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Had radiator, upper and lower hoses, bleeder line, and expansion tank all totally swapped for brand new stuff.

Apparently the expansion tank is lovingly referred to as the 'explosion tank' by the auto techs. Eventually they'll just burst from the constant expanding/contracting with the heat and pressure, etc.

Should be all set for at least another 15 years, I guess. I suppose it's definitely suggested that if you're replacing the radiator just go ahead and do all those other items as well so you don't need to go back and drain/refill and replace the expansion tank when that decides to go.

Hopefully that was the largest repair bill I'll have to deal with for some time. :eek
 

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Nice work,,I presume the coolant was changed too,,,
I think the cooling system is excellent on these cars,,,15 years coolant life is brilliant,,
Both my cars I have replaced coolant with new mb blue...everything else looks like it could do another 15 years easily,,,never heard of a tank rupturing.
 

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Had radiator, upper and lower hoses, bleeder line, and expansion tank all totally swapped for brand new stuff.
What about the water pump?

Currently in the middle of swapping out the E320 radiator for an E500 radiator. Also doing hoses and water pump at the same time. The E320 radiator is the most pathetic thing I've ever seen. Its the same thickness as the AC condenser. The E500 radiator core is more than double the capacity.
 

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Discussion Starter #4
What about the water pump?

Currently in the middle of swapping out the E320 radiator for an E500 radiator. Also doing hoses and water pump at the same time. The E320 radiator is the most pathetic thing I've ever seen. Its the same thickness as the AC condenser. The E500 radiator core is more than double the capacity.
You know, after I got home I thought... the water pump is basically the only thing that was not changed. I wonder how long those usually last? They did a full inspection of the car and didn't say anything about it. I presume it's perfectly fine.

I'd imagine the bigger engine requires a larger radiator? My E320 stays dead center on the temp gauge at all times, without having done any hill climbing (yet) ... seems totally fine to me.
 

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Discussion Starter #5
Nice work,,I presume the coolant was changed too,,,
I think the cooling system is excellent on these cars,,,15 years coolant life is brilliant,,
Both my cars I have replaced coolant with new mb blue...everything else looks like it could do another 15 years easily,,,never heard of a tank rupturing.
Yeah if you're swapping the components you obviously drain first and refill when done.. so yes, fresh coolant. I'd imagine the coolant was definitely changed before... so, while the radiator lasted 15 years, the coolant was changed likely several times (I think I have the records that show at least a couple of coolant flushes)...
 

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What about the water pump?

Currently in the middle of swapping out the E320 radiator for an E500 radiator. Also doing hoses and water pump at the same time. The E320 radiator is the most pathetic thing I've ever seen. Its the same thickness as the AC condenser. The E500 radiator core is more than double the capacity.
You know, after I got home I thought... the water pump is basically the only thing that was not changed. I wonder how long those usually last? They did a full inspection of the car and didn't say anything about it. I presume it's perfectly fine.

I'd imagine the bigger engine requires a larger radiator? My E320 stays dead center on the temp gauge at all times, without having done any hill climbing (yet) ... seems totally fine to me.
My temp gauge stays dead center too (except when I'm towing uphill) because at low speed or any time I'm sitting in traffic the cooling fan is working overtime to make up for the small radiator. 99% of people never notice it until the fan unexpectedly dies. I drive this car pretty hard so I want maximum cooling capacity.

If you're going to invest in the cooling system I would do the water pump too at the same time. Pull the water pump pulley (4 screws) and check the weep hole for any green residue. Or wiggle the water pump pulley to check for play. Mine had a slow leak and a little play. It's dirt cheap so why not. I'm not going to wait for it to fail.
 

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Discussion Starter #7 (Edited)
My temp gauge stays dead center too (except when I'm towing uphill) because at low speed or any time I'm sitting in traffic the cooling fan is working overtime to make up for the small radiator. 99% of people never notice it until the fan unexpectedly dies. I drive this car pretty hard so I want maximum cooling capacity.

If you're going to invest in the cooling system I would do the water pump too at the same time. Pull the water pump pulley (4 screws) and check the weep hole for any green residue. Or wiggle the water pump pulley to check for play. Mine had a slow leak and a little play. It's dirt cheap so why not. I'm not going to wait for it to fail.
Ah, I see what you're saying. Makes sense. Well, the shop took care of everything for me. Never thought to ask them about it. Maybe I will ... not sure if there's a particular test they do or something to check it? Maybe they looked at it, at least I would hope they did.

