[PDC]

From the time I was a kid fetching tools for my older brother and his buddies in the garage, I have always warmed the engine up before draining the oil. The idea is getting more contaminants to pool in the bottom of the oil pan and having the old oil pour more easily and drain more completely.

But with a multi visc oil, don’t the thickening polymers take effect at higher temps to make the oil ‘act’ like a thicker oil when hot? Isn’t the thinnest rating the cold rating? Also, with frequent regular oil changes in your weekend car - haven’t you effectively pooled all the contaminants in the bottom of the oil pan at the end of the last drive?

Not talking about draining outdoors early morning after a hard freeze. Car is in heated garage at 60*. Just wondering if I really need to go for a drive and then wait another 45 min to avoid getting scorched by the headers, or if I can just get the drain pan under there and drain it at ambient 60* temps?

PS - Full Synthetic 10/30.

[i82much]

juice ain’t worth the squeeze. just change it. will you leave a little more old oil behind? probably. will anything be any different after 20 years of doing so? probably not.

[pfilean]

I have always felt it was smart to change oil when warn. I don't want to pull in with a hot engine and have that first surge when the plug comes out and runs down my wrist be hot enough to burn. And for the reasons you point out it may not make any difference. But at least give it time to fully drain. Don't be the guy at the fast lube who puts the plug back in as soon as the flow subsides a bit just so he can make the boss happy by running cars through faster.

[LPete]

Multi-viscosity oil doesn’t get thicker as it warms up, it just doesn’t thin out as much. I’m not sure it really matters, but in my mind it makes sense to change it warm.

[Tom Vaught]

When I worked at my Uncle's Pontiac Dealership, I worked with the "Oil Change" guy on learning that process.

In the summer months, people at times dropped off the vehicle the night before.
In those cases, I was told to always run the engine outside for a couple of minutes to
warm the oil prior to pulling the vehicle on the oil change 2 post lift.
Even after we turned the engine off the oil remained warm enough for a easy drain into
the drain cart.

So I have followed that procedure since 1970 on all of my vehicles over the years.
I also pre-filled the oil filter prior to engine start-up each time. Most of the engine
oil adaptors pointed the filter downward. We used Wolf's Head 10/30 oil in those days, in bulk drums.
The oil change guy said always use Pennsylvania type oils vs SHELL off shore oils.
The oil was cleaner, not so much trash in the oil drums.


Tom V.

[ZeGermanHam]

Originally Posted by PDC

The idea is getting more contaminants to pool in the bottom of the oil pan and having the old oil pour more easily and drain more completely.

I'm not quite seeing the logic here. Wouldn't running the engine suck everything up from the sump and circulate it throughout the engine?

Personally, I'm of the view that if you really want to get the most oil out of the engine during draining, you should let the engine sit overnight and not start it before removing the drain plug. That way, all the oil is in the bottom of the pan and you don't circulate it back up onto the top end. Does it mean the oil takes a little longer to drain out? Yes, but we are generally not in a hurry with our personal toy cars. I sometimes let the oil drain for hours while I do other stuff, or even overnight. Of course this is not practical time-wise in a professional setting.

But in general practice, I just drain the oil as soon as it's cool enough to not scald me, and I keep the plug out until about the time that it drips once every 8-10 seconds. Don't overthink an oil change.

[b-man]

I always try to drain the oil with the engine at full operating temperature.

I want all the contaminants in full suspension so most of them come out during the draining. Any oil in the top end of the engine will drain down plenty fast enough, I’m not running a quick lube shop and usually give the oil a half hour to an hour to finish draining. Sometimes I let it drain overnight if the situation allows.

Letting the contaminants pool at the bottom of a cold oil pan won’t accomplish that, the heavier particles will stay stuck to the bottom of the pan during the draining.

[Dick Boneske]

Whether you're using multi-viscosity oil or not, when the engine has cooled down, heavy solid contaminants will have settled to the bottom of the pan. If you drain when cold, a portion of these solids will remain in the oil pan.

