Prestone AS105 Total Cooling System Cleaner for Radiator, Heater Core, and Hoses, 22 oz., 1 pack

Very good product when you're going to flush out your vehicle cooling system. It's not super acidic and will remove any rust or other contaminants that should be flushed out before you replace your coolant. Economical and price and very effective

Let it sit for 4 hours unclogged a very clogged system! Very happy great product.

Item worked as advertised - Easy to use - suggest purchasing

I don't know if this worked or not because I only used it because this is the first time I have changed to coolant in my 2004 Suburban since I bought it in 12/2003. I drained that out and filled with straight water for 10 minutes of run time. Nothing bad came out so I had no clogs. I drained everything and changed the thermostat and a lot more water came out so I know that was a good drain. Filled to the top with 50-50.

Seemed to do what it is intended to do. Good price.

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.

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.

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.

Extremely nice product. Its worth every penny.

My radiator had relatively clean coolant when I drained it, a couple of particles sure, then I filled with this cleaner and fresh deionised demineralised water, ran for 20 mins and oh my it was brown, so I drained again and repeated the process but left it in for 6 or there about a hours of driving, well super clean result it dislodged everything. I then refilled with water again dropped the bottom hose out and removed the thermostat and replaced with new and connected everything again, filled up with coolant as per spec and drive ensuring all air pockets were gone, took another small sample from the drain and it’s spotless coolant. I didn’t expect to go so far with it but when I saw the progress I had to keep going simply because of the way this works. Very impressed.

The flush and clean worked well,should have shopped around for price overpaid for product. Convenience has a price with it. Took a while to get

I used this to flush out my Jeep GC Limited. Work an absolute treat and was able to put in new radiator fluid. Would purchase again!

ONE OF THE BEST COOLANT CLEANER THAT I HAVE EVER USED, A REMINDER IT'S BETTER BEFORE YOU GET YOUR COOLANT FLUSH, TO DRIVE YOUR VEHICLE WITH THE ADDITIVE IN THE COOLANT FOR AT LEAST 6 HOURS. PLEASE READ LABEL.