2G Thermostat Pinhole

[No_Skillz]

I just bought a thermostat from NAPA that does not have a pinhole around the outside ring like the OEM one does. From my limited knowledge, I thought the pinhole was there to help the head fill after coolant has been drained.

Should there be a pinhole? Are there any drawbacks from not having a hole other than waiting a little longer for the head to fill? Does anyone run one of these thermostats?

 

[snowborder714]

Are you talking about the jiggle valve?

If so, I'd say it's important as it allows air to escape and not become trapped in the cooling system.

I can't give an answer as to whether you need it or not in our cars. All the ones I've bought had them in.

I've also read that it's recommended to install the thermostat with the jiggle valve at 12 o'clock, but again, I don't know how important this is.

 

[JusMX141]

I've been drilling every thermostat I install lately with one hole exactly what you're describing, whether it was intended to have a bleed hole from the factory or not.

The hole prevents steam buildup and airlocks in any system but it's big enough to add any noticeable time to a car's warmup procedure.

 

[No_Skillz]

Thanks Brian and Justin. I'm going to try this thermostat out since in my mind the air should bubble out when it opens. I'll just have to be as vigilant as ever about my coolant levels.

Edit: I've just decided to drill my own little hole. Ha.

 

[snowborder714]

Justin, what size hole do you normally drill?

 

[JusMX141]

I can't recall....I believe it's either 3/32" or 7/64". Any hole is better than none.

 

[JusMX141]

I'm actually at work now, so I was able to look this up to verify what Mike had opened with....

I looked up the t-stat for a 2G (Stant #14078, 180*f) and it does not have a jiggler / pinhole either. The 1G t-stat (Stant #13869, 195*f) DOES have the jiggler. Weird. It's possible that it has to do with the 2G t-stat being mounted on the side of the thermostat housing while the 1G t-stat drops in from the top.

I'd drill the hole anyway....it's not going to hurt the function of the thermostat, and it would never allow an airlock to exist anywhere in the system.

 

[No_Skillz]

I just used a 5/64" drill bit. I figured, like Justin, that any hole would be better than no hole. If it's too small, worst case scenario is that it takes air a bit longer to escape. If it's too big, worst case scenario is that the car takes a little longer to warm up. I also installed at the 12 o'clock position just like the previous one. This thermostat is a 170*F unit.

 

[1992awdlaser]

The hole will help prevent unusually high temps when stopped in some cars also. Don't know if it would be a problem with these cars though. GM's are the ones I know of that have the problem.

 

[Defiant]

I just bought a thermostat from NAPA that does not have a pinhole around the outside ring like the OEM one does.

Look again. If your replacement doesn't have a vent hole, or a vent hole with a jiggle valve (nice thing to have wear-through and wander-off to..... where?), it'll have a dent on the edge of the valve face that does the same thing. It's all that's needed. You're only venting air, and it gets through the smallest opening. There's never a need to drill a thermostat periphery.

However, 170° is too low for a DSM. Stay with 190°.

 

[z24frank]

Why do we need to stay with the 190?I just put my 170 in from autozone and the only other option was a 192.I always thought the lower was better.

 

[cali]

not necessarily, the ecu needs to see about 180-190 degrees for optimum performance.

 

[Jeff99GS]

Why do we need to stay with the 190?I just put my 170 in from autozone and the only other option was a 192.I always thought the lower was better.

The ECU needs to see 190*-195* to know the engine is at normal operating temp. If temps are always at 170* the ECU will change the fuel maps to try and bring the engine up to normal operating temp (190-195)

This will result in poor gas Mileage and could affect tuning performance.

Get that 192* T-stat

 

[1992awdlaser]

For the ecu to go into learn mode on a 1G the temp must be greater than 190*. On a 2G it must be greater than 180*.

 

[snowborder714]

This is where DSMlink's Coolant Offset comes in handy

My car hardly ever gets above 180ish without the offset. I added 5-7* with the offset so the ECU gets the temps it wants.

 

[JusMX141]

DSMLink is a hell of a tuning tool, for sure.

But honestly from what I've found with doing tons of logging on different cars, the cars with a 195* stat seem to cycle around 205*, and the cars with a 180* stat cycle around 190*-195*. I'm keeping a 180* stat in all of my cars just be sure it stays below 200*.

 

[1992awdlaser]

DSMLink is a hell of a tuning tool, for sure.

But honestly from what I've found with doing tons of logging on different cars, the cars with a 195* stat seem to cycle around 205*, and the cars with a 180* stat cycle around 190*-195*. I'm keeping a 180* stat in all of my cars just be sure it stays below 200*.

This is because the temperature rating of the thermostat is for when it starts to open.

 

[need2boostpsi]

I always drill the Jiggle valve out, as Defiant stated i wouldn't want it wandering around in my cooling system.

 

[JusMX141]

This is because the temperature rating of the thermostat is for when it starts to open.

Right- I was just going along with what Jeff99GS was stating about having the car run at 190*-195*....if you want the car to run at a constant 190*-195*, you'd want to use the 180* thermostat. I took it he was implying that if you use a 170* t-stat that your car will never go above 170*, and that's not the case.

 

[Jeff99GS]

Right- I was just going along with what Jeff99GS was stating about having the car run at 190*-195*....if you want the car to run at a constant 190*-195*, you'd want to use the 180* thermostat. I took it he was implying that if you use a 170* t-stat that your car will never go above 170*, and that's not the case.

Sorry i didnt' mean for it to sound that way...however a 170 t-stat isn't hot enough for a stock DSM. 180 as you suggested might be the best for summer use! Unless you want a HOT ass heater...then go with the 195-205*
The t-stat opens at its set rate, but a 2g radiator fan doesn't kick on till about 210* So the temp will never stay at the exact temp stated on the t-stat....that's just it's opening point.

Z24frank said he had a choice between 170* and 192*....I think he should go with the 192* IMO

 

[Defiant]

This is because the temperature rating of the thermostat is for when it starts to open.

When it starts to open, or when it's fully open? I thought it was "fully".

 

[JusMX141]

I think it's when it starts to open, but I could be wrong. I'm just going by what I'm reading on the logger....a 180* stat will yeild a 190*-195* coolant temp.

 

[1992awdlaser]

When it starts to open, or when it's fully open? I thought it was "fully".

All the manufacturers I have talked to say that's when it starts to open. There might be some that are different though.

 

[No_Skillz]

Like Brian, I plan on using DSMLink's coolant offset to give the ECU that higher temp while running cooler in reality. In my mind cooler is better (to a certain degree, of course [pun intended]) and hopefully this could help me reduce some knock.

As for the thermostat rating, I'm fairly certain that the temp is when the thermostat starts to open. If it were fully open, the 170* and 160* thermostats on the market would never allow the car to warm up, or it would only bandaid a faulty cooling system in which case it would only delay overheating.

 

[Defiant]

Eh, I suspect a distinction without a difference. After all, once it starts to open, why would it not open all the way?
Just for reference, "fully open" on a round valve seat is when raised ¼ the diameter.