I purchased my first car in 1982. It was my dream car: a 1967 Ford Mustang Fastback. I still remember the feeling of elation and the thrill of knowing it was finally mine. I was the proud owner of a classic 1967 Mustang Fastback! I spent the rest of the day, and most of the evening, driving all over town, simply enjoying the experience of ownership.

I remember thinking the car's 289 V8 was getting phenomenal gas mileage because the fuel gauge had been sitting at 1/4 tank for quite some time. Then, at about 1 a.m. on a remote scenic parkway, the engine sputtered and died on a hill.

As I tried to figure out what had happened to my new prize, it dawned on me that I had run out of gas. The realization came when I let the car roll backward and slammed on the brakes but didn't hear any fuel sloshing around in the tank. After unsuccessfully trying to flag down a few passing cars, a police cruiser stopped and radioed for a tow truck.

When the tow truck finally arrived, the driver explained that he didn't carry gasoline because his rig ran on propane. Doh! I ended up paying him to tow me to a gas station, where I filled the tank and finally made it home.

The next day, I ordered a new fuel-level sending unit to fix the gauge problem. I would have used RockAuto like I do today, but you guys didn't exist in 1982.

Rob in Canada

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On one side of a turbocharger, engine exhaust spins a turbine wheel. The turbine wheel rotates a shaft which turns a compressor wheel on the opposite (clean air) side of the turbocharger. The goal is to compress/pressurize/boost clean air so more of it can be crammed into the engine's air intake. Unfortunately, significantly compressing air also raises its temperature which makes the air less dense. There may be little benefit in cramming hot, less dense air into the engine if the total volume of air is still about the same as the volume of cooler, denser ambient air that you started with.

An intercooler helps solve this problem by working as a radiator to cool the compressed air before it enters the engine air intake. Now air that is both compressed AND dense can be crammed into the engine air intake. Higher performance is possible because the engine has a greater volume of air/oxygen available to use.

The pipes that connect the turbocharger to the intercooler (hot side) and the intercooler to the engine air intake (cold side) are often among the first parts to wear out. Why do these deceptively simple looking hollow tubes fail? Think about party balloons for a moment. A balloon that is never inflated may last for years. A balloon that is inflated may last for days or weeks. A balloon that is repeatedly inflated and deflated probably will only last a few minutes.

Like that last party balloon, the air pressure in intercooler pipes is constantly rising and falling. Air temperature may also change quickly. The air in the pipes likely contains a trace of oil from the crankcase ventilation system. After many miles of flexing and contracting and possibly soaking up engine oil, it is no surprise that the weakest points in original equipment (OE) intercooler pipes eventually fail.

Turbocharged diesel engines have provided the harshest test bed for intercooler pipe designs. Normal diesel turbocharger boost pressure may be three or four times higher (than a gasoline engine). Diesel turbochargers typically start boosting air pressure at lower engine speeds. The variable geometry turbochargers most commonly found on diesels are more likely to create extreme spikes in boost pressure. Decades of experience with hardworking diesel engines has likely benefited all the new turbocharged gasoline engines that have appeared over the last twenty years.

Many replacement intercooler hoses/pipes (found under "Cooling System" in the RockAuto.com catalog) use the latest knowledge and materials to improve OE designs. Aluminized coatings help prevent corrosion of metal pipes. Metal may replace plastic in failure prone areas. Fluoroelastomer (high performance synthetic rubber) linings reduce oil degradation. Reinforced silicone can better resist heat and flexing. (See the Info pages for specific intercooler hoses/pipes for more design details.)

RAM, Sprinter Van & BMW Intercooler Pipes

A cracked or leaking intercooler pipe will often make noise and generate multiple diagnostic trouble codes. The trouble codes could be related to an incorrect air/fuel mixture. It is important to replace a damaged intercooler pipe as soon as possible. An out of control air/fuel mixture can lead to excessively dirty downstream exhaust parts such as the diesel particulate filter or catalytic converter and create extreme exhaust gas temperatures. A hole in a pipe can let unfiltered air (dirt) into the engine and/or cause the turbocharger to spin excessively fast because there is not enough back pressure and/or a computer is frantically telling the turbocharger to pump more air. Many vehicles will go into a limp-in mode to get off the road while avoiding damage.

Replacing intercooler pipes is something the average DIYer can comfortably do on most engines. It is usually similar to replacing heater or radiator hoses but without any messy coolant to deal with.

Tom Taylor,
RockAuto.com

To read more of Tom's articles, choose from story titles on the Newsletter Archives page.