Ok, so my 97 2WD Blazer LS (4.3) has a small radiator leak, where the plastic tank meets radiator, a couple inches below the tranny line on the driver's side... (top tranny line).

I figure I'd just put some Bar's leak in it and hope it stops (it only leaks less than 1 bottled water every 3 days normal in-town driving)... However, a coworker rold me not to do that on a 4.3 because "those water passages are so tiny you'll gum them up".

My understanding is that the 4.3 is essentially a 350 with 2 cylinders lopped off, so to speak, and never heard anyone say that about a SBC. Is this really true, or is he just blowin smoke up my @ss?

If truth, is the Prestone any better? Other legit alternatives? Trying to avoid the cost of a new radiator at the moment, just replaced the Blazers battery, and a starter and switch in my other vehicle...

 

well i ran stop leak all last winter and spring trying to but time till i did the lower intake gaskets.
i can say two things....it worked and it screwed up my heater core several times.

it kept plugging it up, other than that no known issues that i have found from using it for that long.

 

The 4.3L is in fact a redesigned 350 (5.7), with 2 cylinders cut away, so to speak. Your @$$ can sit in the non-smoking section, sir.

 

DarkRose:
the concensus on every Fox body forum I belonged to in last 25 years is it's not a good idea and only as last resort. Because it clogs heater cores.
No reason to believe GM is any different . Add to that the Dexcool sludging problem. What i found on ONE radiator is I could slow the seepage at the rad- tank by crimping with vice grips. Of course that one had the aluminum bracket crimp tabs instead of epoxy bond
Found it fairly early though.. before the seal eroded too much

 

Lol, I knew that. I meant blowing smoke about the Bar's Leak plugging water passages.

Is there any other alternative that doesn't plug heater cores? The local radiator shop (only one left) doesn't guarantee work on radiators with plastic tanks, they just recommend putting a new one in... Trying to avoid buying a new one at $130 from Autozone, and I don't do junk yard radiators (except for demo derby cars, lol)...

 

I've used stop leak (fine aluminum looking powder) on several vehicles through the years. Had an S-10 with a pin hole in the radiator and it sealed it up no problem. Flushed the system 2 years later and the hole opened up again. More stop leak and kept the truck another year and a half. Had a Buick Century with intake manifold gasket issues and a leak. Shop wanted $700 to repair so in went the stop leak thinking I would sell the car. A year later and 15000 additional miles, it's still going strong. I was told years ago that new car manufacturers put in stop leak in every new car. One of those things you hear once and never again. My opinion.

 

If you can fix/replace the rad yourself, you will cut that bill way down, more then half. I did mine about 2 yrs ago wasn't that hard except for the bottom hose and I just cut if off (Was going to replace both hoses anyhow). That was the same spot mine started leaking, I tried everything at 1st, but in the long run replace the rad and all is fine and I also replaced the therostat and rad cap along with the hoses. Cost a few bucks but worth it. Then the clucth fan (2nd one) went out and thats another story.

 

Yeah, the $130 is for a new radiator alone, no service, because the day I need a shop to put in a radiator for me is the day I no longer need to be on the road, lol. Or at least the day I need a different vehicle.
I'm working 70 hours a week, in town, and close, so most of the time it doesn't leak bad at all. I drive out to the other side of town and back where the speed limit gets up to 50, and it drips a lot more...