99 Chevy Silverado 1500 4x4 Overheating PLEASE HELP!

[ifixedit]

O.K., since we're to the point of asking really stupid questions here (hey, anything is possible): Is the thermostat installed in the correct direction? The thermostat should be installed with the top pointing towards the top (upper hose) going to the radiator. If the bottom (spring side) of the thermostat is pointed in the direction of the top of the radiator it's in backwards. Here's how it should look. https://www.google.com/search?q=thermostat+installed+correctly&newwindow=1&source=lnms&tbm=isch&sa=X&ei=M_Q9VOzONNS3yATgz4CgCQ&ved=0CAgQ_AUoAQ&biw=1518&bih=691&dpr=0.9#facrc=_&imgdii=_&imgrc=Bw16h3EzG-EWWM%253A%3Byi9mvPQEY546CM%3Bhttp%253A%252F%252Fi205.photobucket.com%252Falbums%252Fbb240%252Fauzivision%252FFall2010314.jpg%3Bhttp%253A%252F%252Fwww.fullsizechevy.com%252Fforum%252Farchive%252Findex.php%252Ft-456357.html%3B1024%3B768

The only other ideas I would have would again be to check out the fan clutch and make sure the air is purged from the system. There is a very slight possibility that a part of unknown casting inside the block came loose and has blocked a passage, but this is in the category chances of "slim to none."

[JoshWalkerMedia]

O.K., since we're to the point of asking really stupid questions here (hey, anything is possible): Is the thermostat installed in the correct direction? The thermostat should be installed with the top pointing towards the top (upper hose) going to the radiator. If the bottom (spring side) of the thermostat is pointed in the direction of the top of the radiator it's in backwards. Here's how it should look. https://www.google.com/search?q=thermostat+installed+correctly&newwindow=1&source=lnms&tbm=isch&sa=X&ei=M_Q9VOzONNS3yATgz4CgCQ&ved=0CAgQ_AUoAQ&biw=1518&bih=691&dpr=0.9#facrc=_&imgdii=_&imgrc=Bw16h3EzG-EWWM%253A%3Byi9mvPQEY546CM%3Bhttp%253A%252F%252Fi205.photobucket.com%252Falbums%252Fbb240%252Fauzivision%252FFall2010314.jpg%3Bhttp%253A%252F%252Fwww.fullsizechevy.com%252Fforum%252Farchive%252Findex.php%252Ft-456357.html%3B1024%3B768

The only other ideas I would have would again be to check out the fan clutch and make sure the air is purged from the system. There is a very slight possibility that a part of unknown casting inside the block came loose and has blocked a passage, but this is in the category chances of "slim to none."

as i have stated there is no blockage in anything i flushed everything and as for the stat it is MADE INTO THE HOUSEING on the 99's and up they are no longer a housing and t stat combo just one piece made together so yes it is correct and it is the second one i have put on it brand new.

[butzers09silverado]

I would get one of those garden hose attachments, put it in the heater core line and pressurize the system.

[ifixedit]

I went back and read your original post carefully for any clues. First, I had one of those plastic couplers / nipples that connects the heater core hose to the intake break on me last winter as well, but I don't think that has anything to do with your problem, just thought I'd mention it. When you are inside the truck and you are hearing this noise you are reporting, is it more of a gurgling or kind of like water running through pipes noise? My 98 Yukon made this noise with the heat turned up all the way when it was low on coolant (and just before the intake gasket let loose and puked the contents of the radiator into the crankcase). So the noise you are hearing likely means the system is still low on coolant and what you are actually hearing is the minor amount of coolant mixed with air being pushed to the heater core by the water pump and it's sloshing around in the heater core portion of the system. And yes, if this is the case you would for sure get little or no heat at all.

 

If the upper radiator hose is getting hot (is it also getting firm when it warms up?), that tells me coolant or at least some portion of it is reaching the thermostat and getting it warm enough so it is opening, it would be just about impossible for it not to, unless what is making the upper hose warm is mostly just heat from steam, then it maybe wouldn't open and thus your overheating. But you also have to think, if the coolant is low, it will get hot enough in the block to boil if the thermostat is opening or not and would explain the puking into the catch tank, you've got boiling (and expanding) coolant suddenly being released into a low (mostly just presently air) system and it just needs more coolant to take up the air space and absorb the heat of the released coolant. Your trucks cooling worked fine before your nipple broke off, now it isn't so there's something you are missing obviously and this is likely all it is.

