what is the difference between a regular everyday “fan belt” of the v belt type, and a “serpentine” belt? Is this just something on newer vehicles that an old time shade tree guy like me was left out of the loop on?
Excellent question.
A “V” fan belt of old only ran around the outside of the pulleys. That meant that it only had to flex one way and that during opoeration it tended to keep itself snug on the pulleys. A fanbelt in operation tries to form itself into a circle, much as a lariat (sp?) does when spun. They require no tensioner to maintain proper tension
A serpentine belt goes back and forth around pulleys, flexing in both directions. Because of the convaluted path they travel, and their tendency to try to form a circle as they run, they present problems both with withstanding the additional flex induced stresses but also in maintaining proper tension. Thus, they need to be thinner to be more flexable, wider to maintain strength, and require a seperate tensioner to maintain proper tension.
Willey is dead on correct of course as usual. The mechanic is overlooking something.
The unknown part is this temp gauge shooting up and the truck slowing down followed by quickly pulling over.
A temp gauge does not “shoot up” instantly. It takes a few minutes and one wonders if this slowing down was due to severe overheating; meaning the truck should have been stopped when the gauge started going up, not when it was trying to seize from overheating.
If severe enough this engine may never be the same due to cooked piston rings, valve seals, etc.
I suggest you ask the mechanic to show you this belt, or what’s left of it. Look at it closely and note if it is covered with small cracks. Some small cracks are considered to be normal (iffy) but small cracks on an aged belt could easily cause the belt to break.
If this is the case then that illustrates the reason for not leaving a serpentine belt in place for too long, normal small cracks or not.
Thanks, that was a good lesson, and one more reason to wonder about the value of an engineering degree.
As you will quickly learn, those extended warranty companies are generally in the business of denying claims by any excuse they can think of. I hope you get them to pay up, but I don’t hold out much hope.
[b][i]One Definition For “Serpent” Is “Snake”. A Serpentine Belt Is Usually Fairly Long And “Snakes” Or Flexes Back And Forth Around Crankshaft And Accessory Pulleys.
That’s Where The Descriptive Name “Serpentine Belt” Comes From.[/i][/b]
It’s a snake-like belt.
CSA
Lets establish a time line here…
Belt breaks (for whatever reason).
All kinds of warning lights instantly come on, check engine, alt, Batt, all light up. Temperature gauge is still normal (probably)…
Car continues to be driven. Temperature gauge climbs to “Hot” mark, engines loses power and slows down…
Car pulls over and stops, disabled…
We need to know how much TIME elapsed between lights come on and pulled over and stopped…
If ALL of the pulleys that the belt travels around were found to be serviceable and intact, the belt failed because of age, then the lady is out of luck…
The damage to this engine is liable to be extensive and repairing it is really not an option. Replacing the engine with a salvage yard item makes far more sense…
Iggy, unemployed engineers nationwide are wondering about the value of their engineering degrees right now.
Many others who went to work as letter carriers while they were in engineering school are now retired with nice pensions and medical benefits.