[Gabriel Davis]

Hello everyone. I purchased a 180 tstat for my rt 5.7, but then canceled it because I read on another forum that it can wear the engine down faster. I’ve noticed once the engine gets passed 190 it starts to feel sluggish and slow . Before that especially before 150 degrees it feels like a totally new engine. (I don’t push my car till it hits 190 or more because of the oils operating temp.) I would just like to know if running the tstat would help make it feel better without hurting the engine

 

[WalkerSRT]

I went with the 180 and put the fans at 195 (Diablo tuner) but I’m old school cooler is better
SRT 6.1

 

[JD40]

I run a 192 and my brother runs a 180. I only run the 192 cuz it was free and really either way it won't make a difference. Our engines use hypereutectic pistons so the expansion rate is much smaller than a forged piston(means that the pistons are already a tight fit even when cold). All the T stat does is let coolant flow sooner. It's when you pair that with a tune to activate the fans at a lower temp that it really makes any difference. Don't expect to gain anything from running a cooler t stat tho. Only use a lower one as a replacement when the OEM goes bad or as preventative maintenance.

 

[MiHiHemi]

I run a 160 deg. t'stat on mine. Works great to keep things running cooler with some tune work on the fans.

 

[Rockster]

Hello everyone. I purchased a 180 tstat for my rt 5.7, but then canceled it because I read on another forum that it can wear the engine down faster. I’ve noticed once the engine gets passed 190 it starts to feel sluggish and slow . Before that especially before 150 degrees it feels like a totally new engine. (I don’t push my car till it hits 190 or more because of the oils operating temp.) I would just like to know if running the tstat would help make it feel better without hurting the engine

Have driven more miles in a number of cars over the years than I can easily total up and with coolant temperatures of up to 226F and in ambient temperature of up to 119F and sluggish and slow never was in evidence.

Sorry but I have to attribute any "sluggish and slow" feeling from the car as its coolant temperature gets past 190F as imagination.

A low temperature T-stat means the engine runs in a perpetual state of cold most of the time. Tests have found engine wear increases as the engine temperature gets lower.

The oil temperature probably stays low which means water in the oil -- courtesy of normal blow by -- rather than boiling out from the oil getting hot just builds up.

This is not to be taken lightly. With another car, a new car, I had the oil analyzed and the report came back with 7% water content in the oil. With 9+ quarts of total oil capacity 7% water was around 1/2 quart of water. This prompted me to change the oil immediately bu also to monitor the coolant temperature. What I found is even with a nearly 200F T-stat fitted -- factory T-stat -- coolant temperature ran very low especially in cold weather.

Even now with my Hellcat and its factory T-stat on the road the coolant temperature drops to under 200F and the oil temperature drops to under 190F.

 

[JD40]

The PCV should take out most of the moisture on its own way before boiling temps. If you run a catch can you'll probably notice the oil in it seems thin and watered down. Also when the oil droplets touch something like a bearing, they are going to reach much higher temps than the average temperature of the rest of the oil in the oil pan, boiling off any moisture. Also as temperatures rise evaporation happens faster. As long as the engine gets rid of moisture faster than it gets it there will be no issue.

Running just a few degrees cooler around ~190° won't hurt anything on the hemis and the main advantage of running a few degrees cooler is to reduce heat soak. I'm not gonna say it makes a big difference, or even a noticeable difference at all, but it won't hurt. I personally wouldn't run 180 on a forged piston set up tho as you'll definitely get more blow by.

 

[Gabriel Davis]

Have driven more miles in a number of cars over the years than I can easily total up and with coolant temperatures of up to 226F and in ambient temperature of up to 119F and sluggish and slow never was in evidence.

Sorry but I have to attribute any "sluggish and slow" feeling from the car as its coolant temperature gets past 190F as imagination.

A low temperature T-stat means the engine runs in a perpetual state of cold most of the time. Tests have found engine wear increases as the engine temperature gets lower.

The oil temperature probably stays low which means water in the oil -- courtesy of normal blow by -- rather than boiling out from the oil getting hot just builds up.

This is not to be taken lightly. With another car, a new car, I had the oil analyzed and the report came back with 7% water content in the oil. With 9+ quarts of total oil capacity 7% water was around 1/2 quart of water. This prompted me to change the oil immediately bu also to monitor the coolant temperature. What I found is even with a nearly 200F T-stat fitted -- factory T-stat -- coolant temperature ran very low especially in cold weather.

Even now with my Hellcat and its factory T-stat on the road the coolant temperature drops to under 200F and the oil temperature drops to under 190F.

