New water pump, green coolant, 90C - PeachParts Mercedes-Benz Forum

95E320cab · #1 12-09-2002, 09:01 AM

Had a new (rebuilt?) pump installed last week. When I picked up the car the indie had the hood up, the A/C on, and the car idling. The temp gauge was at 90C. The tech said "pretty good for idling for 45 min. with the A/C on". I agreed. However, I noticed driving over the weekend that the temp runs at 90C, without air on, around town. Before the pump the temp ran just over 80C. I was shocked to see the green coolant when I picked the car up, especially since I had gone to the dealer and bought a gallon of MB coolant before dropping the car off. Left it in the floorboard. Should I as them to change it out? Will it lower the operating temp? The tech said it was important not to mix the coolants, but that the green was okay. They did not change the thermostat out, only the serpentine belt.

Thanks, Dave

euro 287 · #2 12-09-2002, 11:18 AM

It is best when doing such repairs as water pump or radiator to change the thermostate at this time. I prefer the benz coolant over any other. Also make sure the auxilary fans are working with the air on. In your case you said temp stayed same with air or not, I would look at doing the thermostate for insurance, 90 on a warm day idling isnt too far off the scale but I would rather have a known good thermostate than have one leave me stranded.

Kestas · #3 12-09-2002, 11:36 AM

What was the agreement when you brought the car in? I've heard of others using the green stuff, but I get the impression that dealer coolant is better for the car. These things should be put in writing when doing business.

Coolant capacity is 10 quarts for the E320. There should be a minimum of 5 quarts coolant added during a changeout. I would've left two gallons.

#4 12-09-2002, 11:34 PM

Quote:

Originally posted by 95E320cab
Had a new (rebuilt?) pump installed last week. When I picked up the car the indie had the hood up, the A/C on, and the car idling. The temp gauge was at 90C. The tech said "pretty good for idling for 45 min. with the A/C on". I agreed. However, I noticed driving over the weekend that the temp runs at 90C, without air on, around town. Before the pump the temp ran just over 80C. I was shocked to see the green coolant when I picked the car up, especially since I had gone to the dealer and bought a gallon of MB coolant before dropping the car off. Left it in the floorboard. Should I as them to change it out? Will it lower the operating temp? The tech said it was important not to mix the coolants, but that the green was okay. They did not change the thermostat out, only the serpentine belt.

Thanks, Dave

The operating temp is not due to the green coolant necessarily probably, due to not mixing it correctly with water. A simple way of mixing it correctly is pour a cup of water and a cup of coolant after each other. Mxing by shaking both in a bottle is another mehtod also obviously. Another is that there is actually more coolant than water.. Air bubbles from intial fill have to be bled out. That is another possibiltiy. These are simple remedies.

The bad news is that it is required on your car to use only MB coolant or something equivalent due, to the aluminum heads, radiator, and other parts of the engine that consists of aluminum. Look in your MB owner's packet. Better backflush or flush the engine out of any remains of the green coolant.

euro 287 · #5 12-10-2002, 12:07 AM

OK sorry guys had to throw this one in here, on soem late models it will make a differance in not using MB coolant. I know a tech who had a ML causing a temp problem after water pump replaced he worked for the MB dealer. They cked everything replaced clusters ,harness' ect spent alot of time in it tryin to fix inaccurate reading of temp. Well the factory rep was sittin there lookin at this car and he said ( hey why is the coolant green?) they changed the coolant and it fixed the problem with gauge readings. Now thats not sayin its the coolant in your car that is your problem, but I prefer the benz stuff. I have put the green stuff in and never had any problems on the older ones. Just go with your gut , mine would say pop a thermostate in that dude and flush that system and fill with benz coolant.

LuckyF8 · #6 12-10-2002, 12:14 AM

You can mix and match whatever, half & half, none & some, and still it's probably not the problem.

Green, Pink, Yellow......