 

Before we jump to conclusions though, two things I would look over carefully: First (and this is more likely your problem), when you fill it with coolant and are pouring it into the radiator, give it some time to go down, squeeze the upper radiator hose and keep filling until you can't get anymore air bubbles to come out of the radiator cap opening when you squeeze the upper radiator hose. Also, does your thermostat housing have one of those air bleed valves on it? The second thing I would be looking at again is the fan clutch just to be sure it is operating properly. Being you had to replace the water pump this requires you to remove the fan, maybe it got damaged in some way either removing it or putting it back on. Also, is your fan shroud in place?

 

As I mentioned earlier, I had the exact same situation after I replaced the water pump on my 98 Yukon last fall, the first run the water temp soared to about 250 F and stayed that way for about a mile of the drive, then suddenly dropped to 180 F. I thought I had filled the system as full as it was going to get before I took it out and could not get anymore coolant in it, when I returned from the first trip it took another half gallon of coolant which tells me there was a big pocket of air in the system and I suspect what is most likely going on with your truck as well.

 

Edit: Just an addition here to the above. After you have filled the radiator and went through the process of squeezing the upper radiator hose to get all the air out and it will not take anymore coolant, start the truck with the radiator cap off, watch the coolant level in the radiator closely, it may suddenly drop or drop slowly within the first minute or so of running, keep squeezing the upper radiator hose and add coolant as needed until it will not take more. When the engine gets close to full temp you may get a big burp of air that will come up out of the radiator cap opening and the coolant level will drop way off again allowing you to add more, that or it may start puking coolant out of the opening which then tells me the system is getting pretty full. If this happens, put the radiator cap on ASAP, let it idle and observe the temp gauge. It may have to run another 5 minutes or so, the temp gauge may go up into the higher readings but then on the next cycle should drop into the normal range allowing you to add more coolant once again. KEEP THE HEAT TURNED UP ON HIGH THE WHOLE TIME SO THE HEATER CORE ALSO FILLS . It's all a process of getting the air out of the system.

[JoshWalkerMedia]

I went back and read your original post carefully for any clues. First, I had one of those plastic couplers / nipples that connects the heater core hose to the intake break on me last winter as well, but I don't think that has anything to do with your problem, just thought I'd mention it. When you are inside the truck and you are hearing this noise you are reporting, is it more of a gurgling or kind of like water running through pipes noise? My 98 Yukon made this noise with the heat turned up all the way when it was low on coolant (and just before the intake gasket let loose and puked the contents of the radiator into the crankcase). So the noise you are hearing likely means the system is still low on coolant and what you are actually hearing is the minor amount of coolant mixed with air being pushed to the heater core by the water pump and it's sloshing around in the heater core portion of the system. And yes, if this is the case you would for sure get little or no heat at all.

 

If the upper radiator hose is getting hot (is it also getting firm when it warms up?), that tells me coolant or at least some portion of it is reaching the thermostat and getting it warm enough so it is opening, it would be just about impossible for it not to, unless what is making the upper hose warm is mostly just heat from steam, then it maybe wouldn't open and thus your overheating. But you also have to think, if the coolant is low, it will get hot enough in the block to boil if the thermostat is opening or not and would explain the puking into the catch tank, you've got boiling (and expanding) coolant suddenly being released into a low (mostly just presently air) system and it just needs more coolant to take up the air space and absorb the heat of the released coolant. Your trucks cooling worked fine before your nipple broke off, now it isn't so there's something you are missing obviously and this is likely all it is.

 

Before we jump to conclusions though, two things I would look over carefully: First (and this is more likely your problem), when you fill it with coolant and are pouring it into the radiator, give it some time to go down, squeeze the upper radiator hose and keep filling until you can't get anymore air bubbles to come out of the radiator cap opening when you squeeze the upper radiator hose. Also, does your thermostat housing have one of those air bleed valves on it? The second thing I would be looking at again is the fan clutch just to be sure it is operating properly. Being you had to replace the water pump this requires you to remove the fan, maybe it got damaged in some way either removing it or putting it back on. Also, is your fan shroud in place?

 

As I mentioned earlier, I had the exact same situation after I replaced the water pump on my 98 Yukon last fall, the first run the water temp soared to about 250 F and stayed that way for about a mile of the drive, then suddenly dropped to 180 F. I thought I had filled the system as full as it was going to get before I took it out and could not get anymore coolant in it, when I returned from the first trip it took another half gallon of coolant which tells me there was a big pocket of air in the system and I suspect what is most likely going on with your truck as well.

