CAT 330 Injectors

[hewebb]

I have about 67K miles on the CAT 3126. I have put 12K on it. I have had regular service at the CAT shop since I bought it. On occasion it uses what I think is an excessive amount of oil. On one long trip it did not use any. The service guy a the CAT dealer mentioned that CAT had some defective injectors that may leak oil and were offering a credit if getting them changed. They do an oil analysis at each oil change and all is normal.


I have been thinking if having the injectors removed and tested. Probably time for a valve adjustment as well.



Have any of you 3126 owners run across this?

[JNSNWT]

IMHO a bad injector would be an “all the time “ deal not hit and miss.

Are you adding oil in an effort to keep it on the full mark ? Mine does not like to be full. I’d add enough oil to reach the full line and it’s low again the next time I check it. But if I leave it around the ADD level it doesn’t use any more.

[wolfe10]

While something expensive COULD be an issue, but please, please, start by CALIBRATING THE ENGINE OIL DIPSTICK. It is free at the next oil change.


Call Caterpillar with your engine serial number to get the correct capacity-- many manuals overstated capacity and the engines "consumed" down to the correct level.


Caterpillar Corp 877 777-3126.

CALIBRATING THE ENGINE OIL DIP STICK

We continue to see questions about oil "consumption" and oil on radiators and toads It seems to be universal across all brands of diesel engines.THE NUMBER ONE CAUSE IS AN OVERFILLED CRANKCASE. CALIBRATING THE ENGINE OIL DIP STICK TO ENSURE THE CORRECT OIL LEVEL IN THE PAN "FIXES" OVER 90% OF THESE PROBLEMS.If you "think" your engine has an oil consumption problem, you are seeing oil mist on your toad or you just want to verify that yours is correct; you need to verify that you are using the correct amount of oil. Note: the quantities listed INCLUDE the oil filter and is the total amount of oil you put in when changing oil and filter. Now, CALIBRATE THE DIP STICK. Since the same engines/dip sticks are used in many different applications with different angles of installation, do not ASSUME that the dip stick is correctly marked. Calibration costs $0.At the next oil change, drain oil, remove old filter (as usual). Then install the drain plug and new oil filter and add the engine's correct oil capacity LESS THE NUMBER OF QUARTS you want between the "ADD" and "FULL" marks (let's say 2 quarts). So for an engine with 20 quart capacity you would add 18 quarts. Run the engine a few minutes, shut off and wait until oil has descended into the pan (at least 30 minutes and an hour is safer). Pull the dip stick and use a file or dremel tool to mark the oil level "ADD". Add the remaining two quarts, let the oil settle in the pan, pull the dipstick and mark this the "FULL" mark.In many/most cases, you will find that your engine "throws out" the access oil and then "consumption" settles down to next to nothing. Put in the correct amount and your "consumption" issues may go away.This applies to all ages (including brand new) of motorhomes and boats with every brand of engine.Also, when checking the oil level with the dipstick it is safest to do it in the morning after the oil has had all night to flow back to the pan.Do not add oil until the level reaches the ADD mark.Finally, make a sticker to affix near oil fill: OIL CAPACITY INCLUDING FILTER: xx QUARTS.

[hewebb]

Thanks for the comments.
I have never changed the oil myself and my driveway at home is slopped to the point that I cannot get the coach level. Next time at the CAT service center I will ask them to calibrate the dip stick.



I have had several diesel engines in the past and this is the first one that consumed oil. I did have an airplane that burned down to a point then quit using. I marked that dip stick.

[astrnmrtom]

If you are losing oil because it's over filled, you'll be blowing it out the slobber tube. A lot of the deep sump pans (aluminum) were listed as taking 32 quarts which was too much. Shallow pans (steel) were listed as 22 quarts which was too much. I have the deep sump and found my engine prefers 28 quarts to keep it from puking oil out the slobber tube.

You should be able to tell if your dipstick has been calibrated. Pull it out, wipe it off and look at the end. If calibrated, there'll be new add and full marks scratched on it.

