97 E420 - w210 - Engine Cooling SOS!!! - PeachParts Mercedes-Benz Forum

asyrov · #1 08-23-2004, 12:51 PM

Have a problem with engine Temperature....
Cold day keeps ~ 100C (212F), hot day goes to ~120C (248F)

I'm trying to figure out if it is the cooling system itself (does not cool the engine enough) or Engine (generating too much heat)...

If it is the cooling I have only 1 thing left that is not replaced - Water Pump. Is it possible that water pump is working but just not pushing coolant fast enough?

P.S. All the fans are working and kicking in properly

Cooling system parts replaced:
-Fan Clutch
-AC Thermostat
-Front Fans
-Radiator
-Radiator Top Hose
-Engine Thermostat (replaced twice)

y2kimmel · #2 08-23-2004, 02:22 PM

My 1995 E420 was running hot - not quite as hot as your, but close. it has essentially the same engine. I was able to attach a resistor to my coolant temperature sensor - now my car thinks that the coolant is warmer than it actually is - and activates the electric fans to keep the engine cool.

I first replaced my electric fan power resistor (it allows for low speed fan operation by running some of the current through a power resistor). I'm not sure if the 1997 has the power resistor like the W124 has. Perhaps a W210 E420 owner could chime in and help.

So - check for the power resistor (it might be bad), then check to see if your model allows for adjustment of the coolant temp. sensor's resistance.

Regards,
Troy K.
1995 E420
83k

asyrov · #3 08-23-2004, 02:30 PM

all the fans are operational, I'm not sure how would resistors make any difference since fans are getting to the full speed (and it does not help).

on 100 (212F) front fans (grille fans) are kicking in and getting variable speed depending on the engine temp (much faster speed when engine goes ~ 110C)

Inside fan is rotating as well (just changed the fan clutch).

Thank you for the idea though...

00ML430 Bulldog · #4 08-23-2004, 02:59 PM

Quote:

Originally Posted by asyrov

Have a problem with engine Temperature....
Cold day keeps ~ 100C (212F), hot day goes to ~120C (248F)

I'm trying to figure out if it is the cooling system itself (does not cool the engine enough) or Engine (generating too much heat)...

If it is the cooling I have only 1 thing left that is not replaced - Water Pump. Is it possible that water pump is working but just not pushing coolant fast enough?

P.S. All the fans are working and kicking in properly

Cooling system parts replaced:
-Fan Clutch
-AC Thermostat
-Front Fans
-Radiator
-Radiator Top Hose
-Engine Thermostat (replace twice)

Did you try flushing the radiator and installing new fresh coolant

asyrov · #5 08-23-2004, 03:14 PM

Never tried....., but I think after all the work done in the system most of the coolant has been replaced already

- Last year replaced radiator
- This year replaced hoses
- 2 replacements for the thermostat

y2kimmel · #6 08-23-2004, 03:58 PM

Maybe the water pump truly is the last resort. I can't imaging that, however, as the failure mode for a water pump tends to be bearings seizing or bearing seal leaks - not impeller failure.

Is there a cooling system bleeding procedure for your car? Perhaps you have air trapped in the system? I seem to remember that thes enegines are auto-compensting, but I could be wrong.

Best of luck. You could always just wait for cooler weather to solve your problem too.

Troy
1995 E420
83k

Gilly · #7 08-23-2004, 08:09 PM

First make sure the temperture gauge is working correctly, maybe you only think it's getting too hot.
You also have to be very careful in your assesment of the aux fans: with the engine off, turn the left (drivers side) fan hub and make sure that BOTH of the fans are rotating, the drivers side drives the passengers side via a thin grooved belt. When you are seeing both of them rotating, it can be the engine fan sucking air through the radiator that is making the other fan rotate.
A few other things: The apparent speed of the aux fan can be a very subjective thing, at 100% speed it should be absolutely "howling". The fan or fan controller may be a problem.
You should also ensure that there isn't alot of dirt and garbage build-up between the AC condensor and the radiator, it can collect quite badly between there and you can't normally see it.
Does it cool properly at highway speeds?
Gilly

asyrov · #8 08-23-2004, 09:45 PM

The gauge is OK since guess what happens after 120C

yes... you are right you can hear the boiling in the coolant tank and some coolant can be seen outside (pressure is pushing it out through the coolant tank safety opening.

Both of the fans are rotating. I changed the driver side fan last year (fall) and made sure all assembly is functioning properly. I just double checked fans yesterday.

Yes, at full speed (110C) you can hear the front fans rotating from the inside of the car (with radio off)

There is no dirt at all in the front or in the back of the radiator.

At highway speed I can hardly keep it 95C-100C.

I have a check engine on (but I checked on the computer and this is related to Air Flow Meter)

Thank you for helping me.

Gilly · #9 08-23-2004, 10:07 PM

Possibly a blown headgasket, I'd have someone check the coolant for CO.

Gilly

asyrov · #10 08-23-2004, 10:26 PM

Could you please give me some details on how can one check for CO in coolant. I mean are there any tools that I can buy and check myself?... I'm OK with my mechanic replacing the gasket, however I would like to make sure that this will fix the problem.

Gilly · #11 08-24-2004, 10:18 PM

Pretty expensive tool, it's a CO meter or "detector" as they're referred to as. (CO is of course carbon monoxide). If you had one of these you'd warm the engine up with the radiator (pressure) cap and analyze the vapors coming out of the tank. No I sure wouldn't replace anything on this hunch.

Gilly

asyrov · #12 08-27-2004, 02:29 PM

Did a cooling system flush.
After the flush filled it with 1 gallon of MB Original Antifreeze and 1gallon of distilled water.

Still having the same symptoms.
While on the highway, I can keep engine ~ 100C, however on long traffic lights temperature is getting really high.

During the flush I checked for spots of oil in the coolant, however everything was clean, I also checked for pressure buildup in the upper radiator hose (when engine is still cold) and did not notice any pressure there.

I need to check for CO level in coolant, but I have no idea how to do this.
Can somebody give me an idea how to do this (what tool will I need to get)

Gilly · #13 08-27-2004, 10:12 PM

Pretty expensive tool, it's a CO meter or "detector" as they're referred to as. (CO is of course carbon monoxide). If you had one of these you'd warm the engine up with the radiator (pressure) cap and analyze the vapors coming out of the tank. No I sure wouldn't replace anything on this hunch.

psfred · #14 08-27-2004, 10:51 PM

It's pretty young for this, but could you have a clogged radiator? Poor coolant circulation will surely make it overheat.

Peter

BenzRepair · #15 08-27-2004, 11:03 PM

An IR or heat-detecting digital indicator is an indispensable tool for under $100 to check heat differential at the radiator hoses. The appropriate CO detector to purchase is a 2-chamber liquid design that uses special fluid which changes color when exposed to CO; you can purchase this through Snap-on, Matco, or better automotive tool stores for around $80.