Hi guys,

New to the forum, and thank God I found y'all. I'm a female sorta-mechanic and I love to work on cars, my Blazer is the vehicle that I've worked on the most, so it's the one I've learned the most from.

Okay, here goes. I have a 2000 LS 4x4 4.3L Vortec that I absolutely LOVE...er...I did when I was driving it. It's had a crack in the plastic side-tank on the radiator for a while, so I had to fill it whenever I drove anywhere but it ran fine and didn't leak a whole lot, just enough to be a nuisance. One night I had to get it jumped because apparently the negative battery terminal was loose and not being recharged by the alternator, so when I got home I let it run for a while so the battery would recharge. Little did I know that one of the freeze plugs fell out and it completely ran out of water and overheated. I shut the truck off when I noticed that the temp was up much farther than normal. The next day I tried filling the radiator and water was running out as fast as I was putting it in, so I parked the truck and haven't been able to do anything with it since (this was about a year ago.) I thought it was all the radiator, but I know better now...

This weekend is the first time I've been able to crawl around and see what's going on. The freeze plug was the first thing I noticed, which made me check the dipstick and of course it's milky as all get out. I've looked around this forum (and others) and I know the intake gaskets are horrible and I'm going to replace them. I'm going to borrow the tools from my brother to do a compression test to make sure it's not the head gasket/warped heads. This is the first time I'm tearing an engine down this far but I'm not afraid.

I've never done a compression test, but I do know how to do it. Does anyone know what the cylinder PSI reading is supposed to be? I know they should all be within 10% of each other, I just don't know how much compression they're supposed to have. I'm guessing in the 140-160 range?

Thanks guys, and I'll keep you posted on my progress.

 

this should help with your compression check

https://blazerforum.com/forum/2nd-ge...3-vortec-2077/

also down at the bottom of the threads (scroll down to bottom of this page) there is a "similar too" listing...it may help you narrow your hunt for info.

good luck with your ride.

 

Man, that's awesome thanks a lot! I guess I didn't look far enough, that thread was all the way back in 2006.


I kinda figured that's what I should be getting...hoping I don't have to tear down more than the intake manifold.

 

Welcome to the forum! Cylinder heads and head gasket problems are almost unheard of on 4.3L's, unless you really cook 'em, doesn't sound like that happened. The cracked tank on the radiator is common. Core plug, not so common, but they do rust out. After replacing the radiator and core plug, pressure test the cooling system and have the coolant checked for the presence of hydrocarbons, that will tell if the heads or gaskets have a problem. Much easier and far more accurate than a compression test.

 

You were topping the coolent of with water I would guess. Unless you live way down south the Blazer went through a couple of freeze cycles. The plug blew like it should. Before you start ripping things apart do what Hook said, nothing else till then. With any luck there's nothing wrong. If you get it running and you have someone do the hydrocarbon test stand there, watch lot of people looking for work. Better yet buy one and do it yourself.

 

For my 1500th post, let me say I love chicks & cars together. I got STORIES!!! Best driver I ever rode with was a 21 yo supermarket asst manager / cashier with a brand new 63 Impala SS. Ask me some time..
But I got some not so good news, too.

Actually freeze plugs really arent there to relieve ice pressures, they are to fill casting plug holes - used to hold the sand cast in place. In the old days {I mean first half 20th century} when castings werent quite so precise they did save cast iron occasionally because walls were thicker.

Now what they DO indicate when they blow out is possibility of a cracked block. I would caution you that that is very much a possibility in your case.

Had one just like it. Got snooked because I bought a car to rebuild which had a slight cabin fire/ smoke damage. Once I fixed the electrical damage, went to fire it up, poured in coolant which went straight back out the side of the block. First thing I saw was sideways freeze plugs, second was big-*** crack. Found out later* that the fire happened at a dealer just as a buyer was to pick up the car.

Long story short, the cracked block caused the electrical fire if you get my meaning.*

* Sidenote: I'm one vindictive SOB. Not that I was pissed that I had to swap engines, happened to have a spare. It's the insurance fraud. I gathered all my notes and photo's on the case and sent it to the insuror that paid off the dealer's claim. Including the claims adjustor's name from the same company who I bought the car from in the first place. The car was titled to him, not the insurance company. See what I'm hinting?!!!

 

Happy 1500th!!! Bit of a buzz kill tho. "SLIGHT CABIN FIRE" love that.

 

I do live way down South, spitty. We haven't had any freezes to make the plug pop, I'm guessing since I was topping off with water that everything has eventually dried out due to no slick antifreeze. I'm hoping it's not a cracked block, but I don't think it got hot enough to actually do that (it was only running for a little while, and the temp wasn't pegged just on the hot side.)

My next few weekends are going to be FUN. Not like I had something better to do anyway, right?

 

Exactly correct, that's why they're called "core plugs". Not at all designed to relieve pressure from ice expansion. When the sand is removed from the core after casting the block, the area that the sand took up now becomes.... coolant passages.