Oil Change: To heat or not to heat

[bobk]

I'm getting ready for my biannual oil change and just wondering if heating up the engine (and engine room) really has any benefit. Here in the Keys, the oil is easily fluid enough for the pump to remove it. I know the argument of stirring up the sediment, but with modern oils and filters, I have never seen sludge. That wasn't the case in the 50's. What says the group? Do we need to get hot AND dirty? Or is just dirty good enough?

Bob

 

[Bob Bradley]

I go with warm, not hot. But then, I'm in sunny New England, and the molasses gets pretty thick in the winter up here. I run it for about 5 min.

 

[StratPlan61]

You'll remove more contaminents if your engines are warm. Remember, most of the gunk whipped into suspension by a running engine may not be easily visible. Now about the traces remaining in the small nooks and crannies of a motor - well I suspect you'll find many to debate it. The Owner's Manual for my 1940 Chevrolet recommended after draining the crankcase oil, refill with 3 quarts of oil and 1 quart of kerosene to cleanse the crankcase. Run engine 5 minutes, then drain and refill with fresh oil. Probably would work well - but my 12V71TIs take alot of oil for several fillings !!!!!!

 

[krush]

They didn't have detergents in the oil back in the 40's either.....

 

[Avenger]

Krush, I was thinking the same thing. Also, 5 minutes of idling isn't going to warm up anything, but it will put a lot (well, maybe not a lot) of oil into the top of the engine. Where if it's cold all the oil that's going to drain into the pan will be in the pan. I think we're splitting hairs here. If your oil change pump can suck the oil out cold, have at it. The important part is that it's getting changed. A couple of ounces either way isn't going to matter.

 

[Capt K]

I dunno, but I think you guys down South are just way too relaxed for my liking. Up here in the Great Northeast, any excuse to hear the rumble of a Detriot, especially in January or February, is almost as good as sex....I SAID ALMOST.

Anyways, I've always subscibed to the hot oil is better than cold oil during the change.

K

 

[Jaxfishgyd]

The Florida DD mechanics who change the oil on motors here (and are WAY OVERPAID to do a basic job, IMHO) run the motors till temp guage hit 130.

I was told they want the oil circulating so all the smaller "gunk" is suspended and easier to remove.....

Told my buddy who paid them $585 dollars to change the oil in his Silverton I would do it for him for "only" $400 next time....

Hell, he has a built in oil change unit built into the motors!!!!

He saves $200 and I make money....

 

[Trojan]

Your engine was hot when you shut it down. Any crud that was going to drain back would have drained back already and is laying in the pan. If your pump will pump it cold do it. Most pumps won't. 40W is tuff to pump cold. That's why they heat it. Why circulate the acids and condensate that accumulate in the oil and are laying in the pan. If your filters are doing there job and you are changing them when you should. There shouldn't be any crud in the pan.


BILL

 

[bobk]

You'll remove more contaminents if your engines are warm. Remember, most of the gunk whipped into suspension by a running engine may not be easily visible. Now about the traces remaining in the small nooks and crannies of a motor - well I suspect you'll find many to debate it. The Owner's Manual for my 1940 Chevrolet recommended after draining the crankcase oil, refill with 3 quarts of oil and 1 quart of kerosene to cleanse the crankcase. Run engine 5 minutes, then drain and refill with fresh oil. Probably would work well - but my 12V71TIs take alot of oil for several fillings !!!!!!

Krush added that they didn't have detergent oil back then. The 1938 Chevy I drove also didn't have a filter. Those who had them put them on as an after market system. The lubrication system was basically a splash system with just a small pump for the overhead valves.

Yes, of course the filters get changed twice a year too and they ought to be picking up all the suspended stuff. Guess I'll go with cold and dirty this time.

Bob
Chateau de Mer
1981 48MY

 

[REBrueckner]

It's easiest to change oil after returning from a run so the engines are already warm. As noted by others , my oil change system doesn't really pump cold oil and is slow,slow,slow when the 40 wt oil is room temp. No real reason to make a routine job more unpleasant by adding uncomfortable heat to the equation if you can pump the room temperature oil...

Is it biannual or semiannual change? If the later, try an oil analysis at the time of a planned change and see what it says...maybe you don't need one.

 

[Bob Bradley]

No real reason to make a routine job more unpleasant by adding uncomfortable heat to the equation if you can pump the room temperature oil...

It's 33 degrees and freezing rain up here in CT today. You don't know what I'd give right now for some uncomfortable heat.

 

[krush]

Krush added that they didn't have detergent oil back then. The 1938 Chevy I drove also didn't have a filter. Those who had them put them on as an after market system. The lubrication system was basically a splash system with just a small pump for the overhead valves.

Good ole babbitt bearings! Non detergent motor oil is way before my time, but my old man said the engines would gunk up like one can't even imagine back then.

 

[bobk]

It's easiest to change oil after returning from a run so the engines are already warm. As noted by others , my oil change system doesn't really pump cold oil and is slow,slow,slow when the 40 wt oil is room temp. No real reason to make a routine job more unpleasant by adding uncomfortable heat to the equation if you can pump the room temperature oil...

Is it biannual or semiannual change? If the later, try an oil analysis at the time of a planned change and see what it says...maybe you don't need one.

I never could keep biannual and semi annual straight. I change twice a year, every 170 or so hours. Seems long enought when the book suggests 150 hours or once a year which ever is first.
Bob

 

[spartonboat1]

I never could keep biannual and semi annual straight. I change twice a year, every 170 or so hours. Seems long enought when the book suggests 150 hours or once a year which ever is first.
Bob

Ouch. Sorry, don't mean to be impolite. Reminds me of a junior manager reporting to me of another gender (which shall remain unstated) who went ballistic, whenever she was called out in her reports for confusing the two. She never got it straight and was convinced one was the other. Was like touch a Crescent wrench across 12v terminals.

 

[bobk]

Ouch. Sorry, don't mean to be impolite. Reminds me of a junior manager reporting to me of another gender (which shall remain unstated) who went ballistic, whenever she was called out in her reports for confusing the two. She never got it straight and was convinced one was the other. Was like touch a Crescent wrench across 12v terminals.

Don't apologize. No offense taken. I really do mix up the two terms. That's why I put in the detail of what I do.

Bob

 

[REBrueckner]

150 hours is a recommended (average) standard. It does NOT mean you can run an engine 150 hoursd with impunity. The only way to tell is with an oil analysis.
I ran just over 200 hours one year with my 6V53's in a Matthews. Had the oil analyzed: it was fine, no change was recommended. I had already changed it because I don't like leaving used oil in an engine in winter layoff. But for boats
tat are used year round a 150 hour AUTOMATIC oil change is nice but likely UNNECESSARY. Especially with Detroits which use some oil, additives are replenished with toppping off and so should be able to go longer than the standard interval.

At the other end of the spectrum, if engines are idled/stored for five mos over the winter like here in the NE, I'd change oil even at 100 hours, always have, before winter storage.

If bypass oil filters enable virtually unlimited engine time without an oil change you can be sure most can get more than 150 hours with year round use as in mild climates.