I believe your best chance of removing as much of the oil and contaminants as possible is to drain when the engine is hot, or at least fairly warm. As some have said, after it cools so you don't burn your arm as hot oil runs down your wrist, especially from the oil filter. You may want to wait awhile for more oil to drain from the crank, rods, oil galleries, etc., but, since one of the main purposes of an oil change is to remove contaminants along with the old oil, Obviously, quite a bit will remain in the areas I mentioned, but at least you will dump the heavy contaminants from the pan.

What Jim Taylor said!!

[SRR]

Originally Posted by b-man

I always try to drain the oil with the engine at full operating temperature.

I want all the contaminants in full suspension so most of them come out during the draining. Any oil in the top end of the engine will drain down plenty fast enough, I’m not running a quick lube shop and usually give the oil a half hour to an hour to finish draining. Sometimes I let it drain overnight if the situation allows.

Letting the contaminants pool at the bottom of a cold oil pan won’t accomplish that, the heavier particles will stay stuck to the bottom of the pan during the draining.

I will go one farther depending on how dark the oil is coming out. I'll pour a 1/2 QT of clean oil into the engine while the plug is out to push any old oil down to the pan. I buy oil and filters in bulk so my costs are low. I also use full syn. in everything but my diesel truck.

[PDC]

Thank you - I am glad to see enough well-thought opinions on this topic to tell me that I didn’t ask too stupid a question. I now get it that the polymers do not make the oil thicker at temp - they keep it from getting thinner at temp. Makes sense.

It also makes sense to have contaminants ‘in suspension’ in the oil when you drain it rather than settled out in the bottom of the pan. With the weekend car - and the weekend to get a project done - I can think of no reason to be in such a hurry not to take a short drive, park, and then watch a half hour of whatever is on the tube before reaching around under the car to drain the pan and wrestle with the oil filter.

I’m also wondering with full synthetic, never starting the car unless I am actually driving it and getting it up to full operating temp under load, and realistically driving between 900-1200 miles this year, if I might be able to step away from the traditional annual oil change no matter what...

Then again at well under $100 for even pricey designer oil and a NAPA filter, it sure isn’t going to hurt anything to circulate fresh oil over all the moving parts before parking her for the winter.

[PontiacJim1959]

Originally Posted by PDC

Thank you - I am glad to see enough well-thought opinions on this topic to tell me that I didn’t ask too stupid a question. I now get it that the polymers do not make the oil thicker at temp - they keep it from getting thinner at temp. Makes sense.

It also makes sense to have contaminants ‘in suspension’ in the oil when you drain it rather than settled out in the bottom of the pan. With the weekend car - and the weekend to get a project done - I can think of no reason to be in such a hurry not to take a short drive, park, and then watch a half hour of whatever is on the tube before reaching around under the car to drain the pan and wrestle with the oil filter.

I’m also wondering with full synthetic, never starting the car unless I am actually driving it and getting it up to full operating temp under load, and realistically driving between 900-1200 miles this year, if I might be able to step away from the traditional annual oil change no matter what...

Then again at well under $100 for even pricey designer oil and a NAPA filter, it sure isn’t going to hurt anything to circulate fresh oil over all the moving parts before parking her for the winter.

Wow, didn't think changing oil required a lot of thought. If there are all those contaminates in the oil, why do we run an oil filter? And, you are assuming whatever contaminates you speak of are heavier than oil and fall out of suspension and don't permeate thoughout the oil, float in it, or rise to the top.

I always run my engine up to temp or pull up into my driveway and then let the car cool down to warm. The warm oil drains from throughout the engine better and drains from the pan better/faster.

I pull the oil filter and then when re-installing the new one, always check to make sure the rubber O-ring seal is on the filter. Sometimes they are left off and I have caught a couple - you will have oil spewing all over, or in the case of my '73 Fury, the previous owner cranked down on the filter so tight I had to use an extension on my breaker bar to remove it because it had no O-ring seal and they just kept cranking on it until it stopped leaking.

