Warning about using stop-leak in a radiator

[Scott Danforth]

....or any other "mechanic in a can"

thought I would share the quick story as summer and hot temps are quickly here

co-worker had a mid 90's GM 3/4 ton van that developed a coolant leak. so instead of fixing the issue correctly by pulling the radiator and replacing it (aluminum core, plastic tank). he poured in a can of stop leak....crossed his fingers..... then headed out of town to drive up to New Jersey from Tampa Florida with the van loaded with stuff

about the time he gets to the FL / GA line, his van falls on its face and has no power and lots of blow by.

gets truck towed home..... few weeks later replaces motor and does a tear down of the failed motor

the stop leak formed a stalagmite on the knock sensors and temperature sender, so he was running hotter than indicated, loaded while at highway speed with the crap swill you get in FL pumps and the ignition wasn't pulling back the timing like it was supposed to.

2 pistons cracked from the compression ring to the oil ring with the skirt just sort of hanging there flopping around.

morel of the story. there is no mechanic in a can. fix the issue at hand

if your radiator is leaking - fix the radiator
if your head gasket is leaking - fix the head gasket

coolant leak stoppers do more harm than good

 

[fhhuber]

Radiator stop leak and other "mechanic in a can" products are stuff you use to make the vehicle look like it works fine just before you sell it to some "sucker"

They'll do a decent job of hiding a problem long enough for a test drive.

 

[bigdee]

Modern technology has killed many of these remedies that somewhat worked on the less sophisticated engines of the past. Up until the seventies, car manufacturers put stop leak pellets in the engine blocks before assembly. This was done to seal minor gasket leaks that might arise and add to warranty claims. Lower engine temperatures, cast iron,brass radiators, and silicate antifreeze made stop leak doable. Silicate also works a a minor stop leak and forms a very effective barrier against corrosion. New car technology is no longer tolerant of additives and is very coolant sensitive. Todays long-life,non-silicate,organic antifreeze and stop leak can be a death sentence...

 

[gm280]

I have to say, I was never an "add junk into systems to fix things" type person. Yes the repair is some times a PITB, but you have to know that fixing things the proper way actually saves you both time and lots of money in the long run. That is why I could never have been a mechanic for anybody company. They want you to short cut things for profit. I can't don't that type work. Just not my style. JMHO

 

[DeepCMark58A]

I will admit to using STP oil treatment on my son's saturn to try to slow down the oil blow by.:joyous:

 

[bigdee]

I will admit to using STP oil treatment on my son's saturn to try to slow down the oil blow by.:joyous:

Last ditch effort on a clunker when you have nothing to lose. I had a Ford van that used oil like crazy and it was not worth fixing and I did not want to keep buying oil. The plant I worked at was throwing away USED hydraulic so I kept a 5 gallon bucket of it in the van all the time. I never changed the oil...just kept adding hydraulic oil. That crazy,rod-knocking van ran for two years and was still running when I sold it for junk!

 

[DeepCMark58A]

Yeah it is my son's college car, he has been driving it since he was 16, he is 21 now. With a daughter getting married this summer and him in college for 3 more years not the best time to go buy a used car.