Author Topic: Ouch, broke off 6.9 radiator drain plug  (Read 363 times)

jjccp

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Ouch, broke off 6.9 radiator drain plug
« on: 02 July 2019, 04:10 PM »
I can't believe it broke so easily. I just had it off a couple of months ago to replace the thermostat. I guess it's telling me it wants to be re-cored also. I've taken out the radiator on my 280 SE and had it re-cored years ago and that was pretty basic.

What do I need to know about taking out the radiator on a 6.9? Thanks in advance for any info.
1977 280 SE
1979 6.9 #6846

TJ 450

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #1 on: 02 July 2019, 09:57 PM »
That’s annoying, but definitely fixable. Removing the radiator is practically the same as on the 280SE, although there is a lack of space. The charcoal canister needs to be pulled aside if present.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Harv

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #2 on: 03 July 2019, 06:18 AM »
Euro or USA car?

I've taken the radiator out of a Euro 6.9 and it ain't fun. You have to be extremely careful as it's tight and fluids will be flying.

Come to think of it, I have a spare Euro 6.9 radiator that I had my radiator shop clean up and test if you want to go that route. 
1980 300SD
1983 240D
2000 E55 AMG

jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #3 on: 03 July 2019, 07:20 AM »
It's a USA car. The fluids flew pretty good when I broke the drain plug.

Please check me on this: remove the various coolant lines, 2 clips on top/side, charcoal canister and plastic fan shroud. I haven't thoroughly inspected the bottom of the radiator yet.  Are there some oil cooler lines also? Anything else? I looked at the online manual, but haven't found anything on removing the radiator.

Now that I'm looking into getting the radiator repaired, I've come to find out that there are almost no shops left that do radiator re-coring. In all of Metro Detroit, I've only been able to find one shop. There used to be many. I've read that they've been environmentally regulated out of business and of course getting another radiator is a big challenge.

It looks like I have my plan set for the holiday weekend

1977 280 SE
1979 6.9 #6846

Harv

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #4 on: 03 July 2019, 12:01 PM »
You are correct, re-coring is a dying/dead business because of the nasty crap that comes out of radiators can't be dumped in the stream behind the shop anymore and all the radiators in cars now are plastic and made to be disposable. Find a shop that repairs gas tanks. They can probably fix it.

Also removing the fan will help a lot and give you some breathing room. Be very careful pulling it out. Spray some lube down on the rubber slides the radiator sits in. You'll want to "pry' each end out to remove it and kind of wiggle it to get it moving. It isn't going to pull straight up with ease. It will take some force.
1980 300SD
1983 240D
2000 E55 AMG

jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #5 on: 03 July 2019, 06:32 PM »
Thanks for all the great tips. So far everything came apart with no problems.  I believe I have everything disconnected and ready except for the two oil/trans lines pictured from underneath.

If anyone knows, how much fluid can I expect to come out of each one? I want make sure I'm ready to collect it so I don't have a huge mess.
1977 280 SE
1979 6.9 #6846

Alec300SD

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #6 on: 03 July 2019, 07:03 PM »
About a cup or so is in the transmission cooler itself.
Clamp the oil cooler hoses with fuel clamps (or needle nose vise grip pliers) before detaching the lines to limit leakage from the tranny.

I made bypasses to the radiator hoses and transmission oil cooler to allow 'Stormcloud' to be briefly driven when the radiator was out to be re-cored.
http://www.peachparts.com/shopforum/3889842-post1.html
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jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #7 on: 04 July 2019, 02:59 PM »
Thanks to all for the excellent tips.

At this point I can't get the small hose off on the drivers side. I believe that's the last thing to take off. I got the clamp off but can get enough leverage while laying on the ground to get it to slip off the nipple. Also tried putting a wrench on the fitting, but it wouldn't budge. So I sprayed it with more lube and will let it sit overnight. If I can't get it off during my next try, I can always try to disconnect the other end or try to apply some heat.

While I was down there, I put a jack on the bottom corners of the radiator and nudged them one at a time just a bit and the radiator moved up with nicely, so I'm thinking it's going to come out with no problem.

