HomePortalRegisterLog in

Share | .
 

 To warm or not to warm...

View previous topic View next topic Go down 
AuthorMessage
Justwatching
Senior
Senior
avatar

Number of posts : 258
Age : 27
Location : Bumblefuck
Registration date : 2013-06-10

PostSubject: To warm or not to warm...   Mon Oct 28, 2013 11:56 am

I've always followed the 'norm' that it's best to warm an engine up to temperature prior to an oil change. In the last year or so I've begun to wonder if this is actually a good idea. The reasoning behind the warm up is that it'll reduce the viscosity of the oil, thus more oil will run off surfaces and come out during the drain. I don't doubt the benefit in reducing surface tension, but haven't you just circulated oil all around the engine, coating everything? Compare this against a car that's been sitting over-night on your driveway. The engine is completely dry (or as dry as it's ever going to get), with all of the oil conveniently waiting in the sump to be drained. In fact, the engine would have been hot at the time of being parked meaning you get the best of both worlds (benefit of hot oil plus benefit of extended time for it to collect in the sump)? This would apply to contaminants in the oil as well - better to give them time to collect in the sump with all the oil rather than pump them around the engine moments before draining.

Your thoughts?

Back to top Go down
edlithgow
Super user
Super user


Number of posts : 423
Registration date : 2010-06-01

PostSubject: Re: To warm or not to warm...   Tue Oct 29, 2013 8:27 am

Hot as possible, perhaps directly after "Mafia Maintenance" unless you're likely to burn yourself, which I suppose I am.

Bits that MIGHT settle-out in the sump won't necessarily leave it when the oil is drained. My current sump is a lousy design because the drain plug is held by a captive nut which acts as a sill/strainer.

Oil retained by the engine is a non issue IF you can leave it draining for long enough.

If you are going to remove the sump, OTOH, the longer it stands, the better.
Back to top Go down
Justwatching
Senior
Senior
avatar

Number of posts : 258
Age : 27
Location : Bumblefuck
Registration date : 2013-06-10

PostSubject: Re: To warm or not to warm...   Tue Oct 29, 2013 12:40 pm

"My current sump is a lousy design "

Yeah, if your sump is badly designed then neither procedure will get everything out. Let assume complete drainage is possible.

"Oil retained by the engine is a non issue IF you can leave it draining for long enough"

True, but I'd be surprised if most people allow even half an hour for their engine to drain (a garage certainly won't). This brings us back to the question of which is the lesser evil?

Back to top Go down
edlithgow
Super user
Super user


Number of posts : 423
Registration date : 2010-06-01

PostSubject: Re: To warm or not to warm...   Tue Oct 29, 2013 1:59 pm

I've heard of these "garages" of which you speak.

I've only ever dealt with MOT testers, though, who don't do oil changes.

I leave mine overnight. In Taiwan its so dusty I plug it with a bit of rag when most of its drained, but oil continues to seep through.
Back to top Go down
edlithgow
Super user
Super user


Number of posts : 423
Registration date : 2010-06-01

PostSubject: Re: To warm or not to warm...   Sat Nov 02, 2013 5:10 am

Justwatching wrote:
Let assume complete drainage is possible.

If you assume that, its a no-brainer, but I doubt that assumption is valid.

I have fine metallic slurry settling out of my oil. People tell me this is normal. I don't know if that's true, but I doubt that complete drainage of sump-sediment is likely with most sump designs, and the sumps I've removed (3 IIRC) tend to support that opinion.

The optimum is to drain after a run while the oil is still shaken and stirred, and then leave it draining for as long as practical. If you do your own oil changes, this is easy to arrange.

If you don't, you have no control, so there's no point in thinking about it.
Back to top Go down
stereosound
Senior
Senior
avatar

Number of posts : 150
Age : 45
Location : Wiltshire
Registration date : 2007-05-16

PostSubject: Re: To warm or not to warm...   Mon Nov 11, 2013 11:47 am

Interesting though that Father T :Wky: 

I remember reading somewhere in colder climates they have special heaters in the coolant system to trickle heat the coolant so it is just warm enough so cold starts are not an issue and the heater would be nice and warm from first start on a - something morning :Wky: 

Think it was either Norway or Sweden?

Makes me wonder if the have oil warmers too?

Now an oil warmer in you sump heated for a short while would benefit what your suggesting all your dirty oil would be in the sump and heating it gently would aid draining :Wky: 

I recall seeing somewhere in a very old car mechanics magazine you used to be able to buy heaters that sat under your engine at night???

but in theory the idea of leaving the oil to settle overnight sounds feasable if the oil could be gently heated prior to draining :W:

_________________

Back to top Go down
edlithgow
Super user
Super user


Number of posts : 423
Registration date : 2010-06-01

PostSubject: Re: To warm or not to warm...   Sat Nov 16, 2013 6:39 am

Admin wrote:
Now an oil warmer in you sump heated for a short while would benefit what your suggesting all your dirty oil would be in the sump and heating it gently would aid draining :Wky:
:
I think thats exactly wrong. If you have sediment, pre-heating static oil in the sump will encourage it to settle out, since it'll keep the oil at a low viscosity for an extended period of time. Any sediment will then be more likely to be retained in the sump when you drain the oil.

Admin wrote:
 

I recall seeing somewhere in a very old car mechanics magazine you used to be able to buy heaters that sat under your engine at night???

I saw one once in the shed of an empty cottage that was for sale. Thing a bit like a Davy lamp, with a fine mesh cowl surrounding the wick (presumably to reduce fire/explosion risk from ignited petrol vapour), fuelled by kerosene.

I was tempted to knick it (I'm sure the eventual purchasers just chucked it out) but conscience prevailed.

I'm not sure its such a great idea though. Seems possible condensation from the combustion would cause more electrical grief than the heating solved.
Back to top Go down
Justwatching
Senior
Senior
avatar

Number of posts : 258
Age : 27
Location : Bumblefuck
Registration date : 2013-06-10

PostSubject: Re: To warm or not to warm...   Sat Nov 16, 2013 5:36 pm

I have an engine pre-heater. It's an electric heater pad that attaches to the sump pan. It transfers energy by conduction, so no flames or condensation. Haven't used it yet as it attaches permanently by adhesive. Even if I felt my Proton was worthy, I don't have a driveway for the foreseeable year so no accessible power point.
Back to top Go down
edlithgow
Super user
Super user


Number of posts : 423
Registration date : 2010-06-01

PostSubject: Re: To warm or not to warm...   Sun Nov 17, 2013 2:49 am

I have a cheap wee hotplate designed to keep coffee/tea warm, which would probably do the job, but likewise no convenient access to power, which of course is where the combustion-based heaters score.

IIRC some British Army Landrovers were fitted with diesel-powered pre-heater burners, maybe by Eberspracher?

Since it never gets below zero here (except rarely in the mountains) I don't really need one, though I suppose oil-preheating would still be a good thing in the "not -summer".

It'd mean, for example, that I could go back to using straight 40W engine oil all year round.
Back to top Go down
Sponsored content




PostSubject: Re: To warm or not to warm...   

Back to top Go down
 

To warm or not to warm...

View previous topic View next topic Back to top 
Page 1 of 1

 Similar topics

-
» Warm ESC
» cold hands, warm feet
» wish it was warm
» Engine starts fine cold, dies when warm
» Bad hot or warm starting

Permissions in this forum:You cannot reply to topics in this forum
Bangernomics :: Carcare on a Budget :: Servicing-