Once you check for a seal, I fill the oil filter with oil so its primed and the engine does not start up dry. I also wipe oil over the O-ring to get a good seal when I install it. I don't torque the filter, tighten until you feel resistance telling you it is snug, then tighten about 1/2-3/4 turn - you learn to do this by feel and you know it is tight enough. You don't have to crank down on it until it doesn't move anymore.

Then add your clean oil after re-installing the pan plug.

I also will add a 1- Quart of Transmission Fluid every couple of oil changes. This will really clean the engine. If you have never done this and have a lot of miles, might not be a good idea, or use less fluid - you don't want to dislodge a lot of sludge. Let the engine run at an idle and up to temperature. Then shut down and do your usual oil change. Don't drive with trans fluid in the engine as it is thinner and it'll thin the oil and you may see oil pressures drop - so I was told. Obviously, if you are a couple quarts low, I would not be adding any. I'll add it if my engine is 1 QT low or above.

I also always change the filter along with the oil even if it is a high mileage filter. I have been using Napa Gold or Wix brand filters and they seem to be OK. I've run other brands, but I change oil early enough that I don't think it matters.

[78w72]

Originally Posted by PDC

Thank you - I am glad to see enough well-thought opinions on this topic to tell me that I didn’t ask too stupid a question. I now get it that the polymers do not make the oil thicker at temp - they keep it from getting thinner at temp. Makes sense.

It also makes sense to have contaminants ‘in suspension’ in the oil when you drain it rather than settled out in the bottom of the pan. With the weekend car - and the weekend to get a project done - I can think of no reason to be in such a hurry not to take a short drive, park, and then watch a half hour of whatever is on the tube before reaching around under the car to drain the pan and wrestle with the oil filter.

I’m also wondering with full synthetic, never starting the car unless I am actually driving it and getting it up to full operating temp under load, and realistically driving between 900-1200 miles this year, if I might be able to step away from the traditional annual oil change no matter what...

Then again at well under $100 for even pricey designer oil and a NAPA filter, it sure isn’t going to hurt anything to circulate fresh oil over all the moving parts before parking her for the winter.

with a good quality oil & a clean well tuned engine, i dont follow a time frame for changing, if its less than ~1000 miles i dont see any reason to change the oil just because what the calendar says. quality oils, especially synthetics have additives that neutralize any acids that would harm the internals. if the oil will pass a used oil analysis (UOA) which almost any oil will with that low of miles on itl, its perfectly acceptable to leave it in there.

some of my cars dont get even 500 miles in one year & ive gone 2+ years without changing it & when i do, it still looks like new. clean oil doesnt go bad from time, within reason. same goes for storing new oil on the shelf, some guys think it goes bad after 2-3 or even 5 years. if stored in decent conditions oil will last a very long time, been confirmed by a few oil companies i asked some years back.

i just did oil changes to my cars a couple weeks ago & am still using up SM grade oils ive had for 8+ years i bought in bulk on sale... even used some of the good old rotella-t SL grade oil ive had for over 10 years! just shake the bottles every now & then & before use & the oil is perfectly fine to use.

[Sirrotica]

Everyone is overthinking this way too much. After 50 years in the automotive field I have changed it both ways, and drained thousands of gallons of oil from just about everything with an IC engine in it. Boat owners that can't get the oil drained in a conventional method pump the oil out of the pan, you're never going to drain the pan completely with a pump, correct?

Same deal goes for a thread about filling the the oil filter with oil before firing it up, that appeared here within the last year. No manufacturer of cars, nor oil filters recommends it, it's not necessary. In all that time wrenching, I have never prefilled an oil filter during an oil change, it's a waste of time. It never happens at the factory, if they're not concerned about it, and have the responsibility of warrantying the engine during the first 5 years, why be concerned about it at 100,000 miles?