My experience has been a bit different than what I have read from others. I was able to disconnect and just move the fan shroud out of the way just enough to get it out of the way and didn't need to do anything with the fan so far. I've also read about people having issues with the oil cooler, but to me it looks like everything is clear. We'll see tomorrow if it continues to slide up after I get the last hose off.
1977 280 SE
1979 6.9 #6846

rumb

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #8 on: 04 July 2019, 03:36 PM »
Those transmission cooler line are not the correct part at all.  They are suppose to be a hose assembly and do not use hose and hose clamps. The new ones have a spring on the outside to protect them.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

Jed

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #9 on: 04 July 2019, 06:43 PM »
Hey Jim

Be careful (which it sounds like you are) with that lower oil line.  you don't wont to strip the threads of the radiator...a whole different problem. When it does come loose, keep spraying the lubricant and go back and forth with the wrench to prevent shearing the threads right off. I agree that the hose is not original.  Definitely pull the hose off the nipple, remove the radiator, and then you can work on the threaded fitting on the bench instead of on your back.

Lastly, there is an old school radiator shop in Mt Clemens that can probably do what you need. Superior Radiator Shop. I think its on Grand just north of Cass Ave. 

jed
1979 Mercedes 6.9 #5206 - restored
1979 Mercedes 6.9 #6424 - ongoing restoration
1976 Mercedes 6.9 #484 - restoration?

jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #10 on: 05 July 2019, 06:18 AM »
Jed and Rumb, thanks for the good advise.  I'm definitely being careful after breaking off the drain plug. I feel pretty stupid for doing that. Usually I'm so careful with everything on my cars because so many parts are brittle and old. Taking anything apart can lead to a big checkbook depletion if you screw up. 

Great tip on the Mt Clemens shop Jed, thank you, that one is nice and close to me.

Does anyone have a picture of the correct setup for the oil lines? Or perhaps some part numbers? I'd like to put it back together with the right parts.

Also, when I get everything back together (some day soon I hope) I've read about a citrus flush for the whole coolant system. Is that stuff still available and where can I get it?
1977 280 SE
1979 6.9 #6846

jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #11 on: 05 July 2019, 06:29 AM »
I've been trying to read all the posts on radiator removal and found this one:

https://forum.w116.org/mechanicals/how-to-remove-radiator/msg142294/

Squiggle Dog who has given me some great advise in the past wrote:

"Remember to loosen the nuts on the bolts that connect the oil cooler to the radiator. This will hopefully allow you to push the radiator and oil cooler closer together to relieve side tension."

I'm not sure where these are located. At this point it seems like my radiator is loose and will slide up freely. But I want to make sure if anyone can chime in with any oil cooler info. Thanks
« Last Edit: 05 July 2019, 07:18 AM by jjccp »
1977 280 SE
1979 6.9 #6846

rumb

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #12 on: 05 July 2019, 07:49 AM »
https://www.autohausaz.com/catalog/c/mercedes/1977/1367580-450sel/16-cooling_system/10343-auto_trans_oil_cooler_hose?s=d&page=1

My car has two of the straight one.

bulk citric acid powder may be available at your grocery store or local food coop type grocery.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #13 on: 05 July 2019, 08:55 AM »
Rumb, thanks for that link, I'll order those for sure and get it correct. A reasonable price too!

This morning I was able to get the last hose off. Still couldn't get the hose to slide off the nipple, but after soaking overnight the fitting broke loose with a wrench. And as you can see I have the radiator jacked up a couple of inches. Now I can see where the fan might be an issue with hitting the various outlet/inlets sticking out on the bottom of the radiator. I'll keep inching it up and we'll see if it will clear.

Jed, I followed your tip and rocked that last fitting a whole bunch before gradually advancing it off and it came off clean.

At this point, I'm still not seeing any issue with clearing the oil cooler or it being in the way.

"Patience and lots of lube" are the marching orders for this job.
« Last Edit: 05 July 2019, 09:01 AM by jjccp »
1977 280 SE
1979 6.9 #6846

jjccp

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Re: Ouch, broke off 6.9 radiator drain plug
« Reply #14 on: 05 July 2019, 09:53 AM »
Woo hoo, it's out! My biggest concern was the big outlet at the bottom drivers side hitting the fan, but it cleared. After jacking from the bottom, I stood up and wiggle/rocked it a 1/4 inch at a time while pulling up and it graced me with it's presence. As you can see, it wanted out to get re-born.

BTW, it's been 90 degrees and high humidity here in the Motor City the last couple of days, even with a fan blowing directly on me, I have sweated greatly. Great weight loss program.

Also, you can see my original screw up with drain plug. Don't be that guy ha ha

While I have it out, can anyone suggest any other items in that general area that I might inspect while the radiator is out?

I greatly appreciate all the help from everyone. I hope the pics and words help the next person that has to tackle this job
« Last Edit: 05 July 2019, 10:04 AM by jjccp »
1977 280 SE
1979 6.9 #6846