How hot is too hot?

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needlenose

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So my wife pulled another wonder on me. The fixed idler pulley locked up and wrecked the belt. She noticed that the Suburban suddenly went "hard to steer" so she pulled over and left it running(to keep the kids cool) while she inspected what was wrong and marveled at the pretty green fountain spewing from the engine bay. She then decided that her experience did not warrant her the skills necessary to determine what the problem was, so she called me. After learning she was stranded and why, I found out it was still running and told her to immediately shut it off. She said the gauge was at the large hash mark between 210 and 260 (240?)when she shut it off and told me not to worry it was "still a long way from the red mark.". I have no idea how accurate those factory gauges are.....

So I repaired it, got it home, and am still in the process of bleeding out the system. I have random bubbles, but it's still hard to tell if it's cylinder pressure or just trapped air.

How hot would a 5.7 typically have to get before the heads lift? It idled on the side of the road for several minutes before she shut it off. It displaced about 1gal of coolant when it overheated.
 

needlenose

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Yep, has Vortec stamped proudly across the top. And here I thought the vortec heads were supposed to the shiznizzel or something....
 

DerekTheGreat

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So my wife pulled another wonder on me. The fixed idler pulley locked up and wrecked the belt. She noticed that the Suburban suddenly went "hard to steer" so she pulled over and left it running(to keep the kids cool)...

That's kinda funny since without a belt the A/C isn't going to work either lol. I once told Ashley about what depends on the belts yet when we had our C3500 she let 'er rip on the street, it shredded the belt, got home and at least shut I off when she pulled in the driveway but in just the 1/3 of mile from shred to driveway the thing got hot. Spewed coolant everywhere and such but luckily no other damage. I had always wondered how long it would take without a water pump for something to overheat and it's damn near immediate. So even if its "on the way out" it's still better than a dead one...
 

superdave

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And here I thought the vortec heads were supposed to the shiznizzel or something....

Kind of hard to blame the hardware for pilot error. It would have gotten quite hot idling with no water circulating.

Time for a compression check and maybe a leakdown test. It's amazing just how many of my suggestions are "time for a compression check". It's a easy process and will tell you a lot about your truck's health, just like getting your blood pressure checked.
 

needlenose

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That's kinda funny since without a belt the A/C isn't going to work either lol....

Yeah, we had that conversation. It came right after the one about stopping immediately and shutting off the engine when the car suddenly does something it's not supposed to. I swear, if I could get an ear-bleeding siren for high-temp and low-oil pressure....

She's very sharp, but since I'm the tech person in the marriage, she tunes that sort of thing out. At this point I have rebuilt so many of her screw ups she just sees it as, "Oh well... he'll fix it...". I think one day I'm just going to throw up my hands and tell her I forgot. Go see a mechanic.
 

needlenose

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Kind of hard to blame the hardware for pilot error. It would have gotten quite hot idling with no water circulating.

Time for a compression check and maybe a leakdown test. It's amazing just how many of my suggestions are "time for a compression check". It's a easy process and will tell you a lot about your truck's health, just like getting your blood pressure checked.

No blame for the over-heating. Just the blame for cracking under heat. :)

*If* they cracked. But they appear to be running fine. At least, there's no performance difference. Time will tell if it's using coolant.

One thing for sure, you can't beat SBC aftermarket prices. Summit has new 062s for $320 per. I seriously doubt you could get old heads decked, magnafluxed, and all new valves for that price. If they cracked or warped, there's a Summit 30min from my house.
 

DerekTheGreat

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Haha yeah, Ashley tries and she's pretty good yet sometimes it's kind of funny. I remember one time the starter solenoid on her 1990 F150 welded itself together and so the engine wouldn't stop cranking. I've told her what to do in that situation yet one day when it was like 10 degrees out she comes running back in the house and says: "So the truck seems like it didn't stop cranking and so I went to pop the hood and check on it but the thing in the middle was shaking so I thought it was different."
I run out there and deduce what the "thing" was and it turned out to be the engine. Hahahahaha, I couldn't stop laughing. I wasn't even mad at that point. One whap on the SS and it was all over but not my laughing fit.
 
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