Oil weight?

[Revconguy]

What oil weight is everyone running in the their C7? I see many/most seem to run 15/40. I wanted to use Rotella pure synthetic and had trouble finding 15/40. I ended up ordering 5/40. While I've seen different temp ranges specified, it appears 5/40 is perfectly suitable for the weather in the southeast US. However, before changing the oil I wanted to get the opinion of other CAT owners.

[Revconguy]

UPDATE: Well, further investigation indicates that you can't get Rotella full-synthetic in 15/40. Thus 5/40 is my only option if I want to stay with Rotella.


....Rev

Originally Posted by Revconguy

What oil weight is everyone running in the their C7? I see many/most seem to run 15/40. I wanted to use Rotella pure synthetic and had trouble finding 15/40. I ended up ordering 5/40. While I've seen different temp ranges specified, it appears 5/40 is perfectly suitable for the weather in the southeast US. However, before changing the oil I wanted to get the opinion of other CAT owners.

[2 Stroker]

I switched over to Amsoil 5w40 from a 15w40. You get quicker oil pressure at startup plus it can handle the high heat of the turbo if you shutdown hot. Rotella T6 5w40 is a good choice for a full Syn oil. I only run 5 to 6k because of the HEUI oil pump plus the oil gets sheared by the injectors. I have been using Amsoil 5w40 with a by-pass oil filter on my Ford 6.0 PSD for 10 years that has about the same system as my Cat, oil fired injectors.
2 stroker

[FIRE UP]

Well Sir,
I myself, have never been too worried about the use of dino or, full syn oil. I had been using Delo 15/40 for years 'cause that's what we used fleet wide in all our fire trucks for decades. But, recently turned to Rotella T-4, 15/40. It's rated for that C-7 of ours and, so far, that engine's working just great on it. NO issues at all. This is a choice thing. I'm not expert enough to say that a change from 15/40 to 5/40 is, or isn't a problem.

If it works, and no issues, well, I guess you're good to go.
Scott

[Revconguy]

Thanks FIRE UP, While I recognize that the brand name and dino/synthetic question can go into a religious fervour of discussion quickly, I just wanted to make sure I didn't miss anything about the weight of oil to use. The on-line CAT documentation seems to indicate 5/40 synthetic is a good choice, but I see that most owners appear to be going the 15/40 route. Additionally, the previous owner of a coach kept all of his maintenance receipts over the years and they show he always had the oil changed with 15/40. The commonality of the 15/40 verses 5/40 made me want to double check and make sure I wasn't missing anything. While I have extensive experience in gas engine maintenance and mechanics/repairs, I'm relatively new to the diesel side of the house and want to make sure I don't do anything stupid that could be very costly.


Further research seems to indicate that the dino oil for the CAT engine generally always comes in 15/40 weight. From my googling, it appears that synthetic diesel oil generally only comes in 5/40. Thus, those using dino oil are using 15/40 and, most likely, those using full synthetic are using 5/40.


I think I'm good. Still learning about the care and feeding of diesel engines....

(While I love the way the CAT diesel engine performs/drives, had I been aware of the significant repair costs associated with the rare diesel engine problems, I might have reconsidered a gasser....)

Originally Posted by FIRE UP

Well Sir,
I myself, have never been too worried about the use of dino or, full syn oil. I had been using Delo 15/40 for years 'cause that's what we used fleet wide in all our fire trucks for decades. But, recently turned to Rotella T-4, 15/40. It's rated for that C-7 of ours and, so far, that engine's working just great on it. NO issues at all. This is a choice thing. I'm not expert enough to say that a change from 15/40 to 5/40 is, or isn't a problem.

If it works, and no issues, well, I guess you're good to go.
Scott

[FIRE UP]

Originally Posted by Revconguy

Thanks FIRE UP, While I recognize that the brand name and dino/synthetic question can go into a religious fervour of discussion quickly, I just wanted to make sure I didn't miss anything about the weight of oil to use. The on-line CAT documentation seems to indicate 5/40 synthetic is a good choice, but I see that most owners appear to be going the 15/40 route. Additionally, the previous owner of a coach kept all of his maintenance receipts over the years and they show he always had the oil changed with 15/40. The commonality of the 15/40 verses 5/40 made me want to double check and make sure I wasn't missing anything. While I have extensive experience in gas engine maintenance and mechanics/repairs, I'm relatively new to the diesel side of the house and want to make sure I don't do anything stupid that could be very costly.


Further research seems to indicate that the dino oil for the CAT engine generally always comes in 15/40 weight. From my googling, it appears that synthetic diesel oil generally only comes in 5/40. Thus, those using dino oil are using 15/40 and, most likely, those using full synthetic are using 5/40.


I think I'm good. Still learning about the care and feeding of diesel engines....

(While I love the way the CAT diesel engine performs/drives, had I been aware of the significant repair costs associated with the rare diesel engine problems, I might have reconsidered a gasser....)

