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#1
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Thermostat housing corrosion
I pulled the thermostat housing off my 83 617.952 to replace the small hose that connects it to the water pump housing outlet.
I found sever corrosion on the nipples of the aluminum, it's strange this corrosion is ONLY on the side that had contact with the hose, the inner surface is smooth as can be, though discolored by some rust. I'm guessing the PO didn't use the correct coolant, or for that matter maybe just straight water at some point. The question is, I'm not sure the new hose is going to provide a good seal with this level of and depth of pitting. Can I repair it with JB Marine Weld? It claims to be specific for this kind of repair, and specifies aluminum. Thoughts? Thanks
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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission. |
#2
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JB Weld will probably work IF you can get everything clean enough. I cut off the piece that the heater hose slides over and nipped the "bump" off that would prevent a hose from sliding further down the fitting. There may be a pic in my build thread. If you need a pic I'll post it.
Anyhow, that fixed the heater hose fitting - mine was actually perforated under the hose. I'll wager that you're right on the coolant selection. I'll be running water w/water wetter as required by the track in the event of a loss of coolant on the track. Not sure what to do about the electrolysis except to run distilled water. Of course this means draining the system every fall but I'm used to that. Dan |
#3
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You could run NPG as I do in my signature car. No corrosion, no electrolysis, no cavitation, and it boils at 370* so you can run at zero pressure.
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'83 300D, 126K miles. |
#4
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The corrosion is always on the outside because of the air interface oxidation. There probably was a ongoing slight leak which corrodes the outside when it meets air, similar to the oxidation of copper pipe. There is nothing to do with the coolant, red or green.
Sand down the corroded part well, JB weld and sand down surface again. It should be good to go for the next 200K miles.
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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed. W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html 1 X 2006 CDI 1 x 87 300SDL 1 x 87 300D 1 x 87 300TDT wagon 1 x 83 300D 1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry. |
#5
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Quote:
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85 300D turbo pristine w 157k when purchased 161K now 83 300 D turbo 297K runs great. SOLD! 83 240D 4 spd manual- parted out then junked |
#6
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This tends to occur on cars with weak coolant rather than the "wrong" coolant.
Weak coolant is trapped in the void between the aluminum and unclamped portion of the hose. Corrosion grows under the clamped portion causing an eventual leak. Epoxy will work but you must get the surface completely clean ( sand blast / wire brush ) , a more direct route is to replace the housing. The hose (s) should be replaced as well, the rubber will have gotten pretty rough and squished out by now. Grease won't help and can cause slippage of the hose under pressure. |
#7
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I had the same problem.
I scarped the Holes down to the bare Metal and filled the hole with JB Weld epoxy the one that can take up to 250 degrees (not the Fast set Epoxy) and I wrapped tape over the Epoxy and around the Nipple to hold the Epoxy in and make the surface as round as possible. After the Epoxy cured I filed off the excess and filled in what ever holes there were that did not get filled. That was close to 5 Years ago with no leaks.
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84 300D, 82 Volvo 244Gl Diesel |
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Quote:
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85 300D turbo pristine w 157k when purchased 161K now 83 300 D turbo 297K runs great. SOLD! 83 240D 4 spd manual- parted out then junked |
#9
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Repaired parts.
Here's what I ended up with using JB Weld Marine. I chose the Marine product because it said specifically that aluminum was compatible, and that it was good for water applications.
I think these will get me a 100,000 miles further...
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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission. |
#10
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I second that. As far as I know, the only product available is Evan's Waterless Coolant (search). I put their NPG+ in my 85 300D. If it works OK thru the summer, I will start putting it in my other cars. Costs 4x regular coolant, but lasts forever and no more corrosion, nor pressure in the cooling system. M-B parts are so expensive and hard to change, the payback is quick.
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#11
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I've never heard of this NPG stuff before, can you guys tell me more? It's really not much more expensive than the MB coolant to be honest.
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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission. |
#12
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I had the same cavitation when I got my 84 last summer. Did the whole JB repair, it lasted 1 month. I would suggest you get another goose neck. Not expensive, and just better insurance.
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#13
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Quote:
Where does one find this part, our hosts here don't sell it, so would it violate the rules to point someone in the right direction?
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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission. Last edited by crazy4diesel; 02-02-2014 at 04:59 PM. |
#14
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They do sell them if you search for the part number:
A bit rich for me... Thermostat housing I just picked one up today at the junk yard. Pretty good shape, for under $6. But it will be hit and miss. One you pull may end up looking like yours too.
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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino http://i.imgur.com/LslW733.jpg The Baja Arizona Oil Burners Send a message if you'd like to join the fun Left to Right - UberWasser, Iridium, Stuttgart-->Seattle,, mannys9130 Visit the W123 page on iFixit for over 70 helpful DIY guides! |
#15
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I have a good used one. pm if anyone is interested.
Quote:
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85 300D turbo pristine w 157k when purchased 161K now 83 300 D turbo 297K runs great. SOLD! 83 240D 4 spd manual- parted out then junked |
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