Everlasting

Hi my 2012 wrangler started running hot yesterday night while idling and now runs at around 3/4 on the temp gauge. There is no check engine light on and it has orange mopar coolant. The fan is also running and im wondering what can i do to find out if its a thermostat or water pump. My jeep has just over 110,000 miles on it. Im also curious would it running at 3/4 warp the heads?

rob_engineer

There may be more than one fan. I had an overheating at idle issue on my 2012 once. It was caused by a loose battery terminal and the fusible link for the fan which is connected there was getting faulty voltage readings. Fixed that bad/loose battery connection and it was fine after that.

Everlasting

Thats interesting, both battery terminals are tight.

resharp001

You are the original owner of the jeep? You note orange coolant, and your '12 should indeed have orange HOAT from the factory, though you can never be 110% positive unless you are the originial owner and know what has or has not been done in the past. (The OAT they started using in '13 looks orange if you open the radiator cap but it has a purple additive so it looks purple in a clear jar/bottle.....ie, sometimes it's hard to just go by color). Anyhow, have you been noticing the resi tank level decreasing? Have you topped it off and it's still decreasing? You likely could just have air in the system from a slow leak. It's common for our radiators to have tiny leaks at the fins where they meet the side, usually on the driver's side. You typically can't see signs of this until you remove the airbox and intake tube and pull the fan shroud out. That doesn't take but maybe 15 minutes to get your eyes on the back of the radiator to inspect it.

One thing to keep in mind is that the HOAT coolant was 100k miles. It's really time to change that coolant anyhow if it's never been done, and at that point it might be worth swapping the WP, thermostat, and coolant sensor at the very least, and if the radiator is questionable at all maybe that too. If you plan to keep the jeep for a while this is just regular maintenance. I wouldn't say you HAVE to replace the WP but it's one of those things that if you open up the entire cooling system you may as well. Also, that job is easier to do at the same time you replace a radiator just cuz there's so much extra room to work. I have a few pics of what the WP on my '13 looked like at 95k miles in this thread (i just replaced it cuz I was in there as a preventative thing) -

https://www.jk-forum.com/forums/stoc...nstall-354457/

If you're '12 is like my '13, your temp needle at that position is probably in the 237-240° range. I don't think you're warping heads there by any means, but it's something to keep an eye on and address obviously. When you start climbing up into the 240's and near 250 is the really big danger zone. If you can't monitor the actual coolant temp via the computer then it's really helpful to have some sort of OBDII plug in that can display actual temps rather than the dummy needle there. There are a whole host of products that don't cost much and can tell you some valuable information. Jscan app on your phone with a BT dongle is one of those (~$35 total cost) products, but there are many different things on the market as well.

I have observed my fan while idling in the drive before. Mine seemed to kick to high speed around 224° and then would kick back to low around 211° if I recall. Sometimes simple observation can add some value. I watched that thing cycle 5-6 times.

JonesboroJeep

You have a high speed and low speed relay so your low speed relay is fubar. You can get them for less than $20. You will have to get it fixed or you are going to warp a head and be in a serious cost.