why did this happen?

[Rob Thomas]

I have a 1986 560 sl. I was driving it one day when a spray came out from under the hood. I stopped the car and found the upper radiator hose had come off top of rt side of radiator. The plastic neck had broken off and was inside the detached hose. There was enough of the neck remaining on the radiator so I reattached the hose. Before this happened temps were normal(80). The reservoir was to its full mark. It did not appear very much coolant came out. When I continued driving the temp imediattely started to climb and got no more than a half of a mile before I had to stop(120 degrees)and shut off engine. I checked under hood and the hose was on and coolant still showed in reservoir to its full mark. I let cool down to 80 and drove again but could only go a short way(120 degrees) before had to stop and go through whole process of cooling down. I had to do this for about 6 miles until I got home. I let cool down over night. As soon as I opened reservoir it drained down and I put about 8 qts. of water in. Now it works fine. So, what happened. Specifically I am wondering why the neck of the radiator broke? Why didn't the coolant in the resevoir drain into the radiator? the coolant that sprayed out appeared to be only about a quart or two. Did I hurt anything by driving it in short distances, until it got to about 120 degrees and then shutting off for the 6 miles home. The hose appears to be secure on the short neck but would you put new radiator in to have full neck for hose to be attached to? Thanks. Rob Thomas

I would put in a new radiator. Plastic parts last only
so long. It's not worth loosing an expensive engine over
the cost of a new radiator.

Gary

[kfuller]

Appears to be a common problem. Mine, on a '90 300E, split below the neck. Some have suggested that the neck needed reenforcement or that using other than MB antifreeze affects the platic. I personally think that the the plastic material weakens with age and constant exposure to heat. I would be concerned that the present radiator would leave you stranded in the future and possibly damage the engine. I think that excessive temps could at the very least destroy the head gasket. Do a search on radiators in this forum.

[SqueakyBrake]

Happened to me last year in the heat of summer, go get it replaced, estimate $600. Why MB made a plastic radiator is a big question to me. Weight of the car? Plastic was that rad in the 80's? It doesn't rust, just breaks???....


And Keep On Driving!!!

[Q]

The reason it overheated was due to a lot of air in the system.

Mercedes doesn't make the radiator, I think Behr is their supplier, probably for other German marques as well. Most newer cars use plastic (for weight reasons). My brother replaced the radiator in his '96 Acura Legend @ only about 45k miles. All south Florida driving and at a tune of $500.

[Mike Murrell]

Here's my 2 cents.

I had the exact same thing happen to my 126 MB awhile back,
only in my case, it happened about a half mile from home.

The upper hose had hardened, thereby making it easy to slip off the plastic pipe. Many discussions have taken place here and elsewhere regarding why the plastic pipe breaks. If it were my car, I'd search for a new METAL-only replacement and hope the engine didn't over-heat enough to weaken/blow the head gasket.

[engatwork]

You can purchase a new all aluminum radiator built for any MB. I called the folks this morning - Griffin Radiator (800) 722-3723

http://www.griffinrad.com/radiators.htm

They do not have any "off the shelf" units for my E320 - the lady said I would have to send her my radiator and they can build an exact duplicate of it in all aluminum. She indicated that right now it would take about six weeks and she could not give me a firm price but indicated to plan on spending between $900 and $1200. I saw one of their radiators in a fastback Mustang this weekend and it looked like a very high quality item.

I don't think you did any damage since you kept stopping when the temp was too high.I'm sure you know it's time for a new radiator now(hopefully with MB coolant).
The reason that it kept running hot was that you had an air pocket in the upper part of the engine. A very common occurrence on the V-8s. I used to do the initial refill of cooling systems through the upper radiator hose to prevent that from happening. If you get air trapped in the manifold and heads, it can take it a while to "burp". On most models it's a good idea to run the auxiliary water pump with jumper wires while refilling with coolant.
Regards,
Randy D.