Finally got my 1st diesel... where do I start?

[MolonLabe420]

Hey guys, new to the site. I just got my 1st diesel truck! Its an 03 Sierra 2500. I love it, like I knew I would. Im just not really, in love with THIS truck. I wish I could afford a low mileage LBZ with leather and a sunroof and all the good stuff.... my truck, has nothing really. Not even carpet...
It's all good tho, it's a start and it will be usable for my family, for now.
So it's got 135k on the clock and seems to run pretty good. The test drive was ok and my 1st drive home with it was fun and I made good time... had no problems.
But now, 50 miles later, it says low coolant all the time, but the ECT hasnt gone over 210.
The oil pressure seems fine while driving, but as soon as I let off the throttle, it goes down to 6-7 psi and it starts dinging.
I checked for codes before the test drive and there were none. Now there's a ton of codes..... EGR and all kinds of stuff!
It does look to have a 4" exhaust and a CAI, from what I can see..... not sure if anything else.
Has anybody else had these problems?

What kind of regular maintaince should I be doing?
What are the weaknesses and problematic areas I should I be looking for?

Current codes:
P0101
P0380
P0401
P0463
P0540
P1404
P2227


Thanks in advance!
Glad to be here!

 

[gmduramax]

Check your oil see if it has fuel in it. Your maf sensor probably just needs to be cleaned if it’s an oiled air filter, that’s the p0101

 

[MolonLabe420]

Thanks for the tip.
I'm most concerned about the low oil pressure, I don't even want to start it...

 

[Robby Avery]

To the op not sure how the previous owner took care of the truck but the usual start would be to start simple. change fuel filter a must (lb7), front and rear differential fluid if applicable, tranfer case fluid if applicable, transfer case pump rub kit, pressure test cooling system or look for leaks water pump weep hole if none present level sensor could be skewed and need replacement. Might want to flush cooling system and fill with fresh dexcool and distilled water basically bring all fluids new life, a general search of the codes on Google will give you a pretty code answer to what they could or might be or at least a start. P0101 could be air filter, skewed maf sensor, or debris on the sensor, clean it and re-evaluate it also check the driver side intercooler pipe for possible rub through holes on brake lines or power steering lines common boost leaks on older lb7's. a Lbz driver side factory ic pipe will work if on a budget from a scrap yard make sure to get the straight coupler so it'll bolt right up. There's a start let us know what you find so as to better help you diagnose the problems.

 

[ZeroGravity58]

P0380 is for the glow plugs.
P0540 is for the intake air heater

May have a bad glowplug control module as it does both. Check the 175 amp fuse to make sure it has power. A few codes are egr codes, you can delete the egr.

 

[Robby Avery]

The oil pressure issue is it knocking anormally or any unusual sounds? Check oil level as mentioned see if oil level is low or making oil which leads to leaking injectors filling crankcase with fuel hopefully not the case if the level looks good either the stepper motor in the cluster as gone array or the eop sensor is skewed 03-06 had problematic cluster stepper motors if you have access to a scan tool check oil pressure via the scan tool if not invest in a oil filter housing adapter to check pressure and 100 psi gauge and manually check the oil pressure to rule out the sensor or stepper motor. Also check the lower oil pan and make sure it is not leaking If leaking replace the lower oil pan gasket just silicone while there check pick and make sure no debris present causing oil starvation and the low oil pressure concern just thing to check. :thumb:

 

[TheBac]

Moved into the LB7 section.

Get a subscription to AlldataDIY and get to work.

 

[MolonLabe420]

I checked the EOP with an Edge CS. It goes down to 6-7 psi at idle.... thats pretty low. Scares me!
Its my 1st diesel and they are noisey engines to begin with... but I dont think I hear an abnormal knock tho. Is it safe to idle with 6 psi?

 

[duramax on fire]

Like others had said. Make sure it's not making oil. First thing I would do is change the oil. Takes 2.5 gallons. See what it does. Maybe leave it a quart low. See if your making oil. The lb7 return lines are under the valve covers. Could have diesel mixing with oil. And yes oil pressure will drop. Mine runs around 15 hot and idle.

 

[MolonLabe420]

I'm not sure what "making oil" means... The oil was just changed before I got it. It looks clean, doesnt smell like fuel, and has the proper amount in it. The tuner says oil life is at 97%.
Low oil pressure is one thing, but 6 psi with the dash dinging like crazy is a little different... to me at least. should I not be concerned with the warning sounds??

