Coolant Change on W210
 

What are the current thoughts on when to change radiator coolant and hoses?

My '98 E320 has about 65K miles with original coolant and hoses. The car does not have any coolant problems. Should I flush the radiator and change the coolant/hoses? Or, should I leave well enough alone and not loosen up the potential rust and crud?

Thanks.

On the subject of hoses, I don't know of a set interval, but my 20 year old TD still has it's original hoses. My first Mercedes was a 1980 300SD. I bought that car when it was 20 yrs old. It to had it's original hoses, which I promptly replaced. When I removed them, the insides were perfect, not a thing wrong with them. Remember, hoses rot from the inside out. I think as long as the hoses don't have soft spots and they look good inside, keep them on.

I agree that hoses are made much better than a few decades ago. I too used to change all the hoses as a preventive measure. Now when I do it, the hoses seem rather healthy and I realize I'm wasting time and resources. IMO, Five years and 65,000 miles may be a bit too early (we live in the same climate). Ten years/100,000 miles may be more appropriate. As long as you keep poking your nose under the hood, you should be okay.

But you should go ahead with a coolant flush and fill every two or three years. If read betwen the lines correctly, you may have heard stories where people flushed their neglected radiators, only to find that they flushed out crud that sealed the leaks and now the radiator leaks (happened to me twice). This is poor use of logic. You should flush any accumulated crud out to prevent poultice corrosion - both radiator and engine water passages. If the radiator leaks afterward, then you were "skating on thin ice" with the old radiator anyhow, and are forced to make a repair that could have happened on the road.

Do the flush every 3 years. Inspect the hoses with every service job, and if they don't feel "soft" I wouldn't worry about replacement. Keep an eye out for signs of seepage at the hose ends. If you see signs of the hose seeping (either actual coolant loss or the chalky white/yellow residue) then attempt to tighten the appropriate clamp, and if it is as tight as possible, then replace that hose.
If you do your own service work, i'd recommend buying a few jugs of the Mercedes coolant to use.

Gilly

Thanks for the very helpful information. I checked the service booklet and it recommends changing the coolant every 3 years, but doesn't state the mileage. Somehow I forgot about the need to change the coolant but I'm having it changed next week.

The mileage doesn't matter for the brake fluid and coolant flushes. Every 2 years on brake fluid, every 3 years on coolant, whether it's constantly being driven (like a taxi) or if it's in storage, it's supposed to be done.

Gilly