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2003 Clk 55 AMG 1997 E420 Sport
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Discussion Starter · #1 ·
Hey Guys,
Im replacing the radiator on my wifes 97 e420 this weekend.
i thought while i had the radiator off it would be a good time to replace the serpentine belt and thermostat as well.
Any tips or problems i need to watch out for?
We have had a small leak for a few weeks now and while my wife was out, the small puddle was noticed and so to help her out "someone"(not to mention names)added prestone 50/50.So i would like to do a complete coolant flush,where is the drain on the block?how should i do a complete flush?get to operating temp,turn on heat?(to drain heater core)
I know just enough to be dangerous,so any help would be appreciated.
Thanks
Dean
 

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97 E-420 (180K miles), 97 SL500, (93K miles) 2015 GMC Sierra Denali 2500HD CC/SB/4x4 Duramax(55K)
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serpentine belt is a snap even without removing the radiator.

Thermostat is a PITA. problem is the location of one of the bolts needed to remove the housing. It is behind the right angle hose going to the block. Hose is short, so getting it off and back on again is a struggle.

Since my 420 was going on 100K miles and almost 12 years, and my thermostat was opening early, I went ahead and replaced the major radiator hoses at the same time I replaced the thermostat and coolant. Never did find the drain plugs on the block.
 

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1922 Ford T no OBD, no ECU, no SCN
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When serpentine belts wear out and age, the thermostats do not. No need to replace it when it is good. No guarantee that the new one will outlast the "tested" one.
I just replaced radiator on our E300td as well. Got it for $400 from local warehouse.
Colling system is too complicated to do efficient flush to start with, so seeing that my old coolant was clean, I drained all that come from open hoses, added a gallon of new coolant and topped off with distillate water.
The same coolants are allowed 15 years in newer models that suppose have chem pack
 

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2003 Clk 55 AMG 1997 E420 Sport
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Discussion Starter · #4 ·
I did buy the thermostat several months ago,started to replace it and noticed the PITA 3rd bolt and left it alone.i thought since i'll have the radiator off i'd go ahead and tackle it.
So i'll get enough prestone out draining the radiator and pulling the hoses?
Dean
 

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Premium Member
97 E-420 (180K miles), 97 SL500, (93K miles) 2015 GMC Sierra Denali 2500HD CC/SB/4x4 Duramax(55K)
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4,445 Posts
I did buy the thermostat several months ago,started to replace it and noticed the PITA 3rd bolt and left it alone.i thought since i'll have the radiator off i'd go ahead and tackle it.
So i'll get enough prestone out draining the radiator and pulling the hoses?
Dean
Unless your thermostat is bad, I'd leave it alone. However they can fail and end up opening early. My experience is that opening early is a higher failure mode than not opening. In my case, temp seldom got above 60C. When I pulled the thermostat and put it in hot water, it was opening before 60C, fully open by 80C. By contrast a new thermostat was still closed at 60C. Made a big difference in warm up time in the winter, also a slight increase in fuel mileage.
 

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2003 Clk 55 AMG 1997 E420 Sport
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Discussion Starter · #6 ·
well thanks for all the replies.
I think i may leave the thermostat alone.ill just keep it as ive already got it.
sounds like ill get enough "old fluid"out pulling the radiator and just put the MB stuff back in.
Thanks Again
Dean
 

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W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
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I bled the coolant thru the red screw under the radiator driver side and got less than 6 quarts of coolant out, see picture and note the stream of coolant out of the radiator. Is there another drain plug?

 

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1922 Ford T no OBD, no ECU, no SCN
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After replacing the radiator I put more than 2 gallons of fluids, so sounds like the plug is not draining radiator too well, or you've been low to start with.
If you are really picky about babying the car, buy 3 more gallons of distillate water, fill up the system with water, drive around the block with hot engine, while operating heater, than drain again and refill with coolant.
Bear in mind that your household dishwasher has very good drainage and does 3 rising cycles anyway.
 

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W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
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You can use the original Daimler coolant from the dealer or Zerex G-05. I believe these are only two approved products available in US market. Hope that helps.

