New Member With First Diesel

[Lioneyes]

I am beginning a full baselining of it, including, but not limited to all fluids, all filters, all hoses, belts, water pump, tensioners, thermostats, etc. I do maintain all of these items and others on our fleet of SUV's, trucks, ATV, etc., but I've never had any experience working on a diesel pusher, this one having the Cat 3126E engine, paired with the Allison 6 speed transmission. First project will be to remove the radiator to access most of the other above mentioned items, and to assess if the radiator itself might need to be rebuilt or replaced. If anyone has any videos or guidance in that area, I would be eternally grateful. Thanks All, and happy RVing
BTW, what the heck is a CAC??

[Lt Dan]

Welcome to iRV2!

CAC is Charge Air Cooler. It's a cooling radiator for the heated, compressed air coming from the turbo to the engine.

[FIRE UP]

Lioneyes,
Well, congrats on your purchase. May I ask, what year/make/model/chassis of coach this 3126E is in? As for the R&R of the radiator and CAC, Yep, done that three times in ours. Oh, ours is an '04 Itasca Horizon 36GD with the CAT C-7 330HP. Getting the radiator and CAC out can be a daunting task for sure. Depending on the layout of your coaches bedroom, engine compartment, chassis components and more, access to any and all of the fasteners that retain not only the radiator and CAC but also the hoses, surge tank and more can also be a serious bear to get to and actually work the wrenches and ratchets and screw drivers.

If I had to guess, I'd say about 90-95% of the rear radiator coach owners wouldn't even touch this kind of job. They don't have the place, the experience, the desire, the tools and whatever else it takes to dive into a project like this. I applaud you for your efforts here Sir!

Now, some folks say the radiator and CAT comes out as a unit. Well, they sure as heck don't on mine and many others I've helped with. Besides, the radiator on our coach is probably around oh, maybe 80 lbs or so. The CAC, around maybe 40 or so. The problem is, they are in a cumbersome position and again, depending your layout, they are either lifted out the top or , slid out through the bottom. In either case, do yourself a HUGE FAVOR and GET HELP when it comes time to remove them and install them.

Every thing else is easy. Your 3126 supports a fan bearing that is lubeable. There is a grease fitting right on top of the hub. Now, a very large percentage of RV'ers that own coaches with the 3126, and are DIY types for maintenance, overlook that fan bearing grease fitting and it goes neglected for sometimes thousands of miles. You don't say how many miles are on that 3126 so, if you get in there, remove that fan and spin that fan bearging by itself, NOT WITH THE FAN ON IT. The fan, due to its weight, can mask some wear symptoms. That's why you spin it without it.

The C-7 CAT's, were fitted with a permenetntly lubed bearing that sometimes survives for thousands and thousands of miles. And sometimes, they don't. They (CAT) went to the permenently lubed version BECAUSE the 3126 version lubeable types were being neglected due to a very poor access.

Anyway, that's just one part of what you'll find. The belt tensioners do have replaceable bearings in them but most of the DIY types that actually do this kind of work, just opt to replace the whole tensioners due to age and condition. The idler's for your belts are the same kind of scenario. You can pop out the bearings (yes, there are two bearings in some of those) in them and save a few bucks and get the job done.

As for any and all hoses, well, only you can tell what kind of condition they're in. Age and milage are the determining factors here. When it comes to Frieghtliner chassis's, one of the good parts to us owners is, you can become a member of DTNA or, Daimler Truck North America. When you do that, you now have access to all the information pertaining to YOUR CHASSIS when it was born. Every single part number for many, many parts that you may be replacing. When was ready to do what you're gonna do, I gathered all the information on all the part numbers for hoses, filters, belts, and more BEFORE I went to the Frieghtliner Parts counter. Man was that parts person SEREIOUSLY happy 'cause he didn't have to look anything up, I did all the leg work which was quite easy due to DTNA.

