Warm up on idle or Start and Go

Discussion in 'Tech/Mech General' started by Jim, Mar 10, 2010.

  1. Jim

    Jim Ringleader

    Joined:
    Jul 19, 2007
    Messages:
    25,845
    Likes Received:
    76,160
    Location:
    Sutton on Sea
    I have just seen this mentioned on another thread. I have seen conflicting advice. What is the consensus? In the cold should we let the engine idle till it warms up before we pull away. Or should we just start up and go. Also what about the few of us that have petrol engines motorhomes, is the advice the same?
     
  2. laneside

    laneside Funster

    Joined:
    Aug 14, 2009
    Messages:
    3,490
    Likes Received:
    5,289
    Location:
    Oradour sur Vayres
    laneside

    I just bet that you do not get a definitive yes or no answer to this one Jim.

    Cheers Alan
     
  3. Larrynwin

    Larrynwin Funster

    Joined:
    Feb 22, 2008
    Messages:
    8,503
    Likes Received:
    12,699
    Location:
    Norfolk
    Oil pressure will be up to normal quite quickly and as such all bearings etc should be protected. Just dont rev the guts out :Eeek:
    I normally start and then drive after about 1min . Petrol
     
  4. DESCO

    DESCO Read Only Funster

    Joined:
    Mar 11, 2009
    Messages:
    2,651
    Likes Received:
    267
    Location:
    London
    Always on modern engines start and drive don't bother with warming up.

    Have always done this on petrol and diesel.



    Dave :thumb:
     
  5. robnchris

    robnchris Funster

    Joined:
    Jan 11, 2010
    Messages:
    1,332
    Likes Received:
    1,555
    Location:
    Chester
    take it easy

    Thinking about it you have two different engines, petrol and diesel, i`m thinking from cold the petrol should be warmed up first, reason, you are pumping a richer mix of petrol in the cylinder head, engine is cold, not a lot of oil around the piston / rings etc.
    petrol washes away the oil so lubrication lessened.

    Diesel engine, well the fuel you`re pumping in is oil so lubrication from the start, hence diesels doing greater mileage, my only thoughts outside of the engine care would be all the components warming up thus lessening the thermal shock on the system.

    You wouldn`t leave the house on foot and break into a full speed sprint without warming up first would you.

    Mind you I wouldn`t get up to full speed if you threw me off a clliff..:Rofl1:
     
  6. ingram

    ingram Read Only Funster

    Joined:
    Aug 9, 2008
    Messages:
    87
    Likes Received:
    1
    Start and go definitely. One thing that really annoys me; it's mostly 'tuggers' but motorhomers too, is, while sitting outside eating my breakfast on a nice sunny morning they start their engine then leave it running for five or ten minutes while hooking up the caravan or just furtleing about ............ and then there are those who leave the engine running while 'checking in' to the campsite .........

    Harvey
     
  7. Dodgey

    Dodgey Funster

    Joined:
    Oct 15, 2007
    Messages:
    1,603
    Likes Received:
    227
    Location:
    Gone RVing
    Personnally, never start and drive. If a manual trans not so much but I prefer to let the engine settle, just a short 30 secs ish depending on time of year. Often the gearbox can be a little stiff, oil cold and thick so gentle is the watchword in my book and as said above, go easy on the revs.

    Now auto trans, these really do need a minute or two depending on temperature. Example, cold day, start our Grand Cherokee and engage drive, nothing, no movment! Even given a minute or two reverse generates a nasty noise (from the torque convertor) when cold, so common sence in my book don't rush until she's warmed up. Even with a few minutes alot of autos are a bit strange with their shift patterns until warm and at the end of the day, in my book at least, rushing these things could cause damage, and expensive damage at that. Just remembered, the no drive when cold, I had a Laguna that was the same, though it was a company car:Blush:

    And another thing, I have read a few handbooks were it specifically states for autos to let them warm up a bit, one, which I can't remember what car it was for, that specifically stated 2 minutes.

    Anyway, as far as I'm concerened, I like to go gently when cold as it's my pocket the repairs come out of IF I did damage just because of rushing....
     
  8. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,431
    Likes Received:
    25,089
    Location:
    Macclesfield
    On a forum you would not get a definite yes or no to "Is this Wednesday".
     
  9. Jim

    Jim Ringleader

    Joined:
    Jul 19, 2007
    Messages:
    25,845
    Likes Received:
    76,160
    Location:
    Sutton on Sea


    Yes, my mistake, I suppose the words consensus and forum don't sit happily together:BigGrin:

    That's why forums can be so interesting:BigGrin:
     
  10. Jim

    Jim Ringleader

    Joined:
    Jul 19, 2007
    Messages:
    25,845
    Likes Received:
    76,160
    Location:
    Sutton on Sea

    Its not Wednesday everywhere is it?
     
