What kind of damage can "red-lining" do to an engine?

Dear Car Talk

Dear Car Talk | Jul 01, 1991

Dear Tom and Ray:

What kind of damage can "red-lining" do to an engine? I accidentally accelerated to 65 mph in third gear before shifting to fourth in my 1990 VW Fox. My dealer says it's unlikely I did any damage because the Fox doesn't red-line until almost 7000 rpm. But I'm still anxious. Are there any tests I can have done to determine if everything is okay? It feels as if it's lost a little power ever since that fateful day, and also seems to resonate deeper, unless I'm imagining that due to my anxiety. What do you think?

TOM: Well, Steve, driving the car at or above the red-line obviously isn't good for the engine. But I don't think you reached the red-line on this car.

RAY: The "red-line" is the engine speed--marked by an ominous red line on your tachometer--above which the engine has been given permission to self destruct. If you took this car up to it's 7000 rpm red line, the crankshaft would be turning 7000 times per minute--or more than a hundred times a second! I'm sure you can imagine that at that speed, the sheer momentum can cause the engine to fly apart.

TOM: But at 65 mph in third gear, I'd guess that you were doing no more than 5500 or 6000 rpm. That's high, but it's well within acceptable limits. And the truth is, even if you did go higher, it's unlikely that one foray into the red-line district would necessarily ruin your engine.

RAY: So I'd say that the loss of power and deeper resonance are more likely symptoms of your anxiety than engine trouble, Steve. And rather than an expensive series of engine tests, we'd recommend a stress management course and some heavy-duty relaxation tapes. Good luck.

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