DEF hard to find?

[AH64ID]

You mean just like the Fuel Mileage Lie-O-Meter in the overhead console?

No, more fake than that. The pressure sensor (3 wire) was replaced by a pressure switch (1 wire) in early 2001 from what I recall, maybe sooner. First it was software to ignore the sensor then it was just a switch.

The reading on the dash is based on an algorithm not actual pressure, the ECM only knows if you have 6 psi or not. You could have 7 psi and it would read normal, meaning you won’t see changes on the dash from oil differences.

 

[Diesel Gunner]

No, more fake than that. The pressure sensor (3 wire) was replaced by a pressure switch (1 wire) in early 2001 from what I recall, maybe sooner. First it was software to ignore the sensor then it was just a switch.

The reading on the dash is based on an algorithm not actual pressure, the ECM only knows if you have 6 psi or not. You could have 7 psi and it would read normal, meaning you won’t see changes on the dash from oil differences.

Interesting, I have certainly noticed a difference in the gauge reading. I had read about this previously. Just at that point in life that I am not motivated to hook up any more gauges. I am one of those who starts the truck, checks for oil pressure, maybe gives it a minute or so and then I drive. Easy until it warms up, probably nothing over 17-1800rpm and light throttle. However, I have noticed that the oil Lie-O-Meter does indicate higher when towing the RV. I have no explanation for this. I kind of think that my eyeballs are calibrated better than my butt even though I am sure that the chrome exhaust tip added 100hp and 200 ft.lbs. (Got it from a friend off his Honda Civic).

All joking aside, I do not doubt what you are saying. Just don't have any other explanation for the difference in the indication. It is probably only about 5-7lbs, but it is noticeable.

 

[AH64ID]

All joking aside, I do not doubt what you are saying. Just don't have any other explanation for the difference in the indication. It is probably only about 5-7lbs, but it is noticeable.

I would guess you saw a change because you wanted to. The way the system works you could go from a 10w-30 to a 20w-50 and not see a change on the OEM gauge.

Aside from that 5-7 psi is huge. I saw a 2-3 psi change with my oil change and slightly higher 100°C viscosities.

For the change you mentioned, Delo to Guardol, I would have expected a slightly lower operating pressure as the Guardol is slightly thinner at 100°C.

 

[slowmover]

Am at a small KW dealer today. Looks like truck parts is a busy counter.

Stacks of DEF boxes to one side. Wouldn’t he the cheapest retail, but does that matter using a pickup?

Easy in & out. Far better than a Wally. Other handy chemicals & gear as well.

 

[Diesel Gunner]

I would guess you saw a change because you wanted to. The way the system works you could go from a 10w-30 to a 20w-50 and not see a change on the OEM gauge.

Aside from that 5-7 psi is huge. I saw a 2-3 psi change with my oil change and slightly higher 100°C viscosities.

For the change you mentioned, Delo to Guardol, I would have expected a slightly lower operating pressure as the Guardol is slightly thinner at 100°C.

Question then. Why is the oil pressure so much higher when the engine is first started and then goes down when the engine is warmed-up?

 

[AH64ID]

Question then. Why is the oil pressure so much higher when the engine is first started and then goes down when the engine is warmed-up?

Simple, that’s how they programmed it. They programmed it to be realistic to the average driver. (Oil temp is the same way on the DEF trucks).

The pressure on a diesel fluctuates so much from idle to 1500 rpms (15-60 psi) that they were dealing with too many warranty hours for normal operation. So they made an algorithm that people think is normal.

On my 05 the OEM oil pressure gauge was only accurate at one small rpm range on a warm engine (1200-1300), the rest of the time it wasn’t close… but looked “good”

 

[Cummins12V98]

Am at a small KW dealer today. Looks like truck parts is a busy counter.

Stacks of DEF boxes to one side. Wouldn’t he the cheapest retail, but does that matter using a pickup?

Easy in & out. Far better than a Wally. Other handy chemicals & gear as well.

"IF" I venture into the "WALL A COST" I go thru the Automotive entrance. Easy in and out!!!

 

[Diesel Gunner]

Simple, that’s how they programmed it. They programmed it to be realistic to the average driver. (Oil temp is the same way on the DEF trucks).

The pressure on a diesel fluctuates so much from idle to 1500 rpms (15-60 psi) that they were dealing with too many warranty hours for normal operation. So they made an algorithm that people think is normal.

On my 05 the OEM oil pressure gauge was only accurate at one small rpm range on a warm engine (1200-1300), the rest of the time it wasn’t close… but looked “good”

OK, Now I am thinking that I need to put another gauge in. No, not really. Twenty-one years without it and I am not going to worry. I do appreciate the explanation. I have worked this one hard and it only has 207K on it. If it did develop a big problem from lack of lubrication even at this young age I would not be disappointed. But I do expect many more miles from the engine. Wish I could feel as optimistic about the rest of the truck. It is developing the creaks and rattles that "Old" gets. We two are doing it together. Engine and drive train are doing well. Sheet metal is developing it own patina and I like it. The plastic? Let's just say that its aging faster than the rest and me.

