# Diesel belching oil



## JGPenfield (Mar 10, 2016)

I have a 1967 Ford 3000 diesel. It is hard to start in the cold and the intake heater really helps a lot. It is located in the intake manifold and electricity and diesel are fed together and this heats my air intake. If I hold it long enough, the tractor belches as though the diesel ignited and air is forced backwards into the air cleaner and into the oil bath air cleaner. The oil then goes up the air intake tube into the pre cleaner and out onto my hood. 
Is that common? Is there a way to prevent that? Does that affect my pre cleaner or filter element? 


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## Ultradog (Feb 27, 2005)

That device in the manifold is called the Thermostart.
You may be holding the heater on too long. Try it for a shorter time.
You could also try removing yours and test it out in the open. Might not be heating properly or maybe it's allowing too much fuel in. Mine will make a muffled whoomp and then a sizzling sound when the fuel ignites but it has never blown oil back out of the air intake.
I rarely use mine though.
A new one can be had for $35 or so on ebay, amazon, etc.
Thermostart does help a lot but aren't as effective as a coolant heater .
Mine is newer so I have a block heater. Remove the press-in soft plug just in front of the starter and install there.
Yours is older and probably has the screw-in soft plugs so you have to use a tank heater. If you park it near a power source maybe consider one of those.
If I plug it in for an hour or two my 3000D will start like it's July - even in 0 degree temps.


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## JGPenfield (Mar 10, 2016)

Mine will smoke and after 45 seconds it will make the muffled whoomp and send oil up the air intake. Thats when I know it is ready to start. It does it most, but not all the time. Without it, even in the summer, it has a hard time starting. I did replace it 4 years ago and watched it turn red before installing it. I was thinking that in addition to heating, it was also supplying more fuel like a choke on a gas engine or excess fuel button on a diesel. 


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## thepumpguysc (Jan 25, 2015)

45 seconds is WAY to long to hold a thermo-start..
Try 1 one thousand, 2 one thousand.. all the way to 10 & crank it..
What do u have the pump timing at.??
IT "should be" at 0* or dam close to it..
There is an arrow on the inj. pump name plate.. that lines up w/* marks stamped into the engine block.. They may be painted over 15x but they're there..


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## dozer966 (Dec 30, 2014)

On our coldest Canadian winter day I hold mine for 10 seconds and it Fiers right up with no issues


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## JGPenfield (Mar 10, 2016)

I did not know about the pump timing. I have a repair manual and owners manual to look it up and will get back to you. 


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## Hacke (Feb 22, 2011)

Thermostart function:
See the Shop Manual:
https://www.tractorforum.com/manuals/ford-2000-3000-4000-3-cyl-1-65-12-74-shop-manual.6/
Page 51, Paragraph 162.

The fuel will ignite in a few seconds:









User manual:
www.ntractorclub.com/manuals/tractors/Operators%20Manual%20All%20Purpose%20and%20LCG%20Tractors%202000,3000,4000,and%205000.pdf
Start reading at page 14 (pdf page 20) "Starting the engine".

Assuming that the tractor's Serial Number is starting with a "B" or "C":
You have a Simm's in-line injection pump. The timing on this is a bit more complicated than just turning the pump...
Anyhow, the injection pump is not the major problem now, focus on the Thermostart.
Follow the instructions for "*In-Line Injection Pump*", note the excess fuel button on the pump.


Your description indicates that you have a leaking valve in the Thermostart. If so, fuel is always running into the manifold from the reservoir, until the reservoir is empty. When the engine has been sitting for a while, the reservoir is emptied into the manifold. When you try to use the Thermostart, the coils will heat up but there will not be any fuel at the coils. You will not get a flame after a few seconds. You then continue glowing the coils, the temperature rises locally in the manifold and the fuel starts to vaporize. Finally, the vapor will ignite and blow the gases out through the air cleaner.

You need to check the Thermostart:
Run the engine for 5 minutes, and stop.
Disconnect the rubber hose on the intake manifold.
See if it is wet of diesel inside the manifold and/or dripping from the Thermostart.
If not, let it sit over night and check again.

You could take the Thermostart out and rig a testing arrangement, like the one in one of the videos.



A leaking Thermostart valve is not only a problem at cold starts. You will have diesel fuel running into the manifold when the engine is running. The reservoir is constantly beeing fed with fuel when the engine is running. That can cause soot build up on pistons and valves, with a stuck valve or a cracked piston as a result.

