oil in exhaust

[gordon5a]

any one know why my dexta has started putting oil out the exhaust bonnet is covered in dots of oil and there is a drip from the hole in the bottom of the exhaust manifold

[Nick]

It could be one of a few things, first thing i would say is, do you work it hard? If they idle around for a while this can happen. It could be worn rings/liners, does it smoke much? Does it start ok from cold?
Apparently aswell, if the head gasket has gone and coolant leaks into the bores, it comes out the exhaust all black and looks like oil.

[conar22]

i also have this problem...but i did a complete overhaul of the engine less than 50 hours ago.
it hasnt been idling about either...ive been ploughing and rolling grass with her....i expected this to
sort out my oily manifold...but it hasnt!

[gordon5a]

starts first time from cold with thermostart plug, is not to smokey but it does spend a bit of time idling, does not seem to be losing any water either

[Brian]

Common problem on all diesel engines that are not in hard work. I was always taught that a diesel had to be run under full load or switched off. Not always practical but a good guide.

This time of the year was always the worst for this problem as most tractors are on light work like hoeing and grass cutting.

They need to be ploughing for a few hours or working Rotavators and the like.

Also look at the oil you are using an HD 30 or 20/30W is best for these engines IMHO.

50 hours is nothing like enough to run in a new engine, you would need to work on a plough solid for about 200 hours to really get it to bed in and the exhaust to clear, you also need work to replace the hard carbon seal on the piston tops. Did you replace the valve guides?

A run on a Dynamometer would help if you have a friendly local dealer.

[conar22]

Hi Brian,thanks for your response-yes the valve guides were changed-and your definately right about diesel engines needing to be worked steady after engine work has been carried out. We rebuilt a david brown 950 maybe 500 hours ago and we notice a huge difference in starting/overall performance....it shows just how long it takes for an engine to 'run in'.
However another issue that is bothering me is my oil seems to be getting rather hot-im noticing the oil light flashing just as i shut the engine off-at around 350 rpm it lights up-pressumably due to the oil thinning with the heat.
The cooling system isn't overheating...but im contemplating on removing the thermostat just as an experiment to see if it will run colder-thus reducing the oil temp? Any more advice/opinions greatly appreciated.

[Jan 59]

Had this problem as well. What make pistons/piston rings did you use? In my opinion the oil temperature is no issue when the cooling system is running normal temp. Running the engine without thermostat is very bad!
As Brian says HD 30 or 20W/30 is the best oil for your Dexta engine , and work it hard . The best thing you can do is fit an oil pressure gauge at the port where the switch is fitted and see what that shows. I had this sort of problem but was due faulty switch.
After overhaul of my Dexta run in oil from exhaust problem, hard work did not help. Replaced piston rings with a set of SIM expander rings and problem cured.

[Brian]

A Dexta rev. range is from 600 rpm to 2200 rpm so I would expect the light to come on at 350 rpm when hot.

Oil pressure on a new engine should be around 40 psi at 1800 rpm with 30W oil.

[60dexta]

Common problem on all diesel engines that are not in hard work. I was always taught that a diesel had to be run under full load or switched off. Not always practical but a good guide.

This time of the year was always the worst for this problem as most tractors are on light work like hoeing and grass cutting.

They need to be ploughing for a few hours or working Rotavators and the like.

Also look at the oil you are using an HD 30 or 20/30W is best for these engines IMHO.

50 hours is nothing like enough to run in a new engine, you would need to work on a plough solid for about 200 hours to really get it to bed in and the exhaust to clear, you also need work to replace the hard carbon seal on the piston tops. Did you replace the valve guides?

A run on a Dynamometer would help if you have a friendly local dealer.

I have just put this in mine...
http://www.commaoil.com/productsguide/view/6/254/H301G
It seemed to fit the bill so now have it in the engine, back end, injector govenor, air filter but still need to drain the gearbox and steering box.
Rob