Cold starting a new 3520

Dmac1 · Jan 11, 2011

I've got a new to me 2008 3520 and a couple recent cold starts made me wonder what is happening. The dealer mentioned something about pressing in the key heats something but we didn't get into the details. I guess I should have read the manual, but just it starts via just turning the key just like my truck (gas burner).

I thought it automatically ran on glow plugs at first and then, once adequately warm, shifted over to regular operation. Apparently not!

So what is going on when the motor sounds like its running on glow plugs and smoking some? Is the fuel just not fully burning? Is it running rich like a choked gas motor?

I discovered that use of block heater prior to starting helps it warm much quicker. Now I'll try holding the key in for 10 seconds but that seems to probably only give it an initial shot of warmed air so seems like it would only help initial startup and have no affect on warm-up. Right?

Thanks.
Dave

JD755 · Jan 11, 2011

The glow plugs are just for starting. A diesel engine runs by the heat of compression (no spark plugs). The glow plugs preheat the air so it can begin running on its own. They have no effect after it starts.

bud4410 · Jan 11, 2011

i also have a new 3520. after looking in the tech manual & checking with the dealer the injection pump has a "cold start advance device" in addition to the heater in the intake. when the temp gets down around freezing it changes the timing of the pump that makes the engine run slightly faster with a lot of extra knocking & greyish/black smoke. this lasts a short time then it returns to a smooth idle and runs normally. my dealer says this device is on all newer diesel engines to meet gov smog standards. i was concerned the first time mine did it but he said it was normal & to be concerned if the motor doesn't return to running normally after a short period of time. hope this helps...............bud

Dmac1 · Jan 11, 2011

Yeah Bud....thats the odd noise...knocking and such and smoke. I originally thought that was glow plug operations. I guess the smoke is poorly combusted mix.

JD755 - thanks! I always figured, from my construction days and watching/listening to big Cats firing up when cold, that the glow plugs ignited the fuel for a while until the engine got up to temp in the same fashion that spark plugs work in a gas motor. I know they sure sounded 'knocky' and put out lots of smoke!!

USNative · Jan 11, 2011

The engine will smoke a little upon starting but should quit after a it warms up which should take less than a minute. Even with my engine block heater mine smokes just a little on startup which is normal.

If your engine smokes a little on startup you shouldn't be concerned but if it continues to smoke then there could be a problem. Is it hard to start or does it fire right up? Do you have fresh fuel in the tractor? Have you checked the fuel bowl for any condensation build up ?

You may want to try leaving the key turned on for a bit longer before starting it. I leave mine on for at least 15 seconds before starting. Starts easy with very little smoking.

Dmac1 · Jan 12, 2011

It fires right up. I put Power Service white bottle treatment in the fuel before it got cold, but don't really know how old the fuel is because it was in there when we bought the tractor and since we haven't had hardly any snow, I haven't had too many reasons to run it. Still about 1/3 tank. I believe diesel doesn't deteriorate as fast as gas though.

99% of the smoke quits once she's warm. Just a little haze when the lights just right.

I'll try pushing in the key first this weekend! And the block heater!

Going to change the oil, so another excuse to fire her up and run her around a little.

beenthere · Jan 12, 2011

Dmac
Pushing in the key before startup will heat the intake air and reduce the smoke. Just as well use it, as that it is what it is for.

And by now, you've prolly read that in the manual too.

There are no glow plugs as indicated. Apparently that is old technology, for better or for worse. ??

You need more tractor seat time. :cool2:

Chuck Oppermann · Jan 13, 2011

You would think with the electronic system they have, a light would come on to tell you when it's ready.

LaVerne · Jan 14, 2011

Use of a cold start device primarily reduces the beating that your battery and starter take. While the blue smoke, white smoke and misfiring isn't nice, it won't hurt the engine. So use the cold start device when you need it. If your engine readily starts at 10F, don't feel like you are hurting anything firing it right up. Contrary to popular thinking, the CSD can help keep the engine running, or reduce white smoke if you activate it AFTER the engine starts! I have seen white smoke go away when glow plugs are activated on a running engine at -40F, and then start again when the glow plugs are turned off. 99% of operators don't know this, and don't need to!

More important is to run the engine in the 1200 RPM to 1500RPM range (generally for small tractors) while it's cold. Camshaft lobes are often lubricated by slinging oil. If you hold low idle at extreme low temperatures, that is bad because you might not be getting normal lubrication. I have seen Kubota engines with the lobes worn half off because of warming up at low idle repeatedly. 1500rpm warmup cured it, but didn't pay for the new camshaft and lifters.

Likewise, your hydraulic oil is thick like honey. The faster you spin the pumps the more you starve them. So high idle would be a dead wrong way to warm up a tractor too.

Stay around the 1/3 throttle range. After a minute or two start driving the tractor if you need to. Think it has to sit still during warmup? NOPE. That's an old wive's tale. Just don't make it work hard while cold. Wait until the thermostat opens and the hydraulic temp is maybe 32F or higher before you put the engine to full load.

Do this and you will probably never have any cold start damage.

Dmac1 · Jan 15, 2011

Good tips guys! Thanks! Got the manual out and looking through it now. I'd been warming at low idle. Figured slower revs is better...will kick it up a bit. Manual says start at 1/3 throttle and set to 1/2 to warm it. I'm going to see what gets me to 1200 - 1500. 1/2 seems too high (from my computer chair anyway).

beenthere...you're right! I need more seat time! In hindsight...I need more land! That would lead to more seat time!

Dave