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  #1  
Old 03-03-2006, 12:11 AM
NooB
 
Join Date: Feb 2006
Location: Slidell, LA
Posts: 16
240d losing coolant

Just got my '83 240d three months ago so I'm a true noob. Anyway, I'm losing coolant, and the temperature guage creeps up when the Benz is in need of a quart or so which is once a week. I was changing my oil today and while underneath loosening the oilpan plug I noticed something peculiar (to a noob). I was looking up and saw the end of the hose running from the radiator cap and some coolant that had leaked out on something under the hose.

This to me looked like the end that should be in the coolant reservoir. Not to mention I see no reservoir. The hose travels along the side of the radiator on clips and looks like its meant to be this way. This to me seems like the reason why I'm losing coolant. Is this how it's supposed to be. Don't forget...I am a noob!

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  #2  
Old 03-03-2006, 12:20 AM
Registered User
 
Join Date: Jul 2003
Location: Ocean Isle Beach, NC
Posts: 2,532
There is no reservoir tank on the 240D. That hose you see is the overflow hose that throws it on the ground. Not likely that's where your leak is. More likely a water pump, hose, cooler lines, etc.

Len
'83 240D 345,000 miles original owner
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  #3  
Old 03-03-2006, 12:22 AM
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Join Date: Jul 2005
Location: Rantoul, IL
Posts: 68
if its comming out of the hose try to replace you cap...there maybe a chance that the spring does not keep the coolent at the specified temp
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  #4  
Old 03-03-2006, 09:09 AM
t walgamuth's Avatar
dieselarchitect
 
Join Date: Apr 2005
Location: Lafayette Indiana
Posts: 38,837
i t also

could be just overheating and pushing out liquid when hot. in that case the first suspect would be the thermostat. luckily it is easy to change on a 240. buy a new stat behr i think is the preferred brand and take out the old one and test it. then replace if bad. test the new one too. be careful with the tstat housing bolts. they are steel into aluminum and will strip out the al pretty easily. spray on some penetrating oil and work them back and forth gently to get them started. if it isnt the stat the second suspect is the water pump which has a weep hole on the bottom side which will generally leak if it is failing. third suspect is the radiator which in my experience is not very often the problem. i have a couple of good rads in stock if anybody needs one. (left over from 300 conversions on 240s).

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #5  
Old 03-03-2006, 12:06 PM
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Join Date: Dec 2002
Location: Colleyville, Texas
Posts: 2,695
What t walgamuth said

I have a 300TD and a 240D. There is no reservoir in the 240D. So the tube is the overflow tube.

Check the radiator coolant level. It should be at the tab in the radiator opening (About an inch from the top). If higher than that it would push out fluid as it gets hot and expands.

Check the radiator cap rubber seal. If deteriorated then replace the cap. The cap spring is rated at a certain pressure. If weak then the fluid will come out. Or just consider replacing it anyway, not that expensive.

If you have an Infra red thermometer then scan the radiator while at normal operating temperature. When the radiator starts to fail the tubes can collapse and provide poor cooling. The radiator should show consistent temps over the entire radiator, slight variations allowed due to fan cooling/air flow.
If you don't have the thermometer then bring it to a shop who can scan it, or consider getting one.

Check the thermostat. Get a new unit or get a new gasket and take out the thermostat. IN a pot of water with a thermometer, place the thermostat in the water and turn on the heat. As the water heats up the thermostat should start to open and be completely open at the temperature stamped on the thermostat. Usually 80C. (176F) If it does not fully open as described then a new one is required.

If all the above are good then take it to a shop that can do a carbon test of the radiator fluid. If the carbon shows up then you have a blown head gasket. A blown head gasket is not a normal occurrence in the 240D so I doubt this.

I have had 2 radiators collapse and go bad. So this is common, I've also had thermostats go bad also.

Follow these steps and we will get you running.

Dave
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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car
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  #6  
Old 03-03-2006, 04:42 PM
Registered User
 
Join Date: Sep 2002
Location: Utah
Posts: 414
Could be a head gasket...

Cheap easy test is to take it to an emissions shop and have them open the radiator cap and give it a " free" sniff to check for hydrocarbons in the coolant.
When the gasket starts to leak the cumbustion gasses are appear in the coolant.

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Last edited by bennett; 03-05-2006 at 01:12 AM.
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