 

Edit: Just an addition here to the above. After you have filled the radiator and went through the process of squeezing the upper radiator hose to get all the air out and it will not take anymore coolant, start the truck with the radiator cap off, watch the coolant level in the radiator closely, it may suddenly drop or drop slowly within the first minute or so of running, keep squeezing the upper radiator hose and add coolant as needed until it will not take more. When the engine gets close to full temp you may get a big burp of air that will come up out of the radiator cap opening and the coolant level will drop way off again allowing you to add more, that or it may start puking coolant out of the opening which then tells me the system is getting pretty full. If this happens, put the radiator cap on ASAP, let it idle and observe the temp gauge. It may have to run another 5 minutes or so, the temp gauge may go up into the higher readings but then on the next cycle should drop into the normal range allowing you to add more coolant once again. KEEP THE HEAT TURNED UP ON HIGH THE WHOLE TIME SO THE HEATER CORE ALSO FILLS . It's all a process of getting the air out of the system.

 

 

As i said to the others who said this same thing 1 it s a 99 new body style so it is not anywhere near the same as you 98 ( i just got me a 97 the differences are obvious ) i replaced the plastic nipple connecting to the heater core everything is installed correctly and since its a 99 newer style there is NO radiator cap they don't have one at all nothing is by passed or hooked up weird or anything its all done correctly with the recommended parts that should go on it

 

If i need to supply photos of the engine so people can understand what the engine I'm working with is i shall because everyone thinks they are the same as the 98s but they are not and even as other 99s there is 2 very different types of 99 chevy silverados the old body style and the new and i have the new,

 

 

[ifixedit]

Sorry, didn't realize yours is similar to my 03. But regardless, radiator cap or not, I will guarantee you you're still dealing with air in the system. I'll refer you to this, read the last post which covers the procedure "from the book" for your no radiator cap cooling system refill situation. http://www.gm-trucks.com/forums/topic/21568-cooling-system-air-venting/ A little searching of the forum here is all it took.

[butzers09silverado]

...because the radiator cap design worked for 100yrs, we should definitely change it... idiots.... i read the capless filling procedure and that sucks... take the radiator out and put one in with a cap on it and hook the stupid overflow resevoir up like a traditional system. if you can fill the radiator, the water pump will circulate into the engine because the bottom hose feeds the impeller and you're problem will go away.

[tramz]

Unless I skipped it, all I've read is the temp gauge maxes out. I assume the overflow reservoir is percolating as well as the gauge indicating overheating. Confirm your heater core hoses are connected to the correct bibs on the water pump although you repeatedly stated everything is correct. We're all trying to help you out sorry its frustrating and still giving you issues. My '05 lower radiator hose connects to the t'stat housing, the lower hose is cooled fluid pumped into the engine and the upper hose is the hot returned to the radiator from the water outlet where the temperature sensor is located. So you're top hose should be hot and lower hose should be cooler than the top.

[ifixedit]

This summer I completely drained, flushed, and refilled the cooling system on my 03 (also a no radiator cap deal) and all I did was the ol' keep squeezing the upper hose as I filled, let it idle and kept filling after the thermostat opened. Temp gauge never went above 210, just needed to add a little coolant after I drove it, and didn't have a problem at all. No fancy procedures involving removing and filling from puke tank lines or anything. Go figure.

[JoshWalkerMedia]

ok well to everyone who helped i appreciate it and the few people who said i had a blownheadgasket you were correct I ASSUME it was minor at first because we never saw it bubbling into the res but ig as time went on from us messing with it changing the pump and stats and hoses it finaally blew out enough that we could see it bubbling so again thank you to everyone if anyone live in oklahoma and wants to buy a 99 chevy silverado with 280kmiles and a blown head gasket let me know XD but I have a 97 gmc yukon to fix up now if anyone know any good offloading body mods and such let me know

[brucelimerick]

Thanks for letting us know. That explains the air in the system. It seems the air pockets at exactly the wrong spot. A head gasket isn't too deadly of a fix on the wallet.

[JoshWalkerMedia]

Thanks for letting us know. That explains the air in the system. It seems the air pockets at exactly the wrong spot. A head gasket isn't too deadly of a fix on the wallet.

no its only like 200$ for the gaskets but its having the time and the know how to do it which i don't and send it to someone would have cost several 1,000 plus the part so i bought a 97 gmc yukon 177k miles and has a intake manifold leak for 1700$ which wasn't bad wish it didn't have the leak but usually how my luck goes lol

[ltj9296]

I have not had to do a blown head gasket on my truck, not yet anyway. But I would encourage anyone that has the time to learn to fix some of the more common failures on our trucks. Fuel pumps. intake manifold gaskets and drive line noises( yoke grease, u-joints) are some of the things that seem to need attention a lot. Saves a ton of money and you know the job is done right when you do it yourself. Anyway, sorry to hear your truck had a more serious problem, and good luck with your new one.