colder thermostat

[Uberoo]

The engine in my EA81 based off-roader is a phase 1 ej22 (90-94).Even though that engine is fairly reliable and bombproof I still have had several failures with it.The most recent failure was oil related-either the engine got starved of oil at high RPMs or the oil pump died.Anyway I am putting together a replacement engine and I was thinking I could address another potential failure point.As I mentioned before this engine goes in my offroader so it spends its time warming up and then getting submerged in water, then warming up,submerged,etc. Stock T-stat opens at 78*C/172.4*F and the engine currently runs 180-190, I am thinking a 160*F T-Stat would allow the engine to run at about 168-180*F so I am thinking a colder thermostat would help keep the engine just a little cooler and maybe lessen the thermal shock the engine goes through every time I go through a mud hole.I know a lower thermostat wont lower full load temps because a t-stat only sets the lower limit of operating temps and that if I am having a cooling problem a radiator cleaning might be in order.My problem is the engine is stuffed into an 81 hatch and I am already using a legacy radiator, space around the engine is a little tight and as a result it has always ran a little warmer than I would like so I am thinking a slightly cooler thermostat might help that a little bit.I know that when the engine is below operating temp it increases wear,uses more fuel,etc but engines in my offroader only seem to have a lifespan of about 1-1.5 years so anything I can do to extend that is welcome,because a year is a drop in the bucket for these engines under normal use but its an eternity in the offroader.

[Fairtax4me]

Proper cooling system function is more important than a lower t-stat temp.

It's also very important to use the OE style thermostat since it is more able to handle quick temperature changes.

 

Proper running temp for these engines is about 200°, so even at 190 you're still below the normal temp for a road driven car.

 

Driving into water isn't going to bother the engine one bit as long as the bypass route of the cooling system is flowing properly.

The bypass comes from the water crossover, through the heater core(on a stock setup), then back to the water pump on the back side (spring side) of the thermostat. The bypass route is there to help keep the thermostat open in cold temperatures or if there is a sudden change in inflowing coolant temp. (Such as driving into water)

It does this by mixing hot coolant from the bypass with cooler coolant from the radiator right on top of the thermostat. This will allow for a gradual change in thermostat opening, rather than going from completely open to completely closed.

A benefit of using an OE style thermostat is that the larger mass of the OE stat holds heat longer and does not react as quickly to changes in coolant temp that may cause a cheap aftermarket stat to close and stay closed.

 

I'd stick wih the OE temp setting, and OE design. Just make sure that coolant bypass is connected and free flowing. (Heater core not plugged)

[1 Lucky Texan]

Mishimoto (and I think someone else?) makes a 'racing' t'stat that is cooler.

 

but I'm not convinced you'd nee it in your application. But you definitely don't want a cooler, aftermaket that ISN"T built with the larger wax capsule, if the t'stat housing was submerged, it might slam shut.

 

hmmm, have you considered some kind of wrap or insulation on the t'stat housing and lower radiator hose? Might help stabilize temps.

[Uberoo]

even with the oem t-stat when it hits water the temp drops like a stone.

[WoodsWagon]

Do you have the heater hooked up to it? Are you using a heater flow shutoff valve that limits circulation through the heater core?

 

The EJ needs full coolant flow through the heater core and back to the water pump housing all the time to correctly operate the thermostat. I used to have my EJ22 in a loyale with an EA82 radiator in water up to top of the wheel wells pretty often and never had any problems other than the automatic seat belts freaking out when they were wet.

[NorthWet]

I would bet that the sudden lowering of engine temperatures is due to water on the engine surfaces in general, rapidly drawing off heat from the water jackets. 

 

These engines can dissipate a lot of heat from the engine just to the surrounding air... enough so that a radiator is hardly needed in cold weather.  Imagine what happens when water is sprayed all over it?

[Rooster2]

If you simply want to run at a lower temperature, then run without a thermostat. It may not idle well when the motor is cold, but as an off road "mudder," who cares.