Coolant Flush question

[GDawgC220]

going to try and flush the coolant myself, as it hasn't been done in a while. While at it, goin to try and remove the old coolant thermostat and replace it with a new one I got from the dealer.

Does anyone know where the drain plug is? I assume at the bottom of the radiator? How big is the coolant tank? I know to mix 50/50, bought some Zerex G05 from NAPA, which is the same OEM MB coolant from dealers. The guy at NAPA said the tank is 2 gallons (8 quarts?)? Is this true? If so, I can throw in one jug of the coolant and fill it up with water then put that in the tank to mix, so 4 quarts coolant and 4 quarts coolant?

After draining the coolant, is it safe to use tap water to have it run through the system with the heater on high to flush out what's in the engine block? Or should distilled water be used? Where can I buy some distilled water?

Thanks guys!

[jnenad16]

You should use one gallon of antifreeze and fill the rest with water. tap water is ok, but its best to go with distilled water. as for the flush, I would highly recommend the JONSEN'S Radiator Flush instead of the PRESTONE one. the drain plug is located at the bottom of the radiator(usually on the drivers side for C220). I would also recommend you put one of those coolant additives, as they will add rust and deposit protection to your cooling system(good one is Redline Water Wetter). hope you find this useful.

nenad

[GDawgC220]

Originally posted by jnenad16
You should use one gallon of antifreeze and fill the rest with water. tap water is ok, but its best to go with distilled water. as for the flush, I would highly recommend the JONSEN'S Radiator Flush instead of the PRESTONE one. the drain plug is located at the bottom of the radiator(usually on the drivers side for C220). I would also recommend you put one of those coolant additives, as they will add rust and deposit protection to your cooling system(good one is Redline Water Wetter). hope you find this useful.

nenad

Thanks for the help!

is there a drain plug for the coolant on the RH side of the engine block as well to get the coolant inside the engine out? Or should I just drain the radiator and that's enough?

[benzaddict]

On the right side of the block under the exhaust manifold between cyl's 3&4 is the drain for the block, if I remember right you'll need a 19mm wrench. Drain the coolant there and from the radiator on the driver's side, it's a red screw plug. Drain the radiator first to get most of it out so it doesn't make as big of a mess when you drain the block. If you replace the thermostat then fill the coolant through the t-stat hole before you put the new one in and this will fill the block first so you don't have a huge air bubble. Use the entire gallon of coolant and then finish it off with water. jnenad's suggestion of Redline water wetter is good, I would do it in my car, but not a necessity and I don't do it regularly in customer's cars. Once you fill, run the car at ~2000rpm for 5 minutes with the defrost on to eliminate all the air bubbles. Good luck.

[marksbenz]

if the coolant is not that dirty just drain and fill the radiator. flushing your radiator can clog and harm your heater core. Adding Redline watter wetter helps. Add it to your radiator first.

[jnenad16]

i would not use the block drain because most of them are rusty/frozen and once you open it, the chances are it will leak and you will have to replace it. as for the flush plugging the heater, i have never heard of this problem, so do a little research about it if you are concerned. also, to flush the dirty coolant out the block, disconnect the coolant hoses from both sides of the auxiliary water pump and connect water hose to one hose leading to the heater core and blast water through it, the dirty coolant will come out of the other detached hose.

nenad

[GDawgC220]

Thanks for the replies guys!

I just completed the entire job, coolant flush and coolant thermostat replacement (temps never got to or above 80 while driving).

I drained out all the coolant, but I could not find the drain plug on the engine block itself :( so I could not drain what was in the engine. After draining through the radiator plug (wasn't frozen or stuck) I put in 1.5 gallons of 'distilled water' then replaced the old thermostat with the new one. Tightened hoses and bolts then turned on the car and ran the heater on defrost highest speed for 10 minutes. Revved the engine at times to get the water through the system.

Within that 10 minutes time, it did reach 80 finally with the distilled water running through. After the water was hot and 10 minutes was up, shut off the car and waited another 10 minutes for the water to cool down so that I could drain.

Drained the water out of the system, about 1.5 gallons came back out. Then filled up with 50/50 mix of Zerex G05 coolant and distilled water. After that, replaced everything back and took it for a drive. Temps rose up to 80 as it normally did before, within 5 minutes and everything seemed great.

Checked for leaks when I got back, nothing, All the hose connections were dry, checked the radiator drain plug and it was dry as well, no drips or anything.

Total time was about 2.5 hours (first timer :-p) Dealer wanted $150 for the thermostat replacement, spent about $60 for the parts:

$36 for the thermostat
$12 for the Zerex G05 Coolant
$6 for draining pan
$4 for 3 gallons of Distilled water.

So I saved about $100, not bad at all in my book :)

[jnenad16]

good job. im proud of you LOL

nenad

[benzaddict]

Sounds great, congrats!!

[chimchongdlight]

If we I don't drain from the block, while putting water thru the resovior tank, will the water eventually go thru the block and flush it out?

[chimchongdlight]

So I'm finally finishing this. Cap on an heater on and it still at 100 degrees. If I turn off the heater it continues to go higher. How much higher I'm not sure. What can the problem be? Before I even started this DIY I never had a problem with temperature. Now that I want to flush it. I'm having a problem. What's going on? I put a new thermostat too. Text me please someone 408.564.1950

[hvmercy]

I don't get what you're saying.

Did you flush your coolant? Are there any leaks?

[chimchongdlight]

Yes I did flush my coolant. And It doesn't appear to have any leaks from what I see. I did the whole step by step process and now my temp keeps going higher than when I started the flush. And now I think I'm hearing a clicking noise in the resovior. I thought it was bc I didn't top it off with water enough so I filled it and the clicking comes and goes. Im so loss. I got work tomarrow too. I should have never touched it. It wasn't even broken but I figured I'd do it since it was never done. Any ideas?

[hvmercy]

Hmm, that's odd.
What ratio did you use in the water and coolant combination?
Since you replaced the thermostat, put the old one back on and go from there.
Did you check for air lock?

After flushing your coolant and refilling it, did you let the engine run with heater on in high temp with the reservoir cover off?
This is how you make sure there is no air lock in your heating system.

[glenmore]

A rapid rise in temp quickly pasty 100 on a cold car is typically a stuck thermostat. Stuck in the closed position. Of course this is a very bad situation and will lead to overheating. So either your new thermostat is bad or you did not install it correctly.

[c220 tja]

Its gotta be the thermostat, I always put them in exactly how they came out, might wanna check this out....as for the clicking sound, mine does it too, but i think its part of the climate control( only clicks when its on)