DIY Coolant change 83' 380SL

[Jkoch]

1983 380SL I am looking for a DYI procedure for coolant change.

Help is greatly appreciated.

[Roncallo]

First you will need 2 gallons of antifreez, preferably Mercedes antifreez and two block sealing rings PN A 636 997 02 44.

There are three drain points that have to be opened.

One on each side of the block. They require a hex head socket. These plugs are similare to your oil drain plug in style but smaller. I belive the hex is 6mm. You should also have on hand the sealing rings PN A 636 997 02 44 for these plugs before you start. See callout 110 in the picture.

Then there is the radiator drain plug at the bottom of the radiator, I forgot which side. Open it and drain the radiator.

After draining from those three points, reinstall all plugs.

Assuming you are using gallon jugs of antifreez, put in one gallon of straight MB antifreze. Refill the gallon jug with water to the same level the jug came filled with antifreez and put that gallon of water in the car as well. Start the car and let it run for about 30 seconds. Check the gauge lights and verify the coolent level low indicator is on.

Now take your second gallon of antifreez and pour half of it into the empty jug. Fill both jugs to the full point with water and mark both jugs 50/50.

Fill the radiator and overflow tank untill full. Drive the car arround the block a few times at least until you get 80° on the temp gauge. Now top off the coolent level. Recheck the next day.

The 560SL takes 13.7 qt of engine coolent the 380SL should be similare, check your owners manual. You should have left over 1 gallon of 50/50 mix coolent and an additional ~1/4 gallon of 50/50 mix.

Hope this helps.

John Roncallo

[sokoloff]

I'd probably fill it with water at least once, turn the heater on full blast and drive it to heat it up to make sure you've drained the heater completely too. That will also dilute and clean out any of the old coolant still in there. The other thing you can do is just measure how much you drain out and see how close you come to 13.7. On mine I could only break one of the block drains free. Sure wish I could get the other one, because a lot of coolant comes out of there and that makes for a pretty complete draining. All of the above is assuming you don't have to deoil/descale the system and the coolant in there now is reasonably clean.

[Jkoch]

Thanks for the help.

Couple questions:

1. Can I use water from my well or do I need to get Distilled? Can I use Well water for the first flush and then mix with distilled?

2. Do I have to pull the block drains? Can I get by with flushing through the radiator if I do a couple water fills?

3. Is there a an antifreeze other than MB that is good but less $? Someone said Zerex. Where can I buy?

Thanks again for your help.

[Roncallo]

Originally Posted by Jkoch

Thanks for the help.

Couple questions:

1. Can I use water from my well or do I need to get Distilled? Can I use Well water for the first flush and then mix with distilled?

2. Do I have to pull the block drains? Can I get by with flushing through the radiator if I do a couple water fills?

3. Is there a an antifreeze other than MB that is good but less $? Someone said Zerex. Where can I buy?

Thanks again for your help.

I have never used distilled water in my life for a cooling system. My feeling is once you put any water in your cooling system it is immidiatly no longer distilled.

If you use a power flush there should be no problem, but pulling the block drains is a piece of cake. Most dealers will not drain the block (not that they will admit it).

I belive some of the other antifreeze are ok but I dont take a chance here. It's not like I change it once a week.

John Roncallo

[Alkraut]

I agree with John, put the correct coolant in your car. Interestingly, I have done a bit of research on the correct coolant and was told by an MB parts person (and others on various forums) that the MB coolant is produced by Ashland (Valvoline), and is Zerex G-05. This is a phosphate-free "HOAT" , hybrid organic acid technology, product, and it is the correct color. See website: http://www.valvoline.com/pages/products/product_detail.asp?product=10

I purchased it at the NAPA store. More expensive than the plain green antifreeze.

[Jkoch]

Thanks a bunch. I recently had a mechanic flush the system and he used the green stuff. Long story he ripped me off in more than one way. Anyway, it has inspired me to get involved with the fixing and maint. of my vehichle and I am enjoying it.

Qestion: Can you explain what is meant by a "power flush" mention above?
Is this where you buy the garden hose connection and plug it in to the system?

Thanks again.

[WINGAS]

And another question, when do you need to go through the degrease /citric acid wash? Is that just for us oil burner types?

BTW, the Zerex is avail at AutoZone. Guess I need a second gallon though!

Wondering if I can powerflush it throught the windsheild washer heater lines?

[Roncallo]

Originally Posted by Jkoch

Thanks a bunch. I recently had a mechanic flush the system and he used the green stuff. Long story he ripped me off in more than one way. Anyway, it has inspired me to get involved with the fixing and maint. of my vehichle and I am enjoying it.

Qestion: Can you explain what is meant by a "power flush" mention above?
Is this where you buy the garden hose connection and plug it in to the system?

Thanks again.

Yes thats the garden hose connection.

John Roncallo

[Jkoch]

Has anyone added a power flush Tee into their system? I purchased a Prestone Kit but cannot relate the instructions to my SL380 System.

What hose would I tap and where is it located?

Help is greatly appreciated.

[Roncallo]

Originally Posted by Jkoch

Has anyone added a power flush Tee into their system? I purchased a Prestone Kit but cannot relate the instructions to my SL380 System.

What hose would I tap and where is it located?

Help is greatly appreciated.

I would put it in place of the Mono Valve if possible. And then of coarse remove it when done. If not you will for one have to make sure the monovalve stays open for the entire operation. I belive full heat mode will do this but make shure the monovalve is working. Also Im assuming the 380SL has a monovalve????.

John Roncallo

[Jkoch]

Thanks for the help. I checked my CD and cannot locate the monovalve. I'm sorry I do not know what the monovalve is and where it is located.
Can you tell me what it is and where I can find it?

I really appreciate the support.

[Roncallo]

Originally Posted by Jkoch

Thanks for the help. I checked my CD and cannot locate the monovalve. I'm sorry I do not know what the monovalve is and where it is located.
Can you tell me what it is and where I can find it?

I really appreciate the support.

On the 560SL it's on the right side of the fire wall. As shown in the picture. I'm not sure if the 380 is the same.

John Roncallo

[Towel Rail]

The thinking behind using distilled/DI water is to keep from introducing any more mineral/ionic contamination to the system. Many owners' manuals recommend it. (It's certainly cheap enough.) That said, it's probably mach nichts in the long run.