Is it ISC or ISL

[Robi.1014]

In another thread, I'm repairing my radiator. But now that I can see the "front" of my engine (where the serpentine belt is), I see the engine is marked ISL. In my Monaco user manuals, the engine is ISC. Can anyone explain? I need a good night's sleep!!!

[Our Time]

Interesting! I am not aware of a engine upgrade available in the Diplomat series. Best bet is to get the engine serial number and call Cummins.

[Mike Canter]

The ISC has a thin removable valve cover which is probably a 1/2" to 1" thick. The ISL has a thick removable valve cover that is probably 3-4" thick with a removable cap on the front top of the valve cover. The ISC does not have a removable cap on the top. Both engines should have the designator on the front cover just above the crankshaft damper in big letters.

[WindsorDave]

Quote:

Originally Posted by Robi.1014 In another thread, I'm repairing my radiator. But now that I can see the "front" of my engine (where the serpentine belt is), I see the engine is marked ISL. In my Monaco user manuals, the engine is ISC. Can anyone explain? I need a good night's sleep!!!

Robi,

The owner's manual for my 2001 Diplomat was clearly assembled from boilerplate that in some cases matched my coach and some cases did not. e.g. the lube point chart showed an RR8S chassis whereas the coach was built on an RR8R chassis.

Same with my 2003 Windsor. Several references are made to an ISC 350 engine but I know it's an ISL 370 based on the engine markings and the MSRP window sticker.

Your MSRP window sticker (available from Monaco if you don't have one) should be fairly accurate. The "build-sheet" - not so much. The build sheet is a generic form and the production guys just populate the fields with information they have at hand. If the last coach built using the form happened to have some fields populated with info unique to it but not relevant to your coach, and the workers did not clear it out, it will look as though your coach has an item that in fact it does not.

My Windsor's build sheet shows options that I don't have although the serial number fields are usually blank. There are a couple of exceptions though like the hot water heater, complete with serial number, that I don't have because the coach is equipped with an Aqua-Hot system.

Lucky you! You just got upgraded to an ISL! That is a $7,700 option on my Windsor.

FWIW

[Rex]

Does it look like this one?

[Batman_777]

The Engine Serial Number will leave no doubt.. Contact Cummins: 800-343-7357

[Mike Canter]

The designator written on the front of the motor will leave no doubt either (lol).

[Robi.1014]

Rex: It looks just like the picture you provide. But at the moment, I don't have a radiator and a fan blocking this view....hence I now see the "ISL" for the first time.

Mike: I do have (and have poured fresh oil into) the valve-cover's removable cap.

Not being an aficionado of Cummins models, what is it that I got w/o paying the $7700 that Dave is talking about?

[Mike Canter]

If you bought that MH new or used then the price was based on having the ISC motor. You have the optional more powerful ISL motor which would have raised the new or used price.

[Wannabe]

Quote:

Originally Posted by Rex Does it look like this one?

[moderator edit] Rex, whose motor would look like that? That's cleaner than a production line motor. Do you claim it or is it just a picture? I heard you were good-now I'm really impressed!

[WindsorDave]

Quote:

Originally Posted by Robi.1014 Not being an aficionado of Cummins models, what is it that I got w/o paying the $7700 that Dave is talking about?

Robi,

In broad terms the model designator denotes displacement. Going from smaller to larger; ISB, ISC, ISL, ISM, ISX, etc. Within those model designators there can be different horsepower/torque capabilities. ISC can be 330 or 350 horsepower - possibly others. ISL can be 370 or 400 horsepower - possibly others.

Similar engines can be designated differently depending on application - e.g off road, on road, power generation, marine, etc., not to mention age. Older engines used different model designations. Also the introduction of electronically controlled engine systems added another dimension to the designators.

Here's a link that offers additional information. It can make your hair hurt to try and understand all of the permutations and I make no attempt to do so.

Cummins Engine FAQ's

FWIW

[Rex]

Yes the motor in the picture is an ISL and yes it is very clean. Only wish it was mine. I have an ISC which may have been that clean at one time, but no longer.

[Wannabe]

Quote:

Originally Posted by Rex Yes the motor in the picture is an ISL and yes it is very clean. Only wish it was mine. I have an ISC which may have been that clean at one time, but no longer.

ME TOO!

[Robi.1014]

Great help....all of you. Thanks.

Now: to hi-jack my own thread:
When determining which Allison-3000 filters to purchase, I must look at the sump/pan and determine if it is 2" (in which case I order filter-pair "X") or 4" (and thus order filter-pair "Y").....right? First look tells me my Diplomat has a 2" sump. Does that track with engines and trannys that you have?

And from other threads, it's not clear how much Transynd I will lose when removing the filter covers. Because these "filter-covers" are on the bottom of the sump (right?), one would guess that I'll lose quite a bit of fluid.