Thermostat gone bad???

[2ndAmend]

Drove the RE for the first time in about 2 weeks, perfect dry sunny 72deg day. About 3mi down the road driving 35mph, the aux fan comes on. Temp was about 200, it cools to 183 or so, then the temp climbs back to 197, then cools to 183, then fan comes on again, climbs to 203, then goes down again.

I never saw anything like this. I'm guessing the thermostat is sticking. Does this sound right? Has anyone seen this before? Thoughts? Thanks!

 

[Jimmy N.]

Closest to that I've seen is with the V6 Challenger.

It seems to vary (somewhat rapidly) between 190-something and 206. Back and forth, back and forth.
Don't think the fan comes on, though. And last time I drove it was when it was unusually warm, maybe 85, and then it didn't do it. Maybe the thermostat got tired of the constant on/off?

 

[2ndAmend]

Closest to that I've seen is with the V6 Challenger.

It seems to vary (somewhat rapidly) between 190-something and 206. Back and forth, back and forth.
Don't think the fan comes on, though. And last time I drove it was when it was unusually warm, maybe 85, and then it didn't do it. Maybe the thermostat got tired of the constant on/off?

So it still does this occasionally? The S2 has a 180 stat so what I see is similar but a lower range. And it never did this before, the S2 was installed March 2024.

 

[Jimmy N.]

I dunno, haven't driven it since. Either way, it's bone stock, including the thermostat.

 

[2ndAmend]

Also, the Stage docs give the p/n for the Mopar 180 stat as 82215542, but my searches suggest this number does not exist outside of Stage documentation.

Anyone know a highly reliable stat brand that hopefully makes a 180 that fits the HC?

 

[Jimmy N.]

I recall, DGatzby knows which ones don't work.

 

[2ndAmend]

Does anyone know if Mishimoto's are good? Summit has a 180 for $65

 

[2ndgen]

MotoRad/Stant has taken over the market. Nearly all brands are just repackaged and say MotoRad on the part (including Mopar and Gates).
I think the only brand holdouts are Mishimoto and Milodon.

 

[2ndAmend]

MotoRad/Stant has taken over the market. Nearly all brands are just repackaged and say MotoRad on the part (including Mopar and Gates).
I think the only brand holdouts are Mishimoto and Milodon.

Thanks. What's the word on where the brands rate for quality?

 

[rookerrobert]

Does anyone know if Mishimoto's are good? Summit has a 180 for $65

thats what I have in my car and never had a problem and thats what my son has in his.

 

[DGatzby]

I recall, DGatzby knows which ones don't work.

Never had one fail my friend. I have used the cheap MotoRad or less since we changed them tuning the 2006 SRT 300’s. I remember paying like $15 for whatever I am using back in the day. I think my RE has a used one from either @EricG or me in it now. @2ndAmend your description sounds like a hot day operation? Fans can make noise on and off depending on how narrow you have the temp settings.

 

[Jimmy N.]

Sorry, guess I remembered wrong. Your name came to mind when thinking thermostats, for some reason.

 

[2ndAmend]

Never had one fail my friend. I have used the cheap MotoRad or less since we changed them tuning the 2006 SRT 300’s. I remember paying like $15 for whatever I am using back in the day. I think my RE has a used one from either @EricG or me in it now. @2ndAmend your description sounds like a hot day operation? Fans can make noise on and off depending on how narrow you have the temp settings.

72deg, usually just sits at 183 or so. Never saw this see-saw crap before. I'm ordering a new stat. Thanks.

 

[DGatzby]

72deg, usually just sits at 183 or so. Never saw this see-saw crap before. I'm ordering a new stat. Thanks.

At 72 that seems strange. I agree a cheap fix, you hope. You do need to expect it to cycle the fans.

 

[EricG]

I could probably write a book on thermostats and coolant temperatures with the stock tune and fan settings, but it sounds like the OP and @2ndAmend both are running tunes with adjusted fan settings, so numbers in the 180s should be expected with little variance. If your temp is bouncing around @2ndAmend I would change that tstat.

In my very recent experience I would only trust the Mishimoto or Milodon units. I run the Milodon - with the stock tune - so I do drive with a CEL all summer long

 

[DGatzby]

I could probably write a book on thermostats and coolant temperatures with the stock tune and fan settings, but it sounds like the OP and @2ndAmend both are running tunes with adjusted fan settings, so numbers in the 180s should be expected with little variance. If your temp is bouncing around @2ndAmend I would change that tstat.

In my very recent experience I would only trust the Mishimoto or Milodon units. I run the Milodon - with the stock tune - so I do drive with a CEL all summer long

You need to get yourself a little corrective tune for that thing and really enjoy it.