Well Sir,
I wouldn't fuss too much over the "rare diesel engine problems". Those are very, very few and far between. And, don't think for one minute, that CATs are the only "problematic" diesels. The ones on here that will admit it, will also tell you of numerous issues with various CUMMINS engines too. We ran various Detroits in my career with the SDFD. We had 6V-53s, 8V-71s, 8V-92s and the final ones that we ran for 15-20 years before I left, were the series 60 Detroits.

While the V engines were known for leaking (and they did) they were pretty reliable. The 60 series were great. Only once in a great while did we have any issues with those.

But, the point is, All diesel manufacturers have had issues. NOBODY HAS EVER MADE A PERFECT DIESEL. CAT simply bowed out of the over-the-road engine making a few years back 'cause of the issues trying to provide a cleaner engine and keeping with all the newest, latest and greatest SMOG equipment requirements. They simply threw in the towel and, kept on producing off road stuff.

The CAT, C-7 specifically, is a great engine. We've got 90K on ours right now and, that's been with regular maintenance and oil changes.
Scott

[Revconguy]

Thanks FIRE UP, The prime reason for my paranoia is the posts on this board about the costs associated with HUEI pump failures resulting in replacement of all of the injectors. I realize that the only people posting are the ones who have had problems and the ones without problems don't post. Thus, the posts give the appearance of HEUI pump failure being a common thing. I appreciate the information. I feel better about my CAT 7 now. I changed the oil last night and put in 5/40 synthetic and put on a CAT oil filter. The 5/40 is a pretty thick oil! Took me at least an hour to get nearly 5 gallons down my funnel with a extender hose (not counting the gallon that I probably spilled on my driveway). I was a little dissapointed to see that the previous owner had put on a generic obscure branded oil filter. At least I now know that I have a good quality synthetic oil and a genuine CAT filter.

Originally Posted by FIRE UP

Well Sir,
I wouldn't fuss too much over the "rare diesel engine problems". Those are very, very few and far between. And, don't think for one minute, that CATs are the only "problematic" diesels. The ones on here that will admit it, will also tell you of numerous issues with various CUMMINS engines too. We ran various Detroits in my career with the SDFD. We had 6V-53s, 8V-71s, 8V-92s and the final ones that we ran for 15-20 years before I left, were the series 60 Detroits.

While the V engines were known for leaking (and they did) they were pretty reliable. The 60 series were great. Only once in a great while did we have any issues with those.

But, the point is, All diesel manufacturers have had issues. NOBODY HAS EVER MADE A PERFECT DIESEL. CAT simply bowed out of the over-the-road engine making a few years back 'cause of the issues trying to provide a cleaner engine and keeping with all the newest, latest and greatest SMOG equipment requirements. They simply threw in the towel and, kept on producing off road stuff.

The CAT, C-7 specifically, is a great engine. We've got 90K on ours right now and, that's been with regular maintenance and oil changes.
Scott

[FIRE UP]

Originally Posted by Revconguy

Thanks FIRE UP, The prime reason for my paranoia is the posts on this board about the costs associated with HUEI pump failures resulting in replacement of all of the injectors. I realize that the only people posting are the ones who have had problems and the ones without problems don't post. Thus, the posts give the appearance of HEUI pump failure being a common thing. I appreciate the information. I feel better about my CAT 7 now. I changed the oil last night and put in 5/40 synthetic and put on a CAT oil filter. The 5/40 is a pretty thick oil! Took me at least an hour to get nearly 5 gallons down my funnel with a extender hose (not counting the gallon that I probably spilled on my driveway). I was a little dissapointed to see that the previous owner had put on a generic obscure branded oil filter. At least I now know that I have a good quality synthetic oil and a genuine CAT filter.

Wow Sir,
An "Hour" to load the 19 quarts (required) of 5/40 oil? I use a snake-like funnel to install my 15-40 and even if I lag, it might take me all of about 10 minutes to load 18 or so quarts 'cause the first quart was installed in the filter before installing the filter.
Scott

[discovery39s]

Originally Posted by Revconguy

Thanks FIRE UP, The prime reason for my paranoia is the posts on this board about the costs associated with HUEI pump failures resulting in replacement of all of the injectors. I realize that the only people posting are the ones who have had problems and the ones without problems don't post. Thus, the posts give the appearance of HEUI pump failure being a common thing. I appreciate the information. I feel better about my CAT 7 now. I changed the oil last night and put in 5/40 synthetic and put on a CAT oil filter. The 5/40 is a pretty thick oil! Took me at least an hour to get nearly 5 gallons down my funnel with a extender hose (not counting the gallon that I probably spilled on my driveway). I was a little dissapointed to see that the previous owner had put on a generic obscure branded oil filter. At least I now know that I have a good quality synthetic oil and a genuine CAT filter.

