LS overheated last night

[lockman]

I have a 2005 3.9L, 85,000miles. I haven't had any problems with it running hot until last night. I had started it and let it run about 15 minutes to warm up, then drove it about 15 miles into town to get something to eat... no problems...

After I ate, was headed back home and about half way there, my warning light came on and the temp gauge was at about 3/4. Within just a few seconds it was maxxed out. I pulled over, popped the hood, and steam and coolant was spraying everywhere.

I let it cool down for a few minutes, after some of the coolant had dried it was still wet around one of the hoses, so i went to look at it and it wasn't connected. I've been reading and it appears this hose is the "throttle body heater hose", its a small hose on the "coolant outlet pipe".

I got some pliers to relax the clamp and put the hose back on, filled it up with water, and started it back up. The temp gauge never got above the normal, half way mark all the way home. After i got home and it cooled down, i looked but couldnt find any leaks anywhere. I pulled on that hose and it was tight.

Is there anyway this hose just worked itself loose? Could something be clogged and the pressure blew this hose off? If it makes any difference, I turned the defroster on about 5-10 minutes before this happened.

Thanks for any help.

 

[joegr]

I have a 2005 3.9L, 85,000miles. I haven't had any problems with it running hot until last night. I had started it and let it run about 15 minutes to warm up, then drove it about 15 miles into town to get something to eat... no problems...

After I ate, was headed back home and about half way there, my warning light came on and the temp gauge was at about 3/4. Within just a few seconds it was maxxed out. I pulled over, popped the hood, and steam and coolant was spraying everywhere.

I let it cool down for a few minutes, after some of the coolant had dried it was still wet around one of the hoses, so i went to look at it and it wasn't connected. I've been reading and it appears this hose is the "throttle body heater hose", its a small hose on the "coolant outlet pipe".

I got some pliers to relax the clamp and put the hose back on, filled it up with water, and started it back up. The temp gauge never got above the normal, half way mark all the way home. After i got home and it cooled down, i looked but couldnt find any leaks anywhere. I pulled on that hose and it was tight.

Is there anyway this hose just worked itself loose? Could something be clogged and the pressure blew this hose off? If it makes any difference, I turned the defroster on about 5-10 minutes before this happened.

Thanks for any help.

My 04 did that. You'll likely find that the plastic nipple that the hose attaches to is broken off part way up. The clamp was still on the broken part, but now you've moved it lower down so that it is sealing again. It's only a temporary fix. The plastic of the coolant outlet pipe has turned soft and it will crack in other places too. I ended up replacing all the plastic parts at the front as they were all starting to open up, or probably would have soon.

 

[lockman]

Ok, I just went and looked. It's not broken, and doesn't appear to be brittle at all.

 

[joegr]

Ok, I just went and looked. It's not broken, and doesn't appear to be brittle at all.

Perhaps your luck will be better than mine. I didn't catch that it was broken until the top seam cracked too. It did start with that same throttle body heater hose with mine. I think it was about six month later...

 

[tireman]

plastic cracks

mine cracked too. you could not see the crack on the seam. it would only open up when started, a few teaspoons of fluid came out then it would seal up again. the fluid would then dry quickly under the fan air movement. Really hard to find. replaced the entire unit.

 

[lockman]

I've been outside since my last response. I figured I'd bleed the system and see what happened. I never found any fluid leaking from anywhere and it never overheated.

One thing I was curious about though. Are you supposed to completely remove the heater air bleed screw or just loosen it? I took it all the way out and never could get a steady stream of fluid. Just a couple spurts, then nothing, then some drips, nothing, etc. After the engine had been at normal temp for a while, I went ahead and put it back in, tightened it, and proceeded with the following steps.

 

[joegr]

I've been outside since my last response. I figured I'd bleed the system and see what happened. I never found any fluid leaking from anywhere and it never overheated.

One thing I was curious about though. Are you supposed to completely remove the heater air bleed screw or just loosen it? I took it all the way out and never could get a steady stream of fluid. Just a couple spurts, then nothing, then some drips, nothing, etc. After the engine had been at normal temp for a while, I went ahead and put it back in, tightened it, and proceeded with the following steps.

You remove it all the way. If you can't get a steady stream, then there is a problem yet.

 

[lockman]

Ok, I'll keep looking. After I tightened it up and let it run for the 5 minutes, I started unscrewing it and it was coming out good. Also, while it was running the fluid in the Degas bottle was constantly churning / bubbling, is that normal? I filled it first thing, and during the whole process it never did get below the "full cold" line.

 

[joegr]

Ok, I'll keep looking. After I tightened it up and let it run for the 5 minutes, I started unscrewing it and it was coming out good. Also, while it was running the fluid in the Degas bottle was constantly churning / bubbling, is that normal? I filled it first thing, and during the whole process it never did get below the "full cold" line.

Well, I've never seen mine churn/bubble. It might be time for a cooling system pressure leak down test to see if there are any leaks. The best way to do it is with a gauge and a hand air pump.

If you don't have that (few would) and don't want to pay someone to do it, you can try this. Squeeze the upper or lower radiator hose at one of the soft points and note how easy it is to compress. Now, run the engine up to full temperature and shut it down. Try squeezing the hose again. If it is not very hard to compress a little bit, then your system is not holding pressure. If it is hard, then wait about twenty minutes and try it again. If it is soft already, there is a problem.

 

[tireman]

maybe just the hose itself

maybe the hose just worked itself off or someone forgot to put it back on correctly. Never heard of one working itself off though......

 

[lockman]

Well, took it in to the dealer and had them look at it. They couldn't find anything wrong with it. Guess I'll just wait and see if it does it again.

I've also had a humming coming from the rear which I assumed was wheel bearings, so I had em look at that too. They said it's the left, rear bearing going out. They want to replace the wheel knuckle, which is 1,100.00 just for parts. They say you can get the hub for 250.00 but the only way to get the bearing is by buying the whole thing. Autozone sells the bearing for 30.00, and I called another garage and they said they'll replace it for 225.00.