Crankshaft melt killed engine in VW Golf 2005 TDI


#1

After coming down a mountain pass my engine started making a weird sound and then died. I am told that it was because I was in too low a gear for the speed I was going (I was using the triptronic or whatever it is called to stay in a lower gear coming down the pass). I had clean and ample oil and no warning lights came on and there are 98,000 miles on it. Does this cause make sense? I have been reading in other discussions that many cars have crank shaft sensors, do VW cars have this?


#2

So was the engine revving really high? How long was your decline? What was your rpm on the tach? Rocketman


#3

i never heard of a crank shaft melting. you have pictures you can post, i gotta see this.


#4

You really need to define this more clearly because a crankshaft cannot melt.

How many RPMs was the engine turning during all of this? Modern vehicles have rev limiters in the ECM (computer) but that doesn’t always mean anything.
It’s entirely possible to damage an engine from overrevving even with a limiter. A recent issue of a car magazine I subscribe to refers to a Mopar meet and a newer Dodge Challenger needing an engine rebuild now after the engine hit the rev limiter.


#5

The crankshaft POSITION sensor is standard on almost all cars today, even your VW. But, it does nothing to prevent or sense DAMAGE to the crankshaft.

Even with a rev limiter, you were using the engine for braking on a steep downhill. Most limiters are designed to keep you from over-revving the engine with the gas pedal, not from choosing too low a gear for engine braking. If you over-revved the engine in this manner, you still risk damaging the engine. I’ve used engine braking to control the down-hill speed, but usually don’t need to go anywhere near the redline to do it. If you allowed the engine to rev up too much on the down hill, then you could severly damage the engine.


#6

Possibly someone described the damage as “the crankshaft is toast.” Can I just imagine the scenario of a driver descending an 8%+ incline and after the speed exceeded 80mph and the brakes began to fade pulls the shift lever back to 1. How close is that to the situation VWTDI2011?


#7

Follow-up:

Does the VW TDI even allow for engine braking? Most Diesels are free-wheeling by design, and need a Jake-Brake device (exhaust braking) to provide engine braking.


#8

You probably over-revved the engine. Diesel engines often have a very low redline (3k to 4k RPM is common) that is quite easy to exceed doing something like this. You may have exceeded the maximum operating speed of the engine, spun one or more of your bearings and tore up the crankshaft.


#9

“Does the VW TDI even allow for engine braking? Most Diesels are free-wheeling by design”

That’s what I was thinking.
Can someone–perhaps Mr. Meehan–tell us:

Does a VW diesel allow for engine braking, and also–what is the redline of the engine?


#10

Brakes do an excellent job keeping a vehicle going at proper speed.

What made you want to use a lower gear?


#11

andrew_j:

There have been many threads and discussions on this site concerning mountain downgrades and brake use. For long downgrades, many experienced drivers use the low gears and engine braking to maintain speed. Truckers use Jake Brakes (exhaust brakes). This saves the brakes for the unexpected. Riding the brakes on long downgrades can result in overheated brakes and brake fade. Ask any trucker. Engine braking does no damage if done properly.


#12

Since diesels have no throttle, they have little ability to provide any engine braking without a “jake brake”…B-K is right…So yes, you could have over-reved the engine and damaged MANY parts…


#13

Two of our cars have manual transmissions; one has a diesel and the other has a gasoline engine. If the diesel has less engine braking capability, I don’t notice it when driving. Perhaps a simple slowdown test is in order to prove or disprove this. For now it should suffice to say that a diesel has air pumping frictional loss and therefore some engine braking capability and otherwise just bounces off compression but a gasoline engine does those things too.


#14

I once drove my friend’s BMW with a 6 speed MT. That straight 6 had very little engine braking compared to my 4 banger because it uses variable valve lift instead of a throttle. Gas engine’s retarding ability comes mostly from sucking air through the closed throttle.

Back to the OP’s concern, I find it hard to believe that a 2005 VW cannot automatically upshifts the transmission before the engine rev way past the redline.


#15

chunky_azian, I believe the OP stated that they were overriding the ability of the transmission to upshift, if I read that post correctly.

VWTDI2011, I grew up in a mountainous area, and engine braking was the regular practice for descending long hills. Tourists and newcomers were easy to spot - they were the ones riding their brakes. I don’t recall that any of us ever damaged an engine with this practice, but they weren’t diesels. I’m sorry this happened to you.


#16

Thanks for all the feedback. I was going up to 45mph at times in third gear. I didn’t notice the RPMs going into the red zone. I wasn’t rocking out to music or anything so I am surprised that I didn’t hear the engine in that great of distress. I guess I won’t make that mistake again, this car has been trouble since I got it.