A few weeks ago, by 1981 Volvo's heater hoses finally quit so I replaced all of the heater hoses. (gee 20 years, not bad)

So, that got me to pondering some of the greater questions in life, like: "just how long will a set of MB heater hoses go before they so no more?"

As a matter of practice I've changed out the radiatior hoses every 6 years (flushing and replacing coolant every 3 of course). I'm sure the radiator hoses last much longer than that, so I over kill a bit. They are darn fine hoses.

So, what do the more experienced mechs say about those heater hoses? Then add the Momma factor. The momma factor has to do with the relationship of risk vs cost savings vs who is in the car when the hose finally goes. Me or her and her babies? There is a big difference there.

So, "just how long will a set of MB heater hoses go before they so no more?" or stated a slightly different way, "what would be a prudent preventive maintenance cycle on heater hoses, every 20 years?" Clamps too?

And who the heck sells the great hose clamps we find on or trusty German steads? You know, the ones that don't cut up our hoses as we worm the screw.

Stu Ritter wrote a great piece for the current issue of The Star on MB cooling systems. He says that MB coolant hoses typically go for 20 years or better so he doesn't recommend prophylactic replacement, just checking for soft spots occasionally.

400E called it
 

Brother of The Benz, JRBrown,
The article in the current Star on cooling has to be one of the best in many years.
Follow the instructions and you can't loose.
My 1987 300E with 177,000 miles has had M/B coolant changed every year and the citric flush as well.
The heat exchangers are still original as are the hoses under the hood.
The water pump was replaced at 90,000 miles.
Just this spring I replaced the upper and lower radiator hoses, the thermostat and the upgraded pressure cap.
The original cap was coded 120 for 1.2bar(17psi) and it was superceded with cap coded 140 for 1.4bar(20psi).
The system is holding the higher pressure with the benefit of a higher boiling point.
I also use RedLines surfactant Water Wetter.
Happy Trails Beep Beep from The Spiderman in Houston!!!

I just replaced all coolant-carrying hoses on my 10 year old MB. They were tired.

I too am a member of MBCA and read the very fine article. The conclusion I drew from that article and one data point (my Volvo going 20 years) was that a preventive R&R of all coolant carrying heater hoses would be prudent given that my spouse is the primary driver.

But I'm still looking for thoughts. Thanks to all who have replied.

Haven't changed mine yet on my 300E...the ONLY part of the cooling system that is still original...

I changed my hoses and thermostat at 170,000 miles, when the thermostat went bad. The hoses however were still good and the originol hoses.

When I bought my car last Oct., I noticed that both the upper and lower rad. hoses had Mercedes markings. There was the "Star" and the MB part number starting with my chassis number of 116. I assumed that someone at some point spent some good money and bought OEM replacement hoses from Mercedes, never thinking that they may be original. I replaced them as a "preventative measure", not knowing how old they were. When I took them off and looked inside, they looked perfect, no cracking or peeling or large amounts of residue. I also read that article in the "STAR", and then thought...maybe those are the original hoses. I actually still have them. I too, am use to having hoses only last 4-6 years, not 20 +. The article also mentioned that ..."a life of 20 to 30 years is not uncommon. Because they last so long in normal service, no recommended change interval exists for these hoses. They are fairly expensive, so re-hosing an engine compartment means a big bill. Squeezing the hoses, feeling for soft spots, is about the limit of their preventative maintenance."

When we got our 1988 300TE in 1996, on our first long trip (Big Bear @ 102F), the heater-hose between the firewall and the rear engine sprung a leak. Various MB mechanics have told me this a prone area (lots of heat, and stress when pulling the oil-filter), so I have spare with me.

Of course, it was a Sunday afternoon, so we had to improvise with parts from NAPA.

Soon afterwards, the upper radiator neck cracked (original radiator, did not have the metal reinforcement sleeve).

That's when I decided to replace all hoses, the radiator, and the waterpump (105K miles). I also did a degreasing and citric acid flush. I also learned that you do not overtighten the clamps (the German hose clamps while not cutting into the hose, are too narrow and don't spread-out the force). I use a 1/4" flexible-spring drive, and when it deflects, I stop tightening. Also, you don't periodically tighten the hose clamps.

Fill only with distilled-water 55% and 45% MB antifreeze plus a bottle of RedLine Water-Wetter. Yes, distilled-water is corrosive, but NOT when mixed with antifreeze. MB recommends soft-water, and here in Santa Barbara our water is way too "hard."

I flush, every two years, and every 6-months check the PH with PH Coolant Test Strips from NAPA.

I believe by keeping the PH as close to virgin MB antifreeze which is more neutral than the "green stuff", longevity can be had.

Now even the steep grades to Las Vegas at 110F or a full 5-hours of wide-open throttle at Willow Springs barely bring s the temp above 90-C.

Best of luck,
:-) neil

I am having head gasket replaced right now.
Mechanick recomended ( and I agree with him ) to replace some hoses. As I uderstand when engine oil is intraduced into cooling system it makes ruber hoses to crack.

Hoses on my '92 300TE were replaced this year. Upper and lower radiator hoses were soft. I think 6 years is a bit aggressive for a replacement schedule but ten is not -- and of course, one must inspect as well in an exercise of common sense.

Pricey!
 

Brothers of The Benz
Doing as I, becomes pricey.
The M/B Coolant and citric flush will cost you +$40.00 a year.
This wouldn't justify for just the hose replacement savings.
Consider that I'm still on the original radiator, mono valve, 2nd water pump,aux water pump and heater heat exchanger.
Now that's where the savings are.
The engine runs cool on the hotest days in traffic with the A/C operating in Houston.
Happy Trails Beep Beep from The Spiderman in Houston!!!

I don’t wish to enter the fray here, but here is just a little side note on the issue.

The original hoses, at least on the older models, had the actual date of manufacture stamped (molded) into them. It can be hard to spot, but it IS there. This may be of assistance in determining whether or not the hoses on any given car are original or not.

RTH