w124 cooling problem
 

Hi all,

My e220 is in a tropical weather Singapore and the engine tends to get really hot. I have modified the fan to switch on at a lower temperature. What other options do I have.

I was asked to:

1. Add a SPAL fan to improve cooling.
2. Add a engine oil cooler.

Any comments on what is the best and most cost effective, coz I am not sure what the compatibility of after market fans (in terms of airflow) to the original one when I place them one behind the other :confused: . Also, the only oil cooler I found is from renntech (E500) and it costs a bomb...and I am not sure if it fits.

How hot does the engine get? If the radiator tubes are completely clean and the water pump vanes are not worn, then it should stay within operating limits. If not, then an oversized radiator would probably be your best bet if one is available. I would first start by determining that the cooling system you currently have is operating properly and that the actual engine temp is, in fact beyond its design operating limits.

In Hong Kong, many people take off the thermostat. Then, add a fan!!! Finally, oversize radiator!

If you take out the thermostat, it will overheat for sure!

Check the system for pressure when hot -- it's somewhat likely that the pressure cap on the reservoir tank has gone bad and is not holding pressure anymore. This will cause overheating because the coolant will boil in the head, and the steam won't tranfer the heat to the rad.

Also, make sure the visco clutch is working. Fan must move large amounts of air and "roar" when the rad is hot, if not, replace. Easy way to check is to shut the engine off while hot (90C or more) and watch the fan. If it turns more than one revolution after the engine stops, the clutch is bad.

You may also have a bad radiator. Best way to check that is an infared thermometer, make sure there are no "cold" spots in it.

Peter

No thermostat means it would run cooler

No thermostat means it would run cooler
SORRY, not in a Mercedes. The thermostat has TWO plates, main coolant circuit is closed when cold by one plate, the secondary(or bypass)circuit is open, forcing ALL coolant to flow thru block and head. When the main circuit opens as the engine warms up, the bypass progressively closes, forcing ALL coolant thru the radiator.If there is no thermostat, or a slightly leaking one, there will be reduced flow thru rad and higher engine temps.
I concur with psfred, check the simple stuff first.
You do not describe the operating conditions that bring about the *high temp* nor the body type, year or engine (M111 or M102 or....)
If you have the temp rising in stop start traffic, checking or changing the visco fan clutch may be the answer. Check with the parts suppliers for the *tropical fan clutch* that Sachs supply.
If it keeps rising when screaming along at 160kmh, you need a bigger capacity radiator, either more tubes per inch(denser) OR the biggest assembly that will fit in the space ;)
Do not waste your time and money on an oil cooler.
Been there, done that :D

Whan I had my BMW with a similar problem, I installed a manual switch for the auxiliary fan under the dash, which I turned on when needed. Of course, it was a temporary solution until I found out what the real problem was (fan clutch)...

Keep the coolant to water ratio at the absolute minimum. The more water, the greater the cooling/heat transfer capacity.

Singapore hotty
 

MBZ makes a tropical climate radiator and fan and fan clutch. The fan moves more air, the radiator has more heat rejection capacity.

You should stay with 50:50 coolant:water, else the boiling point will drop and it will boil instead of circulate -- this is a tropical application.

You can remove the thermostat in other cars, but will still get overheating problems in most -- the coolant will circulate too quickly, so it won't pick up enough heat in the engine and won't loose enough heat in the radiator!

Peter

Wrong assumption
 

Antifreeze does just that...keeps the coolant from freezing at low temperatures when the car is sitting idle and not running. It doesn't raise the boiling point of the coolant at all, the system pressure does that with the sealed system.

Water has better heat transfer capacity, and thus can remove more heat from the motor. Personally, I prefer ratios around 60:40 or 66:33 because I live in a desert with high temperatures and little freezing.

Anti-freeze does raise the boiling point and lower the freeze point ,but as mentioned above, does not dissipate heat well at all.

I live in a hot climate where winter is non-existent. Using an approx. 30% coolant-70% water mixture, I see reduced temps as reported by the temp. gauge. This reduction is in the 5-8 degree F range.

Every little bit helps.

I beg to differ -- freezing point depression and boiling point elevation are very closesly related, and a 50:50 mix of ethylene glycol and water will not boil (at sea level) until around 230F. With the pressure in the cooling system, it won't boil until about 240F, I believe. Boiling point of pure water is 212F. Pressurizing the cooling system will only raise the boiling point to 220 F. This isn't adequate, as the water will boil inside the head where the surface is considerably hotter than the coolant in bulk ever gets, insulating the head from the coolant and causing severe overheating.

I strongly recommend using 50:50 antifreeze mix in the tropics for protection against boilover -- the minimal reduction in heat transfer ability should be compensated for by the use of a tropical radiator (larger than "normal" for temperate zones), not by using plain water. If the tropical radiator doesn't do the trick and there isn't anything wrong with the engine (ie good head gasket, engine KNOWN to be free of scale, etc), an oil cooler is an excellent idea. This will remove considerable heat from the oil, resulting in both less engine heat AND better lubrication. Most older MB's had oil coolers (all the diesel do anyway), but if one isn't present or the factory one is too small, an aftermarket on is a good idea.

Plain water without an anticorrosion package equivalent to the anticorrosion chemicals in the antifreeze will result in serious corrosion of the aluminum parts of the engine, too.

Peter

You can differ all you like. It's a fact that coolant does not transfer heat well and for those of us in a warm climate, a reduced concentration helps keep the needle from climbing.

Now let's bury this and move on.

compare radiator sizes for your car and other 124s. if the bigger engined cars havea bigger radiator thats the first thing i would do.
use less anti freeze in the coolant. unlike what some people here think it doesnt have good heat transfe capability. i use 100% water in my car. but i live in sunny southern california.
keep your car tuned up.

you can use any oil cooler as long as you hook it up correctly. yuo do not have to buy a mercedes unit, it could be a vw, citroen, toyota unit as long as it looks like a mini radiator and can flow oil its an oil cooler. install behind the bumper, use appropriate hoses keep oil fresh.

also, using an oil cooler will allow you to add a little more oil aiding in heat transfer.