GetaDomTune cylinder 4 cooling mod! Showing cylinder 4 that you still care!

Hey!... Welcome to #modmonday! This week we will be speaking about @getadomtune cylinder 4 cooling mod. This was released during last summer and I decided to give it a go on the STI. With all the logic and science behind it just makes sense. 

Simple, yet effective. Nothing too flashy here.

Simple, yet effective. Nothing too flashy here.

Ask any Subaru owner about issues and most will say something along the lines about cylinder 4 and ringlands. With many debates over why these issues occur... Dom notes that cylinder 4 sees the hottest coolant temps due to a lack of flow. The driver's head sees a dead end to coolant flow that stagnates and raises temp cylinder temps for cylinder 4. 

Borrowed from Dom’s post on nasioc. Upper temps are before the cooling mod and lower are after.

Borrowed from Dom’s post on nasioc. Upper temps are before the cooling mod and lower are after.

These higher cylinder temps also come into play as Subaru decided to locate the knock sensor nearest to cylinder 4 for this very reason. If cylinder 4 isn't knocking than the other 3 most be fine..... Yes, that is the logic there. Leaving cylinder 4 to see the highest coolant temps, least amount of fuel and most aggressive tuning. It makes you feel bad for cylinder number 4... Subaru's unloved cylinder on the Ej motor. 

The coolant galley plug is not the easiest thing to reach. But it can be done from the top side of the engine.

The coolant galley plug is not the easiest thing to reach. But it can be done from the top side of the engine.

So back to the mod, this small hose ties into the return line off the heater core. Which is a suction line to the water pump giving cylinder 4 the much needed flow it deserves. Dom also notes how this is used on the passenger side of the head through the turbo and even with all that extra heat the temperatures are kept in check on the passenger side. 

Hard to see with the other heater hose connected. So after it was finished I quickly snapped a photo.

Hard to see with the other heater hose connected. So after it was finished I quickly snapped a photo.

Installation of this modification are pretty straight forward. With a galley plug on the back of the driver's side head removed and the heater core hose line cut. You are on your way to having it completed. Add your clamps and breathe a sigh of relief knowing your cylinder 4 thanks you for your efforts. 

This has been installed for the last 4 months and it has been problem free. You will need a day to let the gasket sealer dry in order to keep it from leaking down the road. I can’t say I have tested any of these claims but watching his Youtube videos and reading through many forum posts puts my mind at ease. That this is well worth the money and effort.

Questions, comments, thoughts? Leave them below! 

These can be found at Dom’s website: Getadomtune.com or Iag Performance.

Dan Engstrom4 Comments