Agriculture and Farm Equipment

Agriculture and farm Equipment repair questions? Ask a mechanic.

Ask an Expert,
Get an Answer ASAP!

A 4b-390 cummins suddenly started to smoke and drop oil

Customer Question
A 4b-390 cummins suddenly...

A 4b-390 cummins suddenly started to smoke and drop oil pressure. engine starts and runs normal. oil pressure is normal until engine warm then drops and starts smoking. suggestions? thanks

Mechanic's Assistant: What is the complete model and serial number of your machine?

Case 450c gbe 1680

Mechanic's Assistant: Are you fixing this yourself? What have you tried so far?

Yes. the equipment is lightly used 50 hours a year. the engine has had regular service oil, filter, antifreeze once every 3 years. current fluids look normal (no water, diesel in the oil). about to check compression. is there anything common to smoking and oil pressure loss?

Mechanic's Assistant: Anything else you want the construction mechanic to know before I connect you?

No. thank you.

Submitted: 8 months ago.Category: Agriculture and Farm Equipment
Show More
Show Less
Ask Your Own Agriculture and Farm Equipment Question
Customer reply replied 8 months ago
compression test. all cylinders around 300 to 320 psi.
Answered in 44 minutes by:
9/18/2017
Mechanic: Wayne, Journeyman replied 8 months ago
Wayne
Wayne, Journeyman
Category: Agriculture and Farm Equipment
Satisfied Customers: 11,005
Experience: 34 + years as a mechanic
Verified

Hi I'm Wayne

I will help you with this

Oil pressure drop can be caused by fuel dilution

and smoking can be caused from faulty injectors

I suggest to smell the oil ,see if it smells like diesel fuel

injectors will cause both issues

I hope this helps you

Hi. If this helped you

Please rate my answer 4 or more stars.

That is the only way I get credit for the question

or the money you paid stays at JA and I get nothing for my time.

If you need more info use the REPLY button

Not the Poor/Bad service.

Wayne

Ask Your Own Agriculture and Farm Equipment Question
Customer reply replied 8 months ago
these questions should be directed to an experienced cummins mechanic.
is there anything common to sudden smoking and oil pressure loss?
engine starts and runs normal until warms up.
Mechanic: Dan, Technician replied 8 months ago
Dan
Dan, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 6,706
Experience: 17+ yrs. shop and field experience with all major brands of heavy equipment, trucks and farm equipment - 1995 WyoTech graduate.
Verified

Hi my name is***** see you requested a new professional. I agree with the other professionals answers and would also add that a worn oil pump, rod and main bearings, or a faulty oil pressure regulator can effect oil pressure as well as a faulty oil pressure bypass valve.

Ask Your Own Agriculture and Farm Equipment Question
Mechanic: Dan, Technician replied 8 months ago

What color smoke?

Ask Your Own Agriculture and Farm Equipment Question
Customer reply replied 8 months ago
is there anything common to SUDDEN smoking and oil pressure loss? the change from normal to smoking happened within 5 minutes. engine starts right up and runs normal except for smoke and low oil pressure.
current fluids look normal (no water, diesel in the oil), radiator was a little low.
oil pressure is normal when cold until engine warm then pressure drops and starts smoking a lot.
smoke color : i would call it blueish. the engine is a cummins 4b-390. are they know for a crack head or other sudden failure?
are you experienced with cummins?
thanks
Mechanic: Dan, Technician replied 8 months ago

Im very experienced with Cummins and these engines have different fuel systems depending on application. Do you have the rotary injection pump or inline robert bosch? Smoke can be fuel system related or oil consumption related due to wear....

Ask Your Own Agriculture and Farm Equipment Question
Mechanic: Dan, Technician replied 8 months ago

These heads are known for cracking between the valves and injector seating area

Ask Your Own Agriculture and Farm Equipment Question
Customer reply replied 8 months ago
i dont know the difference between the rotary injection pump or inline robert bosch. the injector lines are at the rear of the injector pump, opposite end from the gear drive, (not on top).
could an oil leak in the injector pump cause low oil pressure?
is it likely a cracked head could cause the smoking and oil pressure loss?
from your experience:
the smoking and oil pressure loss happened 'suddenly', can you explain what may have happened?
is this likely to be an inframe or engine remove fix?
thanks
Mechanic: Dan, Technician replied 8 months ago

Thanks for the update. Blue smoke can be both oil and fuel. So let me ask. The oil pressure was it verified with a separate mechanical gauge? If so what is the actual oil pressure?

