[FramingLogic]

Good evening fellow enthusiasts,

I have been tip toeing the idea of a thermostat delete in the water cooling system. Have not exactly gotten far on my research so I hope someone has some feedback or has tried this! Will be doing a coolant flush tomorrow and replacing it with Distilled water for the summer.

[ferocity02]

I would definitely not do it. It's possible to overcool the engine when you delete the thermostat. Not to mention ours is pretty complex and I'm sure it serves several functions that you aren't aware of.

[screaminfast]

Yeah that's not a good idea at all. IIRC our thermostats are electronically controlled, so you'd have to code that out if that's even possible. Plus as ferocity02 said, you can overcool the engine and it will never get up to operating temp.

If you need better cooling, do a 70/30 water coolant mix, and add some water wetter.

[TBN54]

Unless you want to be scapegoat and actually do this.

Let us know how it goes.

[darkkevin]

your car will never go into closed loop operation, dme monitors won't run, gas mileage will suck, etc. also, why replace with straight water? coolant provides more than antifreeze ability, it lubricates seals and prevents corrosion. all cars are made to use coolant, not just water.

[Wolf 335]

Originally Posted by ferocity02

I would definitely not do it. It's possible to overcool the engine when you delete the thermostat. Not to mention ours is pretty complex and I'm sure it serves several functions that you aren't aware of.

I think that's why he's going with the distilled water.

Still I don't think this is a good idea.

[patents]

Coolant lowers the freezing temperature of water and it also raises the boiling point. The engine normally operates at or near the boiling point of pure water. You start to boil the water in the cooling system, and the closed loop system turns into a pressure vessel until something bursts to relieve the pressure. This is avoided by adding coolant, which raises the boiling point above normal operating temperatures.

[Tom K.]

Originally Posted by darkkevin

. all cars are made to use coolant, not just water.

Not quite as my first car, a 1952 Dodge, used straight water during the summer and an antifreeze/water mix in the winter.

But somehow, I think engines and cooling systems may have changed a bit since then

Tom

[The Cleaner]

I wouldn't remove your Thermostat, I don't think anything positive will result. I was reading about cooling system pressure the other day and found this very helpful, it covers the Water vs Coolant topic also.

http://www.tuneruniversity.com/blog/...-radiator-cap/

[E91 M Sport]

Originally Posted by Wolf 335

I think that's why he's going with the distilled water.

Distilled water has no counter effects to a thermostat delete nor should one use water (distilled or not) without an antifreeze additive. As mentioned before it not only lowers the freezing point and raised the boiling point it also lubricates the water pump and aides in fighting off electrolysis.

[AM330i]

I think you will do a lot of damage to your engine by using only distilled water. The coolant plays a critical role in keeping internal parts protected from rust and corrosion as well as keeping things lubricated. I have seen the insides of engines that were run on straight water for extended periods of time and its ugly. The thermostat also plays a critical part in making the engine run at its maximum efficiency. Engines are designed to run at a certain engine temperature range, outside of that range you will have problems. If it runs too cold, which in your case, without the tstat, it will never go into closed loop and possibly start throwing codes. Too hot, it will also throw codes and put you into limp mode. There are products that you can use with just water but using water alone is not recommended and I definitely would not run without the tstat If you do decide to try this, make sure you let us know how it turned out and maybe you can prove us wrong.

[Wolf 335]

If you decide to do this please provide a detailed review of the engine behavior from the initial tstat removal to final engine meltdown.

[FramingLogic]

Originally Posted by The Cleaner

I wouldn't remove your Thermostat, I don't think anything positive will result. I was reading about cooling system pressure the other day and found this very helpful, it covers the Water vs Coolant topic also.

http://www.tuneruniversity.com/blog/...-radiator-cap/

Sorry it's been a couple days, been on travels. Anyhow I did my homework on this subject and I think this is the best conclusion to draw. The car is always exposed to the heat down here, however all the delete would do is keep the car running cooler for maybe 15-20 minutes till it comes to operating temps. SO my answer is simple, it's pretty pointless to do a delete.

[FramingLogic]

Originally Posted by AM330i

I think you will do a lot of damage to your engine by using only distilled water. The coolant plays a critical role in keeping internal parts protected from rust and corrosion as well as keeping things lubricated. I have seen the insides of engines that were run on straight water for extended periods of time and its ugly. The thermostat also plays a critical part in making the engine run at its maximum efficiency. Engines are designed to run at a certain engine temperature range, outside of that range you will have problems. If it runs too cold, which in your case, without the tstat, it will never go into closed loop and possibly start throwing codes. Too hot, it will also throw codes and put you into limp mode. There are products that you can use with just water but using water alone is not recommended and I definitely would not run without the tstat If you do decide to try this, make sure you let us know how it turned out and maybe you can prove us wrong.

When you track a car, it is actually better to run distilled water. I have used 30% coolant to 70% distilled in the past, now running 20% water wetter to 80% distilled and it's the best I've ran so far.

To just let everyone know, the 335i is a track car, not something we run on the roads and it's really never exposed to temperatures under 80 degrees, this was the main reason for the thermo stat delete. Having a constant running cycle would give us a minor improvement in keeping the engine cooler (for maybe 20 minutes, which is pointless).

[Wires]

The quick answer is deleting the thermostat on a EFI vehicle will give you no end of issues. Best to just leave that alone.......

If you want to get lower temps you can keep using products like "water wetter".