To clatter or not to clatter, which is better?

Just a cold climate question... It is cooling down here in Cleveland and my engine is starting to clatter more in the morning. When the cold engine light is on I use light throttle to save the engine but have noticed that under light throttle acceleration the engine clatters much much louder than if I speed up quicker. I was just wondering which is better for the engine when cold. Light throttle with lots-O-clatter or moderate throttle with less clatter?

It's getting cooler here too in Montreal (-2C) and I too observed that the engine is clattering a lot more at low throttle, so I just speed up faster, so not to wake up all the neighboors... My car is still very young, though, below 1000km so still has the original break-in oil. I hope it gets better with the new oil at 8000km?

Folks. It is normal for diesels to clatter louder as it gets colder outside. This is normal. You should hear my 1987 Golf Diesel at 0515... everybody's up when I leave for work When it's really cold, it sounds like there's some marbles running around in the engine, and my engine is WAAAYYYY louder than a TDI engine. Just the sound deadening that VW put into the TDI engine compartment is amazing.... acoustic belly pan, acoustic engine cover, sound deadening pad on the hood, not mentioning the engine itself which is far more quiet than the older diesels.

Harry.

I think as the engine warms up the clatter goes away (or back to normal)....right?

My question is...in the winter...is the "operating temperature" clatter louder than in the summer. Probably the same....but, it just takes longer to reach operating temps?

BTW..how much MPG loss do you have during the winter vs. summer?

Thanks.

As the engine warms up, the pitch and decibels of the clatter subsides to a normal muted clatter (as in summer). If it's very cold out (-40) this clatter may be just as prominent as when the engine is first started. Yes, it DOES take longer to get to normal operating temperature as well.

In fact, if an engine is at normal operating temperature, and you stop for a few minutes and leave the engine running, the temperature will DECREASE.. ie. the engine will cool off, and your heater output decreases Diesels require load to generate heat... idling does NOT warm up a diesel engine!

If a diesel is misfiring when first started when the engine is cold, let the idle smooth out first before driving.. typically a few seconds to a minute.

Now, the TDI has heaters here there and everywhere to help minimize the problems I've just described... I didn't know that until I joined this forum

I've had diesels in -40 weather (1982 Toyota LandCruiser with 3.4 litre diesel), and this engine would start right away with a block heater and battery blankets, but would smoke and misfire for the first few seconds running on number 1 diesel (winter blend).

There is typically a 1 or 2 mpg difference with winter blend fuel... and a trail of blue smoke from the exhaust. I experienced this up in Hinton, Alberta where I lived for a while... brrr! Not too sure if modern chemistry and engineering has changed the formulation of number 1 diesel since those days or not.

Hope this helps,
Harry.



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'87 Golf Diesel (267000+ Km)
'00 Golf TDI GLS (1000 + Km)

I think the manual states to keep the rpm's under 3,000 while the blue temp light is on. So take it easy on the rev's until she's up to operating temp.

Diesels "clatter" because the fuel doesn't burn as smoothly as gasoline. It's not a vapor, but rather tiny droplets of liquid diesel fuel. There is more of a tendency toward sudden "detonation" that a nice gentle burn. A very cold engine makes the situation louder than normal. There is nothing you can do about it, but it is a good idea to keep the rpms low and avoid heavy throttle application until combustion smooths out a bit. That loud clatter is indicative of unusually violent mechanical stresses inside the cylinders. Don't add insult to injury!

I think VW's "3000 rpm" advice is a little too generous. I keep mine below 2000, and use a VERY light foot on the accelerator, until the noise calms down. By the time I clatter my way through the neighborhood and reach the highway the engine is warm enough for a good, stout stomp on the "gas". But I still give it a few more minutes before I use ALL the available tachometer.

-mickey

BUG*PWR mentioned a blue temp light. Is this just on New Beetles? I have no such light that I have noticed on my 2000 Golf. Does any body else in an A4 Golf or Jetta have such a light? Since New Beetles have such a compact instument pod, are they substituing idiot lights for the temperature gauge?

The blue cold engine light is only on the TDI NB's since they do not have a water temperature gauge.

Finally found something better in the Jetta than NB. Every car should have a temp gauge.

