I have a 95 benz s320 and i put prestone antifreeze in there and i am planning on changing the antifreeze, because i heard it's not recommended to put other antifreeze in there, it makes the car run hot. I got 2 gallons of antifreeze from the dealer and i want to know what is the best way to flush the radiator and if i should put on gallon antifreeze and one gallon water, does it has to be tap water or distilled water?

distilled water

I got prestone and i mixed it with tap water can that cause any damage? Why is there a difference using distilled water instead of tap water to mix it.

Distilled water does not have any minerals that can hurt the engine and cause corrosion.

Easiest way I have found is to mix the coolant/water out of the car. If you have an old empty coolant container. Fill it half with water and then fill it up with coolant. 50/50 mix then poor it in. Since you are not going to get all the old stuff out (heater coil and hoses) you will not get the full volume of coolant back in. If you do it out of the car, regardless of how much you put in, it will always be a 50/50 mix.

Hope this helps

__________________
Sent from an agnostic abacus

2014 C250 21,XXX my new DD ** 2013 GLK 350 18,000 Wife's new DD**

- With out god, life is everything.
- God is an ever receding pocket of scientific ignorance that's getting smaller and smaller as time moves on..." Neil DeGrasse Tyson
- You can pray for me, I'll think for you.
- When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours.

Well this is what I did when flushing my system: #1 I bought Zerex G05 antifreeze because I read that this is the original antifreeze MBZ use. I drained the old stuff out via the hose at the bottom left (passenger) of the radiator, I have a 190E 2.6 so it may vary. Then I disconnected the 2 larger hoses on top next to the thermostat and drained what was in there. I then covered each with a cloth and blew inside to flush it out some more. Then I disconnected the hose that is connected to the hearter valve and made sure that was all drained out. I then proceeded to flush the coolant tank with distilled water and let it all drain out into a pan before I refilled the system with Zerex. Took me anout an hour. I also disconnected my coolant tank and scrubbed/cleaned it because it was filthy. I may do an upgrade to a clear one in the future as I still have the original rust colored one....which may or may not have been clear at some point. It is only about 9 years younger than me hope this helps. Oh...and you can buy Zerex G05 at Kragen autoparts or Google it.

Ismalley, you mean you didn't drain the block with drain plug located on the passenger side under the rear-most exhaust manifold? if not, you still had probably about a gallon of old coolant left in it.

As far as distilled water, yes, that would of course be optimal, but tap water is okay to use. It would be very, very unlikely that the gallon and a half of average tap water that you'd use in your system would contain enough minerals, chemicals, salts or acids to do any kind of damage to your system. Unless you change it a couple times a year, I seriously doubt it could do any harm. That being said, I use store bought drinking/spring water.
The antifreeze on the other hand does make a difference. Use only Zerex G05 or MBZ coolant.

Oh yeah, I did use the drain plug! I was referring to that when I said the hose at the bottom passenger side. Thats where most of the coolant actually drained from....maybe half a gal or more, not really sure.

Below is the procedure I use on all vehicles. It completely removes all old fluid, minimizes the amount of tap water in the system, and provides a reasonably close 50:50 mix. Use shortcuts as appropriate for yourself.

1. Drain fluid - radiator and block
2. Remove thermostat
3. Reinstall thermostat housing and upper radiator hose
4. Disconnect upper radiator hose at radiator
5. Flush system with garden hose through upper radiator hose until water runs clear
6. Start car so the engine can flush the water pump
7. Disconnect heater hoses, open heat valve
8. Flush heater core
9. Flush overflow tank
10. Drain as much water as possible from cooling system
11. Siphon water from overflow tank
12. Flush residual tap water from system by replacing it with distilled water
13. Again drain water from system
14. Reinstall thermostat
15. Button everything back up
16. Refill cooling system with specified amount of antifreeze calculated from the system capacity, bring up to level with distilled water
17. Run car, top off coolant with water
18. Keep adding water as required every morning until system is topped off