 

[CarolinaHD]

Lb7 has the injectors and return lines under the valve covers so therefore if there is a fuel leak it will go into the crankcase and increase the oil level = making oil

 

[CarolinaHD]

As for oil pressure you need to put a mechanical gauge on the engine somewhere and verify that it's matching what the dash says. Otherwise it could be a faulty stepper motor for the oil pressure gauge or bad sending unit.

 

[CarolinaHD]

The oil pressure issue is it knocking anormally or any unusual sounds? Check oil level as mentioned see if oil level is low or making oil which leads to leaking injectors filling crankcase with fuel hopefully not the case if the level looks good either the stepper motor in the cluster as gone array or the eop sensor is skewed 03-06 had problematic cluster stepper motors if you have access to a scan tool check oil pressure via the scan tool if not invest in a oil filter housing adapter to check pressure and 100 psi gauge and manually check the oil pressure to rule out the sensor or stepper motor. Also check the lower oil pan and make sure it is not leaking If leaking replace the lower oil pan gasket just silicone while there check pick and make sure no debris present causing oil starvation and the low oil pressure concern just thing to check. :thumb:

Dude, there's some good info in here but you have got to start using punctuation or nobody is going to read your posts.

 

[MolonLabe420]

What is a good oil for an LB7 with 135k on it?

 

[TheBac]

I hate to be "that guy" -- but the search function works pretty dang good here. Try to do that first, as everything you are asking has been covered a hundred times before....

Look in the Maintenance and Fluids section for your oil question. http://www.duramaxdiesels.com/forum/showthread.php?t=56857

 

[MolonLabe420]

Lb7 has the injectors and return lines under the valve covers so therefore if there is a fuel leak it will go into the crankcase and increase the oil level = making oil

Thanks for clearing that up. How long did it take GM to come up with a better design? I knew the early Dmaxs had leaking issues, I just never heard the term "Making Oil", I kept thinking everyone had a typo. (Im totally not up on my diesel lingo yet, except "rollin coal") :woott:

As for oil pressure you need to put a mechanical gauge on the engine somewhere and verify that it's matching what the dash says. Otherwise it could be a faulty stepper motor for the oil pressure gauge or bad sending unit.

I think I have an old fluid filled mechanical somewhere... where is the easiest location to get an accurate reading?
I'm going to have to Google stepper motor some time... that keeps coming up

I hate to be "that guy" -- but the search function works pretty dang good here. Try to do that first, as everything you are asking has been covered a hundred times before....

Look in the Maintenance and Fluids section for your oil question. http://www.duramaxdiesels.com/forum/showthread.php?t=56857

I know, Im the newbie asking all the dumb questions that are no-brainers lol Im usually the guy annoyed with the newbies too, but now that guy is me, because like the title says, this is my 1st diesel anything... I know enough about diesels to know they are very similar and very different from a gasoline engine, thats about it.
Most forums are the same, a bunch of great Americans (and some not) with a wealth of knowledge, if you know how to find it. However, in many circumstances the searches dont result in what I was specifically looking for, they are usually just round about answers to other people's similar problems and questions, where as my questions and issues are something slightly different, resulting in me still not knowing what I was wanting to find out.
Or maybe I just dont have a clue what Im talking about or even looking at and Im just looking for some more reassurance or in depth conversation into an unknown world for me.
But I did search some stuff, Im just looking for other people's opinions on my particular situation... I didnt see anybody else having 6psi, thats why I keep asking about it and it's making me nervous. And the oil change thread is 8 pages of personal preferance... do I read thru all that and just jump on someones bandwagon? Whichever brand scored the most mentions? I've never even heard of Delo, but then again, I dont have a $50k truck with $30k dumped into it too lol. It's more efficient to just ask direct and specific.
I still havent convinced myself that the truck doesnt have major issues and that I didnt screw my family on this purchase.

 

[MolonLabe420]

And thanks for the little check list Robby Avery :thumb:

 

[duramax on fire]

Lly 2004.5 they changed design so the injectors are outside the valve covers.

Delo oil is a very good oil. And rotella t-6 for synthetic

Change the fuel filter asap if you havnt already done. Know matter if they said it was just done. At least drain it from the bottom. There is a drain. See what comes out. Make sure there's no water or brown crap.

 

[Burn Down]

First off do not run the truck anymore until you verify the oil pressure sending unit is reading accurately, put a manual gauge on it. 6 psi is very low and I doubt your getting much oil to the top end at that psi...

 

[Robby Avery]

Dude, there's some good info in here but you have got to start using punctuation or nobody is going to read your posts.

Sorry for the lack of punctuation. This tablet isn't friendly sometimes and doesn't do what I ask it to. Gotta love technology :thumb: