What is going on?

[khaley]

Can anyone point me in the right direction? 2010 4.0 it started making this loud whining sound two days ago and is overheating. It’s full of coolant. There’s coolant in the reservoir, and radiator. When I got it home tonight, it was sizzling and smoking. Is the thermostat stuck? It’s also weak at acceleration, so my boyfriend is thinking it’s possibly the brake caliper. I’d love any insight, thank you!

 

[HeyNiceSporty]

The whining noise is probably your best clue. An old school trick to pinpoint where it is coming from is to carefully use a wooden broom handle. You can put the end of the broom handle on different parts of the engine while running and press your ear against it. It will transmit the sound. Be super careful to keep it away from the belt and fan.

I suspect the water pump but anything run by the drive belt can get tight bearings and create a whine.

 

[khaley]

The whining noise is probably your best clue. An old school trick to pinpoint where it is coming from is to carefully use a wooden broom handle. You can put the end of the broom handle on different parts of the engine while running and press your ear against it. It will transmit the sound. Be super careful to keep it away from the belt and fan.

I suspect the water pump but anything run by the drive belt can get tight bearings and create a whine.

So it only makes the sound when I’m accelerating, I think it’s the fans since the car is overheating. It’s got a brand new water pump. But someone told me the thermostat housing is cracked. I’m sure that happened when it overheated.

 

[HeyNiceSporty]

Fans are typically their best at slow speeds. At highway speed there is enough air coming in the grill that the fan is only doing a fraction of the cooling.

A whining sound is frequently a water pump, power steering pump, alternator, etc getting a tight bearing. Just because you have a new water pump, it does not mean it doesn't have a problem, especially if it is a rebuilt pump.
Are you sure it is not a squealing sound? That frequently is a drive belt slipping because one of the above is getting tight and the belt is slipping. A squeal usually show itself on acceleration.

The thermostat housing cracking is common on these. They are a plastic as is the tanks on the factory radiators and age and heat cycling will do that. I had the top tank in the radiator let go. The thermostat housing was next, now that the system could build some more pressure now that a good radiator was in place. I HIGHLY recommend replacing the thermostat housing with the one piece metal aftermarket housing. This is the third 4.0 V6 I have done this to. The previous vehicle has 14 years on the metal housing and still going strong.

 

[khaley]

Fans are typically their best at slow speeds. At highway speed there is enough air coming in the grill that the fan is only doing a fraction of the cooling.

A whining sound is frequently a water pump, power steering pump, alternator, etc getting a tight bearing. Just because you have a new water pump, it does not mean it doesn't have a problem, especially if it is a rebuilt pump.
Are you sure it is not a squealing sound? That frequently is a drive belt slipping because one of the above is getting tight and the belt is slipping. A squeal usually show itself on acceleration.

The thermostat housing cracking is common on these. They are a plastic as is the tanks on the factory radiators and age and heat cycling will do that. I had the top tank in the radiator let go. The thermostat housing was next, now that the system could build some more pressure now that a good radiator was in place. I HIGHLY recommend replacing the thermostat housing with the one piece metal aftermarket housing. This is the third 4.0 V6 I have done this to. The previous vehicle has 14 years on the metal housing and still going strong.

Where can I find a metal housing?

 

[HeyNiceSporty]

You can get a one piece unit here .... https://simmonsautosportz.com

They are expensive, but it is one piece, no messing around.
You can also get two-piece metal ones from several retail auto parts places. They are an upgrade but I usually keep vehicles far too long. LOL. That is why the one piece unit got the vote.