Ask Your Own Agriculture and Farm Equipment Question
Customer reply replied 8 months ago
the oil pressure gauge is a case (red/green) no psi numbers, i dont know the actual psi. i have had the dozer for 12 years, the oil gauge always was 2/3 in the green until this happened.
could an oil leak in the injector pump cause low oil pressure and oil in the diesel?is there anything common to SUDDEN smoking and oil pressure loss? the change from normal to smoking happened within 5 minutes. engine starts right up and runs normal except for smoke and low oil pressure.
current fluids look normal (no water, diesel in the oil).
oil pressure is normal when cold until engine warm then pressure drops and starts smoking a lot.
the question i am asking is: the smoking and oil pressure loss happened 'suddenly', can you explain what may have happened?
thanks
Mechanic: Dan, Technician replied 8 months ago

We need to get a mechanical guage on it to see what the actual pressure is before and after this occurs for accuracy.

Ask Your Own Agriculture and Farm Equipment Question
Mechanic: Dan, Technician replied 8 months ago

You are getting diesel in the oil? yes the fuel will thin out and dilute the oil causing low oil pressure. The injection pump drive seal can leak in through the front timing cover. Your injection pump will need to be rebuilt. You need to pin the timing pin on #1 TDC under the injection pump. Push in and bar the engine over until the plastic pin plunger drops into the gear slot before removing the pump. Remove the first valve cover and be sure both rocker arms are loose on #1 cylinder. If so and the pin is engaged in the hole you are okay to remove the injection pump.

Ask Your Own Agriculture and Farm Equipment Question
Customer reply replied 8 months ago
hi,
your question: You are getting diesel in the oil?
from my earlier response: 'current fluids look normal (no water, diesel in the oil).'... you are not reading the info i sent, neither did the first mechanic.
thanks for the description on injector pump replacement and i agree i need to get accurate oil psi, but the current oil gauge is acting like it has for 12 years, 570 machine hours.
thank you, ***** ***** are not answering the question: is there anything common to SUDDEN smoking and oil pressure loss?
Thank you again. there is no need to respond.
Customer reply replied 8 months ago
hi,
are you experienced with a cummins 4b-390 engine? it is in a case 450c dozer, 1986 vintage.
i assume you can read the previous messages.
the question is there anything common to SUDDEN smoking and oil pressure loss?
current fluids look normal (no water, diesel in the oil)
compression test. all cylinders around 300 to 320 psi.
the change from normal to smoking and oil pressure loss happened within 5 minutes.
the engine currently starts right up and runs normal except for smoke and low oil pressure.
the question i am asking is: the smoking and oil pressure loss happened 'suddenly', can you explain what may have happened?
thanks
Mechanic: Curtis B., Technician replied 8 months ago
Curtis B.
Curtis B., Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 30,494
Experience: Technican turned service manager on multiple lines of equipment and rental equipment.
Verified

This is the natural engine and not the turbo charged BT3.9 that is also listed with the 450C? Form the Cummins service manual, it states smoke and loss of oil pressure is caused by oil thinned from diesel intrusion, or turbo charger bearing out, which shows a smoke.

Ask Your Own Agriculture and Farm Equipment Question
Was this answer helpful?
Ask Curtis B. Your Own Question
Curtis B.
Curtis B.
Curtis B., Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 30,494
30,494 Satisfied Customers
Experience: Technican turned service manager on multiple lines of equipment and rental equipment.

Curtis B. is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Curtis B.

Curtis B.

Technician

30,494 satisfied customers

Technican turned service manager on multiple lines of equipment and rental equipment.

Wayne

Wayne

Journeyman

11,005 satisfied customers

34 + years as a mechanic

dieseldan55

dieseldan55

Mechanic

42 satisfied customers

Road mechanic for Volvo Construction Equipment.

Cat Man

Cat Man

Cat Engine Expert

35 satisfied customers

I am ASE Master Certified.

