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

edge · #1 07-01-2005, 09:23 AM

Well, I have the whole top assembly that I purchased from the oem supplier for the radiator. You have to uncrimp the old one and recrimp this new one. You can have it for $35 shipped.

halman2228 · #2 07-12-2005, 06:21 AM

Edge -

Mine broke yesterday a.m. (on the 560) - Where did you order the top assembly from?

Kevin

EricSilver · #3 04-25-2003, 01:08 PM

Edge,

PVC would soften and break. CPVC will withstand the heat, but it may be tough to find one that fits properly within the radiator neck. I would think the plastic-to-plastic fusion with epoxy or JB weld woul be more effective than the plastic to copper.

edge · #4 04-25-2003, 01:10 PM

EricSilver, how has your fix been holding up? Maybe it's better to skip the epoxy and just use JB Weld, seeing as that part was holding up well. I am using 1 1/2" brass so even if the hose came undone, hopefully it will stay hitched and provide some coolant rather than come completely undone. Thanks.

EricSilver · #5 04-25-2003, 01:30 PM

NOTE: Post not spell checked.

Edge, (again)

Are you sure the fitting you bought will fit inside the neck? In my experience with Home Depot, only the 1" copper bushing fit snugly. If you can get back to Autozone or WalMart, I'd also recommend a tube of the Metal Epoxy putty.

I recommend doing this repair after the engine has been running hot for a while; the heat will help cure the JB Weld/Epoxy faster.

Be sure to take the time to thorougly clean the inside of the neck, and sand it a bit with rough sandpaper. Also sand the outside of the bushing.

Apply JB-Weld -- or the metal expoxy -- inside the neck, then on the outside of the copper bushing. Insert bushing into neck as far back as it will go, gently but firmly twisting as required. Go spend 2 to 15 hours of quality time with your wife.

After 2 hours (if you use metal epoxy) or 15 hours (if you use JB weld) the copper bushing will be pretty much permanently attached. Roll a "worm" of epoxy putty and wrap it around the exterior of the bushing, replacing the broken-away plastic. That will dry in about 2 hours, after which you can sand it down if needed.

When you reattach the hose, you can pretty much tighten it without fear of breakage. You will need to do this to compensate for the loss of the bulge on the original radiator neck which keeps the hose from sliding off under pressure. The repair will initially leak a bit at the hose connection until the rubber softens and forms a natural seal, which should occur after about 2 days of normal driving.

Let us know how it goes.

EricSilver · #6 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 · #7 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 · #8 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 · #9 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 · #10 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 · #11 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 · #12 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 · #13 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 · #14 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