Anyway, surely don't hesitate to ask if you get stuck on something. As stated, there's a few of us that have done what you're about to dive into. Good luck.
Scott

[Lioneyes]

Fire UP. Thanks so much for your sharing your time and knowledge. Our coach is a 2004 Tiffin Phaeton rh35 on a Freightliner XC custom chassis, with the Cat 330, 3126E engine, and 6 speed Allison. Yeah, I'm quite nervous to tackle this job, but after 19 years, and sparse maintenance records, I need to do it before I take it far from home. It has about 56,000 miles on it, runs great, shifts well, etc. I just always do a baselining on all used vehicles. The local Cat dealer will only work on equipment in our area, so it's going to be me doing the work. If you are ever in the Grand Junction, Colorado area and need some guidance on sights to see, etc. I'd be honored to assist. Thanks again Fire Up!!!

[JaminSamin]

Since previous maintenance records are sparse I would recommend fluid analysis be part of your quest to achieve a baseline…lube oil, transmission fluid and coolant. Do the same for the generator. I use the caterpillar SOS fluid analysis program, and a lot of other people use JB lubricant services.

I find the 3126E reliable and easy to work on. Since it uses the Heui system to fire the injectors make sure you use quality oil and filter, not letting it go past 7,500 mile between changes. I use the Cat high efficiency oil filter 1R-1807 and Cat oil. Mine has the shallow sump and takes 19 quarts. Check and see if the crank case breather tube has been extended past the radiator so the oil mist won’t mix with road dirt and clog the radiator.

[Lioneyes]

Thanks much JaminSamin. I will adhere to your advice on these items. Regarding the Heui pump, two questions: 1) How many miles do you have on your 2001 3126E, and have you replaced the Heui pump? 2) I heard from a local guy that Caterpillar has offered a newer (full metal) high pressure oil line to replace the OEM rubber line. What do you know about that, and have you replaced your high pressure line? I would think with today's modern hydraulic line capabilities, that a simple line replacement would suffice, perhaps maybe even an encased (metal netting covered) line....

[JaminSamin]

My Horizons XC chassis was built in Feb. 2002 and has 80K miles. The original owner provided me with very detailed maintenance records and I see no mention of any Heui issues.

As for the high pressure oil line, I did this upgrade in 2018. The kit I used was Cat. #240-0717, it was about $130.00 out the door. It was an easy repair once I cleared all the wire harness mess out of the way.

The flexible high pressure oil line I replaced wasn’t leaking but it had many cracks.

I copied this from one of my previous posts when someone asked what the difference was between these two kits.
“240-0716 and 240-0717 are kits that are used to replace the HEUI flexible high pressure oil line with a metal tube assembly and they contain many components. The tube assembly component #241-3782 is the same in both kits. The only difference between the two kits is 240-0717 has an extra spacer to be used if you have a middle mounted fuel filter bracket, other than that they have the exact same parts.

The instruction sheet that comes with the kit says,

240-0716 is used on engine models with the following serial number prefixes (S/N: 1AJ; 6PZ; 7JZ).

240-0717 is used on engine models with the following serial number prefixes (S/N: 1AJ; 5GL; 6ZG; 7AS; 8YL; 8SZ; 9SZ; BKD; CKM; CRP; DPF)”

Here’s before and after pictures of my replacement.

[TXiceman]

The key to keeping any diesel engine operating long term is clean fuel, clean oil and clean air. Keep the filters and fluids changed on a regular basis per the manufacturer's recommendations. Also remember to check the engine coolant and replace as required by the manufacturer with the proper coolant.

Ken

[FIRE UP]

Lioneyes,
Well Sir, at present, we have 105,000 miles on our CAT 330HP C-7 and it runs like a top. I haven't done any of the "upgrades" on lines or any other item that's been discussed a time or two for the CAT engines. Probably should. I change my oil and fuel filters and oil waaaaay earlier than anyone. I do it twice a year because to me, oil and filters are SERIOUSLY cheaper than the HEUI pump and or any other oil related components. And our typical mileage for a year is around 5,000-6,000 plus or minus.
Scott

[Lioneyes]

Originally Posted by JaminSamin

My Horizons XC chassis was built in Feb. 2002 and has 80K miles. The original owner provided me with very detailed maintenance records and I see no mention of any Heui issues.

As for the high pressure oil line, I did this upgrade in 2018. The kit I used was Cat. #240-0717, it was about $130.00 out the door. It was an easy repair once I cleared all the wire harness mess out of the way.

