PrestoneAS105 Total Cooling System Cleaner for Radiator, Heater Core, and Hoses, 22 oz., 6 Pack

A wise man once said to me "get a good vehicle and KEEP it". They don't use salt on the roads in winter where he lived and I'll always remember the truck and wagon he drove were born the same year as me. Back when silly manufacturers allowed you to work on your own things. As much as manufacturer's are trying to keep you from fixing things you own or even owning the things you own, there are plenty of things you can still maintain to keep the cost of ownership to a minimum. And no matter what anyone pressures you into thinking, generally, the "greener" option is to keep your old 'whatever' running for another year, if you can do so safely. My vehicles are old and I'm proud to maintain them myself.I don't know if this stuff is formulated to look so gross when you flush it out or I was just really overdue. I ran 3 bottles with distilled water in-between and it got better each time, but comes a time to get it dirty. Hopefully I didn't knock the rust holding everything together out of place.

Easy to use

This is a great radiator flush but don't order from this vendor if you need it right away. It didn't ship for two weeks and I had to cancel 3 appointments to get my cooling systems refreshed.

It does what it's made for,gets the built-up grime out of your engine & refresh 's your gadgets. Just as long as your coolant has not turned into syrup .do it early you won't regret it.fresh oil & a coolant change is the life blood of your engine.2 bottles is better than 1. Danni o. Seattle,wa

The cooling system on my ‘05 Silverado was not bad. The anti freeze was not rusty colored but it was eight years old. So I flushed it all total 4 times with distilled water(12 gallons). I absolutely do not put faucet water in any of my vehicles cooling systems. I keep my vehicles for many years so it is vital to keep minerals out of the cooling systems. That folks is from my experience of 60+ years of driving and caring for my means of transportation. I am 77 years young!

I've used this in the past and it always did a great job. Old antifreeze has a bad habit of corroding the internals of an engine and cause damage you may never see.Hint: If you buy a flush kit to do the entire job you must also take the thermostat out to flush the motor, if you don't then all you are doing is flushing the heater coil and not the engine. Here's the right way, buy this stuff, pour it in, drive around for a day or two and let it cycle into the engine and water pump along with the heater core. Remove the thermostat (good time to replace it since you have it out) put the connector back on without a thermostat. open up the bottom drain on the radiator and take off the cap, turn on the water hose and start your engine and watch it till all water is perfectly clean (around 5 minutes should be enough, more if you want) turn off water,close flush kit with cap, install new thermostat and close drains on radiator making sure the radiator has completely drained. Refill with new 50/50 antifreeze till full, check it later or the next day and top off as needed.

This stuff caused my water pump seal to start leaking. It happend after I flushed and added final mix 50/50 Preston . I now have a leak from the weap hole on the water pump. This stuff did something to the shaft seal so now I have a small leak. Have to replace water pump to fix. On my car that is going to be money thing. My system was so clean that when I ran the flush there was no color change so if you drain several times with distilled water and get it very clear don't use this stuff. Jus add final mix.

I was using this during a heater core flush.I flushed the core out with some water and added this product in to soak in and hopefully remove some dexcool that had gunked it up.Well, it was winter, so it got dark really fast and I decided to leave it in overnight to hopefully breakup the dexcool stuck in the core. MY MISTAKE. DON'T LEAVE IT IN OVERNIGHT.Next morning I flushed this out and added some coolant and tested the car out. The heat went from nothing to blasting out intense heat ...amazing.The next day, I pick up my young daughter and she goes "I smell gas". It wasn't gas she smelled, but a coolant leak from the heater core. I left this in too long and I'm pretty sure it had eaten away enough to cause a leak. Luckily, I had some K-seal laying around that I added in and it seems to have stopped the leak so far.So yes, this product does work...but DO NOT LEAVE IT IN TOO LONG. It was my mistake, not the product.