Wife was driving the car home tonight and noticed that it was smoking from under the hood - she got off the highway (was going approx 60 mph at the time) and got the card parked and let it idle for a few minutes - temps started to drop...

I got there just a few minutes later and then the car stalled out - temps had dropped to just below 100C. Anyway, upon opening the hood, the problem was obvious - the top radiator hose was off as the plastic nipple had broken off. I tried to get it back on enough to get home and added some water and pulled the thermostat - car ran for a bit, but I couldn't get it on tight enough to get it home and it blew off again after just a couple of minutes. So I finally called AAA...

Question is how much damage do you think has been done? The gauge was clearly pegged, but I don't think it was that way for very long. Also, I am a little concerned about adding the cooler water to this really hot coolant - hope I didn't blow out a water jacket...

Any way to find out what the damage is short of first replacing the radiator and seeing what happens??

Thanks for the help.
ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

If the car was not run for long then you will probably be okay but I'm concerned when you say the car stalled out. This would be a good opportunity to flush the entire cooling system and replace all the main coolant hoses. Make sure you use Mercedes Coolant or Zerex G-05.

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1989 300CE

If anything you have either blown the head gasket or cracked the head.
I would get the car checked before going any further.
Leak down test and inspection by independent M.B. specialist.
Check the oil and make sure no coolant is there and check the over flow bottle and make sure there is no oil in there.

May have been a coincidence but I believe my overheating episode led to my head gasket failing soon after. My overheating was from a broken thermostat. The oil started showing up in the coolant tank a couple of months later.

glenmore
1991 300CE

This is a typical effect of water loss.

- Temp goes up when the water level is dropping.
- Then down if the pressure is down to zero.
- The sensor is on top of the head and water vapor without pressure has a max temp of 100C.

Letting it idle without coolant, even for e few minutes, has certainly destroyed the head gasket and probably warped the head.

Switching off the engine when the temp rises suddenly is the only way to prevent further damage.

Sometimes you don't have a choice, I had a hose failing on the German autobahn, better damaging the head of the car than my own.

The head gasket has to be replaced and the head checked.

Depending on the state of the car and the mileage of the engine it may be more economical to replace the engine with a good used one.

Rob

I have a spare motor.
P.M. for details.

I also have had inattentive drivers of my MBZ's

My sympathies to all whom have had this happen.

Ryan, thoroughly investigate the extent of possible damage before thinking your existing engine is toast. Pull the dipstick and check if the oil looks or smells burnt, or shows signs of coolant mixed with it. Check the coolant overflow tank and check for signs of oil. Turn over the engine by hand CW with a 27mm socket on the crankshaft bolt to ensure the engine isn't siezed. If it turns freely and if there is a short section of the upper radiator hose connection remaining then remove the broken off piece from the hose, temporarily reattach the hose and start the engine. If the engine runs fine and there is no white exhaust or oil leaking from the head gasket then replace the radiator and thermostat.

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Fred Hoelzle

Thank you for the replies. I am not ready to condemn the head or the motor yet! As stated, while idling the engine temps dropped below 100C and when I tried to add water and get the hose back on, the car started and ran until the hose blew off and I shut it down. Also, there was still coolant in the block/head because I left more of it on the parking lot after the hose blew off!

Just checked things again and I have no coolant in oil, no oil in coolant - got the hose on again as best I could and started it up. Started great with no smoke out the tailpipe and ran fine (just for a minute or two as I didn't want to blow antifreeze all over the place again - so I didn't let it heat up). Now, I realize that this is not a definitive 'test', but I think it is enough to replace the radiator and thermostat and HOPE for the best. I know I could still be looking at a head gasket replacement down the road...

As a side note, this head gasket was replaced by the dealer many years ago - car had maybe 10-15K miles on it. I don't know why, and I don't know if that matters...car currently has 82,000 miles.

ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Sounds like you got lucky. The replacement head gaskets are far far less prone to failure in an overheat situation.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

Well, not sure if I got lucky yet, or not...got the new Behr radiator and thermostat installed and having been driving it around a little this evening and earlier this weekend. Gets a little hot (although this car has always run hot - right around 100C). Tonight it got up between the 100 and 120C mark - cools down to below the 100C mark, generally when idling. But, I am leaking coolant from the driver's side of the block (it looks like it is coming from the water pump and dripping off the oil pan). Is is possible, or likely, that the overheating caused a water pump problem?

I'm not positive that it is leaking from the pump, but pretty sure...

Any water pump recommendations?


ryan

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RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

If you have a coolant leak then the system cannot build up pressure therefore proper cooling cannot take place.

There is a "o" ring between the water pump and block sometimes there will be a leak at this juncture.
The water pumps internal seals also breakdown and the water pump itself will leak. There is a seep hole where the coolant leaks from


Here's an example of a weeping O ring



Replacement water pumps - OEM are Laso and Graf. be wary of Far east copies - e.g. URO.

Not using the proper M.B. coolant or exact coolant reduces the life of the internal cooling system.

Ryan, if you need a new water pump recommend buying a reconditioned water pump from your local MB dealer.

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Fred Hoelzle

This is a good sign in the fact that it indicates that the rings are not toast.

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Jim

you must have a thermostat in these cars or they will run hot...

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

...
this is incorrect.
water VAPOR can achieve nearly any temp... and frequently does in many facilities.
liquid water without pressure can only hit 100C without BOILING.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!