DIY:W203 radiator R&R
I wanted to buy a new OEM one and chrome dip it but...
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After degreasing everything and washing it off, I've isolated the leak to a metal oil pipe right at the front right of the radiator. It appears to be where the pipe joins the radiator (this is on the left if you're standing in front of the car looking at the engine and scratching your head). I took the little wire clip off the pipe and pulled the plastic ring out of the way, but even with a block of wood and a little persuasion, I couldn't get the pipe all the way out. I've since knocked it back in and put the clip back until I get a better idea of how it all fits together.
I'm thinking it's a push fit with an O-ring on a lip on the inside of the oil radiator which has probably started to disintegrate.
Has anyone else had a similar problem?
Does anyone know if I'm correct about how it all fits together?
Does anyone know how to fix it?
Matt T
Last edited by Guru of Warmth; Jun 19, 2006 at 02:33 PM.
The Best of Mercedes & AMG

*specific to automatic transmission W203s*
Parts required:
(1) 203 500 05 03 radiator
(2) 028 997 62 48 ATF tube seal
(2) 003 997 17 89 coolant hose seal
(1) 140 991 00 55 ATF cap lock pin
Consumables:
Q 1 03 0002 antifreeze
A 001 989 21 03 19 ATF
Distilled water
Specialty tools:
140 589 15 21 00 ATF dipstick
Infrared thermometer
Raise and safely secure the car. Remove the undertray. Drain the radiator via the red petcock.

Remove the upper radiator support.
The horn mount is attached the rear of the bumper reinforcement. It will need to be unbolted in order to pull the support clear.

Disconnect the ‘hood open’ sensor wiring.

There is no need to disconnect the hood latch cables.
Lay the radiator support assembly aside.

Disconnect the fan wiring. Pull the C clip retainers from the upper/lower coolant hoses and ATF tubes. Be prepared for additional fluid discharge.
Gently twist and pull the lines free from their attaching junctions.

Squeeze, and then push the A/C condenser mounting T barb clips from the radiator.
Pull the radiator/cooling fan assembly up and out. Remove the fan while it’s on the workbench. There are two sprung plastic tabs that secure it to the radiator, in addition to the alignment sleeves.
Clean the sealing grooves and fit the new seals to the coolant hoses and ATF tubes.

&

Transfer the existing upper and lower rubber mounts to the new radiator. Lower it in place. Attach the hoses/tubes. Ensure that they are fully seated before snapping the C clips home.
Install the fan and reconnect its wiring.

Refill the reservoir with a 50/50 mixture of MB antifreeze and distilled water.

Check for leaks. Reinstall the upper support, its paraphernalia, and the undertray. Lower the car. Start the engine. Continue to add a 50/50 mix until the thermostat has opened. When the reservoir has been thoroughly purged of its residual air, install the cap.
Because our 722.6xx transmission is persnickety about its fluid level, that which was lost during the installation must be replenished. Remove the lock pin from the fill tube cap, and then the cap itself.

Disregard the 'workshop' admonition.

With the engine running and the transmission in Park, insert the ATF dipstick until it bottoms against the pan. The tool is unlike a conventional dipstick in that when it is measuring, the handle is not flush with the top of its tube.

If the fluid level is too low, estimate the amount that was sacrificed, and then replenish a like quantity. If it reads to at least the minimum mark, it’s time for a lengthy test drive to get everything up to proper temperature. Reinstall the cap. Get it to WOT several times to replicate real-world conditions.

The correct ATF level can only be properly established when the fluid is stabilized at 80 degrees Celsius. MB’s procedure nessecitates STAR DAS. Since I don’t have the scratch for that wonderful ~$15,000 machine, an infrared reading from the exterior of the transmission pan had to suffice.

Add ATF as required to achieve the proper level.
Verify the antifreeze level after several heating/cooling cycles to ensure all is as it should be.
Last edited by splinter; Jan 28, 2008 at 01:32 AM. Reason: part numbers




Excellent work.
Measure with the engine ON?
1st time I heard that.
Are you certain?
Please could you help me with a few questions on this W203 radiator topic......
Was the radiator replaced due to the Valeo ATF/Glycol problem?
Do you know the actual manufacturer of the new MB radiator in your photo?
(ie. Is it a Behr or later type Valeo perhaps?)
The wavy silver metal crimping around the black plastic rad end tank in your photo is exactly the same as on the rad currently fitted to my German built 2001 C200K in the UK. I have been trying to find out how the dealers identify the suspect Valeo rads as the Mercedes TSB pictures (figure 2 & 3) suggests it is by looking for the square notched type of end tank crimping?
If you still have the old radiator could you post a photo of the end tank crimping, especially if it is one of the suspect Valeo?
Thanks again for your help and great DIY.
(Some photos attached for ref from other posts on this subject)
The OE Valeo prompted the swap. I sent a sample of ATF to Blackstone Laboratories for Glycol contamination testing. It came back positive, albeit with only trace amounts. Along with the new radiator, all of the ATF was replaced and a new filter was installed. It was far less expensive than having to replace the transmission and torque converter had the contamination worsened.
C230 Sport Coup- I sent you a copy of the fluid level verification procedure from MB’s service DVD. Let me know if you didn’t receive it.
mab01uk- The TSB is lacking in its clarity. It merely reinforced for me that it’s a known problem of which MB is well aware. They have spent a goodly sum rectifying the failures under warranty. That picture showing the Behr sticker is actually on the A/C condenser. Ironically, my condenser and heat exchanger were supplied by Behr. Only the radiator was from Valeo. Please be aware that not all of the Valeos have proven to be defective. In fact, many are not. There are several on the forum with nary a problem. Perhaps you’ll consider having your fluid tested to verify if indeed contamination exists. If you find that to be the case, exchange it posthaste.

Valeo

Valeo


Behr

Behr



Tell me, now that you have that South African radiator installed, can your car speak Afrikans?

I took the time to go to the Blackstone site, and I read what is possibly one of the best stories I have ever read.
http://www.blackstone-labs.com/tales...oily_side.html
Awesome read about how and why the guy started his business. Awesome read!
E





