DodgeaWrench Posted November 3 Report Share Posted November 3 [2014 DJ 3.6 177k miles] Solid yellow check engine light came on. Code P0128 - Coolant Temperature Below Thermostat Regulating Temperature. This occurred once before, approximately 5 years ago, so I had a clue as to what was happening. While taking a "test" drive, I toggled through the display to show coolant temperature. Coolant temperature would not rise above mid-180 Fahrenheit. (My understanding is that it normal should be above 200-ish). Time for another thermostat. As repairs go, replacing the thermostat is one of the easier repairs to do (2 10mm bolts and a spring clamp, easy access). Having a spring clamp tool (on a cable type) makes it a breeze. As mentioned, mine was replaced once before at 109K miles Jan-2020 $260.00 (repair shop, not dealer). A Mahle brand thermostat was installed. I went to a repair shop instead of doing it myself as it was the middle of winter and I do repairs in the driveway. This time it is a beautiful fall weekend to take advantage of, with winter soon to knock on the door. No time to order an OEM. I went to the local auto parts store and purchased a Murray brand thermostat $19.00. After the swap, the code was reset and a small test drive afterwards had the temps rising into the low 200's with the check engine light stayed off. Next is to watch for leaks. I'll post a follow-up in about a week. The old thermostat in location The new Quote Link to comment Share on other sites More sharing options...
yyz Posted November 3 Report Share Posted November 3 Worst part I find is that stupid plastic bleeder screw.I replaced mine with a brass one. Quote Link to comment Share on other sites More sharing options...
larryl Posted November 3 Report Share Posted November 3 I just reset mine I like it running cool.... Quote Link to comment Share on other sites More sharing options...
14WhiteRTRallye Posted November 5 Report Share Posted November 5 Mopar stat is a Mahle in a Mopar box. I found out the expensive way. 2late4u 1 Quote Link to comment Share on other sites More sharing options...
Daniel Anderson Posted November 6 Report Share Posted November 6 Larryl what oil temperature are you getting Quote Link to comment Share on other sites More sharing options...
larryl Posted November 6 Report Share Posted November 6 usually around the same as the coolant temp rarely over 205* I use 5-30 oil also approaching 210000 miles no consumption so far Quote Link to comment Share on other sites More sharing options...
Daniel Anderson Posted November 13 Report Share Posted November 13 (edited) OK I decided at plus six Celsius today to replace thermostat and housing as it has been stuck at 85 Celsius all Summer (code thrown). What I found out is that NAPA's replacement thermostat housing mounting holes and bolts are too big for my engine. (Dorman OE solutions Part No. 902_3036XD).My original (OEM) was 7 mm Dia. (Included metal bushings inside plastic housing) Now I was only able to use new thermostat, rubber seal, locking bracket and spring from ordered part C a u t i o n Please compare sizes before swapping out Edited November 13 by Daniel Anderson Added supplier name Quote Link to comment Share on other sites More sharing options...
Daniel Anderson Posted November 13 Report Share Posted November 13 8 minutes ago, Daniel Anderson said: OK I decided at plus six Celsius today to replace thermostat and housing as it has been stuck at 85 Celsius all Summer (code thrown). What I found out is that NAPA's replacement thermostat housing mounting holes and bolts are too big for my engine. (Dorman OE solutions Part No. 902_3036XD).My original (OEM) was 7 mm Dia. (Included metal bushings inside plastic housing) Now I was only able to use new thermostat, rubber seal, locking bracket and spring from ordered part C a u t i o n Please compare sizes before swapping out Quote Link to comment Share on other sites More sharing options...
5rebel9 Posted November 13 Report Share Posted November 13 8 hours ago, Daniel Anderson said: INTERESTING..... My shop owner friend swears by the aluminum housing T-stats for ALL the 3.6 engined models. He has them on all his own and family's cars and EVERY taxi minivan fleet he services with NO PROBLEM. With my own 3 3.6 motored DJ's, I;ve only replaced once each on our '11 and '13 with the plastic Dorman units for stuck open stat. I wonder if I have just been "lucky" or something. Quote Link to comment Share on other sites More sharing options...
Daniel Anderson Posted November 13 Report Share Posted November 13 Ya the bolts (too wide) they gave me don't even fit the holes in the housing ! Quote Link to comment Share on other sites More sharing options...
5rebel9 Posted November 13 Report Share Posted November 13 Without looking up the bolt spec.'s, I'm pretty sure the 2 bolts for the "stat" are 6mm, so the holes in the cover should be a little bigger. Are you sure they sold you the correct bolts? Your pic. can't tell definitely, but bolt looks to be an 8mm, and definitely would not be correct for engine or stat housing. Quote Link to comment Share on other sites More sharing options...
Daniel Anderson Posted November 14 Report Share Posted November 14 (edited) I will remeasure for you, the bolts they gave in the box. My eyes are not good for vernier caliper after decimal. But for the two replacement bolts: 29.6 mm x 9.8 mm. (D 10.9 cap head) Edited November 14 by Daniel Anderson Missing letter T for he Quote Link to comment Share on other sites More sharing options...
Daniel Anderson Posted November 14 Report Share Posted November 14 Thermostat housing hole size: 7 mm diameter Quote Link to comment Share on other sites More sharing options...
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