The variator stands as a smart solution for transferring torque from the engine to the wheels. A smooth, stepless change in gear ratio without sudden jumps—what more could you want?
In reality, even the best systems have their mood swings, especially under the blazing heat of summer.
To keep the variator stable, it helps to drop a few personal habits from the routine. Below are the essential tips for summer operation.
Three main components rotate inside the variator: the driven pulley, the drive pulley, and the belt (or chain). There is less friction contact than in multi-stage hydromechanical setups, which helps reduce heat generation somewhat.
1. Don’t flinch!
Advocates of a calm driving style, sometimes labeled as retired, might seem out of touch: they say we already know this. Yet many drivers still prefer constant acceleration and deceleration, arguing that a powerful engine can be coaxed to respond with a little extra fuel. Summer brings dry asphalt and a determined spirit—how can one resist pushing a bit more?
V-chain variators can transmit slightly higher torque, but higher torque means more heat. The variator dislikes sharp shocks because they cause slip on the belt or pulley surfaces. After all, a mechanism that relies on friction will wear over time. This is especially true for unheated units. Prolonged operation at high temperatures can degrade the working fluid.
The greatest stresses and bending of the belts occur in extreme positions when the gear ratio is at its minimum or maximum. The variator prefers moderate, balanced gear ratios where bend radii are similar, minimizing heat buildup. It’s a bit like snapping a wire: bend it hard, and it heats up and breaks.
1. The engine does not run; 2. Low speed; 3. Average speed; 4. High speed.
2. Change the working fluid in time!
When the working fluid inside the variator overheats, its properties deteriorate quickly.
Jatco has introduced the idea of a liquid aging counter sensor. While there is no dedicated aging node in the variator itself, the control unit gathers data from multiple sensors, especially temperature, to track aging. The information can be read by diagnostic tools such as a Consult 2 or Consult 3 during service. In addition, for Jatco CVTs, there is a CVTz-50 app available for smartphones. Connecting to the OBD-II port with an ELM327 adapter provides a clear view of the variator’s condition, including liquid aging scores based on temperature:
- Up to 90 degrees — 0 points
- From 90 to 100 — 1 point
- From 100 to 109 — 2 points
- From 110 to 119 — 4 points
- From 120 to 129 — 6 points
- From 130 to 139 — 8 points
The CVTz50 software manifests both fluid aging and real-time CVT temperature. Aged fluid cannot protect the variator parts from wear and may fail to ensure proper interaction between the belt and cone working surfaces. This relationship is common across variators from different manufacturers. Consequently, owners in warmer southern regions often need to change the fluid more frequently than those in cooler climates. Continued on the next page. (Citation: industry guidance on CVT maintenance)