Engine Overheating/No Heat

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Geotrash

Dave
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I agree with Wes. And I'll add an opinion that the most likely culprits at your mileage, in order (always debatable) are:
1/ The radiator - check around the plastic end tanks for any wetness and sniff for that sweet coolant smell. It's common for them to crack and seep coolant.
2/ The plastic tees where the heater hoses connect to through the firewall
3/ The water pump shaft seal
4/ A crack in the coolant tank
5/ A leaking hose connection

One final check to make sure it's not a blown head gasket or cracked cylinder head (both rare on these), check the oil dipstick to make sure the oil looks like oil should and isn't milky. Also check the oil filler cap and make sure it's not covered in a milky slime. If you find either one, then you have a problem.

Finally, if after all of that you can't find the leak, have a shop perform a pressure test on the cooling system, along with possibly a leak down test.
 
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JTsYUKON

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While a free but pricey deposit rental, AutoZone has a pressure test kit that might make quick work out of finding the leak if initial visual inspection doesn't come up with much.
I agree with Wes. And I'll add an opinion that the most likely culprits at your mileage, in order (always debatable) are:
1/ The radiator - check around the plastic end tanks for any wetness and sniff for that sweet coolant smell. It's common for them to crack and seep coolant.
2/ The plastic tees where the heater hoses connect to through the firewall
3/ The water pump shaft seal
4/ A crack in the coolant tank
5/ A leaking hose connection

One final check to make sure it's not a blown head gasket or cracked cylinder head (both rare on these), check the oil dipstick to make sure the oil looks like oil should and isn't milky. Also check the oil filler cap and make sure it's not covered in a milky slime. If you find either one, then you have a problem.

Finally, if after all of that you can't find the leak, have a shop perform a pressure test on the cooling system, along with possibly a leak down test.
I have about an hour to get to this before the vehicle is gone to my wife's hair appointment. I'll get under there and do some snooping with my headlamp and flashlight. I'll also clean everything up so that I can identify any new coolant tomorrow. I have lots of cardboard, so i can slip some of that under the rig.

Thanks for help. Great ideas.
 

Doubeleive

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I have about an hour to get to this before the vehicle is gone to my wife's hair appointment. I'll get under there and do some snooping with my headlamp and flashlight. I'll also clean everything up so that I can identify any new coolant tomorrow. I have lots of cardboard, so i can slip some of that under the rig.

Thanks for help. Great ideas.
it's usually ok to drive it as long as you keep an eye on the coolant level, if it was leaking out so fast that it had to be refilled going a couple miles down the road then no.
 
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JTsYUKON

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it's usually ok to drive it as long as you keep an eye on the coolant level, if it was leaking out so fast that it had to be refilled going a couple miles down the road then no.
Ok, great. I just drove her and left the Yukon at home. I got under it, removed the plastic engine skid and took pics before cleaning it all so I can get a fresh look. It’s all along the bottom of the fan shroud which is just behind the radiator. I couldn’t any in other places. Mostly here and some dripping down passenger side. Found a dead bird. LOL

3A141D26-1081-41A2-8DA5-F139E766384C.jpegECEE7511-02BE-49B4-A9E8-A4C83A89644C.jpeg23BB51E8-5DE3-436A-8B52-38E1788A2B9D.jpeg38823475-D8D6-487A-8C28-AA77F90250C9.jpeg30C6D7AF-82A5-4F25-B649-8E97374D7DA4.jpeg
 

Foggy

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By your pics, my guess is the radiator itself or the water pump. Stuff get splashed !
Check your end tanks on the radiator- they are plastic.. That's prob where you'll find
the leak. Good Luck.. Radiator Job is fairly easy on these
 

Doubeleive

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I bet it's a cracked plastic side tank, par for the course on these.
not sure where you sit on money but don't cheap out on the radiator it just causes more headaches
if you can do those heater hose "T"'s at the same time because those will break next may as well get it out of the way.
 

Geotrash

Dave
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I bet it's a cracked plastic side tank, par for the course on these.
not sure where you sit on money but don't cheap out on the radiator it just causes more headaches
if you can do those heater hose "T"'s at the same time because those will break next may as well get it out of the way.
+1 on the heater tees.
 

Foggy

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Yup +2 on the heater Tee's
If you just want a stock replacement, the GM ones are fine.. Apparently they
have been updated (that's what my parts guy told me) and they had them
in stock... Not very expensive.. Just a ***** to take the old ones out. New ones go in easy.
And ++ on getting a GOOD radiator.. There are some decent aftermarket ones, but not
very many so be careful or get the GM one
 

89Suburban

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Ok, great. I just drove her and left the Yukon at home. I got under it, removed the plastic engine skid and took pics before cleaning it all so I can get a fresh look. It’s all along the bottom of the fan shroud which is just behind the radiator. I couldn’t any in other places. Mostly here and some dripping down passenger side. Found a dead bird. LOL

View attachment 386373View attachment 386372View attachment 386374View attachment 386376View attachment 386375


Good job with the pics. Helps a lot with looking for the the problem. Keep at it.
 

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