Practical Automotive Maintenance: Hoses

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Hoses

09.35

00:00	In this module we're going to discuss the plumbing side of the cooling system, which refers to the hoses that connect to all our accessories and link our systems together.
00:08	I will note that this isn't a deep dive into the motorsport grades of plumbing, like the use of teflon AN lines and Wiggins clamps.
00:16	If you want to learn more about motorsport grade plumbing, then you can check out our motorsport plumbing course, where we go into detail about motorsport grade plumbing systems, for not only coolant, but every fluid our vehicle uses.
00:27	Automotive cooling hoses function as the critical component for transporting engine coolant between the engine block and radiator for cooling, as well as various accessories such as heater cores, idle valves and turbochargers to maintain optimal operating temperatures and proper component function.
00:45	The importance of these simple components can't be overstated, as their failure will quickly lead to a loss of coolant, overheating, engine damage and costly repairs.
00:54	Modern vehicles typically feature two primary rubber radiator hoses, the upper hose carrying hot coolant from the engine to the radiator and the lower hose returning cooled fluid back to the engine, along with various smaller heater and bypass hoses that complete the cooling system circuit, some of which are often hard lines for toughness and heat resistance.
01:16	It's important to mention that different vehicles will have different layouts and hose locations with varying types of shapes and sizes to suit each application.
01:25	However, the same basic principle applies regardless of the system complexity and design.
01:31	The material composition of the radiator hoses significantly impacts their performance and longevity, with traditional OEM rubber and aftermarket silicon representing the two primary options available.
01:43	Standard rubber hoses remain the most common OEM choice due to their adequate flexibility and cost effective manufacturing, though their durability and performance have come a long way from the natural rubber types that were used in the previous decades.
01:58	If we examine modern day rubber hoses, we often see the term EPDM written on the outside, which stands for ethylene propylene diene monomer, representing a significant advancement in synthetic rubber technology, specifically formulated for automotive applications due to its superior durability, flexibility and resistance to environmental and chemical stresses, like those that can be found in some coolants.
02:24	EPDM hoses are commonly reinforced with a woven polyester or synthetic fibers, which helps them prevent splitting, ballooning or elongation under pressure.
02:34	The major benefit from this synthetic rubber technology, however, is its massive resistance to heat, with EPDM rubber being able to withstand a temperature range from negative 40 to 148 degrees Celsius.
02:46	This wide operating temperature range and ability to cope with modern coolants make them well, suited to all automotive applications, without potential for excessive hardening and cracking that could occur due to temperature degradation with conventional rubber formulations.
03:02	Manufacturers claim EPDM hoses typically have a lifespan of 5 to 10 years under normal operating conditions.
03:10	It's important to note that although EPDM technology works incredibly well, this doesn't mean it's immune to deterioration if pushed outside the normal operating range for this material.
03:22	A final consideration is the effect that UV rays have on rubber materials.
03:26	Although this might not affect the majority, it's still something to consider with the use of large vented bonnets or aftermarket coolers at the front or back of the vehicle, potentially leaving sections of our plumbing exposed to sunlight and UV rays.
03:40	When we move into the entry level aftermarket, we're likely to see replacement silicon hose kits.
03:46	This material offers even greater operating temperature ranges from negative 50 to 220 degrees Celsius, making them a good option for high performance applications.
03:55	This has some manufacturers saying the lifespan of silicon hoses can be up to 10 or more years if third-party contaminants aren't introduced.
04:04	This makes them ideal for turbocharged racing or high stress engines where heat soak is a problem.
04:10	Like EPDM, silicon has great resistance to harsh chemicals that can be found in most coolants.
04:16	The last issue we'll cover is the effect that third-party contaminants like fuel and oil have on our hoses.
04:22	Contact with these will begin to chemically break down the material and cause swelling, discoloration and brittleness.
04:29	The longer the exposure, the worse the effect on the material.
04:32	This effect does vary depending on the material used and we often find that fuel and oil safe rubber hose is made from what's known as layered NBR as this material shows the highest resistance to petroleum-based product.