Chris (aka-Moose)

Chris (aka-Moose)

Technician

22 satisfied customers

16 years of experience

JBFixxer

JBFixxer

Mechanic

20 satisfied customers

16+ years experience, hydraulics,hydrostatics, engines, fuel injection systems. And everything in between.

spankyjr1

spankyjr1

Journeyman

310 satisfied customers

I worked on all types semis,forklifts,farm,fire,ect.

< Previous | Next >

Related Agriculture and Farm Equipment Questions
Engine seized up in my J Deere JS30, is it worth it to
engine seized up in my J Deere JS30, is it worth it to replace engine? … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
I'm installing cylinder sleeves in a deere 4440 tractor. The
I'm installing cylinder sleeves in a john deere 4440 tractor. The sleeve O-rings are orange and gray. I need to know which goes top, and which goes bottom. … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
I have two Deere STXs with Kohler Comand 12.5 OHV motors.
I have two John Deere STXs with Kohler Comand 12.5 OHV motors. Model # CV1255 Spec # 1257. Ones a MOOSTXB15334. INFO on adjusting the idle screw and the mixture screw. It starts but turns off … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
I have a 2120 that won't start. Battery is new, Pto and
I have a 2120 that won't start. Battery is new, Pto and shuttle shift neutral srart shift switches are closed. Starter solenoid doesn't seem to pull in. Fuse link checks out as OK. Where do I go from … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
I have a tarter 5' tiller and the driveline shaft that runs
I have a tarter 5' tiller and the driveline shaft that runs from the pto gearbox to the geardrive for the tines broke in half how do you get the shaft out of the gearbox ? I have removed the half that… read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
1979 550 johndeere dozer makes a loud screeching noise going
1979 550 johndeere dozer makes a loud screeching noise going forward when using right brake, an in reverse using left brake … read more
Dan
Dan
Technician
6,706 satisfied customers
Hydraulic problem 4020 JD remotes have very little pressure.
Hydraulic problem 4020 JD remotes have very little pressure. Steering ok brakes ok … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
Where do I find a 511010 M2 Drag Link? mf10 serial number is
repairing it myself, if I cannot find part. I have searched several sites on the Internet. … read more
Wayne
Wayne
Journeyman
11,005 satisfied customers
Why does mower wheels have to be 3/8" OFF THE GROUND? 1025
Second opinion] why does mower wheels have to be 3/8" OFF THE GROUND ? … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
My friends tractor X734 keeps flashing the H symbol. K. I
My friends tractor X734 keeps flashing the H symbol … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
Have 1999 JD 4600 diesel tractor. Oil gets into selnoid &
Have 1999 JD 4600 diesel tractor. Oil gets into selnoid & won't start. Take selnoid out starts great but oil pours out openening where selnoid goes … read more
Wayne
Wayne
Journeyman
11,005 satisfied customers
I have a 1950 farmal cub, and the starter switch works ver
I have a 1950 farmal cub, and the starter switch works ver iittle if at all. It seems to very light weight and even when new does not work well. Also I was plowing and noticed that the chock was pulle… read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
How do you remove the steering cylinder on a Massey Ferguson
How do you remove the steering cylinder on a Massey Ferguson gc2300 tractor, … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
I have a 320 Deere mower. I removed the blades to sharpen
I have a 320 John Deere mower. I removed the blades to sharpen them. When I put them back on, the blades would not engage. … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
I have a branson tractor model #4720h i would like to buy a
i have a branson tractor model #4720h i would like to buy a set of forks for it the kind where i remove bucket and attach forks can u help me … read more
Dan
Dan
Technician
6,706 satisfied customers
I have a 2010 825i that has 1100 hours on it. Recently when
I have a 2010 825i that has 1100 hours on it. Recently when I drive arount at low rpm below 4000 the engine will stall out and I turn the key off it starts right back up. Runs fine above 4000 rpm. Any… read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
Loose power under load example turn mower deck pto. F680
Second opinion] loose power under load example turn mower deck pto… read more
Wayne
Wayne
Journeyman
11,005 satisfied customers
I would like to know H/P of Shibora DY 27D single Cylinder
Hi , I would like to know H/P of Shibora DY 27D single Cylinder diesel engine. Regards Geoff, … read more
Curtis B.
Curtis B.
Technician
30,494 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x