Does running synthetic oil defeat the purpose of a block heater?

no northern Utah might not be as cold as some places, but in my valley we get inversions where the temps drop well into the negatives for weeks at a time and I frequently snowmobile in a place that has been recorded in the top three coldest places in the lower 48 where my truck sits unplugged all day long and I've never had a problem getting my trucks started from my old carbd trucks to my diesel with and that's with conventional oil to. I never said not to plug your truck in, just that a properly maintained rig should be able to fire up in cold temps just fine. Might fire up slow but should still fire up.

 

Never had a problem starting the tacoma in very low temps (below zero daytime highs) that we have been getting in the past few winters. It would crank over slowly due to my crap battery, but once it fired up it ran fine if you let it sit and warm up.

 

As you said, if it's maintained properly it'll fire up, no debate there. Those days I left it unplugged in -40 and -50 it fired up., but I can tell you that she didn't like it.

Think longterm, later on down the road. What kind of damage is being done if you never plugged it in, ever? How many yrs/miles would be taken off the life of the truck?

Personally I'm not willing to find out. Plugging in my vehicle adds probably 2 seconds to my entering/exiting the vehicle routine... I'll manage.

 

Using a heater never hurts, even on mild days. anything you can do to allow easier oil flow will help prevent wear-and-tear for engine longevity. So the short answer, if you are already considering it, is to go ahead and get one. Your engine will thank you and faster heat in the cabin will always be welcome

 

I've lived in colder climates, (not AK, MT cold) but at -x temps I'd use the heater if available. Just the contraction of the metal at those temps is scary, never mind the thick ass oil. I live in tx now and I dream of cold weather...

The military does all kinds of testing for fluids and materials for just this reason.

 

Well, just an amateur here. I've always had block heaters intalled in my new cars, which goes back to a 1988 Jetta turbodiesel, and then on to Accords and AcurasTL. Oil grade was thicker in those days. That is why I was wondering about the relevance of a BH on my 2016 Tacoma which uses

$52 0W20 oil Toyota/ exxon mobil Case of 6 Quarts Full Synthetic TGMO SN 0W-20 Oil

0W20 oil grade. I had a block heater installed upon purchase, but it leak slightly and I am considering to have it removed. Coldest weather around here is -30°C (-20°F). I had a battery heater installed so as to bolster battery cranking power, just in case. Still wondering.

 

OMG, who ever told you that shouldn't be let near a wrench, and certainly not within 5 miles of my truck. Block heaters are to prevent the freeze blocks from blowing while its sitting in extremely cold temps, it has nothing to do with what oil you have. I hear that block heaters help with diesel engines, even when it's not freezing, but you have a fuel injected gasoline engine.

High 30s? That's Sacramento weather, lol. That's not even cold, you have nothing to worry about. Run your 5w-30.

You shouldn't need a block heater unless it's consistently below freezing for long periods of time. Block heaters just prevent your freeze plugs from blowing. Even if it gets below freezing over night, but warms during the day, I bet your block temps don't get below freezing at all.

 

Thanks for this reply, jbrandt ! Have a nice day!

 

Good answer by a fellow countryman.

 

If you're dealing with temps below -36 then you should be running coolant at 40:60 ratio. At 30:70 you actually start to increase the freeze point. Straight coolant freezes at like -13 (???). The less water in the mixture reduces heat transfer. Race cars run straight water. IMO a block heater above -30 is for human comfort like faster cabin warming. Below like -40 might be for engine block protection. Batteries are much weaker at lower temps but if it starts the oil flows soon enough and you're good to go. Remember modern oils synthetic or natural all have coating additives to protect against wear during startups. Synthetic oils have a better temp range so that would be a better choice in very cold conditions.

 

my understanding of block heaters back in old days wasnt for oil but for coolant. My dad would talk about below zero temperatures in NW Minnesota that would last for a month. Blocks would crack, core plugs would pop ... so cold even the horses refused to leave the barn.

 

Thanks for the comments, TACOVRD, KNAYRB und GLAMISMAN. I am not so much concerned about the engine capacity to start, but about engine wear and time to warm up.
I am actually measuring how much coolant it looses in a month and will decide afterwards.
Seems that some fellows out there are experiencing much more extreme weather that I do... Greetings.

 

I have seen studies of pre-lubers and the big benefits of starting the motor while there is oil pressure already... kind of over-kill but to each his own.

 

What is a pre-luber, may I ask?

 

I don't blame them, I wouldn't want to leave either!

But yeah, that's my understanding is that the block heaters aren't to maintain oil viscosity for startup or anything, proper oil viscosity should take care of that. It's just so your block doesn't freeze solid and blow your freeze plugs which are on the coolant side of things.

 

Aren't those more common with industrial/commercial diesels? Not sure I've ever seen one for a gas vehicle.

 

The oil rating itself is the viscosity at freezing and boiling temperature "5W-30" (0C and 100C)
If the concern is the oil being too viscous (harder to flow) at ultra low temperatures with 5W-30, then you should run a lower viscosity oil for a piece of mind.


Then again I live in California so can't help you with first hand cold weather experience Only time I experience real cold weather is in the Sierra Nevada's in the winter time. My main concerned of that cold weather is all the cheap plastic components breaking off Lol

 

So yea, synthetic or not it's the same viscosity rating regardless..

 

Then again I'd bet my paycheck oil flow is non Newtonian
So if you were to plot viscosity at at 10F intervals or whatever it would be an 'arc' and not a straight line. So technically maybe synthetic oil is better at colder temperatures (below 0C). As manufactures only give you viscosity rating at 0C.


So at higher running temps (+/-10C) = less change in viscosity. Almost non even noticeable.
At lower running temps (+/-10C) = BIG change in viscosity.

So yea even a few degree difference at that low range will change viscosity rather significantly. I would opt a lower viscosity oil for those weather conditions

edit: but back to your point, a synthetic oil may have a less significant drop off point like conventional oil. So technically it could hold is viscous properties much better than conventional in those ultra low running temps.

 

Good food for thought !
If I remember correctly, my ¸former vehicles, especially turbodiesel and V6, would crank faster and seemingly easier at -30°C (-20°F) with a block heater on than without it.