Cheers
I used Mercedes coolant $26 a gallon


Kajtek1 said:
After replacing the radiator I put more than 2 gallons of fluids, so sounds like the plug is not draining radiator too well, or you've been low to start with.
I refilled with 6 quarts of 50/50 Mercedes coolant and got full level, that means it did not drain well, is the red screw the only drainage or is there another plug? if not how can it be drained more throroughly?

Kajtek1 said:
If you are really picky about babying the car, buy 3 more gallons of distillate water, fill up the system with water, drive around the block with hot engine, while operating heater, than drain again and refill with coolant.
Bear in mind that your household dishwasher has very good drainage and does 3 rising cycles anyway.
It is dumb of me to already replace the protective panel under the radiator back. If I'd do as you recommend i'd have to start all over again :(, maybe another time.
 

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2003 Clk 55 AMG 1997 E420 Sport
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Discussion Starter · #11 · (Edited)
After replacing the radiator I put more than 2 gallons of fluids, so sounds like the plug is not draining radiator too well, or you've been low to start with.
If you are really picky about babying the car, buy 3 more gallons of distillate water, fill up the system with water, drive around the block with hot engine, while operating heater, than drain again and refill with coolant.
Bear in mind that your household dishwasher has very good drainage and does 3 rising cycles anyway.
This is what i was contemplating as i would like to get the coolant out of the heater core as well.
So it is ok to fill the level up with 100% distilled water,get it hot then drain all this out in hopes of getting most old coolant out?

TEXHOLDEM.i think weve also got a coolant drain on the block?I dont know where it is either .so sorry im no help.planning my radiator swap this weekend.I got the Benz coolant as well and at the price i want to get the most old fluid out as i can,and by filling with water first i want to make sure i have the leak fixed before i start putting this stuff back in!
Dean
 

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97 E-420 (180K miles), 97 SL500, (93K miles) 2015 GMC Sierra Denali 2500HD CC/SB/4x4 Duramax(55K)
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the 420 engine also has a plug on the intake manifold to purge air from the system. It is a hex head bolt near the thermostat. open it to make sure you have purged all the air from the system when you refill.
 

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W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
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the 420 engine also has a plug on the intake manifold to purge air from the system. It is a hex head bolt near the thermostat. open it to make sure you have purged all the air from the system when you refill.
I did not see such bolt to purge air on my 1996 E320. What happens when air is in the cooling system? I did notice some bubbling noise after refill and restarting the engine, the noise subdued after several minutes though. Is it bad?
 

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W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
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From AllDataDIY's instruction for coolant filling:

"FILLING

•Detach vent line at expansion tank.
•Fill with coolant mix to the markings on the expansion tank.
•Refit vent line at expansion tank.

If Vehicle fitted With Auxiliary Heater :
•Take off cap, unscrew vent screw slightly until no air flows out.
•Repeat operation several times as necessary to remove all air from auxilary heater system.
•Switch on heater and run engine until warm and thermostat opens.
•Following this, top off coolant to the marking on the expansion tank.
"

How do I know if my car has Auxiliary Heater?
 

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There would be a timer and an infrared remote to start it, Tex. I don't think any of them came from the factory with auxiliary heaters in the US.
 

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W210 1996 E320 Smoke Silver. [W124 1990 300CE Artic White - Sold].
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There would be a timer and an infrared remote to start it, Tex. I don't think any of them came from the factory with auxiliary heaters in the US.
I got it, auxiliary heater is then to warm-up the engine before one gets into the car, mostly for cold climate zones like northern Europe. Probably a stronger battery is needed Thanks.
 

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The battery is used for the aspirator fan and the coolant pump, but the main fuel for the auxiliary heater comes from the tank (gasoline or diesel). Running it too long can kill your battery, but it's not as if the battery is supplying the heat.
 

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1922 Ford T no OBD, no ECU, no SCN
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MB is already using over-sized batteries. My American cars had batteries 1/2 size for V8 engines.
I've seen the aux heaters on ebay, but never saw one installed in the car. Had a motorhome with diesel burner, but that was quite big unit. With economical diesels producing minimal amount of heat they are a must just for comfort heating in colder weather (from what I heard).
Now would you try to run aux heater and 1000W stereo while sitting on parking lot for an hour -that might kill the battery. ;)
 
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