Of course, if the Thermostart is leaking, you will need to replace it. Any Thermostart can begin to leak. Put an in-line petcock after the reservoir, and open it only before cold starts. When the engine has started, you close the petcock.


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## thepumpguysc (Jan 25, 2015)

As USUAL, not enough information & I assumed it was a CAV DPA.. thanks Hacke..
very good write up..


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## pogobill (Jan 31, 2012)

Yes Hacke, a great write up.


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## Ed Williams (Jun 13, 2019)

I found several thermal starts on ebay for less than $15. You can get either the OEM blade type or a post and screw. The one I bought was post and screw for $12.50 and free shipping. Mine goes whump at 15 sec, then crank. My 4000 has low compression, so extended cranking. I found an excellent alternate. Remove hose from cleaner to intake, now 10 sec with proper tools, insert B&D heat gun nozzle into manifold on high. After 5 min the entire manifold is pleasantly warm, 15 deg F ambient. Average crank time to start is 2-3 sec. hose replacement is 20 sec. Try it. You'll like it. FYI, with hose off, thermal start is VERY LOUD.


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## JGPenfield (Mar 10, 2016)

I bought a new thermal start from amazon. It heated up but did not ignite fuel. I put the old one back on and it did what it should and did not leak once it cooled down. There was fuel in the line feeding the new one that did mot work. Aftermarket parts are always a problem. I made a video. I hope you can see it. 






The pics are my fuel injector pump. It is a Simms. 



















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## Hacke (Feb 22, 2011)

The old Thermostart seems to work, but did you check for diesel in the manifold like this?:


Hacke said:


> ...
> Run the engine for 5 minutes, and stop.
> Disconnect the rubber hose on the intake manifold.
> See if it is wet of diesel inside the manifold and/or dripping from the Thermostart.
> ...


If you put the Thermostart back with the air tube removed, as in the video, do you get an explosion out of the manifold when you cold start like when you got the oil out of the air cleaner?

Is there something in the tubes or in the air cleaner that restricts the flow?
Is the steel wool in the air cleaner clean?
Do you get black smoke from the exhaust pipe when the engine is running?


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## JGPenfield (Mar 10, 2016)

I ran it and did not see a leak. I do get black smoke on startup then it runs clean. I am replacing the entire air cleaner and two rubber intake tubes. I cant tell if the thing is leaking, but with all the black soit that my comes out of my exhaust, i decided to order a nee one from Yesterdays tractor and see if it works. I am replacing all this stuff because I wanted to replace the nose cone that was beat up and held together with sheet metal screws and I could not attach a front grill to. 


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## Ed Williams (Jun 13, 2019)

Make sure air cleaner oil bath is not overfilled with oil. Did this one time on NAA and got black smoke/oil/soot out of exhaust. Covered cowl back to steering wheel. What a mess.


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## JGPenfield (Mar 10, 2016)

I kept wondering if mine was overfilled. I keep it at the line indicated. I may have been getting water in the bath because the old one had had a tube inserted on top because the old one rotted. This allowed rain water to get in. I am replacing the entire air filter. 


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## Ed Williams (Jun 13, 2019)

I had to stop mine at 1/2" below the fill line to stop the problem. No water in oil, just looked like semi dirty oil. Nothing to indicate water getting into system.


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## Ed Williams (Jun 13, 2019)

One more thing that you might want to look at. On diesels, the burn in the cylinder is affected by the atomization of fuel by the injector. I started getting black liquid coming from exhau SD g on the 4000. Saw several reports from diesel mechanics out YouTube that if the injector nozzles start to soot over, they stop delivering the fine mist of fuel and actually deliver the fuel in drops instead or mist. This can cause the same problem. I did not know how to clean an injector nozzle and not damage it, so I replaced the bottom tips on the injector with new nozzles. You need to pull the injectors and match part numbers to make sure you get the correct lower half. There is a separate posting on this in the forum. There is a YouTube instructional video showing the exact procedure. Lastly, you can talk to "thepumpguySC" on this forum. He knows more about the diesel fuel system than I can ever learn, and can give you great advice.


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## JGPenfield (Mar 10, 2016)

I was thinking of changing out the fuel injectors because it is a recommended maintenance and I do not know when mine were last changed, if ever. But I was reluctant since it starts and runs and why fix if not broke. But I do get a lot of black liquid soot from my exhaust. Maybe it is broke. 


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