Manche757 Posted April 30, 2019 Share Posted April 30, 2019 What temperature rating thermostat are most using in MJs? What was recommended by them? Link to comment Share on other sites More sharing options...
eaglescout526 Posted April 30, 2019 Share Posted April 30, 2019 Most everyone here is using factory recommended 195* Link to comment Share on other sites More sharing options...
Smokeyyank Posted April 30, 2019 Share Posted April 30, 2019 Yep, will only run the OEM 195 temp. Link to comment Share on other sites More sharing options...
Minuit Posted April 30, 2019 Share Posted April 30, 2019 195. Mopar thermostat strongly preferred. Link to comment Share on other sites More sharing options...
Manche757 Posted April 30, 2019 Author Share Posted April 30, 2019 There is no problem with overheating but only warm heat in the winter with gauge reading about 120 degrees. I assume it is stuck open or the spring is broken. I don't really care about lack of much heat here but I am going to have ac installed in a MJ that never had a/c. I thought it wise to not have to bang around a/c fittings later to replace it. My real question to MJ mechanics: Would you have the water pump replaced even if there are no problems with it at present? '89MJ, 4.0, 81K miles. Roll the dice: Yes? No? Link to comment Share on other sites More sharing options...
JMO413 Posted April 30, 2019 Share Posted April 30, 2019 Mopar 195 Thermostat part number is 83501426AD. It has the little bleeder in that makes getting the air out of the system easier. I would replace the water pump if you were doing it yourself. I wouldn't pay someone to do it if it's working. Link to comment Share on other sites More sharing options...
Knucklehead97 Posted May 1, 2019 Share Posted May 1, 2019 195 Mopar thermostat and I hardly ever get up to 195. Since I removed the dented AC condenser the airflow has been so good that even sitting in traffic it takes a WHILE to get to 195 Link to comment Share on other sites More sharing options...
Eagle Posted May 1, 2019 Share Posted May 1, 2019 5 hours ago, Knucklehead97 said: 195 Mopar thermostat and I hardly ever get up to 195. Since I removed the dented AC condenser the airflow has been so good that even sitting in traffic it takes a WHILE to get to 195 Then something isn't right, because the function of the thermostat is to shut off coolant flow through the radiator when the coolant temperature falls below 195 degrees. Link to comment Share on other sites More sharing options...
rylee144 Posted July 15, 2020 Share Posted July 15, 2020 I am in the middle of my coolant flush and pulled my thermostat. It's a 180. Could that be why I am running very warm, average 210 or a tad higher on a 80 degree day. Link to comment Share on other sites More sharing options...
Pete M Posted July 15, 2020 Share Posted July 15, 2020 10 hours ago, rylee144 said: I am in the middle of my coolant flush and pulled my thermostat. It's a 180. Could that be why I am running very warm, average 210 or a tad higher on a 80 degree day. no. the thermostat only affect the bottom end of the temp range. once it opens up, it does nothing more to the situation until the temp falls back down to 180. I would put a 195 back in. you want to maintain the proper heat range. too cool can be bad too. 210 is the normal operating temperature for a renix 4.0L. check for radiator condition, fan effectiveness, etc. Link to comment Share on other sites More sharing options...
rylee144 Posted July 15, 2020 Share Posted July 15, 2020 Thank you. So when I buy another one I should get a 180 or the 195? Link to comment Share on other sites More sharing options...
fiatslug87 Posted July 15, 2020 Share Posted July 15, 2020 195 Link to comment Share on other sites More sharing options...
75sv1 Posted July 15, 2020 Share Posted July 15, 2020 As stated before, the thermostat only controls the lower end. You do want to run at a certain temp to heat the oil. This removes water from the oil. With newer oils this might not be as much of a problem. I have seen congealed oil. It filled the oil pan. I would at least run a 195, a 197 or 205 for mileage. The 160 was used for drag racing in the early EFI days, late 80's. I tricked the computer and gave a bit better ETAs. There are other things to do for over heating. #1 trans cooler. Link to comment Share on other sites More sharing options...