Green is ok, my 4.5, 30year old aluminum shines nicely with the green glow, but it runs 10 over all the time, I have replaced everything short of the water pump, and I wont let um take it off even for inspection, its a virgin with 117,000 miles, still looks like NEW!

Over the years I have seen some MBZ come into the shop with bad water pumps and go home with one running warm.

They don't overheat, just run warm. So after over 27 years of this we throw up our hands and say oh well.

I have read a lot of threads here about it........still unsolved mystery.

I had to put a water pump on my 300ce, M104 motor, last week, and NEW is all you can get for this motor.

Lucky for me it's running cool as always, with green stuff.

Sorry your coupe is running warm, hope it's something simple.

#7 12-10-2002, 08:00 AM

I have to wonder if heating is a coolent problem... If the system is clean inside most any of the coolents today will work, (IMHO)... One thing that will often help a system is putting a cleaner thru it.. some times they get traces of oils in them.. That will make them run warmer..

But besides driving old Mercedes from the mid 50s I am also a motorcycle fan.. And own and run several.. They get far more miles than the cars do.. And most of todays up scale motorcycles are water cooled... One thing that I have learned about Coolent is that the green stuff.. has silica in it.... Thats a fine sand so to say.. It helps polish the inside and keep it clean.. No I can not feel it.. The longer life stuff.. DEX-COOL... Does not.. Thats the pink stuff... Any way.. Seems on motorcycle engines the Silica eats the seals .. Most seals these days on water pumps are carbon.. with springs to hold them together until they wear out.. They run in the coolent to keep them cool.. Long gone are the old rubber seals .... Even on the replacement pumps in my old 123 Diesels.. I would bet that the Mercedes Coolent has no Silica and is low PH like the ones General motors insist on in their newer cars.. Water pump seals were an issue before starting to use DEX-Cool some years back in my old cars and bikes.. Now they seem to last as long as the bearings in them hold up and never leak.. The inside of the system seems to show no difference.. Still very clean.. I change at 2 or 3 years even if the new stuff is 5 year or so stuff..

In case you can not get Mercedes Coolent or do not wish to buy it...I would lean to getting the Dex-Cool (Pink stuff) made by most any coolent company and kind of stay away from the green stuff.. Its not bad stuff.. Just seems a lot harder on the water pump seals and the plastic parts used in cooling systems these days... I have also noticed that I have lots fewer problems with the small pump that runs the heater water leaking.. They too have the carbon seal..

I still see no difference in cooling as far as whitch kind it is.. Just so its the right amount and system is clean (No oil in system.. They all need cleaning from time to time) and pumps work right.. belts right.. fan clutch works right.. Electric fans come on when needed.. Hoses do not kink..

Ken

95E320cab · #8 12-10-2002, 08:00 AM

I am reading all your posts as they come in. Thank you. I am going to take a printout of all to the mechanic when I ask them to flush, replace thermostat, and replace the green with MB antifreeze. More responses are welcomed!

jsmith · #9 12-10-2002, 08:52 AM

as Luckyf8 says this is a common mystery that hasn't been solved. happened to me too after head gasket job - thermostat started sticking. replacing with new Behr 87C produced constant 90C with 95-100C+ in heavy stop and go traffic. a couple of things that have been mentioned in the past are replacing the pressure cap which i haven't done yet and checking / replacing the overflow line from the reservoir that goes into the wheel well. if the coolant concentration is greater than 50% it's worth a couple of degrees taking it down to 40% with some water wetter added for good measure (but not significantly so in my experience). i myself have resorted to an 83C thermostat which has brought back the 80-85C temps i was accustomed to. i should have tried the cap first and i may do that anyway...

95E320cab · #10 12-10-2002, 09:08 AM

Here is a little more clarification on my car's operating temperature. Prior to the new water pump and antifreeze change, the car ran at just over 80C most of the time, including summer (HOT in Dallas ambient temperatures). The RARE exception was stop and go traffic where I would see temperatures approaching 90-95C in the dog days of August.

