Silver_R230

Hello,

After reading up on the STAR Service DVD am even more confused on how to Drain / Fill the Radiator. I think I can figure out the drain part, but the fill part is incomprehensible.

I would like to learn if it is possible to DIY the coolant flush on the R230?

Thanks in advance.

bobterry99

I changed mine last year, and I don't remember anything unusual about the procedure. As I recall it was just as simple as with any other car I have owned.

Silver_R230

The '03 SL500 doesn't have a radiator cap, must be filled via the reservoir. I am not sure if the fluid I pour into the reservoir will enter freely into the radiator -- I would guess that it will. The other concern is air trapped in the system. I would like to think that the system is designed to correct itself. What I find confusing is the actual MB procedure to drain and fill the radiator -- a procedure that requires special tools and binds the vehicle to return to the dealership for service for even the most basic need.

bobterry99

Well, I looked at the DVD. No need for Star Diagnosis or any of the special equipment they describe.

Be sure to use only M-B coolant or Zerex G-05. It probably doesn't matter, but I have the notion that distilled water is preferable to tap water.

It will. To remove any trapped air, have the cap of the reservoir off; and with the engine running and at operating temperature, squeeze the top radiator hose several times.

Silver_R230

Excellent. Thanks. I feel ready to cancel my Saturday morning MB dealership service appointment and do this one myself.

Silver_R230

I completed the drain & refill in about one hour. I removed the driver side front underbody cladding and loosened the front center one (no need to remove that one). This exposed the red knob of the radiator drain port and the spigot to connect the drain hose. I completely drained the radiator with the engine off. I then filled the radiator with tap water while draining it at the same time, turned the engine on and set the A/C heater on as well. The engine ran to operating temperature while more coolant circulated out of the block and out the drain port. I turned the engine off and stopped filling the radiator with tap water -- the remainder clear tap water drained. Finally I closed the red knob of the radiator drain port and filled it with the 50/50 mixture of MB Antifreeze and distilled water, turned the engine on, A/C heater on, squeezed the upper hose a few times, topped of the reservoir, waited for engine to reach 80C, and replaced reservoir cap. The test drive showed engine temp at 80C and A/C heater working, reservoir level stayed ok.

bobterry99

You didn't loosen the bolt on the side of the block to drain the block? Doesn't matter, because you obviously seem to have gotten all of the old coolant out. A job well-done.

Chris_87_300D

Sorry to pile onto this thread so late but there aren't that many for SL55 coolant flushes so good for the ones out there to be comprehensive. While it's best to remove the bolt on each side of the bock (above/near the mounts), if you choose to use Silver_R230's procedure, it would be a good idea to look up the capacity of the system and make sure that you add at least 50% of that as undiluted coolant. The reason is that the block would have a lot of clear fresh water so after filling it with a 50/50 mix you might end up with something significantly less than 50/50 in the end when it mixes with all of the water in the block. One idea would be to mix it 75/25 and add that then, once all the coolant is in, just add fresh water to fill.

Also, the vacuum fill idea is now mainstream - that's the special tool that's mentioned in the WIS procedure. You can get a good one on Amazon for around $70 and it's worth it in my opinion even if you just used it once or twice. It fills so fast and you can have high confidence that there would be very little if any air left in there. The vacuum tool that I bought was OEMTOOLS 24444 Cooling System Refiller Kit which worked great with the 45mm adapter (comes with it, among other sizes) but other tools I'm sure work well also.

_rodeo_

Quote:

Originally Posted by bobterry99

You didn't loosen the bolt on the side of the block to drain the block? Doesn't matter, because you obviously seem to have gotten all of the old coolant out. A job well-done.

[QUOTE=Chris_87_300D;7800149]While it's best to remove the bolt on each side of the bock (above/near the mounts) .../QUOTE]

Could you help locating those bolts on each side of the block?

Sorry, duplicate post. Didn't know how to multi-quote. Now I don't know how to delete a post.

_rodeo_

Could you help locating those bolts on each side of the block?

_rodeo_

How many qts did you guys manage to drain? I'm draining 2 gallons which is around 7.5L. This thing takes 13L. WIS says undo the drain plug both on radiator and crankcase. I'm not messing w crankcase. no way I can get to the plug. What's going on

_rodeo_

Replying myself haha... depends on how tough headed you are but you're not gonna get 90 to 100% drained w/o using pressurized closed systems. If you're planning to deal w/ drain plug only you can help it by raising the back of your car and letting gravity takin care of the rest. So far I've done 4 rounds of distilled water but I still don't have a clear drained water. The only reason is the previous owner put green color coolant in it. Now I'm switching back to blue. Might as well take as much out as I can avoiding mixing coolants.