Revcon,
Not going to debate brand , type or viscosity. Only to say that it is relative to where your travels take you. The HEUI pump does NOT like "thick" oil due to being a axial piston pump. Cavitation and foaming can damage internal rotating parts of the pump. The only reason I prefer T6 pure in my coach is due to living in Ohio and sometimes the temperature dips low while we attempt to get the most out of camping for the year. Cold starts with normal Dino oil is, well, like you stated, pretty thick. If I lived in southern states with moderate climates then I would consider Dino oil due to cost savings. For me, I like a "thinner oil" in the event I need to go and the temp is low.

As far as the Cat 3126/C7 engine and the HEUI, yes the HEUI has had some long time failure rates due to various design issues. Some, as Fireup, have had no issues with a HEUI. However, he changes his oil religiously at shorter intervals and most likely has the newer generation HEUI. NOT to say that frequent oil changes will guarantee you no HEUI issues at some point.

The C7 is a fine engine. I would much rather have to spend $1,400.00 for a HUEI pump then $8,000.00 on a Cummins because it dropped a valve in #3 cylinder.

The best any of us can do is provide solid maintenance and everything else is out of our control.

Safe Travels to you.

[Airstreamer6]

I've stuck with Rotella 15/40 conventional oil all these years because 1) it works and has served engines that go 800,000 to a million miles without major overhauls in commercial equipment and 2) it's less expensive and I feel less guilty at changing it at 5000 miles or so, and sometimes a lot less if I don't go very far within the 12-month expiration period I follow.

[boyland]

discovery i am curious to know how you know if you have the newer pump.

Fireup has a c7 i have 3126e his is a 2004 mine 2002.

As far as oil I have will and probably always will use rotella based oils and fluids mostly i use t4 or t5 but would not hesitate to switch to t6.

[discovery39s]

Originally Posted by boyland

discovery i am curious to know how you know if you have the newer pump.

Fireup has a c7 i have 3126e his is a 2004 mine 2002.

As far as oil I have will and probably always will use rotella based oils and fluids mostly i use t4 or t5 but would not hesitate to switch to t6.

Now that's a loaded question. It's nearly impossible to know for the fact that I have searched high and low for a service bulletin, including starting serial numbers, to verify when the new revisions were completed. It seems to be a big secret! I'm told somewhere in and around late 3126 E prefix engines and the C7. Best information so far.....

I just pulled one yesterday to replace because it rumbled like a train. Wasn't the bearing. The front nut came loose and the gear was "wobbling" on the input shaft. Tightened the nut with red loc-tite and all is now good.

Regarding oil. Scott and I differ in opinion on type. I live in Ohio where I believe cold starts (30/40F) can been a detriment on any type of engine at initial start. I have poured both pure syn and dino at the same cold temp. BIG difference in viscosity. Difference to me is, I like oil getting to my high friction areas now when the frost in on the windshield. Some may say it's no big deal. I say Okay, whatever makes you happy. I run T6 and I have confidence in it.
George

[boyland]

Thank you for the information.

I should add more information i live in Indiana.

But generally have never started the motor home much lower the 20-30's.

I generally change the oil beginning of year usually the nicer weekend December/January then somewhere in the middle of the year miles in the 3000-5000 range just depends on my conference schedule. I run about 7000 miles a year.

I do believe the t6 is the best oil product available. But i figured i rotate so often that for my applications I would not claim the benefits in the motorhome.

Now in my everyday truck cummins i do run t6 but i also run the oil for 10k or when the dash monitor gets to around 25% oil like.

I am more of the do not wait until things break kind of owner i tend to replace things before they are done water pump, turbo, alternator etc. The Pump has been on my mind as i approach 70000 miles. I may just replace during the off season this year just to be preventive.

Water pump, alternator, and turbo i have used aftermarket products for the pump i likely would just use cat reman unless someone finds something that seems to meet the need with a lower price point.

Fireup,cat,discovery i always appreciate reading your post and i hope sometime my input provides some value.

[Mr_D]

Originally Posted by discovery39s

Revcon,
Not going to debate brand , type or viscosity. Only to say that it is relative to where your travels take you. The HEUI pump does NOT like "thick" oil due to being a axial piston pump. Cavitation and foaming can damage internal rotating parts of the pump. The only reason I prefer T6 pure in my coach is due to living in Ohio and sometimes the temperature dips low while we attempt to get the most out of camping for the year. Cold starts with normal Dino oil is, well, like you stated, pretty thick. If I lived in southern states with moderate climates then I would consider Dino oil due to cost savings. For me, I like a "thinner oil" in the event I need to go and the temp is low.

As far as the Cat 3126/C7 engine and the HEUI, yes the HEUI has had some long time failure rates due to various design issues. Some, as Fireup, have had no issues with a HEUI. However, he changes his oil religiously at shorter intervals and most likely has the newer generation HEUI. NOT to say that frequent oil changes will guarantee you no HEUI issues at some point.

The C7 is a fine engine. I would much rather have to spend $1,400.00 for a HUEI pump then $8,000.00 on a Cummins because it dropped a valve in #3 cylinder.

The best any of us can do is provide solid maintenance and everything else is out of our control.

Safe Travels to you.

Actually with an ISX 650 it's #6 and $30,000 to $40,000.