Hi All,
I performed a complete CVT oil flush today and thought I'd share the process here for other people's clarity as well.
EDIT - Here’s a video link by another member for the oil flush. Some slight differences but anyone who wants to opt for oil flush can view it: https://youtu.be/eF6pJRUy3DA
Oil Type: Mitsubishi Diaqueen ATF SPIII
Transmission Capacity: 8.1 L
Required Volume: 9.0 L to 10.0 L accounting for some wastage and any leaks, etc.
20.0 L oil barrel part no.: 4024401 (other sizes of 1.0 L, 4.0 L and 5.0 L may be found on the internet)
Let's start with an extract from the Factory Service Manual and the marking of the oil return line on the radiator.
There are some important points to note here regarding the process outlined in the FSM:
The process is outlined for a car with an ATF warmer/cooler whereas the lancers sold here cool transmission fluid by running it through the bottom of the radiator. Therefore, we will tailor the process as per our cars.
Instead of the ATF warmer/cooler line, we will be using the return line from the radiator.
OIL FLUSH PROCESS:
Park the car on a level surface or jack up the front left wheel (transmission side) to angle the oil towards the drain bolt (and also to gain better access to underside).
Remove the oil return line (marked on the radiator in the image above) from the radiator end and attach a clear hose angled downward into a catch can (any container which can preferably measure the quantity too). I used an empty nestle 5.0 L water bottle for this purpose. (You will see 8 ribs on the bottle. Each represents 0.5 L and amount to 4.0 L in total. The 5th litre fills up the conical area above the top most rib up to the cap.) I also had an empty 1.0 L coolant bottle with 1.0 L capacity and 0.1 L (100 ml) markings.
Start the car with gear shifter in the N position. The fluid will start to flow slowly into the bottle. Once the fluid level reaches the 6th rib from the bottom you should turn off the car. Ideally the fluid volume discharged should not exceed 3.5 L, otherwise, a rattling noise may be heard from the transmission (i.e. running on very low oil). Ideally, the amount of fluid discharged should be noted down by measuring it. We will assume that 3.0 L were discharged for the sake of our discussion.
Remove the drain bolt (keep a large pan underneath) and let the oil drain out completely.
Clean the drain bolt and reinstall it. Reattach the oil return line back to the radiator.
Measure the amount of oil in the large pan and add it to the volume discharged from the oil return line. The total volume will be approx. 5.0 L.
Using a thin tipped funnel, add 5.0 L of Mitsubishi Diaqueen ATF SPIII oil.
NOTE: This is the only oil recommended in the owner's manual without any mentioned of acceptable alternatives. Therefore, my recommendation is to stick with this oil only and not use ATF SPIII oils of other brands. Mitsubishi has specifically formulated its oil for use in its CVTs of this era.
Remove the oil return line from the radiator. Connect the transparent hose and angle it downward into the catch can (container).
Start the car and observe the oil flow in the transparent hose while also monitoring the level in the catch can. The old darkened oil should be flowing into the catch can and around the 3.0 L to 3.5 L mark the old will cease to flow and you will see the fresh oil bright red in colour flowing in the transparent pipe. Switch off the car at this point. Remove the transparent pipe and reattach the oil return line to the radiator.
Measure the volume of the oil discharged and refill fresh oil of the same volume using a thin tipped funnel. Approx. 3.0 L to 3.5 L will be discharged and same will required to be refilled.
Take the car for a test drive till the temp needle is in the middle. Then park the car on a level surface and check the oil level as given in the owner's manual/FSM. Top up the fluid level if low. In my case approx. 8.5 L were used in total.
Pics of old oil which has darkened significantly and become opaque:
h
Pic of fresh oil which is bright red in colour and transparent: