6.9 cooling System

[aussie 6.9]

6.9 cooling system.
Hi every body. Does anybody know where the plug for draining the water jacket of the engine is located. On the 117 engine it is on the right side towards the front.

 

[Oversize]

Near the engine mounts on both sides I believe. Easy access? Highly doubtful....

 

[aussie 6.9]

Thanks for the info. Car runs hotter than I like in the summer. Have done just about everything else. I also have a 450sl which had similar issues. I managed to get the pug out on the right side and flushed it and now it stays around 85c even on the hottest days. Have you had experience flushing m100 system?.

 

[Oversize]

Yes I’ve just flushed mine & I use various techniques. It’s actually quite easy but messy & you don’t want to rush it

 

[Oversize]

Basically remove clamps at the radiator for top & bottom hoses plus the bleeder hose and the heater hose at the tap. Drain old coolant then reconnect hoses without clamps & refill with fresh water. Pull off lower hose at radiator to allow coolant to rapidly drain. Do this several times. Disconnect lower hose and use high(ish) pressure water hose to blast old coolant out by directing flow through heater tap & also through disconnected heater hose. Continue flushing & backflow where possible until old coolant flushed out & only fresh water visible. Block water leakage with hands or other means to force backflow where necessary. Then fully drain system of fresh water, reconnect all hoses, replace clamps & refill 50/50 coolant concentrate & distilled water. Run till hot to bleed & recheck level when cold. Done

 

[Styria]

I have always gone a simple, but effective step further when, to all intents and purposes, the Water Pump needs replacement. I remove the Radiator, plus the triangular water housing and water pump as one unit - just to get away from the Crank shaft pulley that makes it difficult to remove the Water Pump by itself.

Once the Pump and Housing are removed, I can train a garden hose full pelt into the engine block. It's always satisfying to see all the rusty sludge being expelled from the engine block. BTW, I have comprehensively covered this subject matter in other threads. Regards Styria

 

[Oversize]

Seems rather extreme to just change the coolant lol!!

 

[BenzBoy]

You want to do more than change the coolant - you also want to flush the entire system of any gunk that does accumulate. I use Styria's same process and of course you need to remember to turn on the heater tap if there is one. Modern cars don't have a heater tap but if there is one you also want to flush the heater core.
Regards,
Brian