Hi,

My first post (sorry, a long one) and my first MB. I got my first MB about a year ago. It's a 1995 E320 Sedan and I have had lots of trouble with the cooling system. I already replaced the water pump, top radiator hose and heater hose. Recently I got a mayor damage and the coolant became mixed with motor oil. First I thought It was a head or head gasket problem but after checking the head and replacing the gasket, the workshop found a leak in the intercooler system (I'm not sure if that's the correct name. It's like a small aluminium radiator inside the oil filter housing). I replaced the intercooler but now I have all the cooling system contaminated with oil. I have changed the cooling fluid like 10 times since then (3 weeks) but I still get oil floating in the coolant.

I'm thinkig about doing a cooling system flush (been reading a lot in this forum), but I do have some fears and some questions about the procedure. The radiator is 11 years old now and has never been flushed. The previous owner used only tap water in the cooling system with no coolant at all. That's really comon in my country and most mechanics say coolant is a waste of money (no winter here). I think that's the root cause of all my problems because of the lack of corrosion protection.

I'd really appreciate your help on this one:

1. I bought a can of radiator cleaner but I think it will remove all calcium deposits in that 11 yr old radiator and maybe cause lots of leaks. The radiator has no leaks at all and I don't want to buy a new one now. I already spent a fortune on the water pump and intercooler. I have the idea that using chemicals to flush an old radiator for the first time, will "kill" the radiator and cause lots of leaks.

2. I think a deoil (detergent) flush could be a better solution. I don't want to remove corrosion but to remove the motor oil contamination. What do you think? What kind of detergent (deoil agent) should I use? Is it ok to use one of those general purpose liquid degreaser used to clean in the kitchen?

3. My termostat is working perfectly. Do I need to remove it before starting the flushing procedure to get a good flow?

4. If I open the termostat housing, do I need to replace any gasket or o-ring or something?

Thanks a lot guys,

Juan

Juan, are you sure there are calcium deposits in the cooling system? From what you describe, I would expect calcium deposits in a system that ran tap water, but you should be sure, because you don't want to needlessly treat the cooling system with harsh cleaners if it doesn't have these deposits.

But if it definitely IS contaminated with calcium, go ahead and treat the cooling system. Any leaks that could occur afterward are the result of false sealing. It's best to know if the radiator is compromised now, and not on a long trip.

There's no need to use any special flushant for the oil contamination. Oil can be flushed from the system using any common detergent such as dishwashing or lundry detergent.

I remove the thermostat for flushing. I get better access to the cooling passages during the flush this way. There is a gasket for the thermostat. I'm cheap, so I reuse the gasket as long as it doesn't leak.

Though you live in a hot climate, you should still run a 50% coolant mixture. With this mixture, the coolant boiling point will be elevated. Ford paid me good money to study what happens when pure tap water is used as a coolant. With just straight water - besides losing corrosion protection - the system experiences enhanced boiling. Steam is a poor conductor of heat. Plus, the bubbles can do nasty things to aluminum. In extreme cases, the bubbles pound through the casting section until the heads are junk.

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95 E320 Cabriolet, 159K

Kestas,

Thanks a lot for your opinion. I'm not sure about calcium deposits. I don't see anything strange in the radiator but since it's been runing on tap water for too many years I just suposed there must be some calcium. Water in the system looked 100% clean before the oil contamination. How can you tell if there is calcium or not? By looking inside the hoses or something like that? All I see inside the hoses and fittings is oil contamination. BTW, our local tap water is potable and soft with neutral PH.

I think I'll remove the termostat and do a flush with comon detergent first and if everything looks clean after that, I'll put some new coolant and leeve it like that.

BTW, the part that caused the oil contamination is called the intercooler or does it have a different name?

Thanks again,

Juan

To check for calcium deposits, look for white deposits inside the radiator, or on the metal surfaces when you remove the thermostat. Since the MB design has no radiator cap, this may be difficult.

I'm not familiar with the water down where you live. You may have lucked out and have good water that leaves few deposits.

You may have to do multiple flushes before you get the level of oil in the cooling system down to something managable.

I'm not sure of the name for that part, intercooler sounds about right. I don't have this feature in my model.

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95 E320 Cabriolet, 159K

Thanks again Kestas. I'm planning to do the flushing tomorrow and check for calcium.

I'm not sure if I have air in the cooling system or if I have a leak. I see some water under the car after driving but I can't tell if it's A/C condensation. I'm trying to detect possible leaks and I see some drops close to this component (see picture). What component is that? It looks like some kind of electrical pump and is located close to the battery. What is it for? Does it has something to do with the cooling system?

Thanks again,

Juan

Attached Thumbnails

 

Any imputs? Please help me identify this part !

Is it the auxiliary water pump?

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Juan
1995 E320 Sedan
2008 Ford Escape
RC Helicopter

The larger cylinder is an electric coolant pump. If a coolant temp in excess of 110 C is sensed after engine shutdown, this pump will start and run for about 10 minutes. Coolant is circulated through the engine to prevent hot spots.

The other two cylinders are pulsed valves. They receive inputs via the cabin temp selector and regulate coolant flow through the heater core.

The MB service information describes a procedure to insure this part of the coolant circuit is open for flow during a coolant flush procedure. Sorry I can't remember the exact details.

Hi,

I flushed the system last night using a liquid detergent to eliminate the oil contamination. I turned the heater on (and that electic pump has operating!). Nothing happend and oil remained on the hoses.

After that, I made another flush using a can of a comercial "radiator cleaner". Some oil came out of the system but I still see a lot of contamination. Upper and lower hoses have lots of oil. They look like if I had apply butter inside the hoses. This is crazy. I don't know how to remove this thing from the system. I guess this will take a lot of time and some aditional flushes but flushing the system takes a lot of time.

Thanks

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Juan
1995 E320 Sedan
2008 Ford Escape
RC Helicopter