Hi folks. I am sorry if this is a re-thread, but I have searched hi and low on this forum for some sort an antifreeze change narrative, but unfortunately, I haven't had any success... So, I thought I'd just ask...

As background, I bought my srt three weeks ago. It has 16k florida miles on it and is in really beautiful condition. Being an auto geek and wanting to start anew, I have changed out the oil (mobil 1 0w-40 and mann filter), the 2 air filters (NAPA Gold 6875/OEM Mann), and the cabin air filter (i produced a forum narrative with pictures of this procedure in case you're interested).

Next up was an antifreeze change, so I went out and bought all the necessary goodies, to include the Zerex G05 and distilled water. Now, I've changed out antifreeze countless times over the past 40+ years in many different cars, but I still completely read the chapter 7 procedure on changing it out, and I also read everything I could on the Mecedes Benz forum about changing it (there are several good narratives).

Thinking myself adequately prepared to do a simple task, I attempted to change the antifreeze out yesterday, and much to my surprise, I didn't meet with much success. Here's what happened:

As you may know, Chapter 7 says to leave the cap on and open the under radiator valve. So, I opened the valve and for several minutes nothing at all happened. I then removed the cap and the antifreeze started to immediately flow. After about 5 minutes of good flow it started to just trickle a little, but after about 2 minutes it then began to flow again at a good rate for a couple of minutes, and then I just let it drip out for about 10 minutes. For what it is worth, what happened above is exactly what happens when I change the antifreeze on my wife's e320 (same basic engine).

Being a stickler, I then filtered the old antifreeze thru a coffee filter into a container with accurate volume indicators. I was very happy to see that the antifreeze looked clean, fresh, and almost new, and that there was absolutely no debris of any kind found in the filter (I knew the previous owner so I knew that it was the original MB factory antifreeze). So, so far so good..

I now took note of how much fluid I had collected, and was somewhat puzzled to see that I had only collected 8.1 quarts total. On page 243 of the Crossfire owners manual it says that the cooling system holds 11.8 quarts total, but the SRT6 obviously holds 15.3 quarts, according to several sources. So, I had only collected just a little over 1/2 of the total coolant, which concerned me.

I now refilled the cooling sytem with distilled water, left the cap off, started the car, and watched the temp gauge slowly start to rise. When just sitting in the driveway at idle I have noted in the past that my temp gauge needle typically sits just below middle, or 4th tick (there are 7 ticks total). The needle rose to this very same position and I checked the coolant reservoir fluid and it was cold. I then reved the engine up and watched the needle climb to slightly over the middle tick, and then watched it rapidly plunge back down to its original position. I attributed this to the thermostat opening, and when I check the reservoir again I noted that the fluid was now warm. I then shut the car off.

After the engine had cooled I then repeated the steps above and was only able to get 8.1 quarts out again, albeit the coolant color was obviously not nearly as dark this time around. I then refilled the system with distilled water and pulled the car into the garage for the night.

Well, does any or all of this ring a bell with any of you who have changed out their antifreeze before? Am I doing something blatantly wrong which might account for my only getting 8.1 quarts out each time? Given my reading, I'm pretty certain that most of the fluid that I'm not getting out is probably trapped in the intercooler system (pump plus IC radiator, etc), and that I probably just need to take the car out for a good supercharger run to get it all mixed with with the distilled water, right? And then drain it again and do the same supercharger run again? My thinking is that since I am replacing the original MB antifreeze with the Zerex G05 MB certified coolant, that I should just do this supercharger run a few times with distilled water, drain, and then fill it with the G05. Then, since I have a lab grade specific gravity tester, I will be able to adjust the antifreeze/distilled water mixture to my desired 50/50 ratio. Does this seem right, or is there an easier procedure/solution? (i read of dropping the IC radiator to get the fluid out)

Lastly, given that I found absolutely zero debris in my filter both times, and that the fluid that I removed both times looked just about new, I do not plan on using any radiator "flushing" product.

Any and all comments and suggestions will be appreciated.