If you're seriously worried about removing contamination from your oil, the best way to do that is to get a real oil filter, not the OEM version of a strainer. Too many compromises in the OEM oil system, and filter to keep the oil clean with the standard setup. You do have to keep draining and flushing the system with fresh oil periodically, correct? That's because the inefficient OEM filter doesn't get the abrasives out because the media is incapable of filtering the oil to a fine standard. It has to have pores large enough so it doesn't severely restrict oil flow to the internally oiled engine components, not to mention a bypass valve, as I said a compromise.

Put a by pass oil filter on the car, and you'll be doing yourself, and the car a huge favor. Your oil will last a minimum of 5 times what it does now, and the oil will analytically come out just as clean as it did when you poured it in initially, all the abrasives that this subject are about will be captured in the by pass filter, not floating in the oil, or lying in the bottom of the pan. I'm now past 10 years using by pass oil filters on my own vehicles, gas and diesel, and thoroughly satisfied with them, wish I had paid attention the first tme I saw a Frantz by pass oil filter demonstration in the early 70s. Trying to do the perfect thing, with an imperfect system, is an exercise in futility.

Here's a visual on what I saw, and chose to ignore in the early 70s:

https://www.youtube.com/results?sear...il+filter+demo

Carry on!!!

[vertigto]

Is there a way to mount a bypass system that is inconspicuous enough for those looking for a stock-ish application?

If using the rationale of necessity based on the factory not providing it, is it really only for the truly retentive? I'm all for going a step above to lengthen engine life/performance, if I can hide it well enough.

[78w72]

Originally Posted by vertigto

Is there a way to mount a bypass system that is inconspicuous enough for those looking for a stock-ish application?

If using the rationale of necessity based on the factory not providing it, is it really only for the truly retentive? I'm all for going a step above to lengthen engine life/performance, if I can hide it well enough.

doubt you will be able to mount a bypass filter to where you cant see it, its a large canister with a roll of toilet paper inside, plus the plumbing to & from it. that is the main reason 99%+ of classic car owners dont use one. that & the fact the stock type filters are good enough to get older cars to 100k+ miles back in their day with far less advanced oils than today. & modern daily driver cars such as toyotas or even GM's & fords go to to 200-300k+ miles with standard filters, the rest of the car will fall apart before any real engine damage from using a normal spin on filter occurs.

IMO it is definitely for the "retentive"... they are mainly for over the road semi trucks or fleet vehicles that see millions of miles & need to get every last ounce of time out of the engines. yes they filter better than a spin on, but is that really needed on a classic car that gets driven maybe a couple thousand miles a year with frequent & usually sooner than needed oil changes? no.

just my opinion based on facts.

[F ROCK]

Originally Posted by vertigto

Is there a way to mount a bypass system that is inconspicuous enough for those looking for a stock-ish application?

If using the rationale of necessity based on the factory not providing it, is it really only for the truly retentive? I'm all for going a step above to lengthen engine life/performance, if I can hide it well enough.

I had no problem mounting a hidden one in the fender of my '71GTO, behind the battery.
The supply and return lines can be made invisible as well.
Amsoil sells a spin on version, the canister is about the size of a small toilet paper roll.
I spent $8000 building/ improving an engine; I didnt mind spending $125 more for some extra filteration.
When i pull the dipstick on my investment, I like to see super clean oil.

[Sirrotica]

Originally Posted by vertigto

Is there a way to mount a bypass system that is inconspicuous enough for those looking for a stock-ish application?

If using the rationale of necessity based on the factory not providing it, is it really only for the truly retentive? I'm all for going a step above to lengthen engine life/performance, if I can hide it well enough.

I've seen them mounted behind the bumpers, under the car, and in the trunk or in the bed of trucks. If anyone with just a little bit of mechanical ability wanted to make a filter incognito, it's entirely possible. The excuse for not using one in a classic car is right up there, if you never want anything to break or wear out, just leave it in the garage, and nothing will ever happen to it.

The wear rate of internal engine parts is reduced 7-8 times over a conventional filter. Think about that with a $5-10,000 investment in a well built Pontiac street engine. Reliability is increased in every part in the internal engine assembly.