The flexible high pressure oil line I replaced wasn’t leaking but it had many cracks.

I copied this from one of my previous posts when someone asked what the difference was between these two kits.
“240-0716 and 240-0717 are kits that are used to replace the HEUI flexible high pressure oil line with a metal tube assembly and they contain many components. The tube assembly component #241-3782 is the same in both kits. The only difference between the two kits is 240-0717 has an extra spacer to be used if you have a middle mounted fuel filter bracket, other than that they have the exact same parts.

The instruction sheet that comes with the kit says,

240-0716 is used on engine models with the following serial number prefixes (S/N: 1AJ; 6PZ; 7JZ).

240-0717 is used on engine models with the following serial number prefixes (S/N: 1AJ; 5GL; 6ZG; 7AS; 8YL; 8SZ; 9SZ; BKD; CKM; CRP; DPF)”

Here’s before and after pictures of my replacement.

Well thanks so much for the info. Now I'm really concerned for a couple of reasons: 1) my serial # doesn't incorporate any of those prefixes, as it starts with HEP, and 2) I've inspected my engine from top to bottom and cannot see anything like the old line or even the canister in your photos. I'm wondering if my engine (being a 2003 manufacture date, which is also the year that Cat replaced this engine with the C7) might have some different components / configurations such as with the C7. I know that that sounds really dumb, but my serial # doesn't match up with any of those that show for the two high pressure line upgrades, and again, from top to bottom, side to side of the engine, I don't see anything that resembles your pics....BTW, that is some clean looking engine you have there.....

[wolfe10]

Need to check the engine serial number to determine of greasable or sealed fan hub bearing:



3116 and 3126 with serial numbers up to HEP15357 (Engine build date
1/7/03) have the grease zerk fitting.


3126 with serial numbers above HEP15357 and all C7s have permanently
lubricated/ sealed bearings.


Yes, it is an important issue, as Caterpillar change from greasable to sealed because so few actually greased the original (good) design. Both greasable and sealed are available as replacements.


Greasable that is greased is best.
Sealed next.
Greasable that is not greased worst.

[JaminSamin]

Originally Posted by Lioneyes

Well thanks so much for the info. Now I'm really concerned for a couple of reasons: 1) my serial # doesn't incorporate any of those prefixes, as it starts with HEP, and 2) I've inspected my engine from top to bottom and cannot see anything like the old line or even the canister in your photos. I'm wondering if my engine (being a 2003 manufacture date, which is also the year that Cat replaced this engine with the C7) might have some different components / configurations such as with the C7. I know that that sounds really dumb, but my serial # doesn't match up with any of those that show for the two high pressure line upgrades, and again, from top to bottom, side to side of the engine, I don't see anything that resembles your pics....BTW, that is some clean looking engine you have there.....

You probably have the later Heui pump on your 3126E, the style Cat changed to for the C7. I’ve attached a picture of a C7 with this rectangular shaped pump circled. Did you see one of these? It’s on the intake side of the engine above the air compressor.

[Lioneyes]

Originally Posted by wolfe10

Need to check the engine serial number to determine of greasable or sealed fan hub bearing:



3116 and 3126 with serial numbers up to HEP15357 (Engine build date
1/7/03) have the grease zerk fitting.


3126 with serial numbers above HEP15357 and all C7s have permanently
lubricated/ sealed bearings.


Yes, it is an important issue, as Caterpillar change from greasable to sealed because so few actually greased the original (good) design. Both greasable and sealed are available as replacements.


Greasable that is greased is best.
Sealed next.
Greasable that is not greased worst.

Good info. So, from your serial #'s, mine is definitely sealed, so will probably replace that too, as I tear into all the formidable job in front of me. Thanks

[Lioneyes]

Bet you're right. When it warms up above 20 or 30 today, I'll craw under there, if I have the necessary clearance to do so, and see if this is how my late manufactured 3126E was equipped. Thanks again so much for taking your time to educate me. I probably sound like a real novice DIY'er mechanic, but I have done all my maintenance on all of our vehicles, motorcycles, ATV's riding mowers for many decades. Just don't have any experience on a diesel pusher of any brand or model, or on any Cat engine. THANKS