Oil Flow...
Been reading some very informative posts on this web..thanks mostly in part to Joey and Chongo..
What I would like to understand is how oil flows through the system... specifically I am trying to understand places in the system an oil leak can occur and where they fit into the system..
Can someone explain this to me or point me to a web site that can...
I ask because I have a growing oil leak problem .. while I was OK seeing some on the pavement when I pull off I am beginning to worry about the quantity I am now seeing..(and the smell of oil burning off the engine and exhaust)
I have tried to clean the engine to locate the leak to no avail. I recently tightened the bolts in my valve covers (which were very loose) but I'm not sure if that helped the problem...
I am seeing leeks directly under the engine block to well back on the drive shaft in the mid to rear of the vehicle... (I imagine some of this is blown back while driving)
Thanks..
Neill 96 Disco SE7 92K
To start off with The Land Rover engine as well as most engines can only get 2 types of oil leaks, the pressurized oil passages, usually internal leaks are associated with low oil pressure, and 2nd are the gaskets separating the Crankcase areas to the external engine areas. External leaks can be hard to locate due to it getting all over the engine. The pressurized passage ways called oil galleys, seldom leak externally, normally internally. These oil galleys supply the oil to the bearings, pistons, rocker arm assemblies, camshafts, valve
train, sometimes tensioners, Timing chains, oil pumps, silent shafts, gear or chain drive mechanisms, and of course any other mechanisms that are driven internally. On Land Rover engines the top rocker arm assembly is fed pressurized oil through the block and heads, sealed by the head gasket.
Crankcase areas:
This area includes all areas the oil vapor or internal air can travel. Underneath the valve covers, underneath the intake manifold in most V design engines, in the block areas, not including the combustion chambers, and oil pan areas. These areas is where the oil that was pressurized to the highest engine point, usually in the cylinder head areas, drains back to the oil pan.
Path of pressurized oil:
The oil is Drawn into the oil pump by means of pressure differentials. Once in the oil pump the oil is pressurized by means of displacement. Then the oil passes through the filter and Then it travels through the pressure regulator system, “in the front timing cover “, The excess oil bleeds off into the oil pan. The oil then is pushed through the drilled passageways in the block to supply the main and rod bearings as well as Camshaft, lifters and rocker arm assemblies.
Finding an external leak:
When finding an external engine oil leak, one must remember you have an engine cooling fan which blows very hard on the engine, and well documented at well over 200 mph winds under the hood. This literally blows oil everywhere making the source difficult to find. I recommend pressure washing the engine, or using a dye in the oil to find the leak. In your instance where you say you can smell burned oil points to, but doesn’t mean the oil leak is at the highest point of the engine, i.e. valve covers. Finding this location where the oil is burning on the exhaust can be done by simply letting the engine idle for a while. If it drips on the ground the leak will be directly above it. If it drips on the exhaust you’ll see the smoke, and above it will be the problem.
Due to the surface tension of oil, it usually clings upside down on the engine and travels for a ways before it drops, but on a clean engine this is usually easier to find. Using the colored dyes makes it easier to find the leak on a dirty engine.
Hard To Find Leaks
There are a couple of other ways of locating an oil leak. The method of choice among professionals is a florescent dye and an ultraviolet (UV) light. This dye will work with all types of fluids, oil, transmission fluid, fuel, coolant, and A/C refrigerant, and makes spotting a leak pretty easy. When seen under the UV light, the dye glows a bright greenish/yellow that can't be mistaken for anything else.
By aiming the light a small dye mark will show you the location of the oil leak. I have dye kits in my shop that have special yellow glasses that make the dye stand out even more.
Dye kits usually come with two bottles of dye, one for anti-freeze and one for oil. Dyes for A/C refrigerants are very specific for the type of A/C refrigerant and require the proper equipment to add to the system. They are not included with a general-purpose kit and should be done by a professional.
When you use the dye, follow the directions that come with your particular kit. In general you mix an ounce of the dye and mix it with about a quart of oil and pour it into the engine. Don't put the dye directly into the engine. It will get caught up in the oil filler area and take much longer to mix with the oil.
Put some newspapers under the engine and let it run. When you see some drips on the paper, look at them with the UV light. If they glow, you can start searching for the leak. Shut off the engine and starting from the bottom of the engine. Turn on your UV light and follow the trail of dye. The oil may go round and about but follow it up to the highest point and you will spot the source of the leak.
Most times it will be a valve cover gasket and tightening the bolts will end the leak. Or it may be a distributor "O" ring or leaking Oil Pressure Sending Unit. But sometimes it will be from a gasket that is totally gone and will need to be replaced.
Oil also may be seeping past a worn crankshaft or camshaft seal. The rubber lip that seals to the rotating shaft will eventually wear to the point at which the tension in the garter spring won't keep oil from leaking. This type of seal will only leak when the engine is running--and when it does oil will spray everywhere from the spinning shaft.
There is another way to locate an engine leak that is almost as effective as using a trace dye. And you probably already have it in your medicine cabinet. It's foot powder. What you do is get the engine as clean as you possibly can and let it completely dry.
Now spray the general area of the leak with the foot powder and work your way up as far as possible. The powder will stick to the engine and cover the metal in a white film. Don't be stingy with the stuff either.
Now drive the car fairly slow on clean, dry roads so you don't mess up the powder. Hopefully the oil will take a fairly direct route down. If it does, you will see a single black path down the side of the engine. You may need to do this higher up on the engine to locate leaks from the intake manifold or head gaskets. If the oil leak is too bad you will have to go with the trace dye to determine where the oil leak is.
This is where to find the dye……………
http://www.sjdiscounttools.com/tptp3090-0601.html
I hope this helps………. Chongo