Because many of the engines in these cars are trying for maximum HP the air filtration systems are sometimes less than optimum, dirt ingested through the intake tracts ends up in the oil. Many times it's silica based because it's road dirt. Tough on any engine if ingested ending up in the oil, circulating and causing wear until the oil is drained, too fine to be removed by the OEM filter.

Recently I replaced the water pump on my 6.5 diesel truck, to do so you get to see the timing chain because of the way the timing cover is designed. The timing chain has no slop in it whatsoever. That proves to me that an item that commonly wears quickly in almost all Pontiac engines, is going to maintain much closer to new tolerances with superior oil filtering than with the conventional oil filter. The cam timing will remain closer to what it was set at upon assembly. Why bother to degree a cam, when in 10,000 miles its off 6 degrees of where you set it?

I spend the money to equip my vehicles with a by pass filter because the initial investment pays back in reduced engine wear and oil life. At 67 YO pulling engines because they are worn out, when I could have prevented them wearing out isn't my idea of fun. Few OEM GTO engines made it to 100,000 miles, many never made it to 50,000 miles to be truthful.

Maintaining an engine the best possible way to improve longevity of all the parts, as opposed to doing it the same way it's been done for decades by the average person that treats their car as an appliance. I'm not going to belabor the point of superior filtering because the thread wasn't about that initially. The information is available if someone is interested in it:

https://www.machinerylubrication.com...ass-filtration

[64speed]

I by far am no expert and probably the least likely person that any of you would take advice from but here’s my two cents. I drain it cold to luke warm simply because and for NO other reason than I don’t wanna burn myself. This is one of those topics that I think you could ask 10 people and get 10 answers on this forum. Kinda like a conversation I had with my best friend and fellow retired veteran. He was an Eagle Scout, now his 17/18 boys are getting their eagle. We were talking about it and he said one of the biggest things he struggled with as a young scout was the motto. I thought out loud “be prepared” and he said yeah but what does that mean. I said I’m not tracking. He said do you keep jumper cables? I said yeah. He said well why not go a step further and carry a fully charged battery, etc, until the point that you’re so prepared you’re towing a car to fix the car you’re driving should it break down. Point being, unless you’re running the bypass oil filter, set your interval, use good oil and filter and get as much out as you can. In my mind no sense in reinventing the wheel!

[propuckstopper]

Originally Posted by PDC

From the time I was a kid fetching tools for my older brother and his buddies in the garage, I have always warmed the engine up before draining the oil. The idea is getting more contaminants to pool in the bottom of the oil pan and having the old oil pour more easily and drain more completely.

But with a multi visc oil, don’t the thickening polymers take effect at higher temps to make the oil ‘act’ like a thicker oil when hot? Isn’t the thinnest rating the cold rating? Also, with frequent regular oil changes in your weekend car - haven’t you effectively pooled all the contaminants in the bottom of the oil pan at the end of the last drive?

Not talking about draining outdoors early morning after a hard freeze. Car is in heated garage at 60*. Just wondering if I really need to go for a drive and then wait another 45 min to avoid getting scorched by the headers, or if I can just get the drain pan under there and drain it at ambient 60* temps?

PS - Full Synthetic 10/30.

Take the car out for a nice drive. Put it up on your hoist, ramps, or whatever you have to access the oil drain plug. Unthread the drain plug.

Leave it overnight to drain, and you will have 100 percent defeated the 20 minute oil change places.

Leave a big note somewhere that the engine has no oil and needs to be re-filled.

Fill when ready, and go for another drive.

[69hardtop]

I also do it this way: drive car to get to operating temperature, wait about an hour or so, drain oil/drop filter (i have a big thick rubber glove i use to protect my hand), go eat lunch or do something for an hour or so until it stops dripping then replace filter I’ve pre-filled with oil, install drain plug and add oil. Been doing it this way for about 40 years, regardless of oil type