[Jimmy_MGF]

So today I changed the oil and filter, but when emptying out the old batch only 3 litres came out instead of the expected 4.5L..

Before you judge me - I check once every couple of months and intermittently when I'm doing fluid/air checks for a long drive, and have always used the dipstick as an indicator. The car sounded tappet-y the last month or so but as I thought the oil was at the correct level I just put it down to needing an oil change. Now the oil is filled to 4.5L the tappet sound has stopped, but my faith in the dip stick has been shook.

Has anyone else found the dipstick to be misleading, and although it's just a dipstick check, is there anything I could be doing wrong or tricks/quirks I don't know about the MGFs funky dipstick positioning?

On a side note I also cleaned the Idle Air Control Valve (IACV) so I'm hoping the rev-hunting will stop - tomorrow will tell. Fiddly thing to get out, though!

 

[Chris T]

How did you fill the oil, via the main filler or the remote?

 

[Jimmy_MGF]

Main filler - the plan of the day was to get into the engine compartment to access both the filler on top of the engine and clean the IACV at the same time. I removed the dipstick whilst filling, and used one of those 5L measurement jugs to get almost exactly 4.5L.

I'm going to check the oil level once again tomorrow as I'm hoping when I read the dipstick after filling the high level on it was due to oil splashing up the remote filler tube. Even if this is the case, it doesn't make sense that my previous dips were showing max oil when I estimate at least 1L was missing!

 

[Man in the Car]

I don't think you would ever drain as much as 4.5 litres out of the K anyway - I never do with my ZR, and always get to the full mark on the dipstick with a little over 4 litres when refilling (that's after starting it up and getting the filter filled).

The method of draining will also make a difference over time - if the car is always taken for a decent run before doing the oil change, and drained out immediately whilst it is hot, any solid debris will have been stirred up from the bottom of the sump and will be drained out with the oil (and the oil itself will drain quicker and more fully).

If in the past it has repeatedly been drained cold, or drained after only being warmed up at idle for a short while, the sediment in the sump will remain, and will build up and after a good few years can easily reduce the oil capacity by more than half a litre. If left like this, even a long energetic drive will not loosen it up and get rid of it. Even a flushing additive is likely to have little effect. One of my ZRs was a bit like this when I got it - only just over 60000 miles, but when I took the sump off during the headgasket change, there was about an inch depth of solidified sludge in the bottom which had to be physically dug out.

 

[EllisoJo]

Interesting thread..................... I was amazed by:

only just over 60000 miles, but when I took the sump off during the headgasket change, there was about an inch depth of solidified sludge in the bottom which had to be physically dug out.

Though I can well believe it. I have long believed that many garages rarely give old oil (engine and/or transmission fluids) long enough to drain fully. Also, many cars are drained either very-nearly cold, or only lukewarm. To be fair to the garages, if the car's owner lives near the garage and has not driven far, perhaps in the middle of winter, the oil will not be hot. Leaving an engine idling will take ages to warm properly, and most cars will wait several hours between being dropped-off for service and the oil draining being started.

Two other points:
1. I seem to remember that on my TF, the oil drain plug is at the Offside end of the sump, near the front edge. Obviously, leaving the front wheels (suitably chocked!!) and raising the nearside rear as high as your jack allows, then axle stands under the most solid be of subframe, helps to give a tilt which encourages oil to drain from the bottom of the sump.
2. I am not convinced that any accuracy can be achieved measuring the volume of DRAINED from a car. Jimmy said:

So today I changed the oil and filter, but when emptying out the old batch only 3 litres came out instead of the expected 4.5L..

You probably have thought about this, and perhaps you measured, and meant to say how much you put IN, but the old oil filter cartridge "holds onto" a surprising amount of oil, possibly including much sludge and dirt. It is therefore very difficult to capture then measure everything which WAS in the engine, before the oil-change. Personally, I always end up with amazing amounts of dirty oil on overalls, gloves and usually the garage floor. That's just me be clumsy, I guess, but it would never have been measured, if I had tried.

Finally, I CAN confirm that 4.5 litres of oil WILL fit into a fully drained, completely empty sump and new filter. I measured the volume I put IN, during my first oil-change, which I did via the dipstick tube, though it IS important to remove the dipstick before adding oil there, as advised IN CAPITAL LETTERS in the owner's manual. After starting the engine to fill the new filter, a long lunch, and probably 2 hours delay, the oil level on the dipstick was exactly on the mark, with a total of exactly 4.5l (slowly) added.

My TF is low mileage, and I know that the sump was off 12,000 miles ago, because it has been fitted with the strengthened oil-rail. So (hopefully) no sludge etc. in my sump, and I had used all the techniques above (and a long time leaving it to drain) when emptying the old oil.
If I would, if your shoes, use a good flushing oil, and all Man in the Car's advice, next time you change the oil, take your time if at all possible to drain everything properly, then measure how much oil goes IN.

Good luck & happy motoring!

 

[Jimmy_MGF]

So checking the dipstick this morning the level is above the 'max' letter imprint, which in turn is above the max pinhole on the stick (picture attached; red marks min-max indicator pinholes, green is the oil level)

I guess I fill to that level now?
Next time i change oil and filter I'll take the pan off and see if it needs a scrape, but as the car is running silky smooth I'm going to leave as-is.

Another small note, cleaning the IAC Valve stopped the rev hunting, now the car is learning how to operate correctly after resetting. Hopefully it'll sort itself out when cold over the next few drives.

 

[IanMc]

Overfilling with oil is not good for any engine - you need to let some out.

 

[jr795]

How did you fill the oil, via the main filler or the remote?

Not to hijack the thread but I have to ask, is filling from the remote not advisable? (I'm still pretty new to the TF world)

 

[MidgeVVC]

It's very slow to get oil in using the filler by dip stick. Topping up is easy, a full oil change and you could be there all day.

 

[Jimmy_MGF]

Good morning everyone, probably the last post to finish this thread off.
Drained the extra oil this morning and now the level is sitting bang on the max pip.
Turns out removing a little oil from the sump is quite easy, and the oil being cold probably helped too. Didnt even need to jack it up as I could lever my socket wrench enough just in front of the back wheel - even enough room to put the short extender on just to pinch it up.

I thought I drained enough out when I was fiddling with the new sump plug washer but had to go back and drain a bit more!
First drained down to minimum so I topped up little by little using the top-up tube. Picture is of how much oil I removed to bring the level down to the max pip.

The moral of the day is put 4L in after changing the oil and filter, measure then top up a little bit more if needed, as there is not much between the min and max pips!
Also, the IACV clean seems to have done it. I'll occasionally dip below but then it instantly settles on the ~800rpm mark, and this only really happens before reaching running temp. Considering it cost me the price of a carb cleaner can I'm calling it a cheap win!

Thanks for the advice people, lessons were learned.