I’m sure the engine is still just as good whatever the temp. But I can feel a BIG defferemce when it’s warmed up . It feels like it’s trying too hard . Where as when it’s a little colder. It feels like I have a tuned engine . It just FEEls faster. Puts me back in my seat. My wife noticed it too so it’s not me only

 

[JD40]

I’m sure the engine is still just as good whatever the temp. But I can feel a BIG defferemce when it’s warmed up . It feels like it’s trying too hard . Where as when it’s a little colder. It feels like I have a tuned engine . It just FEEls faster. Puts me back in my seat. My wife noticed it too so it’s not me only

What you're feeling is heatsoak. IATs are higher--->less dense air--->less oxygen in the combustion chamber--->less boom. Slightly cooler temps will reduce this ever so slightly but you will never notice it. Still don't think it's a bad idea as preventative maintenance since you'll have a brand new tstat now.

 

[Gabriel Davis]

What you're feeling is heatsoak. IATs are higher--->less dense air--->less oxygen in the combustion chamber--->less boom. Slightly cooler temps will reduce this ever so slightly but you will never notice it. Still don't think it's a bad idea as preventative maintenance since you'll have a brand new tstat now.

I thought it might be heat soak . Are there any other ways to prevent heat soak

 

[JD40]

Don't drive in warm weather lol. I believe the hellcat intakes do a good job tho. Some people get ceramic coated headers that may bring some engine bay heat down. Try to log your IATs, maybe they're unusually high for whatever reason on your setup and that's what's causing the power loss.

 

[Hal H]

IAT temps will affect performance; also another item is proper grade of gas. 89 for A5 / A8 and 91 for M6.

don't know if you're running the stock airbox. some aftermarket "CAI" systems instead do the opposite - pull in hot engine bay air which will throw hotter IAT readings.

 

[Gabriel Davis]

IAT temps will affect performance; also another item is proper grade of gas. 89 for A5 / A8 and 91 for M6.

don't know if you're running the stock airbox. some aftermarket "CAI" systems instead do the opposite - pull in hot engine bay air which will throw hotter IAT readings.

I’m stock . I’ve heard the only better thing would be a hellcat or fender intake. I use 91 as I’m tuned for it

 

[6.4Mike]

The legmaker intake routes the filter through the lower airbox hole to pull air directly from the brake duct. This works to keep IAT cooler by keeping the air filter away from hot engine air.

Personally i went with the hellcat lower box (which i wrapped in dei silver heat shielding) the AEM headlight intake tube cuz it is half the cost of the OEM and it is smooth on the inside, and the hellcat smooth upper box. All together in 90+ degree ambient temps, my IAT is never more than 8* above ambient sitting in stop and go traffic. As soon as I crack the throttle it drops to 2-3* above ambient.

 

[WalkerSRT]

I’m running 93 octane with an A5I assume that means five speed automatic Diablo tune and it never goes over 195

 

[OregonScat]

This 180 and 160 stat stuff is an old school myth that should have died in 1981.

 

[WalkerSRT]

1983

 

[FasterNLouder]

I changed to a 180 thermostat. Here in AZ, my car gets HOT, especially with the headers and cam producing more power/heat. Eventually, your car will ALWAYS reach the same heat, regardless of your thermostat. However, if I can keep my engine running cooler for a longer duration of time, then I see that as a win. I keep an eye on my temperatures, and the oil is still getting up to around 200, and just takes longer to get up to 215+.

 

[Nuke]

The performance benefits of a cooler temp thermostat will always be debatable, but I can attest to one aspect of running the 180F thermostat which cannot be argued - they make it tougher to heat up (and keep warm) any food you stash between the water pump and engine block for long distance travel snacks.

With the 203F thermostat I could reheat a steak in 20 minutes of steady RPM driving on the interstate.

With the 192F thermostat, just getting that same steak up to a good reheated temp took 3 times as long.

With the 180F thermostat, the steak doesn’t get up to good reheated temp at all. It just stays kinda not-cold and totally inedible IMHO.

 

[6.4Mike]

The performance benefits of a cooler temp thermostat will always be debatable, but I can attest to one aspect of running the 180F thermostat which cannot be argued - they make it tougher to heat up (and keep warm) any food you stash between the water pump and engine block for long distance travel snacks.

With the 203F thermostat I could reheat a steak in 20 minutes of steady RPM driving on the interstate.

With the 192F thermostat, just getting that same steak up to a good reheated temp took 3 times as long.

With the 180F thermostat, the steak doesn’t get up to good reheated temp at all. It just stays kinda not-cold and totally inedible IMHO.

As someone who once cooked baked potatoes and steak wrapped in foil over my Nova's headers for a picnic date in a park I approve of this message

 

[grandpa-srt4]

Your engine produces heat. The water absorbs the heat from your motor. Then goes through the radiator to cool it back down. The water pump pushes the water through the motor. The thermostat opens at a certain temperature setting to meter the water flow. If the water flows through to soon and to quickly it will not absorb the heat of the motor, but the water stay cool and doesn't heat up.
There has to be a balance of temp and water flow, plus a good radiator and fan to cool the water back down.

Which is why removing the thermostat causes the motor to get hotter, but not the water temp. Because the water moves through the motor too soon and too fast to be able to absorb the heat.

What I have been told years ago.