Thanks and best regards -- Bob

 

Did you turn on the heater?

 

yep, I sure did, each and every time.

In fact, this afternoon I started it, turned on the heater, took it out of the garage, and then let it idle until hot (near mid-scale on temp gauge. I then took it out on the interstate for a "supercharger run." Once on the interstate I opened it up full throttle several times and the supercharger engaged, no problem... I then brought it home, let it cool down for 30 minutes, and then drained the antifreeze using the same method as describe above. What I got out was 8.1 quarts, just like before, though with even less color than before. I then filled it back up with distilled water and parked it in the garage and plan on doing the supercharger run tomorrow. The good news is that the fluid always looks near perfect, the car runs flawlessly, and I don't have any cooling system problems, so I'm not complaining. Just wondering why I only get 8.1 quarts out each time, and thinking that I may be doing something wrong procedurally.


best regards -- bob

 

As soon as you turn the ignition to "Off", the heater solenoids will close and isolate that volume from the outside world. You may have flushed the heater core using this procedure, but draining it while "Off" may be problematic.

 

How many qts. does the overflow/recovery tank hold?

 

Yes, you are correct, but given what I have read in the srt6 service manual and elsewhere, it appears that this has been taken into consideration. More specifically, it states that after an hour or two of driving, the cooling system is designed to eliminate any trapped air in the system, such as that which may happen in the heater core.

best regards -- bob

 

So, where does that leave you? Did you ever get 15 qts out of it? I haven't flushed mine yet, but definitely want to do this.

 

Well Doc, funny you should ask... I've now changed out my coolant 4 times (with distilled water each time), and each time I've only been able to remove 8.1 quarts. That said, and given all the research that I've done on this forum and others, I'm beginning to think that there are a lot of SRT owners out there that may have thought that they had changed out ALL of their antifreeze in the past by themselves, or that they thought that their mechanic had done it properly, when in fact neither is probably correct.

Hear me out on this one: The SRT6 cooling system is comprised of two systems; the engine cooling system and the intercooler cooling system. In total, they apparently hold 15.3 quarts, though the 2005 Chrysler Crossfire Coupe SRT-6/Roadster SRT-6 Spec sheet says 11.8 quarts. But regardless of what the actual quantity may be (i'm still investigating this and hope to write a complete antifreeze change narrative later), the service manual and other references state that the two cooling systems (IC and Engine) do not interact "mechanically" with each other in any way, shape, or form, and that their only common item is the cooling system reservoir, which is only used to replenish fluids to each system (the reservoir has two separate chambers).

So, if you drain the fluid via the engine radiator draincock, all you are draining is the engine coolant, and NOT DRAINING THE INTERCOOLER FLUID AT ALL. Since the intercooler system is completely separate from the engine cooling system, in order to drain the intercooler system you must either remove one of the lowest intercooler hoses connected to the "charge air cooler radiator," as it is technically called, or do it by the book, chapter 7, and drop the intercooler radiator and open up its own separate draincock (see picture). Only in this manner will you be able to drain the fluids from both systems (15.3 quarts?).

The real sticklers out there (me being one of them, i guess..) will probably note that even these techniques won't get out all of the old antifreeze, as some of it will still be stuck in the engine block. Now, to remove this there is apparently, at least on the Mercedes SLK32 AMG, a separate draincock attached to an engine block plug to help remove this remaining block antifreeze, but I haven't been able to locate it on my SRT... That said, we can still remove that small amount of engine block antifreeze by draining our systems as best possible, and then refilling the system with straight distilled water and then running our cars until the themostat opens, at which time they will all mix together. Then, just drain it again and add your mixture to yield whatever coolant mix you desire. (50/50 in my case. But remember not to keep just distilled water in your system for any long period of time because you will suffer impeller erosion, which is prevented by the lubricants in antifreeze.

But, to get back to my original premise, given what I've been reading, I believe that when a lot of SRT owners change their cooling fluid they are only draining the engine cooling side (8.1 quarts in my case) and not the intercooler cooling side, unless they drop or remove the charge cooler radiator and drain it as part of their procedure.