I agree! I wish that the NB actually did have the guage instead of the idiot light. That way you can tell exactly what range the engine is operating in...

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~Nathan
92 TD Jetta
soon to be TDI NB (w/ WETT chip)
http://www.wnec.edu/~nbecker

But our cars look cooler.
Or not, depending on who's looking, I guess.

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Yellow 2000 Beetle

Hey Cage, et.al.,

Having gone from an old Saab with temp gauge to an NB with blue light, I can say that on a GAS engine, I'm more concerned with overheating, and therefore appreciated having the gauge to tell me what was going on, particularly in heavy summer traffic. Saab manuals say to drive the thing hard and not idle the engine to warm it up. Always did; always got high 190k's on the odo before any engine related stuff (mostly hoses) got me thinking about getting a new one.

With the TDI, an engine that is predisposed to cooling OFF, the major concern I have is whether it's safe to go ahead and stomp it once it's properly warmed up, particularly in winter.

That little blue light is pretty persuasive to me. If it were a gauge, I might tend to push it a little early if the gauge said the engine was already somewhat warmed up. With the blue light, I baby it along until it's official (i.e. the light turns off). THEN stomp on it! ;-)

Just my $.02

Hi Dezlboy,

With my '81 Diesel Rabbit, I always lost about 10 mpg in the winter time. I think the "winterized" fuel that they sell in the winter is pretty lousy. In the Summer I'll get 48-52 mpg, and in the winter it drops to about 38-42. Still, that's really incredible mileage!

I have no idea how a TDI would do, but I'd be willing to bet that it would do much better than one of the IDI engines.

Matt

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'81 Rabbit Diesel
310,000 miles and still clattering!
2000-something Golf TDI in the future!
http://matt_lisa.home.sprynet.com/

Does anyone make a lot of short trips in their TDI? I have recently had intermittent problems with my '98 TDI NB not starting up on the first crank...I might have to wait 10 minutes before it'll fire up.

It's only happened once so far with the cooler weather, but it seems harder to start (or it could be my paranoia!).

The dealer's check out the battery, and electrical output. I first noticed it after washing my car. However, I've been washing my car weekly for the past year...it *doesn't* have any problems during heavy rain, though.

Dealer says only thing to do is wait for it to get worse, before they can pinpoint the problem.

Thanks.



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Bill - '98 NB TDI

I had a little difficulty starting my 99.5 Jetta TDI when the weather began to get cold...i.e. stumbling/stalling on startup and smoking. I found three key things that completely eliminated the problem. First, I started using only the best fuel I could find (Amoco powerblend 45 cetane, in my area) plua an additive (power service fuel conditioner). Second, I made sure I always wait for the glow plug light to go out before turning the key. Third, I learned that diesel have tough starter motors and according to the manual its OK to hold the starter for a minute or so. Holding the starter for a few extra seconds, combined with the fuel change did the trick! My Jetta starts immediately now, even when it is 35 in the morning, and there is barely a wisp of smoke. Try these tips, and I bet you'll be pleasantly suprised. Good Luck!

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ThinkDiesel

1999.5 Jetta GL TDI

P.S. Karl- I have to admit, your car does look cooler, but I've grown quite fond of my temperature gauge.... I think relying on an idiot light would make me really nervous when I'm climbing a series of mountains with 2 buddies in the car and camping gear on the roof on a hot summer day. I only wish there was an battery/alternator gauge and an oil pressure gauge as well

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ThinkDiesel

1999.5 Jetta GL TDI

My oil pump partially failed on my 94 Golf. There's nothing like going down the road, and then all of a sudden..beeeeeep, with the little oil can light lit up. I think the light was blinking. As I found out later, there are high-low and low (no)-low warnings, and mine was high-low so I still had some fluid pumping. A gauge would have helped.

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Yellow 2000 Beetle

Could someone PLEASE post a picture of this "engine low temperature warning light", as there is none in euroland?

Thanks!

I would, but I don't have a digital camera. I tried doing a search and I found a cool aftermaket sunroof for the beetle. It seems well made. What do you think?
http://members.aol.com/sunwebasto/fullsizephoto.html

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Yellow 2000 Beetle