ACDelco GM Original Equipment 10-108 (12378255) Cooling System Sealing Tabs - 4 g

I have a 2013 Prius, 3rd generation . 210,000 miles. It had been running perfect, when it developed very rough engine noise and severe shaking from time to time when starting. Once underway the car ran normal. A couple of well reviewed mechanics were unable to figure out the cause of the problem. One even said the engine had something lose inside and wasn't worth fixing and should be sold for junk. That made no sense to me. Said he would give me $500 for the car as a trade on one of the used cars he had for sale. The other mechanic said he was certain the head gasket was not leaking (I suspected it was the problem until I got that advice)The check engine light came on and the code said the problem was with the #2 cylinder.I decided to use the internet to find an answer. Turns out this generation of Prius often suffers from the head gasket leaking a bit of water often into the number 2 cylinder. It's a somewhat common problem at around 200,000 miles.Number of options. 1, replace engine with a new or rebuilt or use a low mileage engine from Japan. 2. replace the head gasket. Costly options on an older car with lots of miles.fortunately, I came across a retired mechanic who was aware of the problem and suggested as a first and least costly option, I buy and use this AC Delco product to try and stop the leak. Said he used it on his own car with good luck. Said he was into the second year after using it once and no leaks.I bought it and put into the engine per the instructions. It has now been over 1000 miles since I used the product, only one application, and NO PROBLEMS!!! Talk about a cheap and effective fix. Plus it pin points the cause of the problem. So much for considering top mechanics as the last and best word on my problem.Two lessons learned. 1. This a great product so far. If problem shows up again I will just repeat the fix and take from there. Could not ask for more. 2. The internet is wonderful tool to use to help solve a problem, if only you will take the time and effort to use it fully.

These work good. I put three tablets in my streetrod all aluminum radiator that was leaking in three corners. Immediately sealed up and has held up so far.

This worked surprisingly well on an aluminum radiator that was leaking coolant.

Have a Silverado with the 5.3l. Had a leak that I couldn’t find without tearing everything apart. More than likely the manifolds on the side of the radiator, as this is common on these trucks. Didn’t want to change a radiator this month before a short trip to the mountains.Broke the tablets up. Dropped in reservoir. Drove for 30 minutes. Let it cool down and set in. No more leak.Easiest and cheapest fix I have ever witnessed. Not sure how long it will last but so far it has lasted a month and driving off road on some rough stuff. I blew out a CV axle but not my coolant leak!

These things have been around since the dawn of time. GM used to put these in new cars off the line during the LIM-gasket fiasco. They work as intended most of the time and can even be a permanent repair in certain cases. I had a slight external head gasket leak from a crossover coolant port. The leak was tiny, a seep at best and these took a good little while to actually seal up such a tiny leak but they did after a couple hundred miles. The product works most of the time (within reason) and is worth a shot before doing more expensive repairs.My only complaint is the shipping from Amazon, once again they fumbled the packaging and shipping. They sent me an open package with one of the tabs completely missing. The envelope wasn't breached so it had to have been packed that way. Another one of many Amazon shipping gripes.

A wonderful product for insuring that a major cooling system repair doesn't have any seepages or dribble leaks after a lengthy labor operation.

Great product

These work awesome! Do not bother with the other stop leak products!! I used a few of these to stop a leak in a 2005 Honda Element heater core months ago for a broke friend. Saved them a $800+ shop bill. Stopped the overheating issues due to coolant loss. Excellent product!!!