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-   -   SL500 1995 Radiator Neck Crack repair? (

Gusfazekas 10-24-2009 11:05 AM

SL500 1995 Radiator Neck Crack repair?
The neck on the radiator has a crack extending from the opening back towards the radiator body, also, extends past the hose connection. Anyone had success repairing this? Saw an item sold to make this repair sometime ago but I can't find the link anymore. Repair consisted of a metal sleeve epoxied into the neck. Don't know if it worked.

Also, a second problem. On top of the tank, adjacent to the filler neck, there is a plastic connector connecting the overflow hose to the overflow tank. I have leakage around that connection as well. How is this plastic connection inserted into the tank? O-Ring? Does it twist out? I don't want to break it off and I think it must have a seal underneath it. Any help with this is appreciated. Steve

rocky raccoon 10-24-2009 11:25 AM

Radiator repair
The copper sleeve insert you refer to is intended as a preventive measure since these plastic radiator necks are so fragile. I have used it on my 560SL. The insert arrangement however, will not work for a repair since the sleeve must be epoxyed in place and the heat related expansion/contraction will cause the crack to reopen.

I'm afraid a new radiator is in store for you. After you get it, go to your closest big-box hardware store and buy an internally snug-fitting copper pipe nipple to epoxy inside the upper radiator hose connection. Can't help with the expansion tank connection. I will say however that most people tighten those hose connections way too tight. Not necessary.

Gusfazekas 10-24-2009 03:01 PM

sl500 radiator cracked inlet
The connection I need some help with is the plastic connector at the top of the radiator. This black dome-like plastic piece looks like it twists into the top of the radiator and the small black overflow hose runs from this connection to the expansion tank. I suspect that there is a seal or O-Ring keeping the radiator fluid from leaking out.

Jack M 10-25-2009 02:02 AM

Tank repair
Hi, This is exactly what happened on my 560SL some 5 years ago. The radiator repair shop owner explained the issue.

The hot water comes from the block and pours into the radiator. Plastic inlets primarily are not built to deal with the heat and the concentration of hot water. If your water level is low then the heat is concentrated in a narrower area and the plastic deteriorates.

Moving along: the "radiator" consists of three parts. the inlet tank and the outlet tank, these are crimped onto the radiator core and can be removed and replaced. Since the water on the outlet tank is cooler than the inlet tank and the water is covering the whole area of the connector, these cracks develop less often.

You need to call around for a repair shop that either has, or can order the inlet tank for your car. If you like, and the cost is reasonable. you might do both tanks as long as you have the radiator out of the car. If you were not experiencing any overheating problem then the core could be ok and not need replacement. My core was a Behr was fine, so the repair shop said the outlet tank which was on the driver side was ok and did not recommend replacement

I do not know if your radiator has top and bottom tanks or side tanks.

Is your core aluminum? are you using the correct coolant? This will happen again if you allow the coolant to run low and the heat gets concentrated in a narrower area of the inlet connector.

If the repair shop is local, great. If not and they can not find the tank, than order the part. If you can, remove the radiator and take it to a shop.

The 560 was a pretty easy Remove and replace others way not be.

Good luck, JackM.

Jack M 10-25-2009 02:07 AM

PS RE Copper Sleeve
:) A good idea. Put it into the new inlet, that will radiate the heat and protect the plastic. J

Gusfazekas 11-07-2009 03:16 PM

Fixed the cracked filler inlet on the SL500 radiator
I can tell you a product sold at NAPA worked for me to fix the cracked filler inlet on my radiator. Its a two part epoxy with fiberglass matt, looks like it might be JB Weld epoxy but it is strong and so far it has held up. You will need some cylindrical "rasps" mounted to a drill and some medium grit sandpaper to contour the surface, otherwise its a piece of cake. Steve

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