Community Forums

bigdog · 08-20-2013, 11:11 AM

IMHO, all of us with 3126B engines from around '98-'03 or so,should call Cat and ask what oil and how much we should be using for an average application,what brands of oil are best and what the correct Cat filter numbers are and what they cross reference to in other approved manufacturers. (somewhere on here,I think several folks have said that almost all of them are made from the same company anyway.so who knows???) Then we can come back here,compare our answers and come to a concensus.

stardalo · 08-20-2013, 07:15 PM

Are the HEUI pump problems also on the 3126 engines or is the problem primarily with the C7's? Seems almost all the HEUI pump failures I read about on here are on the C7.

Skip426 · 08-21-2013, 10:41 AM

Quote:

Originally Posted by stardalo

Are the HEUI pump problems also on the 3126 engines or is the problem primarily with the C7's? Seems almost all the HEUI pump failures I read about on here are on the C7.

I haven't kept track of any kind of; reports of failure ratio; 3126 > C-7, but I have seen posts on both.
Given my understanding of the overall similarities of the HEUI system on both engines; unless there is a fundamental internal difference , or parts supplier, involved; then the potential for failure, should be equal.

wb7auk · 08-23-2013, 04:33 PM

As a friend who has worked for Cat many many years told me. Change the oil
and fuel filters often. He strongly recommended a 5 micon oil filter and 2 micon
fuel filters and by often he stated 5k miles.
He like some others on this issue stated do not pre fill any filters the risk is to high.

captedrich · 08-24-2013, 07:45 PM

Amen on the 2 micron fuel filters. I retired a 3208 turbo cat marine engine I had in my boat after 25 years of service with 19,000 hrs on the service meter. The engine still runs good and the fuel pump is original. It was serviced and resealed twice. The fuel filter system was a Racor FG-1000 using their 2020SM 2 micron filter. I continue to use their 2 micron filter for the 3126 in the motor home, and I always carry a spare.

gatorcq · 08-25-2013, 09:58 AM

5K max on oil change, drop in a new filter only at 2500 miles (cost cheap). I also make sure not to go beyond 1000 gals of fuel burned for oil change. Very inexpensive insurance for prevented maintenance.

Cat · 08-25-2013, 04:16 PM

There is a difference between C7 and the 3126B HEUI pumps. They do the same thing but they are physically different. I have seen more of the C7 pumps fail than the 3126B pumps. I've not kept count but it seems that way.

andrei · 09-08-2013, 09:26 AM

I was reading this post since one of the rigs I am looking at has the C-7 engine 2005 model year, 33K miles. Should I be concerned about the HEUI, versus a Cummins engine in another rig I have looked at? As far as I can tell the unit has had 2 owners, don't know anything about the first owner, but last one was involved with heavy equipment and was maintenance conscious. I don't know how often he changed oil, will ask when I look at the rig next. I will ask if I can do an oil test and see what that says. I realize that there can be issues with any engine made, some more than others of course. Does anyone here have any idea in terms of the rate of failure, particularly compared to Cummins or any of the other Cat products when they still made OTR engines? Is this something that will definitely fail, or just luck of the draw, with maintenance changing the odds? Any input will be appreciated. Thanks

rbh44 · 01-14-2020, 09:31 AM

Quote:

Originally Posted by calhyatt

My advise to all of you CAT owners is to sell the damn thing before it leaves you on the side of the road. The history is terrible on these engines in motorhomes. I am stuck with one and as soon as I can get out from under it, I will. No help from Caterpillar on their obviously defective HEIU fuel injection system. They just keep selling replacement pumps and injectors. Great for them, terrible for the end user. Such a great company that sold an engine that cannot run for more than a few years, without a total leave you on the side of the road failure even when you follow their maintenance program to the letter of the law. Read some of the posts on this forum, I am not the only one stuck with these boat anchors.

First I'd like to thank you for your service to our great country.
Now- we have the exact same MH as you.Always been great but now acting up so we have appt.with CAT Garage tomorrow.Not looking forward at all.!!!

discovery39s · 01-15-2020, 11:57 AM

There is no "perfect" engine out there. Cat does have HEUI issues, Cummins has valve dropping issues. I'd much rather replace a HEUI on the side of the road then worry how I'm going to extract an intake valve sticking out of a piston!

I for one think the 3126B/E, C7's are great medium duty engines. I have an E and like it very much. Give a little love and attention and she purr's. The ownership demand isn't any different regarding the maintenance/service required on our cars, it's just more expensive.

Would you change the oil in your car at 10,000 miles? Hopefully not. I change oil every 5-6,000 miles in my Cat with Cat filters. Not because of the HEUI, because it's the right decision for a long lasting engine of any type. I shake my head when people say "that is to expensive to change that often". That said, drive less or suffer the risk factor when bad things happen.

These are expensive "Toys" in every aspect. They are homes on wheels with extremely high HP and torque engines. They demand attention if your going to enjoy them.

Maybe I should have stuck with a tent!!!

Happy trails to you

moisheh · 01-15-2020, 12:12 PM

Because that pump uses engine oil it is imprtant to change it often. Cat recommends thatyou use 10/30. It is very expensive as when the pump goes metal gets into the whole system
Not domething that can be repaired on the side of the road. Very expensive and often does not last more than 25000 miles. All engines that use the same setup have the same problems.
.

discovery39s · 01-15-2020, 05:50 PM

Quote:

Originally Posted by moisheh

Because that pump uses engine oil it is imprtant to change it often. Cat recommends thatyou use 10/30. It is very expensive as when the pump goes metal gets into the whole system
Not domething that can be repaired on the side of the road. Very expensive and often does not last more than 25000 miles. All engines that use the same setup have the same problems.
.

I agree 100% with your statements. However, filtering post HEUI can and does protect metal from getting into the system. That is a fact
So, engines can be protected from HEUI pumps that fail catastrophic.
And yes, you can then replace a HEUI "on the side of the road" and drive away.

moisheh · 01-15-2020, 06:03 PM

A simple bypass oil filter could be added
Would really help. The C7 is a good engine other than the pump. And the fan hub bearing! When we had a C7 I caried a soare bearing
Genuine Cat.

Cat · 01-15-2020, 07:49 PM

Quote:

Originally Posted by moisheh

Because that pump uses engine oil it is imprtant to change it often. Cat recommends thatyou use 10/30. It is very expensive as when the pump goes metal gets into the whole system
Not domething that can be repaired on the side of the road. Very expensive and often does not last more than 25000 miles. All engines that use the same setup have the same problems.
.

I agree with most of this, but most engines will not fail the pump. The failure rate was only 1-3%. Depending on the application the engines were installed in. Even the ones that fail- usually fail above 25,000 miles. There are exceptions but again most last more than 25000 miles. Safe Travels.