cyberfarmer

Hi! I have a 2000 w220 s500 and I noticed that coolant and oil has mixed in the reservoir tank. I brought it to the nearest dealer workshop and they said the transmission oil cooler inside the radiator broke letting the atf and coolant mix. I checked the engine oil through the dipstick and fortunately there is no coolant mix inside the engine. The dealer said I have to replace the radiator assy and rebuild the transmission which would cost me a fortune to do so. My questions are:

1. Is the oil cooler integrated inside the radiator?
2. Would flushing the transmission with new atf be possible and replacing the filter (if any) help just in case the milk mix reached the transmission?
3. How to remove the radiator?
4. What ATF to use?

In spite of the problem, the s500 still pulls well and now parked in the garage to avoid more problems. FYI, I'm new with MB had a BMW unit.

Thanks.

Alex
Manila Philippines

karwerk

I had a similar problem in my 03 e500 and i bought an aftermarket oil cooler and routed the trans cooler to that with some slight modification and didnt even change the radiator. But yes you have to do a thorough trans flush with MB fluid of approx 12-14 quarts. hope this helps and good luck.

tusabes

wow I didnt know the fluids could mix, usually there is a separate cooler mounted to the front of the radiator on most cars...

but yes using a separate external cooler will work, make sure to flush both the trans and the coolant with fresh correct fluids.

cyberfarmer

tusabes - yes i think the oil cooler is internally mounted with the radiator

karwerk - thanks for the tip

ill post once i update the status. thanks guys

Oxygen

Correct - the radiator has an integrated transmission cooler in it. The feed from the tranny is on the bottom passenger side of the radiator.

cyberfarmer

I was able to remove the whole radiator assembly and it was full of milk mixture. I brought it to the nearest radiator specialist but he said it was clogged and due for replacement.

Should I still continue with the external oil cooler for the transmission or just rely with the quality of the replacement radiator?

Any suggestions on how to fully drain the coolant from the engine?

Thanks guys

cyberfarmer

Hi just a little update and a few questions,

I already have the radiator replacement and and external cooler system. My question is how to fully replace the engine coolant and the transmission atf and any idea how much atf and coolant mixture to use?

Thanks

babyman1737

Do you mean how to add the antifreeze and atf? The atf has a dipstick just behind the engine on passenger side. You need to break the safety tab, then install a new pin when you put the cap back on. You'll also need to purchase the dipstick transmission measuring tool on ebay. Purchase ATF at Mercedes dealer, expensive.
The antifreeze just gets added into the overfill tank. Purchase Valvoline G-05 antifreeze, mix 50/50 with distilled water. I purchase mine at Napa. $16/gallon.

tusabes

Actually he has to FLUSH both the tranny and the cooling system to get rid of the "milk mixture" of ATF and coolant. Just adding fluids wont work.

To flush the cooling system completely get something like this

http://cgi.ebay.com/ebaymotors/Prest...Q5fAccessories

This will backflush your cooling system and remove all the milk mixture from your cooling system, heater core, overflow bottle, etc.

Also is your replacement radiator new or used? If its a used part, flush the cooler with something like this

http://cgi.ebay.com/ebaymotors/LIFE-...Q5fAccessories


To flush the tranny, its a bit trickier. In the USA many newer repair shops have a "fluid exchange" machine like this

http://cgi.ebay.com/ebaymotors/TRANS...motiveQ5fTools

which removes all the fluid including from the torque converter where a lot of fluid is located. If you cant find that kind of machine/service shop in the Philippines, drop the tranny pan, drain all the fluid, then replace the pan and refill. You wont be able to do a complete flush, but it will be better than not doing it.

AH1W-COBRA

i posted pics and instructions on how do to do a complete fluid flush at home on the S500.just do a search and youll find it in this forum. imo i would find the cheapest "compatible" non synthetic ATF fluid from the MB spec sheet and do a complete flush. allow the trans to get up to normal op temps, drive around the block a few times allowing the trans to shift through all gear changes including reverse. bring it home and dump/pump the fluid again. get 18 qts of the MB synthetic and flush according to the post. you want that crap out of the trans, dont change the filter or pan seal until the final synthetic fluid is in to stay.i will get some WTF from my next advice, but run the car without the dip stick tube "cap" installed. you want any residual condensation to have a easy way out while you drive. if the fluid level is correct no atf will ever come out the tube. each time you drive the car and shut it down put the dip stick tool in the tube and leave it there until the trans is cool. remove the tool and check for water droplets on it. when it comes out clean install the cap and cross your fingers on the future of the trans.Estimated cost of all the flushing $300. cost of trans $5000.

tusabes

heres the thread'
https://mbworld.org/forums/s-class-w...ilter-pix.html

cyberfarmer

I was able to flush the cooling system and still under observation- thanks guys for the help

Ill be doing the ATF replacement this weekend.

Thanks again