  11. laneside

    laneside Funster

    Joined:
    Aug 14, 2009
    Messages:
    3,490
    Likes Received:
    5,289
    Location:
    Oradour sur Vayres
    laneside

    Quite definitely its Wednesday Brian, surely that will get a definitive answer.

    Cheers Alan
     
  12. JeanLuc

    JeanLuc Funster

    Joined:
    Nov 17, 2008
    Messages:
    2,782
    Likes Received:
    1,857
    Location:
    Warwickshire
    I thought the advice, for modern diesels, was not to let them idle for long as it can lead to the risk of cylinder glazing. I try to 'start and go' - perhaps allowing 30-60 seconds for oil circulation.

    Philip
     
  13. Jim

    Jim Ringleader

    Joined:
    Jul 19, 2007
    Messages:
    25,845
    Likes Received:
    76,160
    Location:
    Sutton on Sea
  14. Larrynwin

    Larrynwin Funster

    Joined:
    Feb 22, 2008
    Messages:
    8,503
    Likes Received:
    12,699
    Location:
    Norfolk
    Guvnor is now the Speaking Clock :Rofl1:
     
  15. froghopper

    froghopper Read Only Funster

    Joined:
    Nov 29, 2009
    Messages:
    413
    Likes Received:
    176
    Location:
    winchester
    is it wednesday

    morning brian,, well it is in sunny winchester, not so sure wed has reached you yet,,, well it is a long way,,, but please, when it gets there, realy enjoy it,, :thumb:
     
  16. IrasciBill

    IrasciBill Funster

    Joined:
    Mar 6, 2010
    Messages:
    186
    Likes Received:
    19
    Location:
    SW Scotland
    My Twopenceworth

    Hi Guys,
    It's definitely Wednesday up here North of the border.
    Re the original question, I was always told that a diesel would not warm up significantly when idling because of two factors
    1. - Diesels don't generate a great deal of heat when they are not working hard.
    2. - Diesel engines have a higher thermal mass than comparable petrol engines.

    Personal opinion is that all engines should be given a minute or so to settle down before setting off and will only run efficiently when up to normal operating temperature. Difference is that a petrol engine can achieve normal operating temperature while idling for 5 mins or so but a diesel can run for over an hour without moving the temp gauge needle much at all. Certainly our MH (diesel) needs to be driven a couple of miles before the temp rises significantly.

    Of equal or even greater importance, if you have a turbo, is to let the engine idle for a few minutes before switching off to let the turbo cool off a bit; but then that's a different topic.

    So there we go - my first post on this site - and I can say without fear of contradiction that it is definitely Wednesday here (I think) and as for warming up - "Don't really know for certain"!

    Regards all,
    Bill :Smile:
     
  17. Spacerunner

    Spacerunner Read Only Funster

    Joined:
    Apr 7, 2008
    Messages:
    609
    Likes Received:
    195
    Location:
    Hampshire
    I would have thought by the time you have faffed about getting off the pitch/drive then the 'shotgun/navigator has fought the seatbelt and settled that would be quite enough for the engine to warm up on.

    As long as you don't go straight up to 70mph then just letting the engine idle at a standstill is IMO a complete waste of time and fuel.
     
  18. MAUBRI

    MAUBRI Funster

    Joined:
    Aug 9, 2008
    Messages:
    195
    Likes Received:
    4
    Location:
    Lanner - Cornwall
    Well its still Tuesday in Alaska.

    getting back to topic, Slightly different I've got LPG / Petrol. I start up and idle until the LPG kicks in which takes between 5-10 mins dependant on the weather. But I concur with the previous.

    Petrol a short idle then go. Diesil go at start up, which is good as its the worst pollutant.

    Brian
     
  19. JJ

    JJ Funster

    Joined:
    May 1, 2008
    Messages:
    14,554
    Likes Received:
    25,688
    Location:
    Quinta Majay, Pinheiro Bordalo, Portugal
    OH MY LORD! It is wednesday... I have to go to work...

    JJ
     
  20. ehuplad

    ehuplad Read Only Funster

    Joined:
    Feb 9, 2009
    Messages:
    509
    Likes Received:
    93
    Location:
    North Yorkshire
    The worst thing you can do to a engine is let it idle to much. Start up and go but not to many revs until it warms up.
     
Loading...

Share This Page