I have a 1972 Case 1737 gas powered skid steer. Last winter as I was moving snow it started billowing smoke out of the engine compartment and I thought I'd blown a hydraulic line. Turns out, engine oil was spewing out of the breather fitting atop the valve cover, as though the oil pan was being pressurized. I checked the oil and it was a couple quarts high and smelled like gas. I would have blamed the mechanical fuel pump except that I replaced it with an electric pump two years ago. I installed an in-line pressure regulator set to 4PSI, drained and replaced the oil and the problem persists, though it hasn't elevated the level of oil and the oil no longer smells like gas. The engine runs fine and no smoke is coming out of the exhaust pipe. When the loader warms up the problem reappears. I'm stumped! Any advice would be appreciated. Thanks.
- Thread starter farjohn
- Start date
Janicholson
Well-known Member
One common issue with a gear driven Hydraulic pump is the seal at the drive end of the pump. If bad it will leak hydraulic fluid
into the oil pan. If it has a gear driven pump I would look there. Jim
into the oil pan. If it has a gear driven pump I would look there. Jim
Janicholson
Well-known Member
The problem reappears. Which part of the problem? Jim
I'm wondering if this could be some kind of PCV problem. There's a fitting in the top of the valve cover that could contain some type of PCV.
There is a hose attached to that fitting that runs down beside the engine and appears to either be dead-ended or terminated with some kind of small device, maybe a filter. The oil is being blown past the rubber bushing that the top fitting is attached to.
There is a hose attached to that fitting that runs down beside the engine and appears to either be dead-ended or terminated with some kind of small device, maybe a filter. The oil is being blown past the rubber bushing that the top fitting is attached to.
Janicholson
Well-known Member
If the breather (or a baffle in the point of attachment of the breather) was damaged or moved when the forst event happened, it
will still let engine oil get out into the air. If the engine has a PVC valve (Positive Crankcase Ventilation) it could be plugged
up and keeping the blow by pressure in the crank case. That pressure might push out crank case vapors and mist through the
breather. Worn rings and excessive blow by are also real causes of the problem. Maybe others will chime in. Jim
will still let engine oil get out into the air. If the engine has a PVC valve (Positive Crankcase Ventilation) it could be plugged
up and keeping the blow by pressure in the crank case. That pressure might push out crank case vapors and mist through the
breather. Worn rings and excessive blow by are also real causes of the problem. Maybe others will chime in. Jim
Janicholson
Well-known Member
That hose might be the PCV hose and it should attach to manifold vacuum. The PCV valve must be in the manifold, or it would never
start or run with that much vacuum leak. It could have a venting system that attaches to the air cleaner or carb intake tube from
the air cleaner in which case it may just be a restriction of 1/8th inch or so. Jim
start or run with that much vacuum leak. It could have a venting system that attaches to the air cleaner or carb intake tube from
the air cleaner in which case it may just be a restriction of 1/8th inch or so. Jim
Thanks again, Jim. I don't doubt that there is a lot of blow by in an old engine like this. I haven't seen any attachment points at the end of the hose, but I may have missed something. The problem came on suddenly and there has been no obvious change in the way the engine runs (missing, etc.). It starts up and runs just fine. I appreciate your insights.
Adirondack case guy
Well-known Member
The 148 Case engine in your skid steer has major compression problems. That vintage of Case engine had no PVC valves etc., just a crankcase breather tube.
Get back to old school basics!!
Loren
Get back to old school basics!!
Loren
MARK ROBKE
Well-known Member
Does the engine miss when running?That could mean blown head gasket to the crankcase.If you run the engine with the oil filler cap off-do you have pressure coming out?Otherwise I agree with Jim about the PVC system and maybe a baffle broke under the breather.May need to pull the valve cover to check.Mark
Thanks to all. I'll check to make sure the breather tube isn't plugged. If a baffle broke it would play all kinds of hell with the rocker arms and again, the engine doesn't miss of smoke excessively. I can see a head gasket leak between a cylinder an oil port as a possibility but again, the engine doesn't miss or run rough.
jon f mn
Well-known Member
Your engine shouldn't have any pvc system
as Loren said, all it should have is a
breather. I'm betting broken rings are
allowing compression into the pan and
blowing the oil out. This would also be a
source for unburned gas to get past the
rings and into the oil. A compression test
is in order.
as Loren said, all it should have is a
breather. I'm betting broken rings are
allowing compression into the pan and
blowing the oil out. This would also be a
source for unburned gas to get past the
rings and into the oil. A compression test
is in order.
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