[Cat]

The C7 is sensitive to oil level. I noticed when I did an oil change if I got the oil level right on the full mark it would use oil until it dropped to about 1/4-5/16" below the full mark. Then it wouldn't use anymore oil. This was using correct quantity. Noticed the same thing on my service trucks. And it wasn't being pushed out the breather. So I just made sure it was 1/2 way between the full and low mark on the dip stick/ oil gauge. Safe Travels

[ftodaro]

So i have been chasing an oil consumption issue in my 3126B, Mine was mfg in 2000 and I think the E came out in 2001 anyway. I noticed i was using a lot of oil about a qt every 400 to 500 miles. So this is what I did and what I am going to do.

As to what I have done.

First as others have discussed you have to calibrate your dip stick. Be careful on what the oil should be. I have a shallow pan which means that it takes 19Qts with a new filter. I called Cat and they told me 22Qts, but on the shallow pan you will find out that this 22Qts is on a new build, oil changes are 19Qt. on the shallow pan. So i changed the oil added 19 to confirm the full mark.

Next I inspected the turbo, The oil feed bearing can leak and be a cause. Inspected mine all was good and dry.

On my motor, i have no significant blow by, not a lot coming out of the slobber tube. I have it extended with a bottle, no accumulation there.

I do not ever see any soot or black smoke suggesting that i am burning a lot of oil.

I have good power no issues with performance.

It runs well, starts well, sounds normal at idle.

I recently took a trip towing my white Jeep, and no carbon, no oil, no evidence of a discharge at the tail pipe. You might ask whats the problem.

Well from my oil change point, i drove 850 miles and used 2 qts of oil. and it drives me nuts.



So this is what I am going to do next.

I am going to swap out the oil seals on the injectors, there are three O rings on each injector, they are 20 years old. If the oil O rings are failing i could be consuming and burning oil there. Its low hanging fruit at this point as the cost of the seals is cheap compared to the Injectors.

This is a DIY, for me.

They recommend replacing the two bolts that hold in the injector when removed. so I am thinking the cost will be about 100 to 150 for the project.

If this does not solve the problem the next step would be to swap out the injectors, 1500 to 2500 for parts alone, but I am thinking the rig would not be running as well as it is with bad injectors. So hopeful the O rings are the ticket.



I did do an oil analysis early on, I would put that early on your list.

[Cat]

Originally Posted by ftodaro

So i have been chasing an oil consumption issue in my 3126B, Mine was mfg in 2000 and I think the E came out in 2001 anyway. I noticed i was using a lot of oil about a qt every 400 to 500 miles. So this is what I did and what I am going to do.

As to what I have done.

First as others have discussed you have to calibrate your dip stick. Be careful on what the oil should be. I have a shallow pan which means that it takes 19Qts with a new filter. I called Cat and they told me 22Qts, but on the shallow pan you will find out that this 22Qts is on a new build, oil changes are 19Qt. on the shallow pan. So i changed the oil added 19 to confirm the full mark.

Next I inspected the turbo, The oil feed bearing can leak and be a cause. Inspected mine all was good and dry.

On my motor, i have no significant blow by, not a lot coming out of the slobber tube. I have it extended with a bottle, no accumulation there.

I do not ever see any soot or black smoke suggesting that i am burning a lot of oil.

I have good power no issues with performance.

It runs well, starts well, sounds normal at idle.

I recently took a trip towing my white Jeep, and no carbon, no oil, no evidence of a discharge at the tail pipe. You might ask whats the problem.

Well from my oil change point, i drove 850 miles and used 2 qts of oil. and it drives me nuts.



So this is what I am going to do next.

I am going to swap out the oil seals on the injectors, there are three O rings on each injector, they are 20 years old. If the oil O rings are failing i could be consuming and burning oil there. Its low hanging fruit at this point as the cost of the seals is cheap compared to the Injectors.

This is a DIY, for me.

They recommend replacing the two bolts that hold in the injector when removed. so I am thinking the cost will be about 100 to 150 for the project.

If this does not solve the problem the next step would be to swap out the injectors, 1500 to 2500 for parts alone, but I am thinking the rig would not be running as well as it is with bad injectors. So hopeful the O rings are the ticket.



I did do an oil analysis early on, I would put that early on your list.

