biker349

hi, looked into dvd for changing coolant. they showed an attachment that attached to a cap that went on the overflow tank with i believe three attachments. i believe it purged the air out, then created a vacuum that drew antifreeze out of a container into the system. my question is- since i don't have this specialized equipment is there away to change antifreeze without out the equipment and purge all the air out of the system?
thanks for your help.

Turbomode

do not change anitfreeze w/o this device. otherwise air comes into system and make jam.
after change make engine/turbo test. for proper boost pressure.

j21importer

without the proper don't attempt changing the coolant. If its not properly bleed you will have low power under load.

biker349

had a check engine light. dealer changed the throttlt body and accelerator pedal. 3 days later light came on again. code 300 i believe random misfire. brought it back, light went off. could not duplicate. found a cracked radiator hose and replaced and added 1 quart antifreeze.someone told me that an air bubble in the turbo cooling system can cause this code. is that true. it appears the problem is solved. would an air bubble, or slightly low coolant cause that?
thanks

saintz

Changing the coolant is super easy (on W215 CL, should be similar for the S and SL).

Remove under tray. Place catch pan under car. Unscrew red valve from driver side of radiator. It will slowly drip into your catch pan. Loosen reservoir cap and it will drip fast. When done, close red valve and refill with coolant and water mix. Run car with heater to get bubbles out. Wait to cool, then refill.

The reservoir is the high point of the system, so it will bleed itself. No real issues with bubbles.

I did this without even lifting the car.

biker349

what about the antifreeze that goes through the turbo chargers? is this affected and are air bubbles in there as well?

saintz

The method I gave will flush about 2 to 3 gallons of coolant from the radiator and reservoir. There is coolant everywhere in the car. Turbos, oil cooler, intercoolers, intercooler heat exchanger, engine block, heater core, etc. Probably several more gallons in total. The only way to reach this would be to disconnect basically every coolant hose. Not worth it.

Instead, flush the system. If the coolant looks like new (mine did) just refill. If it looks bad, refill with distilled water only, then run for 30 minutes and flush again. Doing back to back flushes is the easiest way to get more fluid changed. You will need to add more coolant than water the second time to account for the extra water you added the first time.

In terms of air bubbles, they should work their way to the reservoir, since it is the highest point of the system. The system seems pretty good about not harboring air bubbles or pockets. It basically is self bleeding. After 30 minutes of driving and using the heat on full blast, you should have gotten all the air into the reservoir. Wait for it to cool again, then top it off.

The Intercooler system is different in that it does need to be manually bled. To do this, check the two tire stem type valves on the intercoolers. Push the internal button and see if they weep coolant. If so, the system is fine. If not, you either have air in it or more likely need to replace your intercooler pump.

biker349

saintz, thank you very much for taking the time to explain the procedure. i really appreciate it and now understand.
the best, harv