My long winded 2-cents. best regards -- bob

 

Used the 3 flush method. Put 6qt g5 in first. Should have saved a little g5 for the overflow tank.

 

Actually the heater solenoids are 'normal open'. They require voltage to shut off the coolant flow.

James

 

Has anybody that running a NWS supercooler changed coolant in both systems ? Maybe rob can chime in with some thoughs on the subject.

 

James1549 = very interesting comment....good to know.
Note - the OEM IC circuit is only 2 litres (quarts)

 

So did you end up draining the intercooler system too?
I am looking at purchasing a 05 SRT-6. Original owner 33k miles. He said he has never changed the coolant. Has me worried a bit. Supposedly 5yr/100k coolant, whatever comes first.

 

Thank you so much!


I'm Richard and I'm new to having an Srt 6 until today! I really want to get it started, the same as you, from cleaning everything out and starting there. I'm still trying to figure out how to get 50/50 of distilled and the other stuff you mentioned that I already bought and is sitting in my living room in a box. I'll take it up tomorrow to the usual oil changer guy.. who actually is pretty good, and ask him about it. I'm kind of in the same way as you though, since if I just do the 50/50 of 8.1 quarts it would seem that more of the old stuff would still be in there in the coolant vs. the radiator and it will mix and be hard to figure out if it's 20/80, 60/40 etc etc... so I'm of concern myself too!


Good luck and let me know what you find you can do about that since I am certainly concerned myself too! Ha ha.


Richard

 

So this is how we should do it. Drain out the coolant out of the radiator. Then fill with just distilled water. Drive the car and get it to operating temps, then drain it again. Then fill with 50-50 mix with Zerex G-05 5yr/100k coolant.

Is there a how-to on draining the coolant from the car?

 

Thanks so much guys! I'm seriously going to take this to an aftermarket Mercedes place that has a good reputation in savannah, which is where I obviously live, ha ha...


I will definitely make it know that I want the radiator and the intercooler both drained purged with distilled water and then done with 50/50 of the stuff I already bought... if there's anything else anyone can add...it would certainly be appreciated!


Thanks a lot!


Richard


Oh... I'll probably be selling the 37000 mile Srt 6 Black with no scratches or anything on it at all, even with a navigator too! I found one with 15,000 so I don't need both. If anyone wants any information I'll be happy to tell them.


Richard

 

When I bought my SRT6 in 2012, I drained the system and as I was replacing the stock heat exchanger with a larger one from EC, I did drain the intercooler also. I had it jacked a bit at the rear and it had been down a bit to start with but I got a little less than 10 1/2 qts, when I filled it, it took 11 1/4 qts. I never heard the 15+ qrts for an SRT but I am curious about the systems "not connected" thing as I did purchase Robs isolation kit.

 

Hi Guys,
Well, here's what I'm planning instead.... yes it's the easier softer way.... I'm going to take it to an out of the way place that works on Mercedes and has a great reputation... so I'll ask them if they can:
1.Drain the radiator
2.Drain the intercooler


Then fill it up with 50/50 distilled water and famous liquid that I bought but is sitting across the room and I'm too lazy to go look at it again!


That way I'll be sure it's been done and I can start anew as they say....


Mine only has 15,000 miles on it too, so it probably doesn't even need it, but better safe than sorry.


Richard

 

I did my SRT6 the other year by draining the system, refilling with distilled water and running it up to temperature for a while, I then repeated this process again. Low pressure air was used to remove as much fluid as possible from the IC and radiator systems, and I drained the lower hoses once. When the car was running on distilled water the system was topped up as much as possible when hot up to the fill mark in the tank, I think that is not too clear in the write up.
I then calculated how much of the original fluid was in there still, I found that .37 liter of the old antifreeze remained along with .37 liter of the old water. These figures are based on the system holding 14.5 liters when full.

That was good enough for me, I then added 7.25 liters of Zerox and topped it up with distilled water.

See the old post here.

 

In all cases - just make sure you use MB approved fluids...