Eagle Posted July 15, 2020 Share Posted July 15, 2020 On 4/30/2019 at 6:14 PM, Manche757 said: There is no problem with overheating but only warm heat in the winter with gauge reading about 120 degrees. I assume it is stuck open or the spring is broken. I don't really care about lack of much heat here but I am going to have ac installed in a MJ that never had a/c. I thought it wise to not have to bang around a/c fittings later to replace it. My real question to MJ mechanics: Would you have the water pump replaced even if there are no problems with it at present? '89MJ, 4.0, 81K miles. Roll the dice: Yes? No? You heater core is probably clogged. Replace it. Link to comment Share on other sites More sharing options...
Eagle Posted July 15, 2020 Share Posted July 15, 2020 10 hours ago, rylee144 said: Thank you. So when I buy another one I should get a 180 or the 195? 195. Link to comment Share on other sites More sharing options...
BeatCJ Posted July 15, 2020 Share Posted July 15, 2020 OK, so the Mopar thermostat is recommended, what about water pump? I'm having a cascade failure thing. I blew up the upper radiator hose. The coolant that came out was brown, probably should have changed it when I got the truck. The radiator petcock was stuck, so I ripped it off of the end of the radiator, which I was planning on upgrading anyway (thanks @Gjeep). Now I have a bearing noise, pretty sure it's the water pump. So, before that gets any worse, I plan on swapping it out. Suggestions on brand? Link to comment Share on other sites More sharing options...
Pete M Posted July 15, 2020 Share Posted July 15, 2020 just be certain that you don't accidentally receive the reverse rotation pump. Link to comment Share on other sites More sharing options...
rylee144 Posted July 16, 2020 Share Posted July 16, 2020 I need new thermostat housing bolts. can't find any in stores do these work if I add a washer? Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted July 16, 2020 Share Posted July 16, 2020 Why do you think you need new ones? If it was me, I would brush off most of the rust, run a tap into the holes in the head, and chase those bolt threads with a die. Then slap it back together. What am I missing? Link to comment Share on other sites More sharing options...
rylee144 Posted July 16, 2020 Share Posted July 16, 2020 My threads are pretty worn. I don't have a tap. Thought new bolts would be easy Link to comment Share on other sites More sharing options...
Pete M Posted July 16, 2020 Share Posted July 16, 2020 19 minutes ago, rylee144 said: I need new thermostat housing bolts. can't find any in stores do these work if I add a washer? yes? I mean, that would work but you should be able to clean those up. Link to comment Share on other sites More sharing options...
rylee144 Posted July 16, 2020 Share Posted July 16, 2020 Ok I'll look and cleaning them first. Thanks guys Link to comment Share on other sites More sharing options...
75sv1 Posted July 16, 2020 Share Posted July 16, 2020 I use NAPA water pumps. Seem OK. Some will insist on MOPAR. I would recommend a MOPAR clutch fan though, especially if you intend to use a HD (2-row or 3-row) Radiator. Link to comment Share on other sites More sharing options...
Eagle Posted July 16, 2020 Share Posted July 16, 2020 On 7/14/2020 at 11:52 PM, rylee144 said: I am in the middle of my coolant flush and pulled my thermostat. It's a 180. Could that be why I am running very warm, average 210 or a tad higher on a 80 degree day. No. Link to comment Share on other sites More sharing options...
AZJeff Posted July 16, 2020 Share Posted July 16, 2020 This is debated CONSTANTLY on automotiive forums, because many people don't understand the function of the thermostat. The thermostat in a liquid cooled engine controls the MINIMUM operating temperature for the engine, NOT the maximum temperature. The maximum temperature is governed by the amount of airflow over the radiator, the condition of the water pump, the condition of the water jackets in the block, the condition of the hoses, and finally, the condition of the tubes and fins of the radiator. As others have mentioned, the OEM thermostat is a 195* item. That means normal operating temperatures should be around 200-210* when the engine is fully warmed up. I live in AZ, and my temperature guage is slightly off. It reads about 220* when it's really only about 212*, but I am not too worried, because that engine temperature is reached when the outside air temperature is 116* F. Yes, it really was that hot the other day Link to comment Share on other sites More sharing options...
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