Low temps and boiling sounds from 3.8

[Ivycon]

Hi everyone,

2010 3.8L 170k miles

My gauge is reading that my engine isn’t reaching operating temps for a couple of weeks now. (It’ll be at like 160ish.) then one day I was idling at lunch and my water started boiling over and the temp got up to operating and a little more. Once I was in drive that issue went away but still ran cool.

So I replaced the thermostat and water pump but am still seeing this issue. I got home from work today and I could hear the water boiling in the radiator. and my fan doesn’t kick on while driving.

If I put the ac on the engine will create a weird feeling when sitting at a traffic life.

Ive dug into this some and haven’t seen anything similar. Does anyone have any thoughts on where to start or what could be wrong?

Thanks in advance!

 

[BLACKJKU]

If you had the coolant drained out you'll need to burp the cooling system, remove the cap raise the front up about 6" and start the Jeep. Then as the coolant lowers add some more to it.

 

[Ivycon]

If you had the coolant drained out you'll need to burp the cooling system, remove the cap raise the front up about 6" and start the Jeep. Then as the coolant lowers add some more to it.

Thanks. I thought I burped it correctly. Filled it up, pressed the top hose multiple times to lower the coolant, fill it up more, ran it with the lid off, and then once dropped I added more. I can try this method you mentioned though.

 

[Dirty Dog]

Thanks. I thought I burped it correctly. Filled it up, pressed the top hose multiple times to lower the coolant, fill it up more, ran it with the lid off, and then once dropped I added more. I can try this method you mentioned though.

If you don't elevate the nose, you will never get all the air pockets out.

 

[Ivycon]

If you don't elevate the nose, you will never get all the air pockets out.

One of the issues is, I can’t get it to operating temps due to the sensors or something to be off. So I think it doesn’t get the Jeep the opportunity to burp itself.

 

[BLACKJKU]

One of the issues is, I can’t get it to operating temps due to the sensors or something to be off. So I think it doesn’t get the Jeep the opportunity to burp itself.

The sensors only read the temps don't have anything to do with controlling the temps, the T-Stat controls the temps along with the cooling fan.

 

[Dirty Dog]

One of the issues is, I can’t get it to operating temps due to the sensors or something to be off. So I think it doesn’t get the Jeep the opportunity to burp itself.

The sensor can't read the temp if it's in an air bubble. And the Jeep will never, ever, burp itself.

 

[Anybodyhome]

The easiest way to know if there is air in the system is a fluctuating temp gauge. Regardless if you're moving or not, with no rhyme or reason, the temp gauge is all over the map from where it should be to the higher range.

1. Raise the front end and remove the rad cap. As has been said before, don't be shy about getting the front end off the ground by 6". I use a floor jack and then slide jack-stands underneath. Air travels up, so the higher, the better.
2. Add coolant to the rad, not the reservoir.
3. A little at a time, as you add coolant, it will settle into the rad and force the air out the cap.
4. Each time it burps, add a little more coolant until it's at the cap level and no more burps occur.
5. Make sure the reservoir is filled to either the cold or hot limit line, depending on the engine state when you add coolant. I've always preferred cold, it's just safer.

 

[Ivycon]

The easiest way to know if there is air in the system is a fluctuating temp gauge. Regardless if you're moving or not, with no rhyme or reason, the temp gauge is all over the map from where it should be to the higher range.

1. Raise the front end and remove the rad cap. As has been said before, don't be shy about getting the front end off the ground by 6". I use a floor jack and then slide jack-stands underneath. Air travels up, so the higher, the better.
2. Add coolant to the rad, not the reservoir.
3. A little at a time, as you add coolant, it will settle into the rad and force the air out the cap.
4. Each time it burps, add a little more coolant until it's at the cap level and no more burps occur.
5. Make sure the reservoir is filled to either the cold or hot limit line, depending on the engine state when you add coolant. I've always preferred cold, it's just safer.

The sensors only read the temps don't have anything to do with controlling the temps, the T-Stat controls the temps along with the cooling fan.

The sensor can't read the temp if it's in an air bubble. And the Jeep will never, ever, burp itself.

How long could this process take? I jacked it up this morning, easily more than 6". Had the rad cap off, turned on the engine, had it run for about 35 mins, the temp on the gauge never rose past half way to the middle(the normal opp temp). Fluid never dropped. My issue is the engine isn't A. getting hot enough to burp or B. it's hot enough and the thermostat isn't opening up. But as stated I replace that t stat already.

Thanks everyone! Sorry, I can fixed things, just can't diagnose them sometimes. lol

 

[Anybodyhome]

So, let's walk thru these one at a time.
1. "I jacked it up this morning, easily more than 6". Had the rad cap off, turned on the engine, had it run for about 35 mins, the temp on the gauge never rose past half way to the middle(the normal opp temp)." Okay, good. These are good signs. The gauge didn't fluctuate and stayed where it should. Good. Coolant never dropped in the rad, also good.

2. "My issue is the engine isn't A. getting hot enough to burp." The engine does not have to be hot enough. Matter of fact, the engine doesn't even have to be running to burp. All you are doing is adding coolant to the appropriate level. The engine does not need to be running to burp. You add coolant and the coolant displaces the air out via the open rad cap.

3. "B. it's hot enough and the thermostat isn't opening up." But you said the temp gauge was in the middle, where it's supposed to be. That's a good thing. If the engine temp was indeed "hot enough and the t-stat isn't opening, you'd be overheating, the temp gauge raising above normal (beyond the mid-point).

Sounds to me like everything is normal. If you can run the vehicle up and down the road for 30 minutes, hit some lights or stop signs, drive in traffic and your temp gauge remains consistently in the middle, you're fine. Maybe I'm missing something, but I'm not reading where there's a problem now.

 

[Ivycon]

So, let's walk thru these one at a time.
1. "I jacked it up this morning, easily more than 6". Had the rad cap off, turned on the engine, had it run for about 35 mins, the temp on the gauge never rose past half way to the middle(the normal opp temp)." Okay, good. These are good signs. The gauge didn't fluctuate and stayed where it should. Good. Coolant never dropped in the rad, also good.

2. "My issue is the engine isn't A. getting hot enough to burp." The engine does not have to be hot enough. Matter of fact, the engine doesn't even have to be running to burp. All you are doing is adding coolant to the appropriate level. The engine does not need to be running to burp. You add coolant and the coolant displaces the air out via the open rad cap.

3. "B. it's hot enough and the thermostat isn't opening up." But you said the temp gauge was in the middle, where it's supposed to be. That's a good thing. If the engine temp was indeed "hot enough and the t-stat isn't opening, you'd be overheating, the temp gauge raising above normal (beyond the mid-point).

Sounds to me like everything is normal. If you can run the vehicle up and down the road for 30 minutes, hit some lights or stop signs, drive in traffic and your temp gauge remains consistently in the middle, you're fine. Maybe I'm missing something, but I'm not reading where there's a problem now.

The gauge was halfway to normal operating temp. Not at normal operating temp.