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Originally Posted by ashwinprakas And I used to think I was paranoid!
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There is a fine line between paranoid and experience.
Many people will not think of things, just because it never happened to them and the likelyhood of it happening isnt all that apperent. It has happened to me. I knocked over a small bowl with bolts and nuts that had been sitting on the air filter and the oil cap was off. I picked up all bolts and nuts and noticed one nut was missing. I spent at least half an hour inspecting the engine bay, the garage floor and so. All to no avail, so my conclussion was it had fallen in. So it meant checking taking the camshaft cover off and the sump where I eventually found it. So never keep your parts and pieces on the egine!. If you must use magnetic trays!
In my merchant navy days I have had worse. One day we were inspecting the gear teeth on the main gear box. These are huge gear boxes as the main gear has a dimension of well over 125cm! There is a small cover on top of the gear box for just this purpose. My second engineer was helping and he was using his torch to get some extra light. All of a sudden, without warning the front of his torch, followed by two batteries fell off and went straight into the gearbox!! There are no inspection covers or anythign at the bottom of the gear box. So we had to get a specialised company with some very clever cameraas and tools to help us get everything out again. Apart from a huge embarrassement it was also quite expensive as we lost a day worth of charter money as we were not operational anymore!
So from then on whenever working near openings in engines and gearboxes I made sure none of us had anythign on us that could become loose. No watches, no bracelets, necklaces, empty out pockets and for God Sake check the damn torches!
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Originally Posted by ashwinprakas Not exactly, the oil is the galleries stay there irrespective of whether the oil is changed or not, and the lack of oil in the new filter is not a matter of concern as the oil pump fills it the moment the motor cranks, though this is one of those debatable things that finally depends on personal choice. |
I think it is quite different how it works, although the outcome is as you say very debatable.
On most engines the oil pump will draw from the sump through some type of strainer. Usually just a fairly wide mesh kind, just to catch any major debris from getting into the oil pump. The oil pump pums oil out into the filter and from the filter it will go to the gallerie.
When you stop an engine, oil is left in the bearings and all over de various parts. Taking the oil filter off doesnt change that. So normally when you start an engine there is sufficient oil left for those initialy few seconds upon starting. Also the pump, all supply line and the filter typically remain more or less filled.
If you do not fill the new filter with oil, you effectively will pump air into the gallerie and thus the bearing. As the oil pumps starts rotating it will push fresh oil into the filter that is filled with air. The only place the air can go to is to the gallerie and thus the bearings. Now, initially there is still a film of oil left on the bearings, but as that airpockets gets dispersed through the gallerie and the various outlets to bearings and so, you effectively are blowing a bit of air into the bearings instead of oil. Look at your oil cannister, but it could be a volume of 200-450ml easily.
You can check for yourself. Just notice when you start your engine how quickly the oil pressure gauge will register normal or oil pressure light extinguishes. It is near immediate upon starting.
Now replace the filter without filling and observe the same. You will notice it can take up to 2-3 seconds before the oil pump has built up normal pressure. That is because it has to push the air pocket our first. Next oil change, fill the filter prior installation and you will notice that the 2/3 seconds will most likely halve. You will still notice a slight delay to normal starting, but it will be notable less than with an unfilled new filter.
To your point, does it matter. Its one of these car forum topics that is debated heavilly and usually has two streams of dedicated followers. Those who do not fill and those who do fill. The do not will claim they have never seen any adverse affects and so do the do fillers. There is no way to prove it.
And of course, it all takes place in less than 1/2 second, at idle during each oil change.
But here is my thinking. The larger engines get, the bigger the effect is going to be. Very simply put, a larger engine in size, will have larger bearing surfaces, larger sump and a larger filter volume. Bearing surface is a function to the power of 2, but volume is to the power of 3.
So the effect on larger engines of leaving air in the filter is increasing rapidly.
Im also still an engineer at heart. I dont see why an engine, any engine, should run with suboptimal lubriciation even for a second. Especially, if it takes virtually no effort on my part. I'm there hovering over the engine with my tools, my new filter and my new fresh oil. Filling the filter prior to installation might take 10/15 seconds, so why not"
Also, I still have various official workshop manuals that actually stipulate that this is the correct procedure, but it does vary a bit from manufacturer to the next.
I still do it on all types of filters, the ones with a fixed filter housing, rather than the cannister, such as my Mercedes 123.
See
http://www.team-bhp.com/forum/diy-do...ml#post4156444
But also on my Jagaur where the filter cannister is mounted horizontally. Obvioulsy, you cant fill it completely as the oil will run out when you tilt it. But about 1/3 works as well.
See
http://www.team-bhp.com/forum/diy-do...ml#post4224354
Final note on the new oil filter, only tighten by hand, no tools
Jeroen