Description
Replaces OEM p/n 059121737R and 059121737AM
A fancier version of my original bypass valve delete redesigned and verified off of a 3D scan of the stock part. By exactly matching the OEM part’s profile the OEM hose can be used, allowing for easier installation.
The stock bypass valve is part of a divorced coolant loop between the cylinder head and engine block in the Gen2 (and Gen3) engines and is controlled by the ECU to regulate coolant in the engine block 15C higher than the primary thermostat (which itself is also has partial ECU control :P)
This is to allow the oil in the engine block to run slightly thinner, marginally increasing efficiency at the expense of slightly worse lubrication. Not only is this valve simply unnecessary, it is notorious for leaking through the shaft and cracking at the junction between the paper-thin coolant barb and the valve body.
If the vacuum bag ruptures, the valve becomes uncontrolled and can lead to overheating.
The stock valve can close almost completely so that coolant is stagnant in the cylinder block loop, especially in cold ambient temperatures. At warmup, and peak operation, the valve remains fully open.
With this valve deleted, not only is the OEM part’s leak and failure points removed, but the cylinder block coolant temperature is now regulated to 90C by the primary coolant thermostat, allowing it to run cooler and slightly thicker oil film on cylinder walls.
Will you notice any difference? No, and this part has NO effect on warmup time as the OEM valve is fully opened during warmup.
Anodized black to match upcoming cooler delete kit, although this is totally for aesthetics, as this part sits on the cast aluminum sandwich plate, there is no corrosion from dissimilar metals.
As usual, all machining and finishing is done in the USA.
Country of Origin:
- Flange: United States
- Seal: Germany
