macjohnw
Re: Overfilling engine oil - Good or Bad?
Right - I went to see the workshop manager at Union Motors in Nelspruit yesterday, seems like we kept on missing each other's calls. Ian was very polite and offered to replace my gearbox oil and filter due to the dipstick that was not fully inserted by the mechanic, to their cost. He also undertook to follow up the problems with the workshop guys.

Still reckon I will replace my own oil and filters from here on.
macjohnw
Re: Overfilling engine oil - Good or Bad?
Update: My gearbox oil and filter was replaced on Monday, to the cost of the agent. The did not hassle about the issue and did it without complaints. I also asked them to make a note on the system for future reference, should any problems come to light.
Re: Overfilling engine oil - Good or Bad?
Generally speaking 4x4 and marine engines have deep sumps for obvious reasons related to engine incline. Marine engines side to side and 4x4 engines forward and aft. These deep sumps are especially designed to ensure adequate oil supply to the oil pump suction pipe at the most acute angles. Angles of approach and departure are nominally less than the oil starvation angle of the sump suction.
Looking at the oil line when a marine engine and or 4x4 is at the maximum incline means there is some oil "splashing around the crank webs for'ard or aft in the engine which is not a problem at all.

Unless you have water in the oil whereby an emulsion is formed, modern day oil does not "foam" readily, especially synthetic oils designed for high temp high pressure applications like in turbines. As the sump is abnormally deep for 4x4's and marine engines the likelihood of "foam" reaching the suction intake is pretty low.

When looking at an overfilled oil level as per the dipstickit might be more prudent to find the actual oil level pertinent to the sump. 10mm overfill is unlikely to reach the crank web on a diesel engine as the crank centre is generally higher into the block than a petrol engine (higher compression , longer stroke). Using a steel wire coat hanger first cut the wire about 50mm longer than the dipstick from the highest entry point on the dipstick. Mark the high and low points on the steel wire equal to the dipstick. Follow the path of the diptstick tube on the outside of the tube by bending the steel wire until the entry point into the sump, then bend the wire vertical. By then looking from the outside where the high and low level marks are, you can then judge the following. The DID 3.2 has a stroke of 105mm and the petrol 90 mm. Half it and add 20mm for the web and crank big end. From the main pulley centre line at the front of the engine measure 75 mm or 65 mm for petrol engines this gives you the bottom of the moving parts Max on the outside of your engine. Go back to your steel wire and see the high point of the oil. You will now have the differential distance between high oil level and bottom of web.
It is unlikely the high oil mark is closer than approximately 20 - 25mm from the sump gasket line ( again especially for 4x4 and marine engines). So in short 10mm overfill is not an issue.
Some agents know this (not only Mistsubishi) and they do purposely overfill by a specific amount for two reasons. If you are on a motorplan, they know that at x millilitres per 1000kms Diesels specifically, it would be unlikely you would need a top up before your next service. (they offer to top up your sump anytime between services on most motorplans free of charge) More than 10mm might be unwise and definitely above the sumpgasket would be pretty stupid.
The second reason is that they sometimes use cold oil (from a drum with a dispensing unit normally outside the workshop area) which drains slower than warm oil. Time to drain versus us owners who wait to see the level means a slight overfill can occur. Again 10mm is no real sweat at all.
Another reason though not often is that the dispenser meets out the correct amount each time. However when they drain the sump the vehicle might not always be level or the engine is cold resulting in left over oil. The result higher than normal oil level on the dipstick. After getting home from your service, if your oil is a bit black when you check the level this is likely what has happened.
On a humourous note the workshop manager might back charge you for the extra oil supplied!
2004 3.2DiD LWB, 2006 Club Cab 4x4
gerald randall
Re: Overfilling engine oil - Good or Bad?
I have a 3.5 v6, I topped it up as I seem to have a bit of a leak after the last oil change. Want to find the leak and fix it, but topped up in the interim. However, I topped up as the sump level was on the lower level. So I added about 2 ltrs. It is now 10mm above the top line. I use Castrol Magnatec, which is partly synthetic, so not sure if it will foam. Although it seems from this forum that it is not a problem, I am going to bring it in line with the upper level. With the bit of a leak I figured a bit over would not be a problem, but I am told by another source that the excess oil can cause higher engine pressure and will either increase the leak or blow a seal. Or nothing will happen.
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