| Author | Message | ||
     Pkforbes87 |
Long story short - I'm trying to get dirt and rust out of a cooling system that's been neglected. I've flushed it 4 times now, once with a bottle of prestone radiator flush, and every day I empty it the water is still dark brown. SO.. I've got 2 questions: #1 Can I let the engine run cold and pull the drain plug on the radiator to flush 100% of the liquid from the system, or will running dry damage the water pump? #2 Can I start the engine cold with the drain plug open and a water hose running into the top of the radiator to continuously flush the system? What I've been doing every time I drain and refill it is to pull the drain plug and run fresh water into the radiator cap until what's coming out of the drain looks clean. But I'm beginning to get the idea that this process is only flushing the radiator while the majority of the dirt and rust is inside the block and hoses. | ||
| Birdy |
Buy a back flush kit. It will force water backwards through the motor and you can run it days. Depending on how bad things are you may never clean. I had a old Land Cruser that was "Left For Dead" by the PO I never could get it 100% clean. I gave up and dumped 50/50 anti-freeze and water and it ran fine for years | ||
| Patches |
When your Flushing the radiator turn the water on low so the motor will heat up enough to open the thermostat or take the thermostat out so water can flow through the block. Had a 63' Impala SS the motor froze and busted one winter (block split between freeze-plugs #3 cylinders), the guy that had it at the time put block sealer in it. No matter how many times I flushed the radiator the water still looked rusty after a few days. The only way to clean it would be to tare it down, flush the block and heads out thoroughly in an acid bath, but that could cause more problems to show up. | ||
| Xl1200r |
At the shop I used to work at we had a machine that you would hook up between the top radiator hose and the radiator inlet. It would push fresh, clean fluid in while sucking the dirty stuff out. This was mainly just for a straight-forward flush, main advantage being you didn't have to burp the system when you were done. If this were me, I would do something similar to your second idea, but instead of opening the drain plug, I would disconnect the upper hose and seal off the radiator inlet, and have lots of water on hand with one of those funnels that attach to radiator cap hole. You'll either need to do this long enough for the engine to get hot for the t-stat to open or just take it out. I've also heard that a vinegar and water solution can clean the system out. I wouldn't run it dry if I didn't have to. | ||
| Odie |
Works good, lasts long time. I know it's for a diesel but same principle should apply to a gas burner. http://www.dieselsite.com/index.asp?PageAction=VIE WPROD&ProdID=8 | ||
| Blake |
Sounds like you need another actual chemical flush treatment. | ||
| Fast1075 |
The problem with cleaning out a rusty cooling system is what you SEE (the rusty water) are only the particles that are small enough to go into suspension in the water...the "parents" of the rust you see are large flakes of rust that are trapped in the bottom of the major cooling passages. The good and the bad of it is this...use another flush treatment and put on a backflush kit like Birdy recommends...flush it till the water is clean (check a water sample by looking at it in a clear glass)...when it is as clean as you can get it...put in a new t/stat and refill with good engine coolant and let it ride... If you persist, there is very good probability that there are pinholes in places like the freeze plugs or metal coolant lines, or even possibly the radiator and heater core that are currently sealed with rust particles...that will start leaking if you flush to much...get as much use from it as you can. | ||
| Swampy |
Another thing you can do is to flush the individual components separately. The heater core is real simple to flush/backflush, then you can remove the radiator and flush/shake/flush/backflush, all with a garden hose. Then all that is left is the engine and with the radiator off just fill through the top and bottom hoses with the thermostat removed. We are talking about a car....right? | ||
| Pkforbes87 |
yep 89 gmc s15. previous owner left the cap to the overflow tank off for who knows how long and obviously enjoyed off roading. It's running fine, no overheating problems - I just wanted to get the cooling system cleaned out a little. Fast makes a good point about causing other problems and leaks to show up though. I'll probably just drain and refill it a couple more times to get the loose stuff out then fill it 50/50 and leave it. New thermostat and radiator cap of course when I refill it for the last time. | ||
| Fast1075 |
Living in Florida, a lot of people don't maintain the cooling system like folks do up north...it has been forever since it was cold enough here to freeze a motor. When I worked on cars, I saw a lot of really fouled up cooling systems where the first thing the owner saw was loss of fluid from a freeze plug rusting thru from the inside out... Trust me...the last thing you would want on a S15 would be for the freeze plugs on the back of the motor to start leaking...there is no bigger pain than getting to those...those S series are a serious pain to work on... | ||
| Thetable |
+1 for that. I am running something very similar in my 93 E350 with well over 300k miles. It does a good job of trapping the contaminants without aggravating the system like back flushing can. There comes a point where the rust and sediment are keeping things from leaking or failing completely. |
