Is it safe to use radiator stop leak?

[grecko]

I used Bar's Stop Leak on my Wrangler TJ before. It stopped the leak but after 3 days it clogged up the coolant passages and got overheating issues. I ended buying a new radiator and hoses from 4WO|jeep accessories. I won't recommend using Bar's or any product similar to it. Getting a new radiator is a better idea.

[a64pilot]

I had an international 574 tractor that I put a stick through it’s radiator in about 1980 or so. Put a bottle of Bar’s stop leak in it, clear plastic bottle, yellow writing, looked like it was full of rabbit pellets.
It never leaked again, and worked at least until 2017 when I sold the tractor to go cruising.

I didn’t expect it to work, expected at best a temp fix, but I wasn’t going to buy a new radiator until it started leaking again, which it never did.

Yes GM installs from the factory stop leak in all their cars, it’s due to all of the aluminum castings I believe, light brown compressed tablets, available at any GM dealer
https://m.acdelco.com/auto-parts/veh...seal-tabs.html

[zeehag]

my chevy luv truck loved the barsleaks stuff. i would not dream of clogging a heat exchanger with those beads.

[hellosailor]

a64-
"Yes GM installs from the factory stop leak in all their cars, it’s due to all of the aluminum castings I believe,"
First I've ever heard of that. What's your source of that information?

On the Jeep radiator...odds are that if the radiator got clogged, the heater core is shot too. FWIW. The collateral damage of "leak stop".

VWG/Audi has had problems apparently from conventional (sodium silicate) anti-leak coolant in some cars, forming sludge that jams turbine cooling pumps and causing engine fires in parked cars. Not nice. But the rumor is the Germans require the sodium silicate because their aluminum alloys fail without it. In the US that was a great new product (Xerex?) back in the 70's IIRC. And Dodge/Chrysler was the holdout that refused to use it because the antileak coating caused overheating and clogging.

Maybe the rabbit pellets have better magic.(G) Chiltons and the other shop manuals never suggested adding any of that stuff.

[a64pilot]

Originally Posted by hellosailor

a64-

"Yes GM installs from the factory stop leak in all their cars, it’s due to all of the aluminum castings I believe,"

First I've ever heard of that. What's your source of that information?

Factory service manual for my 1993 Z28.

[David M]

Still waiting for a radiator explanation from ClarencePeters. An actual radiator or a heat exchanger?

[AKA-None]

Last ditch radiator stop leak is ground black pepper if there are no other options. Very old school but it does work for tiny leaks.

[hellosailor]

a64-
"Factory service manual for my 1993 Z28."
Makes me wonder if they were addressing a particular problem in the Z28, since those weren't your run of the mill production cars. Most curious.

[a64pilot]

Originally Posted by hellosailor

a64-

"Factory service manual for my 1993 Z28."

Makes me wonder if they were addressing a particular problem in the Z28, since those weren't your run of the mill production cars. Most curious.

No, it’s also used in the Wife’s 05 CTS-V and in my 01 Duramax Diesel.
I had the factory service manual for the Z28 cause I was taking it to Germany and the Z28 was not imported into Germany, so I figured I may be on my own service and parts wise.
The Pontiac was imported and of course except for plastics, they were the same car, so it worked out.

The GM sealant is used to seal micro pores in aluminum castings is the reason given, and if you take an expansion tank off of a GM automobile to clean it, you’ll notice a light brown sediment in the tank, that is the sealant / stop leak, it’s in or was in all GM vehicles.
I don’t know now, but ten years ago it was, and was used for decades.

It was used with Dexcool, which got a real bad name, but undeservedly so.
Yanmar has for a long time used Dexcool, just under a different name.

Trivia, but the LT1 motor in the 93 Z28 was I believe the first reverse flow cooling system, cars until then always had the water flowing backward through the engine, it went first to the block and then to the heads, the heads are the hottest of course and should get the coolest water, but didn’t.
NASCAR started pumping the water in reverse, to the heads first and GM adopted that with the LT1.
http://www.corvetteactioncenter.com/...ystem-526.html

[hellosailor]

You got me curious enough to go looking it up last night, and of course my memory is fuzzy today. IIRC several sources including a GM bulletin and ACDelco refer to it as a largely obsolete product that *was* used up to 1996(?) because of not only porosity problem, but apparently they had steel cylinder liners in aluminum blocks (the ghost of Vega engine lessons learned, huh?) and engines with iron blocks and aluminum heads.

