Hello everyone! has anybody encountered breaking their radiator hose or any hose in the water line after driving their cars hard.

It happened to me thrice. On my way home I was driving like 140 to 200kms in a 30km drive. The next day I noticed that I broke a radiator hose. Whats up with that? At first I thought it was just normal wear and tear but the second time it was the hose at the back of the engine, the third time was the main radiator hose. The common denominator I think is everytime I drive it hard this thing happens.

Guys I need your expertise on this?

I don't think "wear and tear" applies to radiator hoses.

They are made of rubber.

Rubber is rubber.

It gets dry and brittle with age.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

And running hard STRESSes the system.

It might be interesting to note that some combinations of antifreezes can cause embrittlement of hoses and the plastics used in radiators.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Just for discussion, I only use MB antifreeze and hoses. I also understand that the hoses get brittle through time specially when subjected to extreme temperatures.
So what you guys are saying is its just the hose and specifically its condition.
Unless there is no other reason i dont see why a cant drive my car hard again since all my hoses are brand new.
Yehey! But if you guys have other insights please let me know!
Thanks Steve and Suginami

Personally, I would have my coolant checked for oil or gasoline contamination. A slightly faulty pressure relief system on your overflow tank could also lead to over-pressurization when running hot, followed by hose failure. A faulty head gasket, as was common on the straight 6s (I have suffered that failure on my c280) can lead to system overpressure even if the cap is capable of handling gradual overpressure. Again, hose stress is possible. A head gasket problem can lead to one of 3 problems, depending on your driving and the actual failure point.
You can have water into your oil return passages as the coolant pressurizes.
You can have oil into your coolant from a supply passage.
You can have the cylinder compression pressurize the coolant system if driven hard, or you can suck coolant into the cylinders under high vacuum conditions (the same ones that cause leaky valve seals to show themselves in a puff of oil smoke from the exhaust).
In any case, have your cap checked and your coolant analyzed. This will rule out 1 easy fix and 1 not-so-easy fix.

Thank you benzfan for the helpful insights. How do I know if the pressure relief system is faulty? (is that the same as the cap?) And also how will I know if there is a head gasket problem? (Other than oil leaks on the sides what else should be visible?)
I know I just changed my cap, what can I do to check if its faulty or not?

Yes, your cap is the only pressure relief you have. Make sure it is rated properly for your car. A pressure test of your cooling system will indicate if it is working properly or not. It also might indicate other problems with your cooling system and should be cheap to have performed.
As for the head gasket, sometimes pressurization of the cooling system from engine compression is only slight, if the point of failure is one that allows that flowpath.You require at least a compression test. (done wet and dry, to rule out rings). This is sometimes referred to as a cylinder leak-down check. The cylinder is allowed to pressurize, and you note if there is any drop in pressure over a period of time. In any cylinders that are showing leakage, you squirt some oil into the cylinder and repeat to see if either you get a higher compression figure, or the cylinder leaks less compression. If either occurs, it indicates ring problems. If the cylinder still leaks, and didn't show a slightly higher compression figure initially, the problem is related to the head in that cylinder, either valves not seating, or gasket. Removal of the head is the only realistic option at that point and a careful mechanic will look closely at the head gasket and will be able to determine the point of failure. I had a bad factory gasket on my Honda many years ago and removal indicated the point of cylinder charge tracking into the coolant.
You might be able to smell something in your coolant IF it is in fact head gasket related. You can also smell traces of coolant in exhaust long before you see the tell-take white smoke.
I don't mean to alarm you, but worst-case scenario is a cracked head, if indeed your hose problem is caused by overpressurization. It's a long chain of ifs that I have outlined, and some simple tests should show quickly if everything I have suggested is out to lunch or whether further digging is required.
You did examine the hoses to check what type of failure you were dealing with? A deteriorated hose you can probably tear by hand in other spots. In that case the fix is easy- just replace them all.

Thanks again benzfan! I will try to schedule a checkup this week and I will give you some feed on the outcome. I will keep you guys posted thanks buddy!

FWIW I read somewhere that the original hoses last about 10 years or so. If you haven't done so already, I would replace all the original heater/radiator hoses (esp the ones in the engine bay), along with new clips.

Just a thought, how are your motor mounts? Is the engine moving around much under load?

Hello BobK my motor mounts seems to be ok. I didnt notice anything that will say its worn out. Engine seems to be tucked in perfectly. How can I tell if the motor mounts are worn out and if it is worn out how can it effect the increase in pressure in the water line? Thanks