I still have my 97 4wd blazer. Well i had my truck running smooth for awhile. But yesterday on my way to work, it completely overheated on the highway, temp gauge went from cold to 260 within 5 minutes of driving it. I know that could be because my t-stat closed and got stuck. I didn't have time to worry about it right then because i was on my way to work and was going to be late. So after work, I got a new t-stat, antifreeze (50/50 mix and a bottle of pure that i mixed today at home 70/30) well on the side of the highway yesterday evening i replaced the t-stat and dumped the 50./50 mix in, the truck temp went to round 210.
Didn't worry bout that, figured it was normal. Drove it to my mother-in-laws since her house was only 2 minutes away from where i broke down at earlier that morning. Got there and let it run for a minute and the temp gauge flew up again. I got out and looked under the front and seen the coolant just leaking out. And it has no heat coming out of the vents at all.

Problems:
Overheating (has new t-stat)
Coolant leaking
No HEAT

What could this be? Could it be my water pump causing this?

 

gotta find where it is leaking from

 

Sorry been working a ton since this happened. my 2 days off that iw as supposed to be working ont he truck, i got called into work. So yesterday I got out of work early and went and took a peek.

Update:
Tempo still goes to 210, maybe 220.
Loss of coolant seems to be from the lower or upper rad hose (There is a puddle directly under the rad. spanning the length)

As I was defrosting my radiator (used a hairdryer to melt the ice inside of it cuz I thought that was the problem) I had my heater on and every few seconds I would hear a rattleing coming form my heater core, confirmed this was just ice melting and flying through.

Still no heat and today im chaging both hoses Upper and lower rad hose. Thats gonna be a huge mess... im gonna try tog et the truck home to do this though because I doubt my Mom in law wants a **** ton of antifreeze all over the road infront of her house.

HOPEFULLY after the hoses' are changed, everything will be great once again.


Update 2: Don't think my water pump is leaking since the puddle is centralized directly under the radiator.

changed the hoses, i still got the same problems. It still over heats, gives no heat and leaks. But now the leak seems to be coming from the driver corner of the rad. The otherday when i switched the hoses, i took it round the block and when i parked it is when the fluid began dripping out but it still over heated. So im going to dump another 2 gallons of antifreeze into it and start it up, climb under and see if i can find the leak for certain.

So due to frustration and anger I looked up pictures for the soft plugs on a 4.3L Vortec. This is what google found for me.. are these it? I know it says freeze plugs but I was told that soft and freeze plugs are the same thing?

http://img689.imageshack.us/i/freeze1q.png/

http://img254.imageshack.us/i/freeze2.png/

http://img221.imageshack.us/i/freeze3.png/

ALSO i notied that after it gets parked after overheating is when it will begin to leak. Don't know if thgis helps or not, but i know I can't afford to keep buying gallon upon gallon of antifreeze just to try to figure out why it is doing this. I done spent over 100 on antifreeze alone. 7 gallons at $15 a gallon. its insane and expensive.
__________________

 

The engine in those pictures is much older.

There are only 4 core plugs (aka freeze plugs) that open up to the water jacket on the engine in your truck. The 96+ SCFI engine never had core plugs in the front of the block.

How are you making sure that all of the air is out of the block?

 

The weay im burping the system is by running the truck, then loosening the rad cap for a second, then retightening it. Its what my brother told me to do to get the air out. Opposed to taking the cap off and running the truck. from my understanding if theres air in the system then i won't have heat, but i wsas never informed that it would overheat the motor as well. PH and before i forget, the resevoir is still full up with antifreeze. Once again, dunno if this is relavent or not, but figured it might be.

Edit: just added my last gallon of coolant, waited for the truck to warm up, felt the top hose it was still cold (temp read 210 at this point) looked and seen the dripping under the driver corner. Took the plastic oil filter cover piece off and seen that the entire vertical length of the driver side of the rad was soaked. Still didn't see my petcock though. Is it directly on the bottom of the rad (faceing the ground) or on the front of the rad in the corner (facing the motor)? While I was under the hood I looked and watched my water pump, found the weep hole and it was dry. nothing was coming out of that, so im assuming my pump is still good. But then again, if nothing is reaching the pump, nothing can come out of the pump correct?

I need to figure thos out asap. I can't go without my truck anymore.

 

You have to make sure that you have the front of the truck elevated as much as possible with the passenger side (cap side of the radiator) slightly higher than the driver side. If the truck is sitting level, it will be very difficult to get all of the air out.

 

i havent really been bothered with trying to burp it because of the loss of coolant. i understand the overheating can be due to air in the system, little or no coolant, or a blocked hose. but my main concern is the loss of coolant right now. I see no point in me trying to burp the system if its empty and will drain right back out. I did find the leak source though. Definately not my petcock. My prtcock is on the passenger side, finally found it. The leak is coming from the driver side of the rad. The entire length of it is wet and just dripping out coolant. So im most likely either going to pull the rad and figure it out from there or get a new rad and hope its all great. the upper hose isn't wet, the wetness starts about 2 to 3 inches under the upper hose. And since im out of coolant (dumped my last gallon in just to find for certain where the leak is) and have no vehicle, i closed up the truck and began research on a new rad (which is how i figured out that my petcock is on the passenger side instead of the driver side). If anyone has any other suggestions, im up for them. Replacing my rad seems to be my last resort unless someone else has had this same thing happen to them and can let me in on what they did to fix it.

 

*Bump*


After a couple weeks of searching and working, the cheapest radiator i can find is 130-150+ from advanced. Radiator shops round me want over 400 to do it, does anyone know of anywhere cheaper to get the radiator??
Also can anyone tell me what size the cooler line nuts are that go into the radiator? Just incase something happens to them when im taking them off and need to be replaced.

 

Sounds like you determined that the radiator needed to be replaced weeks ago. You could remove it and have it pressure tested to be sure.

 

Yeah i determined it was indeed the radiator the entire time. It wound up sitting that entire time up until tuesday, thats when I had the time and money to get the new rad. (Talked the guy down to 96 and change for the rad due to a expiered promotion at advanced). Sized up the new line nuts with wrenches, found out the transcooler lines are 18mm and the oil cooler lines are 1". Used a pair of vice grips since i couldn't afford to buy the wrenches needed (25 for the 18mm and 30 for the 1"). Got the old rad out and thats when I seen it.. like i said earlier how the coolant was leaking from the driver side spanning the length of the rad.. well theres a HUGE crack in it. The crack had to be at least 6" long. So that was definately my problem.

Got the new rad in after and got it all buttoned back up, left the lower fan shroud off though, mainly forgot to put it back in until I had everything else buttoned up. Let it warm up, it went to 210, got a bit of heat but not much, dropped to 195 after the T-stat opened. LOST ALL HEAT. i forgot to burp my system. Tomorrow, im off from work so im going to burp the system and throw a few gallons of gas into the tank and take him for a good spin. Talked to a few local mechanics, of course they wouldn't tell me jack while they were "on the clock" but when the shops closed and I talked to them they opened uip telling me that i do need to burp the system. Once it is burped ill regain all heat and won't have any more worries.

Im hoping thats all there is to it. Ill finalize this post tomorrow though after i get the system burped. Heres hoping.


EDIT: But i was windering Swart, if I buy a quick release cap, the lever kind, can i just use that to burp my system instead of having to jack up the front end and such?