 

[bcbender]

Twenty-one years without it and I am not going to worry. I do appreciate the explanation. I have worked this one hard and it only has 207K on it. If it did develop a big problem from lack of lubrication even at this young age I would not be disappointed. But I do expect many more miles from the engine. Wish I could feel as optimistic about the rest of the truck. It is developing the creaks and rattles that "Old" gets. We two are doing it together. Engine and drive train are doing well. Sheet metal is developing it own patina and I like it. The plastic? Let's just say that its aging faster thatn the rest and me.

I remember when many more miles were a negotiation point, Cummins not so, every engines has its way... and personality.. some get shorted, but I buy these trucks BECAUSE of the engine and nothing more... the rest of the machine I accept and deal with. I am happy with what I've been privledged to drive and hope mine pays back. Clearly those using them for $$ and not vacations are happy (for the most part), but again .... the inline 6 was why I spent the same money for the best truck....... seriously have you drove the others??? anyway... JM2C.

 

[Diesel Gunner]

I remember when many more miles were a negotiation point, Cummins not so, every engines has its way... and personality.. some get shorted, but I buy these trucks BECAUSE of the engine and nothing more... the rest of the machine I accept and deal with. I am happy with what I've been privledged to drive and hope mine pays back. Clearly those using them for $$ and not vacations are happy (for the most part), but again .... the inline 6 was why I spent the same money for the best truck....... seriously have you drove the others??? anyway... JM2C.

Yup, back in the day, when I had decided to go diesel, I sought out the advice of a friend who owns a diesel machine shop. He told me that if I wanted a "Fast Diesel" to buy a Ford (6.0 at the time). He said that he did not know about the GM since it was an imported engine that had a good reputation but no history here in the US. Then, he said, buy the dodge with the Cummins and the engine will still be running when the body and frame rot off of it. Well, I made my choice, and I am living with it. Still love my wife more, but the truck runs a fair second. Got 43 years on the wife and only 21 on the truck. I don't think that the truck will win.

 

[Cummins12V98]

"He said that he did not know about the GM since it was an imported engine that had a good reputation but no history here in the US."

Don't think that is exactly the case. As far as I know the DuraMax is and has always been US Made engine.

Someone please correct me if needed.

 

[Diesel Gunner]

"He said that he did not know about the GM since it was an imported engine that had a good reputation but no history here in the US."

Don't think that is exactly the case. As far as I know the DuraMax is and has always been US Made engine.

Someone please correct me if needed.

My understanding is that it was in collaboration with Isuzu. At the time it was fairly new.

See here for more detail.

Who Designed The Duramax Diesel Engine? - Engine (vistabbqclassic.com)

 

[brillmtb1]

I havent seen an issue getting DEF but engine oil...oh my...just got enough for my three vehicles. Parts guy said he thought the plant in TX that produces a lot of diesel oil burned down but that wouldnt explain the low auto oil stock.......I hate to get political online but I suspect this has something to do with current petroleum policy...

 

[nukegm]

still no synthetic rotella or valvoline 5w 40 near me - golden , colorado. anywhere. its been months and months. empty shelves at all auto parts stores and big box places. not to mention the grocery stores. they are a joke by me. and fuel prices are at an 8 year high. gee - who would have predicted that? YAY sarc. cheers all!

 

[brillmtb1]

So much for stocking up on toilet paper for covid, Im stocking up on oil Oh no may have just started a panic rush to the stores

 

[Larry Willard]

In December the only place I found 15W40 was freightliner dealer.

 

[Wiredawg]

Friends, kinda tagging the oil pressure gauge discussion: My 2019 International MV607 (new version Durastar) has a 2018 Cummins 6.7L and has a real oil gauge. At temp and idle, it shows ~18 PSI and at 65 MPH shows approximately 50 PSI. I noticed slight variations on my 2017 Ram 5500, but not much variance, I guess Ram wrote the algorithm to do this to look sorta real.

 

[NIsaacs]

I was in Napa yesterday and no 10w-30 or 5w-40. They did have Valvoline and Delo in 15w-40.

 

[Dasmoeturhead]

Yesterday at wallyworld I talked to the manager in the automotive section, and I asked about 5/40 syn oil , 10/30 and DEF. He told me the Truckers buy up all the oil and DEF because they can't get it cheaper anywhere else. They did have a full shelf of Blue def and wallyworld brand. He said they come in and buy what's on the shelf.

 

[bcbender]

here in NC... it hits the shelves and is gone immediately. Lots of traffic here I40/I85 so maybe part of it. I only need one more gal of 5w40 and Im good for the year but feel for those looking. I have to go get some vent line for my son's ATV today at the parts store so we'll see if they have stock and its only the low cost of Walmart or not, but I know Home Depot is also out but coincidentally they are only out of Rotella.