Engine Overheated...

[AZ-Yukon]

Moved from tech forum...

I'm looking for some suggestions on what I might need to replace after having my Yukon overheat and shutdown on its own. I have a 2003 5.3L. I know the reason it overheated... let's just call it operator error (coolant drained out at the intake to the radiator). So are the any particular items I should definitely replace? I'm thinking hose from output of water pump to top of radiator (mainly because it was collapsed, presumably from the superheated coolant). After a tow home, I filled the cooling system with water to see if the engine would start and verify I hadn't warped or cracked the heads before going any further. She fired right up as if nothing had gone wrong. I'm planning to flush the system before refilling it with fresh coolant. Any suggestions/insight would be greatly appreciated!
Thanks in advance

 

[Wake]

change the fluids.

Change the engine oil, and you probably should change the trans fluid as well. I'm not sure of your setup but if you don't have an external trans fluid cooler then it run through your radiator and without coolant it likely cooked.

Trans fluid start to break down above 225F, if you ran it close to the top of the temp gauge, 300F then change it. the fluid breaks down faster the hotter you run it. I wouldn't flush it, but I'd change it frequently a few times to get as much of the old fluid out as possible.

 

[ATL]

if nothing is crazy wrong, just swap the hose(applying a tiny bit of oil on the inside of the hose will make it slide on and off with ease its entire lifetime), and change the fluids. personally, i would completely flush the trans, it most likely could use it anyway. heres a great how to article: http://www.gmfullsize.com/forum/showthread.php?t=179148

 

[AZ-Yukon]

Thanks for the feedback. After flushing the cooling system and replacing the hose, it runs fine. It is probably about time for an oil change anyway so I'll do that as well. I had the transmission replaced about 2 years ago so the fluid is fairly new. It looks like there are a couple lines coming off of the radiator that go back to the transmission. I'm guessing the transmission doesn't have it's own cooler.

The overheat was a very short occurrence. Coolant dumped, temp shot up, I pulled over, it shut down all in a matter of 1 minute. Could it have that quick of an impact on the transmission fluid?

 

[Wake]

The overheat was a very short occurrence. Coolant dumped, temp shot up, I pulled over, it shut down all in a matter of 1 minute. Could it have that quick of an impact on the transmission fluid?

No, I'd say you're fine if that was the case. Originally I got the impression that you drove it for awhile hot.

 

[afpj]

I'm thinking hose from output of water pump to top of radiator (mainly because it was collapsed, presumably from the superheated coolant).

Glad you got your ride working again. I had the same hose collapse issue not from overheating, but after replacing my hoses and then letting engine cool. Opened the overfill cap and hose reinflated so to speak. i wonder if that's what I get for using Dayco, sold at the closest autoparts store. What brand did you use for replacement? Was it the OEM hose that collapsed? Normally would think of getting OEM but today was the only day I have free for awhile, and access to the kon. BTW, for a short overheat like you had, check the water pump for leaks thru that weep hole over the week. Them bearings don't like heat too much IIRC.

 

[ATL]

does your truck have the tow/haul option? if so, you should have an external trans cooler

 

[AZ-Yukon]

So, I replaced the oil yesterday and no signs of any water in the oil. Good Sign! I didn't want to worry about replacing the heads, especially after learning about the common problem these engines have with exhaust manifold bolts breaking (sticky). I realized I have one broken. It hasn't been an issue for as long as it has been that way so it is staying that way for now.

AFPJ, it was the OEM hose that collapsed. It was very odd since it had disconnected from the radiator and could not have been under any sort of vacuum. It looked all decrepit. But once I reconnected it, refilled the cooling system and started it up, it went back to its normal shape. I figured I didn't want it failing on me and going through another overheat session so I replaced it. Although, I did the same thing you did and ran down to Autozone and picked up what they had available. I don't recall the brand. It had a slightly larger outer diameter which made it tricky to get the clamps back on. I hope to not have to take them back off anytime soon.

The water pump is brand new. That is how this whole thing started. I replaced the water pump and didn't get the upper radiator hose clamp on good. I'll keep an eye on it to see if it leaks any.

ATL, my truck does have the tow option. Is the external trans cooler different than the trans fluid going through a portion of the radiator? I traced a couple small coolant lines coming off of the passenger side of the radiator that go back to the transmission. Would you expect something different with the tow package?

I've never knew some vehicles somehow use a portion of the radiator to cool the trans fluid. Is there just a tube inside the radiator end cap that runs between the inlet and outlet of the trans coolant line connections?