pressure and possibly drop the pan on the lm7 in my jeep and do the orings. She sounds kinda pissed sometimes when cold.

 

[Tin Roof]

My GMT900 6.0L has 83k miles and hot idles at about 20 and is between 35-40 when driving. i want to check my 6.0 wirh a mechanical gauge and depending on what that reads might start tossing some parts at it. I’m really not overly concerned with those numbers as long as they stay consistent which they have so far.

The 6.0 has covered a lot of miles towing since I posted this, has 105k miles on it now, and still runs at the same oil pressures without any issues.

 

[Bebop]

The GMT800 8.1L with 111k miles I had hot idled at 20, ran down the road at about 40. My GMT900 6.0L has 83k miles and hot idles at about 20 and is between 35-40 when driving. i want to check my 6.0 wirh a mechanical gauge and depending on what that reads might start tossing some parts at it. I’m really not overly concerned with those numbers as long as they stay consistent which they have so far.

exact same with my 2002 8.1 and 2002 5.3.
The Big block has the biggest swing. When it's cold it'll show 60 driving, then around 40 when hot.