If the injector orings are leaking you will start seeing your fuel turn dark. The high pressure leaks by the injector seals part of the leakage will go through the return line back to your fuel tank. If the fuel in your filters has not darkened your not leaking from the orings. Safe Travels

[ftodaro]

Originally Posted by Cat

If the injector orings are leaking you will start seeing your fuel turn dark. The high pressure leaks by the injector seals part of the leakage will go through the return line back to your fuel tank. If the fuel in your filters has not darkened your not leaking from the orings. Safe Travels

Ok 3 questions.
Do we have a return line in our set up? and If my fuel at the water separator is clear, then can the failure be internal to the injector? not showing up in the fuel tank. I read this but wonder if we have a return or it its just going into the combustion chamber at 1 qt for 500 miles?

Lastly then where is my oil coming from, would you not expect some evidence of it at the tail pipe in some form?

[Cat]

Originally Posted by ftodaro

Ok 3 questions.
Do we have a return line in our set up? and If my fuel at the water separator is clear, then can the failure be internal to the injector? not showing up in the fuel tank. I read this but wonder if we have a return or it its just going into the combustion chamber at 1 qt for 500 miles?

Lastly then where is my oil coming from, would you not expect some evidence of it at the tail pipe in some form?

Yes you have a return, on the 3126 on some models it on the front of the head on some its on the rear of the head.

No if the fuel is clear at the water bowl then no, but it does depend how long this oil disappearing has been going on. Since you most likely have 90 gallon fuel tank it would have to leak for awhile before you would see it.

Some definitely would be burned in the combustion chamber, but approx 1.5 times the fuel you burn is returning to the fuel tank. This is to cool the injectors. injectors cannot with stand dirty fuel or heat.

Yes--- maybe you will see it at the exhaust.

I haven't gone back and reread this stream, but make sure you have the correct oil level. As mentioned here Caterpillar has had problems getting the correct oil quantity recommendation.

So measure how much oil you put in on a oil change.
Do not trust the oil gauge/ dip stick untill you've made sure of the correct quantity. most of these engines have very long oil gauge/dip stick, and they are not well supported. This make the dip stick tube very easy to bend toward you or away from you this makes the dip stick inaccurate.

The most common areas of the engine that cause oil consumption are

1.leaks
2.wrong oil level
3.turbocharger seals and or if the air filter is restricted it can cause the high vacuum and pull oil past the turbocharger seals.
4.Injector seals
5.valve guides
6.engine ring
7. air compressor--- the air tank starts to get oil in it and blows it out the brake relay/quick dump valves

Again my C7 would burn oil until it reached about halfway on the dipstick. And it would do it very quickly. Once I left it in the middle of the dipstick between the add oil and the full mark it stopped using oil. And my engine had the correct amount of oil in it. I could not see any signs of the oil in the exhaust.

So really put some effort to make sure you have the correct oil level.

Safe Travels

[Skip426]

Cat; has covered the injectors leaking oil very well , I would add that the oil in the injectors is at pressures starting at 800 psi ; so any leaking from the oil section of the injectors into the fuel section , would be consistent .

A pdf on the HEUI system .

[ftodaro]

I do not want to hijack this thread but I took a small fuel sample out of my water separator, and it looks darker than when I started the season. So this sample was after 500 miles from a fuel tank and at least 1 qt of oil consumed and 850 miles from oil change and 2 qts consumed. Its hard to photograph the contrast with a smart phone that is going to try and correct the photo but it IS darker than the lime green fuel I started with.



So I am leaning towards trying the seal replacement.


I buddy of mine is politely telling me that am over thinking it, that a qt in 500 miles is not enough yet to worry about it, but its a flaw of mine what can I say.


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[ftodaro]

Just an update on my post above. I did put in new oil seals on the injectors, and sadly it did not stop the oil burn. I just did a 2000 mile trip and i am using about 1 Qt per 750 miles. So I have eliminated what i can, I am down to oil rings or valve guides and at this point I am good with it. Oil is pretty cheap. I was towing a jeep and was getting 8.5mpg doing an average of 67mph. That is as good as it gets.

[Cat]

Again try setting your oil level drop to the half way mark on the dipstick. And see if you still use oil. Don't put your oil level right at the full mark. Good Luck and Safe Travels