Tuesday, May 13, 2014
Warm it Up, Cool it Down, Keep it Happy...
Turbochargers are a great way to add lots of fun and power to your vehicle, however, they also need some special care to last a reasonable amount of time and prove reliable over the long run. Turbos need extra attention, but all machines can benefit from the same care that keeps a turbo unit happy.
The other day I went to visit a good friend and as usual, I got to hear about all his latest mechanical woes. Apparently, my buddy’s mechanic says he needs a new turbocharger on his Subaru- AGAIN. This is the third turbo and second engine in 60,000 miles. My only question- since I know he runs a decent synthetic engine oil- was 'Do you religiously let it warm up and cool down for a few minutes every drive?' He looked at me curiously, and said, 'No I don't, thats a waste of fuel isn't it?'
'Maybe' I replied, 'But its a greater waste of resources and energy to ruin equipment, throw it away and make new if it can be avoided.' If we check out the real costs and real results, we find that choosing to expend a small amount of fuel for the long-term good of equipment makes great sense. When people claim they are saving fuel, but wasting engines and energy intensive parts, I get frustrated. Angry even. The ignorance of the enviro-weenies scolding people for warming up an engine are encouraging machine owners to destroy and throw away a car early and consciously destroy equipment because they refuse to consider the amount of energy that goes into mining, refining, manufacturing and maintenance really chafes me. A tiny bit of fuel spent to extend the life of equipment is miniscule in the long run compared to the much larger expense of replacing an engine, or the entire machine. This is one case where high-minded ignorance is costing more instead of saving resources.
The relatively small amount of fuel consumed over 10 years in a 3 minute warm-up or cool-down is miniscule compared to the energy that has already been invested in building that car. Remember too that the more vehicles we 'consume' and resources we waste, the more the corporate behemoths profit; the more we waste and throw away, the more money they make. The idea of choosing to spend a bit of fuel to increase the longevity of equipment is directly counter-to and opposed-to the throw-it-out mentality and corporate bottom lines. Sure, the fuel companies make a bit more, but overall our long term energy footprint will decrease. We live in a throw-away society: that needs to change, and soon. Taking a few minutes in the morning to warm things up slowly, together, as a unit, as opposed to sudden, spot heating- causing huge temperature differentials- can make equipment last much, much longer.
A few minutes of cool-down can do the same to add longevity. Allowing a cooling period before shutdown allows the pumps and fluids to remove the heat from the metal where it can cause damage. Shutting down a turbo-charged engine while hot causes much more damage than on normally aspirated engines because the turbo unit is running- on gasoline engines- near metallurgical limits already- any hotter and the metal would be melting. A turbo can be running at well over 1000F since the exhaust gasses that power the turbocharger are hot enough that the exhaust housing itself can be seen glowing reddish- orange in the dark. When the engine is shut down hot, oil stops flowing and the oil that remains in the turbo bearings gets cooked into crusty coal-like grime. This process of turning oil into crunchy abrasive coal is called 'Coking'. Bearings suffer the damage when the shaft is forced to spin next time the engine is started and that abrasive soot grinds metal out of the bearing or shaft until the oil can flush it out.
A little extra time for cool down to remove that damaging heat via the oil flowing through it will increase the life of the turbo dramatically. Warming the engine for a few minutes prevents the other major problem with turbochargers- bearing galling. When things heat up, they expand. Period. The amount of expansion depends on the material, but the rule holds. If a shaft is heated rapidly while the bushings it rides in are still cold and small, the shaft expands and tears, stretches, or can even tear loose the bushings or warp the shaft permanently. This same situation happens to exhaust valves in every engine very easily, and does, over time take its toll.
So, in 60,000 miles, my friend has spent $3200 for a new engine, and $3300 for three turbochargers; thats $6500 total. That equates to over 1600 gallons of gasoline at $4 per gallon. It would never cost you 1600 gallons of fuel to prevent the destruction of engine and turbos in that time. It may cost as much as 1/10th of that in fuel to counteract that damage and all the repair costs involved.
Think about it next time you start your car when you are running late or get in a hurry to shut it off to get into the party. If a few minutes and an extra few ounces of fuel can save you thousands of dollars in the long run and prevent the environmental damage from mining, refining, and manufacturing to build new engines or parts, where is the waste? When we look at the entirety of the situation, it quickly becomes obvious that warm-ups and cool-downs are vital to the bigger overall picture of mechanical, environmental and economic well-being. Make your machines last longer by giving them a few minutes at each end of the ride, be patient with them, and down the road, your pocketbook will thank you for the extra miles you get back out of them.
Soon again, MW