100% radiator fluid in the radiator?? Is that ok?
 

I had a leak recently, thought it was the lower radiator hose. Got the parts, upper AND lower hoses (no sense having a hose burst on you in 10 degree weather at night, on some back country road where the next house is 2 miles away, just change them both), took it to some mechanic for a flush and hose change. He looked at the radiator closely (thank God), and said it was rotting; the hose wasn't the problem.

I ordered a new radiator, went back today. He changed out the radiator and hoses, and to my surprise, he filled it up with 100% radiator fluid. I thought it was supposed to be a 50/50 mix of that with water. He said 100% radiator fluid is better. You can go to Alaska and not have a problem, and there won't be any rust in the radiator. I don't know how there could be rust anyways; the inside is plastic.

Bottom line, he said pure radiator fluid is better than a mix. Is that true?

Jeff 1991 300d, 116k

Jeff

no dont ever go back to that guy again. Also did he use the right fluid the orange not the green. If its green get it out and go to another mechanic who knows what he is doing.

It's MB fluid
 

I didn't look at the color of it, but it's Mercedes radiator fluid.

jeff

well get some of the fluid out and put in some distilled water. I dont care where you live it will never get cold enough to freeze the coolant. The 50/50 solution will go down to -34 degrees so get it out and replace with water. I have heard of trucks running 100% antifreeze and overheating. Coolant itself is a poor conductor of heat so the car will over heat with it only.

5050 is the accepted standard. It is supposed to cool better than just antifreeze alone or just water alone, IIRC.

Tom W

O and get a bottle of wetter water from the parts store it will condition seals lower temperature and will prevent further rust more than just antifreeze alone.

Straight coolant will freeze before 50/50 will. Straight water will carry more heat (for a while), but you will get rust and scale buildup that will reduce cooling efficiency. Most of the literature I've seen says to run 50/50 for general use, down to 33/67 in hot weather if overheating is a problem. Most of the books say 70% coolant is the max you ever want to run.

What kind of coolant did he put in your system, make sure it is the right stuff. Get either the MB coolant (which is a yellowish-orange) and pay more for it, or pick up some Zerex G-05 (same stuff but almost clear in color).

It is better to have mix, the proportions of which will be determined by how much freeze/boil protection you want/need; however, nearly everyone will do fine with a 50/50 mix. Your mechanic was right about one thing, you could go to northern Alaska, where temps can reach -50 F and you would be okay with 100% coolant. However, I think he probably just wanted to charge you more to fill 'er up with straight coolant.

The Zerex specs are as follows:

40% coolant = -12 F freeze point and 260 F boil point
50% coolant = -34 F freeze point and 265 F boil point
70%* coolant = -90 F freeze point and 277 F boil point**

*70% is the maximum protection point
**boil point assumes a 15 psi radiator cap

I just did a drain and flush on my system because the PO had just had a flush done in prep for the sale. Unfotunately there was 100% green stuff in there. Not only do you not want the green stuff (doesn't provide enough protection for diesels and the various metal types of the cooling system), but I also believe there might be some disadvantage to running straight coolant - don't recall what off the top of my head, maybe a pH issue.

You should just drain out about a gallon and save it for later (if it is the right stuff) and then add a gallon of distilled water.

To find out the percentage of coolant/water mix. there is a little gizmo
that the part houses have. It has a rubber bulb and some colored balls
that float, kind of like a mini turkey baster.

This way there is no guess work.

Charlie

I think some jugs of antifreeze come pre-mixed at 50/50. If it has MB on the outside, should be OK.

Take it back to him and demand he put a 5050 mix in it. 100% coolant only has about 60% the cooling capacity of a 5050 mix.

Are you joking? He put 100% antifreeze into the cooling system? We used to make fun of people like him in shop class!:D

1. Never go back to this guy ever. I wouldn't trust him to tighten a hose clamp.
2. Take it to another shop, have them replace it with the proper mixture.

Only coolant will cause it to overheat, amoung other really cool problems.

Coolant is thicker than water - I've always heard it will increase the wear on your waterpump and shorten its life.

What's a house clamp? :D

Maybe he had one of those "pre-mixed" bottles of radiator fluid/water?...

Maybe he's just a moron.