Now, I see 90C almost all the time. The ambient temperature since the waterpump and antifreeze was replaced has not been over 50F. I am almost sure that with warm/hot weather, the operating temperature will be above 90C, which I consider totally unacceptable. I must mention that at highway speeds in this cooler weather we are having now, the operating temperature drops to a normal 80C.

Thanks for your interest!

jsmith · #11 12-10-2002, 09:12 AM

idling with ac on is not really a good test because the engine is in a steady state. with the aux fan on at low speed the heat is being dumped by the radiator adequately. i would be more interested in heavy stop and go or prolonged cruising followed by stop and go. this really loads up the cooling system and is a better test...

Kestas · #12 12-10-2002, 09:15 AM

Quote:

Originally posted by Ken Downing
One thing that I have learned about Coolent is that the green stuff.. has silica in it.... Thats a fine sand so to say.. It helps polish the inside and keep it clean.. No I can not feel it

Just to clear up any misconceptions, the silica in glycol coolants is in the form of sodium silicate (water glass), not silicon oxide (sand). The sodium silicate plates from solution onto the water jacket surfaces, thus protecting the surface from corrosion. That's why a properly maintained cooling system looks clean and shiny.

I've been paid good money by the automotive manufacturers to look at issues involving sodium silicate. I've examined it in the lab using microscopy methods, and can tell you it is not nearly as abrasive as sand. In fact, it has a consistancy more like talc, which is so soft, under some conditions it is sometimes considered a solid lubricant.

Data shows glycol coolant loses its corrosion protection after 30,000 miles. That's why regular coolant changes are so important.

I don't know if MBZ dealer coolant has sodium silicate. I'll check the jugs in my basement to see if it's listed as an ingredient.

#13 12-10-2002, 09:16 AM

After a blown head gasket.. or just after years you need to clean the system.. MB has cleaners and others are on the market.. You need to get the oil film out of the cooling system.. If you coat the inside of the cooling system with a film of oil.. It will not exchange heat as well.. Thats fact.. Often a system that just heats some and every thing else is right just needs to have the oils that have gotten inside cleaned out.. Just changing coolent will not do the job.. and they always need to be cleaned after replacing head gaskets, radiatior, ect.. All the engines of the last 15 or more years have computers of some type.. If you run them cooler than they call for they will not perform well as the computer does not take over until they are up to the given temp.. Below that they stay on a start up program.. So its best to stay with the Thermostat Called for on your car..

Ken

95E320cab · #14 12-11-2002, 09:43 AM

Think I'll order myself a new thermostat. They're cheap. Behr or Wahler preferred? They look different in the online catalog, too. How do I know which fits?

Thanks for all the good posts!

suginami · #15 12-11-2002, 01:57 PM

Quote:

Originally posted by tkamiya
Mine is a 1994 E320. Basically identical car to yours. I live in Central Florida.

My car usually warms up to about 80C.
After some city driving, it goes to 90C.
After extended stop, it goes to 100C.
On rare ocassions, I've seen 102C.
On prolonged highway driving, it goes down to 82C.
A stop after prolonged highway driving, it goes quickly to 100C.
Highest I've ever seen was 108 or so when my AUX fan fuse was blown.

This is true regardless of ambient temperature.

Hotter the outside, faster it goes to higher temp and slower it goes to lower temp, but min and max doesn't seem to change much.

It's been this way for 2 years I owned this car.... and my cooling system has been checked and rechecked by a professional mechanic.

It's interesting that your operating temp changed after a surgery, but seeing 90C is not at all unusual. I'm just trying to tell you all this, so that you won't spend your money trying to fix phantom problem.

I have a '93 and it is the same car as TKamiya's '94, which is the same as your '95 E320 Cabriolet. My car runs at exactly the same temperature in the same conditions.