Edit: Seemed fine for them, spinning freely, no leaks. So I guess that's why a replacement wasn't suggested.
 

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The cluster gauge is dummy gauge, or at least on my 2008 model.
I drove it with temp displayed on climatronic and when going downhill engine cooled down to 75C, the dash gauge did not drop from 82C.
Water pumps can outlast the car, so you never know.
The best preemptive repair is get a new car.
 

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For me a water pump is not a maintenance item....if it ain't broke ,,dont fix it..
The water pump might not be a maintainance item for you but it is a maintainance item for your engine. It ain't broke until it's broke and you're sitting on the side of the road with an overheated engine.
https://youtu.be/OhLqWu5yCK4
 

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I don't think the radiator on the e320 is inadequate. Having a larger radiator isn't always a good thing. If you are doing something that stresses the engine like towing or racing, etc then you DO want a larger radiator. But a radiator that's too large for the engine means the engine is going to struggle to maintain the proper operating temperature and that's not good either.

Remember Mercedes have been using the same engine and radiator since 1998 in the W210. So they believe the setup is fine.
 

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Per my experience MB designs cooling system for pulling 2 tons trailers on Sahara desert in triple digits temperatures and driving E300DT with engine fan removed proves it.
But I am religious on using MB only coolant.
With water pumps you just never know.
Sure when you are doing other jobs, replacing the pump at 250,000 miles might be reasonable, but as pointed above -failing bearings will give you some warning with drip.
 

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Remember Mercedes have been using the same engine and radiator since 1998 in the W210. So they believe the setup is fine.
They didn't use the same radiator on the W210 E320. That radiator core is 32mm thick. I've worked on a lot of MBs and I've never encountered a 16mm radiator core before this 04 E320. I'm not sure how a 34mm radiator core could "over cool" an engine with a functioning thermostat but I'd love to hear more about that theory.
driving E300DT with engine fan removed proves it.
E300 diesel has a 40mm radiator core from the factory. But I've got this fancy new and improved 16mm radiator just gathering dust in my garage. I think you should try it in your fanless E300. Its no thicker than your AC condenser. I head it does wonders for your engine's cooling system.
 

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For radiators it is frontal surface and number of rows that counts for heat exchange.
Obviously thicker radiator might indicate more rows, but not necessary.
I also did remove the only fan on Fiat 125 and drove it just fine without it.
But that was in Poland, where we did not see triple digits temperatures.
So once again, I never had any signs of MB overheating even I routinely drive in temp above 100F and some of my cars had high 200's thousands miles. .
I prize MB coolant for high efficiency and used it even in my trucks.
First result was that truck engine visco fan stop coming on in city traffic. Those fans were over 20 hp rated, so you could definitely tell when they are on.
That not only made driving more comfortable, but saved fuel as well.
Consider that before trying to save 5 bucks on Zerex
 

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I'm not sure how a 34mm radiator core could "over cool" an engine with a functioning thermostat but I'd love to hear more about that theory.
The same reason why people that live in extremely cold climates block off part off their grill or radiator. Too much cooling is not good. The thermostat won't be able to keep up with the extra unneeded cooling.

How do you explain the E320's not over heating? If the radiator was too small then why hasn't anyone had a problem?
 

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Had radiator, upper and lower hoses, bleeder line, and expansion tank all totally swapped for brand new stuff.

Apparently the expansion tank is lovingly referred to as the 'explosion tank' by the auto techs. Eventually they'll just burst from the constant expanding/contracting with the heat and pressure, etc.

Should be all set for at least another 15 years, I guess. I suppose it's definitely suggested that if you're replacing the radiator just go ahead and do all those other items as well so you don't need to go back and drain/refill and replace the expansion tank when that decides to go.

Hopefully that was the largest repair bill I'll have to deal with for some time. :eek
Horrid! Only 15 years. Should last 30 years or more with other than annual coolant changes and occasional coolant hose replacements. No reason for the radiator or expansion tank to have failed that fast unless you've been filling it with salt water.
 
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