I am planning to change coolant in my 1998 SL500. However, I am not able to determine location of the drain plugs, which should be located on both sides of the engine block. Also, I am not sure how to bleed the system.

Any tips how to do it will be appreciated.

Marek

If I were you, I would give it to the dealer. My dealer charges $50.00 for the change w/ coolant. The coolant costs $13 and if you do it yourself youll also have to buy the distilled water as well as drop it off to a recycling center. Plus I think the drain plugs are located on the middle on each side of the blocks on top of the headers. Do a search

If a dealer will do it for under $100, then go that way.

Otherwise, be advised that the block drains are aft of the motor mounts, and screw straight up into either side of the block. Be advised they often require single-use washers of a particular material.

Beyond draining the block via these drains, I'd also undo the hoses going to/from the heater core, and insert some sort of extractor hose to suck any coolant out of there. Also, unhook the lower radiator hose, as it's lower than the drain.

Your system is self-bleeding; in my experience, I added equal parts coolant & water (via a disconnected upper radiator hose)until the system stopped looking for more. Hook the hose back up & fire up the car; keep the radiator cap off at first in case you need to add additional fluid. When warm, turn on the defroster full blast (once car's warm) and that'll get fresh coolant into the heater core. Turn the car off & let it sit; in a few minutes it'll burp and the coolant level in your expansion tank will drop. Top off & you're done!

__________________
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Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo