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15903120696
Date registered: Dec 1899
Location:
Vehicle(s):
| Do you let your G warm up before you drive?
I usually warm 4 minutes. Only I warm more than 4 minutes, the engine could runs "normal", otherwise it will get loud sound and powerless. |
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: Do you let your G warm up before you drive?
This depends whether you live in Inuvik or Agadez.. 
Irrespective of that, 80% of an engine's wear comes from the first 12 minutes when it is "cold". |
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Jean
Veteran
Date registered: May 2006
Location: Belgium
Vehicle(s): 1980 SWB 300GD
Posts: 103
| RE: Do you let your G warm up before you drive?
Idling is for an engine a quite severe condition as it needs to 'pull' the air inside. I was always told that the best way to warm-up an engine is by driving (as you then have air flow), of course avoiding high revs until the engine is at its normal temperature. - Jean |
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: Do you let your G warm up before you drive?
Jean - 1/25/2016 4:54 AM
Idling is for an engine a quite severe condition as it needs to 'pull' the air inside. I was always told that the best way to warm-up an engine is by driving (as you then have air flow), of course avoiding high revs until the engine is at its normal temperature. - Jean
Sound very wrong as there is NO ram-air effects on passenger cars and not even most race cars.
If it was so the air filter and air ducks would have been designed very differently!
On motorcycles the ram-air effect comes in above 140 mph, and this is with special designed air intake channels and very large air filter to avoid resonance waves inside the air filter for smoother air flow.
The only engines/vehicles that should be driven warm are air-cooled engines as the heat would only build up in the cylinder head. |
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emlmcb
Veteran
Date registered: Dec 2006
Location: Buenos Aires, Argentina
Vehicle(s): 1986 LWB 300GD / 1998 E320 / 1996 LWB G300TD
Posts: 119
| RE: Do you let your G warm up before you drive?
Ever since carburated engines with manual chokes became a thing of the past, I do not warm up the engine anymore.
By "warming up" I mean let it idle for some time.
What I just do is drive gently until the engine is at working temperature, which, if your thermostat is working properly, should not take more than a mile or so. |
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| RE: Do you let your G warm up before you drive?
emlmcb - 1/25/2016 10:24 AM
What I just do is drive gently until the engine is at working temperature, which, if your thermostat is working properly, should not take more than a mile or so.
Except if it's one of the new common rail diesels. It then takes several miles before full operating temperature is achieved. |
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4x4Cal
Veteran
Date registered: May 2007
Location: Calgary, Canada
Vehicle(s): a Desert Silver & a Brilliant Silver G500
Posts: 260
| RE: Do you let your G warm up before you drive?
Is your secondary air pump working fine? |
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koly
Elite Veteran
Date registered: Jul 2006
Location: Scottsdale, AZ USA
Vehicle(s): 2000 G500
Posts: 823
| RE: Do you let your G warm up before you drive?
Just happened to be flipping through my owner's manual and came across MB's official recommendation, at least for the 2000 G:
 (idle.png)
Attachments
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 idle.png (487KB - 0 downloads)
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| RE: Do you let your G warm up before you drive?
koly - 1/26/2016 4:37 PM
Just happened to be flipping through my owner's manual and came across MB's official recommendation, at least for the 2000 G:
I think that is strictly for environmental emissions reasons. Not for engine protection or whatever else. This is the same as trying to get long haul diesel trucks to not idle while parked. It's Politically Correct. |
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AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| RE: Do you let your G warm up before you drive?
For what it is worth, I don't warm it up except in the very cold. Procedure: - Glow
- If <20F, glow again
- Crank. If it fails to start, go to back 1
- If firing on all cylinders, put in D or R.
- If <20F, wait for a minute
- Drive off slowly, no more than 1/3 throttle until fully warm.
I have yet to have a failure to start. The coldest start was an overnight cold soak at 0F. The year round oil is Chevron Delo 400 15W40.
Step 5 is a bit of a toss up. Waiting warms up the engine a little bit, but the after-glow timer will also shut off the glow plugs. And that makes for a really grumpy diesel.
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| RE: Do you let your G warm up before you drive?
AlanMcR - 1/26/2016 4:27 PM
For what it is worth, I don't warm it up except in the very cold. Procedure: - Glow
- If <20F, glow again
- Crank. If it fails to start, go to back 1
- If firing on all cylinders, put in D or R.
- If <20F, wait for a minute
- Drive off slowly, no more than 1/3 throttle until fully warm.
I have yet to have a failure to start. The coldest start was an overnight cold soak at 0F. The year round oil is Chevron Delo 400 15W40.
Step 5 is a bit of a toss up. Waiting warms up the engine a little bit, but the after-glow timer will also shut off the glow plugs. And that makes for a really grumpy diesel.
Smart to drive off at 0°F, that keep the oil pressure up - important on old diesel engines.
If you don't drive off, use the hand throttle to keep rpm and oil pressure up, avoid idle when close or below 0° F.
A cold start at about 14°F, without an engine block heater, has the same wear on the engine as you drove 6-800 miles (with early semi-synthetic or mineral oil).
Too many owners with the old OM617 have the old glow relay (pre 1998) that don't have the after-glow!
You was supposed to change the glow plug too with the new after-glow relay!!!
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emlmcb
Veteran
Date registered: Dec 2006
Location: Buenos Aires, Argentina
Vehicle(s): 1986 LWB 300GD / 1998 E320 / 1996 LWB G300TD
Posts: 119
| RE: Do you let your G warm up before you drive?
Big diésel truck or bus engines are left idling (the same is true for any engine) for a combination of the above mentioned reasons.
Any rotating shaft in a bearing (not a ball or roller bearing) is lubricated by what is known as "hidrodynamic lubrication".
In a similar way as when a fast motor boat "takes off" at a certain speed, at a certain rpm the shaft generates a ram of oil that lifts it from the bottom of the bearing, thus avoiding metal to metal contact and wear.
When the engine stops, this ram of oil is broken and the shaft sits on the metal bearing.
When you start your engine, for a certain time the shaft rotates in contact with the bearing thus generating the extreme wear mentioned in other entries.
Many people thinks wrongly that the high oil pressure generated by the pump when the oil is cold, in a certain way avoids this, but it is not so.
The oil presure generated by the pump and that (if equiped with it) we can read in the oil instrument, has nothing to do with this ran effect.
The oil pressure in the meter just shows us the prssure in the oil circuit of the engine, thus letting us know that oils is reaching every point in the engine, but does not generate the "hidrodynamic lube" effect.
The other reason to let an engine idling during short stops is related to the cylinder - piston ring lubrication.
Both parts fit snuggly with each other in order to supply a proper seal for the combustión, but just like any other metal, the contract or exoand with temperatura changes.
They are designed to have the proper gap between each other at the normal operating temperatura, so that a fine layer of oil can be generated between them.
If temperature is too high or too low, the gap is not the right one and the oil film does not do its job. In extreme caonditions this leads to engine seizure.
Yet another reason, is that all engines work with a combination of air and fuel.
At the right temperatura, the fuel reaches the combustión chamber completely vaporized, but when the engine is cold, some fuel particles can remain liquid, specially when close to cold metal, thus destroying the subtle layer of oil generating more friction and in extreme cases making their way to the oil sump contaminating it.
Ed |
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hipine
Date registered: Jul 2006
Location: US, CO, Bailey
Vehicle(s): 460 1980 280GE w. 617A
| RE: Do you let your G warm up before you drive?
The only time I let mine run a little bit before setting off is when its super cold, like -20 F or lower and I want to stir up the peanut butter in the transmission and transfer case. I put the t-case in "N" and the transmission in 3rd gear and let it idle for a few minutes to churn the oil in both boxes around a little.
The 617A will never really warm up at all just sitting at idle. If it's cold-cold like that I run the Webasto to bring the coolant up to operating temp before I start it.
With a petrol engine in mild temps you're best off just setting off, using light throttle until the motor is warm.
-Dave G. |
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