How to choose replacement hoses

Question

I'm doing a couple major repairs on my car right now (about half way done). It required removing a lot of hoses. I'd like to replace a lot of them while they are off (or soon going to be off).

I already bought oil cooler and upper and lower radiator hoses from my regular parts supplier. But there are so many other hoses.

How does one know what to use to replace? Do I need specific material? Some need wire mesh in rubber others don't.

I know that the size is important. Is that all that really matters? Where do I buy these generic hoses?

Answer 1

Dealer

Head to your dealer and grab OEM Exact parts for your vehicle.

Aftermarket OEM

Find out what brand(s) your manufacturer uses, and see if you can source them sold somewhere else. Often times you can use a manufacturers/dealers parts website and then look for a cross for the part number(s). For example, GM generally uses ACDelco as their OEM, so you can freely source parts from an seller.

Aftermarket

Some brands have been around for a long time, and have a strong reputation like Gates, for example. Granted it's like anything else, it's very subjective, and people tend to pick favorites etc. But look for names that you might have seen before, like ACDelco, Gates, Dayco, Michelin, Goodyear, etc. That's generally a safe bet.

Keep in mind you'll likely have to trim them to fit. This is best accomplished with a soft-vise or a lightly closed clamp and a straight razor. You'll want to be very careful, and assure that the hose doesn't want to move around on you so you end up with a straight cut. Aesthetics aren't important here, you just don't want to end up with a diagonal cut leading to poor sealing etc.

Vacuum Lines

You will want to be very careful when removing vacuum lines. The plastic Tee's and other fittings and couplers can become extremely fragile as they age. Also, sourcing these parts can be very difficult. Be sure to take a picture before disassembling any of these connections, and try to remove the vacuum lines as careful as possible.

I like to plan the job first, and get a vague idea of the fittings and couplers I might need and hit up the local auto-parts store parts trees/displays for random vacuum fittings to see if I will be able to manage without the originals in the result that they do break on me.

If a vacuum line has become dry-rotted and stiff Do not force it off the fitting!! cut the line in the middle, well clear from each side. Then with the line and fitting off the vehicle and in your hands, and in a comfortable position, safely remove the fitting from the line by slicing into the line perpendicular to the end (Cut along the length, rather than width of the hose.)

This is the one situation where choosing a different product than OEM can make sense. Going with Silicone Vacuum lines, if sourced from a quality manufacturer, can make it a lifetime repair. They are much more resistant to chemical and other environmental aspects which can damage traditional rubber lines. The price difference for quality Silicone Vacuum Line is often trivial, if not cheaper in some cases depending on the seller.

Important Caveats

You'll want to replace the original clamps, or get clamps of the same style. Depending on the components used in your cooling system, worm-style clamps won't work properly without leaking, allowing air in, and/or damaging components. If you have any plastic water-necks, or plastic anything involving a clamp, you need to use the style that is original to your vehicle.

Generally these are Constant-Tension/"Spring Clamps" but there are other styles which will allow the clamp to "move" with the various expansion cycles of the components.

Answer 2

Typically the only hoses which need to be special (rather, something other than just rubber) are fuel lines. These are usually reinforced with some form of fiber, like a polyamid (nylon) or sometimes steel or other metal mesh to increase their structural integrity. Fuel lines are generally under considerable pressure. Fuel lines also have special rubber in them which will not break down in the presence of fuel.

Coolant lines are also usually reinforced though more commonly only with a flexible fiber of some sort or sometimes just thicker rubber. Upper operation temperatures for an automobile's coolant system can, on some models, exceed 230 degrees. This puts the coolant under considerable pressure (as it remains a liquid at these temperatures), which the hoses need to withstand.

The only hoses which are typically un-reinforced are vacuum lines of various diameters. Evap system lines can be large outer (and inner) diameter, but are generally not reinforced.

Using a fuel grade hose for coolant is usually ok, using a coolant grade hose for vacuum and emissions is generally ok. Going the other way can get you in trouble, from a burst coolant hose, to an engine fire from fuel spraying around your engine bay due to a burst fuel supply line.

Beyond the considerations for material and pressure above, the only important factor in a hose is the inner diameter (so it fits over the fittings properly) and the wall thickness (usually only a concern on vacuum lines). A hose with too thin of a wall may collapse under vacuum and not perform properly as a result.

Hoses can be found at your local auto-parts store, but I prefer to shop on amazon, as the guy at the local auto-parts store may tell you that "sure this will work for X liquid" without actually knowing or looking.

The best place to get hoses is from the dealer, if it's in your budget. These hoses will come factory-fresh, and be pre-formed to exactly the right size and shape for each exact hose. You can search google for "OEM Parts" and find dealers which do a booming business in internet sales at a very low markup. In my experience (mitsubishi) I can order from a dealer in 5 states over, and get it shipped to my house for a third of what my local "stealership" would charge me for the exact same dealer part. The only concern is that internet parts departments tend not to be patient with helping you find a part. It's best if you have the part numbers before you shop with them.

Additionally, your engine gets hot and cold. The entire engine bay has thermal cycles as a result of this.

Worm drive clamps are easily the worst kind of clamp and fall into a group of clamps that could be termed as "constant size" clamps. With the exception of a compression fitting (another type of constant size clamp) constant size clamps should only be used on tubing systems where there is expected to be little to no fluctuation in temperature.

Constant size clamps will cause the hose material to be compressed by it's own expansion when heated, and will "squeeze out" around the clamp when warm. When the hose cools, this will eventually leave a gap between the extruded hose end and the fitting and the vehicle will develop a "cold start leak" which may seal as the vehicle warms.

It's usually wisest to use those "cheapo looking" spring clamps, if you can get the correct sizes. The are generally easier to install than to remove. These fall into a class which could be termed as "constant pressure", meaning the keep a constant clamping force on the end of the hose. The dealer is the easiest place to find the right size, but likely most expensive. I've had good luck with getting various sizes from Grainger. You need to measure the OD of the hose when it's installed on the fitting, and the max size of the clamp needs to be large enough to fit over barb on the fitting with the hose installed, but the minimum size of the clamp needs to be larger than the hose after the barb. There are other types of worm-drive-like constant pressure clamps, but they are very expensive, generally.

Another solution I've used recently on a motorcycle (where worm drive clamps were factory, ugg) are the Gates PowerGrip. You need a heat gun, but these clamps work great and have a wide range of sizes they will adjust. They are likely to be at least somewhat more expensive than getting spring clamps from the dealer, depending what sizes you need, but they are very reliable, are self tightening, and very easy to use (both installing and removing). They also make a tool to remove them, but careful use of a utility knife makes short work of them without damaging the hose.