Apparently they couldn't get the casting and machining done well enough, and the different expansion rates were causing additional problems, so for SOME engines they put the stuff in initially, expressly stating NOT to use it during coolant changes afterwards because one dose should "complete" the original engine. Then for other engines they say to keep using it--but not to exceed the recommended quantity. And then somewhere around 2003? 2006? they simply said not to use it any more, they've solved the problem.

The "answers" from generally reliable sources (like ACDelco's online specs, versus GM's tech bulletins) seem to be about as much in agreement with each other, as any dozen sailors being asked "What is a bluewater boat?"

So remind me again, why can't I just use Crisco as engine oil? (VBG)

[a64pilot]

I think everybody has steel liners in aluminum blocks, and puts aluminum heads on iron blocks. Vega had no liners, which worked, but it was overheating and warping that did them in. Interestingly to me, but the Vega was supposed to get the Rotary engine that had already been developed and tested etc, but the oil embargo killed it as Rotary engines are thirsty engines, and tough to get to meet emissions, after the Rotary didn’t happen, GM came out with the “Iron Duke” engine for the Vega, but the damage was already done.
My wife when we were dating had a Vega, that died due to overheating, I had a wrecked Mercedes 220D that I wanted to put the engine and powertrain into the Vega, but her Father scrapped it. I still think that would have made a good car.
My Duramax Diesel, a joint venture between Isuzu and GM, although mine had an Isuzu data plate was highly unusual as it was a Diesel with aluminum heads, and all the experts said that would never last long, but it did.

I knew it was stated it was for casting porosity reasons, assumption is that a very few castings actually had tiny leaks, which castings I have no idea, but you right it was likely a band aid fix until they got their act together and fixed the problem, whatever it was.

However it does seem to show that not all stop leak products will cause harm.

[hellosailor]

I knew a brand new Buick in the late 70's that had a porosity problem. Man said "No coolant, there's a leak!" and the shop tried to refill it and spot leaks 3x before they called in the zone man. Then they figured out it was a porous block, it could drain out in 24 hours. So, qc is always an issue.

From what I understand (I had a badly abused Vega sportwagon that I had mistook for a cheap very used car) Chevy tried to copy Porsche on the engine design. That is, an aluminum block with a special surface treatment, no liners. And in order to get more power and efficiency, they bumped the thermostat form the usual 170-ish to something like 200, also copying Porsche. What they forgot was that "cheapest Chevy" buyers usually were ignorant about little things like oil...and the oil IS the primary coolant in the engine. Porsche owners put oil in their cars, Vega owners didn't. It wasn't so much that Chevy made anything wrong--just that they were vulnerable to ignorant owners.
OTOH, my car gave me a stress attack one morning when it refused to start and threw an OIL light. By then, they had an oil pressure sensor that would cut off the ignition if there wasn't enough oil and in my case, the sensor itself had failed. Phew. Way cheaper than an engine. And I learned, never trust sensors in engines. Sad just how many new sensors all the new engines have, even the diesels now are all computer controlled and vulnerable.

[a64pilot]

Many, many engines, especially motorcycle engines have aluminum cylinders, often Nitride is the coating I believe, and last a very long time.
Only drawback I know of is your not boring those out, unless somehow you can reapply the coating.

My Brother had a 928 Porsche, a car I didn’t like at all, it’s V8 engine was I believe four separate castings stacked on top of each other as Porsche couldn’t cast something as big as a V8 in a single piece.
It worked.

[hellosailor]

I'm convinced that while SOME of the engineers at VWG have a good idea of what "fun" means, they were never very good at reliable anythings and that includes the original Beetle, which was an outright POS in so many ways.

Maybe five years ago I recall reading something about someone using lasers to micro-etch cylinder walls, instead of the conventional lapping, and that was supposed to do incredible things. I think it was either Renault or Peugot that used replaceable iron cylinder walls with o-ring seals...some odd designs but one had center dash vents that could be pointed UP at the windshield to help defrost it. Which was good, because the engine needed a piece of cardboard in front of the radiator in winter.(G)

Yeah, there are some fine engineers out there somewhere. And more that have simply gone madder than the proverbial hatter.

When IBM's r&d folks came up with the Selectric typewriter using that whirring golf ball instead of keys, they did it because it allowed faster typing especially for computer terminals spitting out pages. The company brass apparently looked at it and said "That's too complicated, they'll need service too often" and someone chimed in "That's a great way to sell service contracts, they'll need them." Yeah, business users learned they really needed that service contract...Engineers are usually kept out of sight for good reason.(G)

[AKA-None]

Well my diesel Audi is sitting at 190k miles and still going strong.