'87 300D, purchased in August 2001. The car has always run warmer than I thought it should, by 5-10C. I have a receipt from the prev. owner for a radiator in Feb'00 and Mar'00 - coolant leak and towing charges each time. Its a star marked Behr. In Apr'01 the prev. owner changed the coolant to decool. In Oct-Nov'01 one morning after it got cold, I had to fill the coolant resevoir because it went dry (coolant light was on when I started it in the mroning). In Jan'01 I flushed the system with prestone flush, changed the t-stat, filled with 50/50 MB coolant and distilled water, and changed the ATF while I was at it. That dropped the temp about 5C - it never goes past 100C. (I think there was too much coolant and not enough water). Last night I flushed the system again, with MB citric acid powder. I noticed there were hot/cold spots in the radiatior, and the mechanic confirmed it this morning. Now, with 100% distilled water and 50F ambient temps car runs 95-99C on the freeway with the heater on MAX. The coolant comes out clean, the car idles smooth and has plenty of power. There are no unusual exhaust smoking problems.

Is this a sign of problems to come? What's going on?

I'm all set to buy a Nissens radiator instead of a Behr, I hear they are just as good and cheaper.

thanks,
Brian

My mechanic is Danish. He says Nissens, a Danish company, can't build a radiator. Use only Behr.

FWIW, contact Reseda Radiator (http://www.resedaradiator.com) For $125 they can give you a rebuilt (new tanks w/neck reinforcements), rodded, flow and pressure tested radiator.

Most likely, yours is in stock. Otherwise, it's a one-day turn-around if call ahead.

I did this for my 500E and it is keeping the temperatures under control now. Sure beats spending almost $400 for a new Behr.

:-) neil
1988 360TE AMG
1993 500E

BTW: run 60% distilled water, 40% MB antifreeze, and one-bottle of Redline Water Wetter.

Don't every run 100% distilled water. It is corrosive at 100%!

I took the car in for the new radiator because it also needed new A/C condensor. The owner/mechanic said Nissens are junk and leak, he tried one on his wife's car. He doesn't like Behr much either, but believes they are worth it. Got the car back yesterday. 30F outside and the car runs 98C on the interstate. This is about the same as it was before the new radiator was installed. Around town it was running 80-90C mostly. Sitting at a stoplight long enough and the temp would drop to 80C. Climbing a long, winding hill at 45 then stopping to turn left and the temp gauge reads 100C and then cools down.

Before the new rad went in I ran a few types of flush thru the system and each one came out dirty. Prestone Super Radiator Flush + 100% water came out so dirty that I could not see thru it. I don't know if that's just a chemical reaction from marketing or it was actually doing something

I changed the t-stat in January, ordered from here (Wahler).

In the cold weather we are having, it seems that it works fine around town at but on the highway I think it should run about 90-95C even on long grades in this weather.

Any ideas as to what i should be looking for?

Brian

With regards to temperature, diesels are opposite of gasonline engines. It is not uncommon for diesels to cool down at a red light, particularly in very cold conditions. New Volkswagen TDI diesels do this as well. Diesels also like to run hot. Diesels like to work.

Its my understanding that 603.960 engines rarely need water pumps.

My mechanic has an infrared temerature sensor so I will ask him to look it over. Its possible the thermostat is not working correctly (not opening fully?) so I will try changing that as well.

Brian

i cant tell you about your problems to come(if any)but i can tell you that the Behr is the only way to go .
the neck on my original rad snaped ,so i was faced with the Nissens or Behr.
300 for the Nissens 600 for the Behr
i first ordered the nissens.it arrived damaged.(crushed on the bottom).the second one came the same way,so i took it as a sign .finally ordered the behr.
putting them side by side the behr just looks like superior product hands down!! the behr was sleeved and the nissens wasnt.
im glad i went with the Behr,even for double the money

__________________
1992 500E silver
1990 300ce AMG
1993 500e smoke silver-sold
1992 500e sold pearl black-sold
1966 mustang converible 289
1969 camaro x11
1991 ZR-1
1972 corvette roadster
2000 dodge cummins 4x4 sold
1994 e320 sold
1987 560sec Brabus
1987 300E (my first benz)

Maybe an oversimplified version, but diesels are more efficient. They produce less waste energy (heat) - can be measured by lower EGT, lower coolant temperatures, lower fuel consumption.

Brian

Maybe an oversimplified version, but diesels are more efficient. They produce less waste energy (heat) - can be measured by lower EGT, lower coolant temperatures, lower fuel consumption.

Brian

You don't want to hear this and you don't want to think about this, but. If you do a search of the posts on this sight you will notice that there are more than a few that start like this one and end with a leaking head gasket or for these 603 motors cracked head endings. Some believe that the higher temps occur when the engine is running hard because hot combustion products can get forced into the cooling system increasing temps, some believe that gases replacing coolant in the head spaces allow localized overheating or at least localized temperature disparities that contribute to head cracking. I've got an 87 SDL that has been temp freaking, that I'm about to pull the head on so I can check the gasket and for cracks. These heads and the gaskets have been redesigned numerous times each. It may be coincidental but I started to notice my car's symptoms soon after I rehabbed my turbo boost system. The boost control pipe from the manifold was plugged with carbon, I cleaned it and the restored boost was working better than ever, I wonder if the renewed increase turbo function stressed the engine causing a head gasket leak/failure? I'll know something when I pull the head this week.


P. S. Why do you think your radiator is "plugged", the increased temp? Could be at least a couple other cheaper things, no?

And whats up with the distilled water being corrosive? I'm not questioning if that's true, I'm wondering actually the how and why of that, I don't understand.

I'm prepared for a head job on this car. Once the cheap stuff was done, i.e. verifying engine fan, flushing system, changing t-stat, was done and the problem did not go away and seeing brown sewage lining the upper radiator connection to the block I thought the radiator might be plugged up. I noticed that it was not an even temperature, asked a mechanic for his opinion and he agreed that it was not in great condition. I didn't think the rad would solve 100% of my problem, but believed it was part of the problem and neede to be done AND the A/C condensor needs to be replaced, which requires moving/touching the radiator anyway.

Since I've never had a cooling system get plugged up before, I'm wondering if deposits are causing the slightly higher temperatures? The flushes I ran thru the system seemed to "loosen up" the deposits, but did not comletely remove them.

I see NO oil in the coolant and no coolant in the oil. The turbo boost sense line was cleared maybe 45000 miles ago before I purchased the car. And I'm pretty sure the coolant temp has run about the same (actually, its SERVERAL degrees lower than before my first coolant flush in Junuary) since I purchased the car, about 33000 miles ago.

The chemistry of distilled water is such that it attracts metals since its so pure. Regular tap water has a small % of stuff in it that keeps it happy. Antrifreeze + distilled water is a happy combination.

Brian

I boiled the Wahler thermostats (the one that came with the car, and the one that I installed in January) and concluded that I need a better method of boiling thermostats! However, both seemed to operate just about the same. While those were cooling down, I found the dealer thermostat I bought and installed it. It was getting late and I did not have time to boil it for comparison. Now the car runs at 90C on the interstate in 80F weather. So, it would seem that my problem is fixed, OR (pessimistic) that this thermostat opens too soon and I still have problems For time time being I'm leaving things as they are.

Brian