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Toyota Tacoma Service Warning

Here’s a good example of something to watch out for the next time you have your Toyota Tacoma (and other models as well) serviced at a garage or dealership whenever your spark plugs are changed. Plus, find out how to tighten your spark plugs properly without the use of a special torque wrench.

Oil Filters, Finger Tight; Spark Plugs, More So

The reason why torquing your vehicles various nuts, bolts, screws and other components require differing levels of the correct “amount of tightness” is that depending on the part and what it is there for, falls under a wide range of parameters to ensure things stay secure…but not too secure.

For example, the cylinder head bolts are often torqued anywhere from 70 to 110 foot pounds (depending on the engine) due to the cylinder is under a massive amount of force each time a spark plug fires igniting the air/fuel mixture.

In contrast, your oil filter under much less pressure is typically torqued only to a “finger tightness” degree to prevent the oil seal in the filter from being crushed which would lead to oil leakage.

Somewhere roughly between the two extremes you have other components such as the valve nuts or bolts holding your valve cover down that if torqued too loose or too tight would lead to oil seepage onto your engine and manifold resulting in a burning oil odor.

Whenever in doubt, always consult your owners’ manual or other service repair manual.

Toyota Tacoma Spark Plug Example

What sparked this article topic was a recent Toyota Maintenance YouTube channel episode where the host (Peter) does a show and tell of spark plug blowby whenever spark plugs are screwed in only finger tight. Blowby is the escape of exhaust gases from the cylinder passing partially past the spark plug hole rather than entirely through the exhaust valve opening.

Related article: Spark Plug Car Maintenance Mistakes Many Car Owners and Service Centers Make

Another example of “blowby” you commonly hear about is when a piston and its rings are so worn that some of the cylinder exhaust gases pass into the crankcase and/or oil escapes past the rings into the combustion chamber of the cylinder.

In the spark plug example, Peter shows how blowby can be determined by simply pulling the plugs out and observing blowby residue burned onto the threads and body of the spark plug. In this case the blowby was presumably caused by the last time a service center had replaced the old plugs with new but failed to tighten the plugs to their correct torque.

The Value of the Video

The value of this video is that it serves as a good warning to car owners having their vehicles serviced to ensure that the spark plugs were tightened correctly. In many cases---such as with this Tacoma---access to the spark plugs is relatively difficult and a service tech may be tempted to just screw in the plugs only finger tight rather than remove components to get good access to the plugs.

Another value to this video is that it demonstrates how to properly tighten down a spark plug if you do not own a properly sized torque wrench to do the job with.

That said, here is the video in its entirety well worth watching.

Related article: Ford F-150 EcoBoost Spark Plug Replacement Demo

Engine Spark Plug Blowby

And finally…

A special note: In case you should ever replace your engine’s bolts with non-OEM performance bolts, be sure to check on the torque values recommended by the bolt manufacturer and whether or not any special assembly lube is required on the threads. Sometimes the numbers recommended will differ from your owners’ manual or repair manual for your vehicle.

For additional articles related to car repair and maintenance, here are a few for your consideration:

Ford Triton 3-Valve Engine Spark Plug Problem You Won’t Believe

Do Champion Spark Plugs Really Belong in Chrysler’s and Lawn Mowers?

Timothy Boyer is a Torque News automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWrites for daily new and used vehicle news.

COMING UP NEXT: Avoid This High-Performance Parts Scam on Your Toyota

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