04:46	EPDM and silicon hoses however are not resistant to petroleum chemicals and are broken down very easily.
04:53	This is especially true for silicon hose being that it's a porous material and capable of a faster absorption rate, accelerating deterioration.
05:01	There are some other exceptions with specialized fluorosilicon hoses that combine the flexibility and heat resistance of standard silicon while also having enhanced chemical resistance provided by their fluorosilicon liner.
05:15	These liners prevent chemical breakdown that would normally happen.
05:18	However, they aren't usually popular amongst motorsport applications as it's arguably not necessary when we consider motorsport grade plumbing incorporating the use of braided steel and teflon lines offering far superior chemical resistance, rigidity and longevity than all the options we've just covered, if made correctly.
05:39	So, what should we be looking for when inspecting both OEM and aftermarket hoses? Signs that a replacement might be needed include visible cracks, splits or leaks, especially near the connection points.
05:50	If a hose feels overly soft, spongy or swollen when squeezed, it may be deteriorating internally.
05:57	Conversely, hoses that feel brittle or hardened are at the risk of cracking and should be replaced.
06:03	Bulging, blistering or bloated sections indicate internal weakening and can be a sign of a rupture.
06:10	Loose, corroded or slipping clamps at the hose ends are also red flags and engine overheating, coolant loss or vacuum related performance issues like a rough idle or poor acceleration can be an indicator of a problem even if damage isn't physically apparent on the hose itself.
06:27	When it comes to hard lines, it can be a little trickier to pinpoint an issue as it's often corrosion hidden on the inside of the pipe that's the problem.
06:34	Without cutting the line, external clues like flaking, pitting or bulging can be solid indicators that something is wrong.
06:41	The condition of the fluid as well as the behavior of the system can also point out problems.
06:46	When in doubt, it's safer to just replace any type of questionable hose rather than risk failure under pressure.
06:53	Before wrapping up, let's quickly run over some of the common hose clamps we're likely to see from OEMs and in the aftermarket.
06:59	In automotive cooling systems, the most common hose clamps are spring clamps, worm gear clamps, t -bolt clamps and occasionally quick connect fittings.
07:08	Spring clamps are widely used by OEMs because they maintain constant tension as the hose expands and contracts with heat, offering reliable sealing over time.
07:18	They are very simple and only require a good set of pliers to remove and reinstall, but may fall short sealing hoses in high pressure situations.
07:27	Worm gear clamps are a popular aftermarket choice due to their adjustability and ease of installation, using a threaded bolt to tighten and loosen the grip.
07:36	This means we're able to be more exact with our level of tension, however they can apply uneven pressure and may loosen with thermal cycling leading to leaks.
07:45	For high performance or race applications, t -bolt clamps are often used thanks to their strong clamping force which is ideal for high pressure coolant systems, especially in turbocharged setups.
07:55	Lastly, some modern vehicles use quick connect fittings in their cooling systems for fast, secure connections during assembly.
08:03	But these can be harder to source and replace in the aftermarket.
08:07	Selecting the right clamp depends on the system pressure, access space and whether long term serviceability or high performance is the priority.
08:15	Again, for a more in-depth look into everything we've covered, be sure to check out our motorsport plumbing course.
08:21	Let's quickly summarise the key points covered in this module.
08:23	Automotive cooling hoses are vital for circulating coolant between the engine, radiator and accessories like heater cores and turbochargers, helping maintain proper operating temperatures and preventing engine damage.
08:36	Hose material plays a key role in durability, with EPDM rubber being the modern OEM standard due to its excellent heat resistance, flexibility and resilience to environmental and chemical stress.
08:48	Hard lines are also used by OEMs for their extreme heat resistance while rubber is often replaced with silicon hose in high performance aftermarket applications.
08:58	Although EPDM hoses are durable and widely used, they can degrade under UV exposure or contamination from fuel and oil, issues that silicon and less fluoro lined also struggle with.
09:10	Identifying when hoses need replacement involves checking for cracks, swelling, brittleness, leaks or performance issues like overheating or rough idles, while hard lines may show signs of internal corrosion through fluid condition or external damage.
09:25	Ultimately, when in doubt, replacing worn or questionable hoses is the safest choice to prevent failure under pressure.