Coolant flush
 

I'm planning to flush my cooling system (1994 sl500) and have a few questions:

1. Is there a drain plug for the block ...if so, where is it located?
2. Should I run the heater during the flush or should the heater
hoses be disconnected and flushed with a garden hose?
3. Which heater hose is the input to the heater core and are
there any special valves (i.e., mono) that need to be
opened?

I appreciate any help/advice you folks can give me. Thanks.

Hi rjpeters98,

I don't know your car but assume it's a V8. There should be a drain plug on each side. If I recall right, Larry Bible has described a flushing routine, but it might have been a different car. Do a search and you will get an idea.

If you do it with the car running, you would want the heater or defrost on, so the water will circulate through the heater element.
I did a flush with citric acid and had the stuff circulating through the engine for 15 minutes with heater on.

Somebody else can probably provide more details for your specific car.

Good luck

Reinhard Kreutzer

Reinhard,

Thanks for your reply. I'll try to find those drain plugs tomorrow.
Hopefully they are not prone to leakage after being used!

There are 2 kinds of drain plugs for the V8 engines. Mine have the type with a very soft aluminium washer that can damage easily when putting them back in. They are cheap and I think worth replacing every time.