Radiator Neck Fix/Preventive Maintenance - Page 3 - PeachParts Mercedes-Benz Forum

EricSilver · #31 04-25-2003, 01:35 PM

Hassman,

Yep -- under pressure, the JB-Weld will indeed fail. It is also not waterproof. I compensated with metal epoxy putty, but when my next radiator failure occurs, it will be time to replace it.

Interestingly, even the ones with metal sleeves fail at the neck. Every broken radiator my mechanic has has the metal insert in the neck. It does not seem to work.

edge · #32 04-25-2003, 01:44 PM

ESilver, well it's actually a brass 3/4" x 1 1/2" pipe nibble, that is, it is a connector with threading on both ends. I got it in the bathroom plumbing area at Home Depot. I measure it as 1" across including the threads. I'll have to check it for fit this weekend.

EricSilver · #33 04-25-2003, 03:00 PM

Edge,

Just be sure the fitting is not so big and heavy or it will split the remainder of the neck open, and a total radiator replacement will be necessary. Your brass threading should, seemiingly, be helpful in securing the fitting to the radiator neck, but I am still more comfortable with the copper bushing. You decide what's best.

My repair is holding well (knock wood); I am running at between 80 and 82 in 70 degree weather. I had some freeze/thaw issues with the radiator this past winter, but the repair itself held.

psfred · #34 04-25-2003, 07:55 PM

The plastic embrittles, especially in the presence of phosphates (in green coolant), so nothing will every completely fix the problem except replacement with a brass and copper radiator.

The electrolytic corrosion problem is between iron and aluminum, copper isn't a problem.

Peter

edge · #35 04-28-2003, 01:51 PM

ESilver,

Well I krazy glued the broken neck piece back to the radiator neck and I JB Welded around it and let it sit overnight. I found that the 1" sleeve wouldn't fit and the 3/4" was too small. I also felt that the neck needed that ridge or lip on the end so the hose wouldn't fall off under pressure. I just hooked it up and am crossing my fingers.

EricSilver · #36 04-28-2003, 02:33 PM

Well, crossing your fingers won't help much. If you can get the 1" copper bushing, I'd do so. The Krazy Glue and JB fix you just did will not hold.

haasman · #37 04-28-2003, 03:21 PM

I did not have long-term luck with the glue repair of the neck. It did work for a while. I didn't find copper that would fit well inside the neck or outside. I have seen some where someone advertising an aluminum insert.

It seemed that over a periord of time (6 mos) the JBWeld couldn't stay attached to the plastic. My guess was due to thermal expansion and contraction.

I found this company who rebuilds the plastic tank radiators for about 1/2 cost of a new one: http://www.resedaradiator.com/

It is my understanding that all of the later-styled radiators come with the insert in the upper neck.

It is my opinion that it is over-tightening that makes the plastic start to crack.

Per my previous post:

I spoke with a radiator specialist and he said, over tightening is the number one cause of the cracking. Everyone is used to the metal tube/ radiator hose setup. He said that yes it is a very common failure.

He said as you tighten the clamp twist the radiator hose, when it stops turning, tighten about another half to full turn of the clamp, but not more.

He also said something that still sits in my mind: the clamp is not there to hold the hose on to the radiator, it is there to keep the hose from slipping off.

He suggested purposely not turning the clamp very tight at all. It is better to tighten the clamp a little more than to replace the radiator. But he also added: "I love it when everyone does over tighten them, it means business for me."

Keep us posted,

Haasman

edge · #38 04-28-2003, 03:23 PM

How about a large bushing on the outside of the neck rather than on the inside? Then the palstic won't get crushed...I couldn't get the 1" to fit inside.

haasman · #39 04-28-2003, 03:31 PM

Could work. The neck seems to be at a slight angle and has a notch at the end to help hold the hose on. My guess would be to use an aluminum sheet, cut to size, that is wrapped and molded around the outside of the neck. Then mix up a large batch of JBWeld and cinch the whole mess on, say with HD tie-wraps for over 24 hours. Then see.

Keep us poste,

Haasman

edge · #40 04-28-2003, 03:42 PM

I did buy a small copper flashing material that they use for roofs at home depot. Perhaps I will wrap it around the neck with JB Weld tonight.

EricSilver · #41 04-28-2003, 05:57 PM

I should add, once the copper bushing is *inside* the neck, you can squeeze the daylights out of it with no harm. Any external aplication will likely fail (my bushing popped out under pressure several times until I epoxy/jb welded it on the inside of the neck; all attempts to fasten it externally eventually failed.)

The have to have this piece, it's only a dollar, and will save you from doing the job all over again a few days from now -- particulalrly now that the weather is getting warmer.

EricSilver · #42 04-28-2003, 06:01 PM

Did you specifically get the 1" copper bushing from home depot?

william rogers · #43 04-28-2003, 06:23 PM

years back I was a partener in a small machine shop. We used a product called Devcon witch is like super JB it comes in 8 oz cans and can be drilled and tapped and machined.They have added some new products. Type devcon into google and check out their web site.You can buy it at most industrial supply houses.....
William Rogers...........

edge · #44 04-28-2003, 06:38 PM

ESilver, yes I did buy the 1" copper bushing at Home Depot but it wouldn't fit into my Behr radiator neck and the 3/4 was too small...that's way I resorted to the other method.

edge · #45 04-30-2003, 12:53 PM

Ok, I cut to fit and wrapped the copper flashing (roofing material) around the radiator neck and JB Welded it. After sitting overnight, it looked pretty solid so I attached the hose and filled it with water and tighten the hose. I took it up to 85mph going uphill on the highway, so far, so good. If it holds through the weekend, I will put the MB coolant in.