Leon441

My truck had a new engine installed at 35,000 due to a bad injector causing a piston to burn. After getting the truck back I noticed a very small crack in the turbo housing just below the exhaust manifold. Didn't seem to cause a problem. I also had the rear freeze plug fall out twice dumping all the antifreeze on the ground. It was fixed with a plate, from cummins, to keep the plug in. I noticed the truck burning oil and the original engine never burned a drop. I pulled the intake apart to check for oil in the intake and couldn't find any residue. I thought maybe the rings or pistons were hurt but the engine runs really well much better than the original engine.

The other night I had the engine idleing for several hours. When I started the truck later and headed home the truck smoked like crazy. White/blue smoke nothing like the black I'm used to seeing when I am towing hard. So I figured it may be oil. I ran the truck kinda hard and it cleared up in a couple miles. After letting the truck set I noticed the oil was at the bottom of the safe mode on the stick. I just changed the oil about a 1,000 miles ago.

Could the seal in the turbo be bad? The reason I ask is when you idle you are not making boost. Oil may have a much easier time leaking by the seal under a low boost conditions.

I think I am going to idle the truck for a few hours then pull the intake elbo to see if there is oil present.

What do you guys think about this?

Leon

bradler

not sure about the turbo seals but i would never idle my truck for hours. seems that over-idling can wash down cylinder walls and score them damaging rings...

Leon441

I don't know about over idling washing down cylinder walls. Electronic fuel injection should be better than mechanical. Besides ever stop in a truck stop? Big trucks parked everywhere idling 8-10 hours at a time. What is different about their engines that lets them get away with this and go 500K miles minimum before rebuilds?

Back to topic.

djbikeman

Jake Brakes

Cylinder temps get low enough in a CR that the fuel will not burn completely, causing diesel fuel to wash down the cylinder walls reducing the effective lubrication and causing problems with rings and pistons.

It is not a good idea to let the Common Rail trucks idle normally for extended periods. If you are going to do it, you probably should have an exhaust brake.

AH64ID

Sorry.. but idling is bad.. even on semi's... They are lucky enough to run hard every day and some of the downsides to idling are cured from the running hard...

But like it was said idling for hours, especially on a common rail, produces very low combustion temperatures, and you get cylinder washing.. You can also get varnishing of the injectors (if the cylinder temps are low enough)... This is most likely where your smoke came from.

Also, how many miles on the rebuild? It could be that its not broken in yet... Cummins remans are supposed to be great engines, sometimes better than new because they are hand built and inspected one at a time, not on an assembly line.

If you do plan to idle for extended periods there are a couple things you can do.

Enable the fast-idle and idle at 1100 with either the A/C or Defrost on to increase engine load

Add an exhaust brake, it will keep the engine temp to 180*

Use a Mopar winter front with all 4 flaps closed when idling (cold-cool temps)

Peterbilt

The big trucks idle up when parked and have a different system.
If you go to high idle you will be better off.
Pete

DBLR

Idling also is hard on Turbos even on semis. I know first hand as when I first started to drive OTR I let one idle for about 3-4 hours and it took out the turbo and boy was the boss mad. After that I was informed to be sure the engine ran between 1100-1500 RPM's if I had to have it running while parked.

AH64ID

I can't find it but there is a big presentation from Cummins on why its a myth that diesels can idle indefinitely.

Leon441

Just so happens defrost was on the hole time the truck was idling. The windows where fogging due to rainy weather nothing fun going on in the truck. LOL

This truck has a new engine not a rebuild. It has about 13,000 on new engine with lots of hard towing. The engine that came in the truck never burned oil. This new engine burns oil. That's why I asked the question. Trying to determine why it burns oil. That's all.

AH64ID

Well if its a new engine and its burning oil I would take it to the dealer.. At least have it documented... While your there have them enable your fast-idle.

I still would not idle it unless you have to, and certainly don't make a habit of it.

Busboy

Is the engine up to temp all the time? I know with mine when it's really cold the engine temp actually decays at idle to the point there is no heat left and the fuel washes the cyl walls and the exhaust turns blue even though I have a winter front. I don't have high idle enabled but just use the snow brush on the go pedal, (1400) doing that is enough to keep the heat built up.

LovinTheTorque

I understand there is issues with idling. I can tell that I bought my truck with 25,000 miles on it and started pulling campers and then started a hot shot business.My truck rarely got shut off as I sleep in the in the back seat. There would be several days pass before it was shut off idling 10 to 12 hours a day sometimes. Now is this good for it probably not. I can tell you mine still has the original injectors with 100 horse tips installed by me and just had all of them checked along with a compression test and everything checked out to be fine. I did need a valve adjustment and yes it makes little ticks not knocks alittle when it is started in cold weather. I have changed the oil and all Fleetgaurd filters every 10,000 mile.I used Schaffers products. That is my 2 cents worth. I did not have a high idle option but if I had it I would have used it.

Leon441

Whether or not idling is good for diesels is not the question!

Talk about that in another thread please.

My question has to do with is likely for a cracked turbo housing to leak in low boost conditions?

Leon

bradler

well you asked for possible reasons why your burning oil and see blueish smoke in a post with the words "idling for long periods" in the title. to summarize, one possible reason your burning oil is you have a new engine with rings that may not have seated yet that has been idled a lot and MAYBE excessive idling has caused damage to rings due to cylinder wash down which COULD result in burning oil. It was also suggested that varnish on injector tips after long idling could cause the blueish smoke you saw. so not sure why you think were so off topic, but if your 100% sure rings are fine and that idling for hours doesn't have anything to do with your problem then i would suggest asking in a new post called "cracked turbo housing leaking oil?"

any oil coming out blow by tube or leaking around rear main or front crank seals? good luck mate!

sallyman1

some idling is ok. im not going to fire up my truck in -40 celcius weather and then drive a minute later. idling is ok as long as its not for REAL REAL long periods and also ALWAYS run her up to 1200-1500 rpm at idle.