Recommend an oil choice to me - used 2005 Highlander V6

N

NissanMaxima

Joined
Oct 21, 2015
Messages
366
Location
Colorado
Hi all. Just purchased a very nice 2005 Highlander V6 3.3L. 125k miles and impeccable carfax with regular 5k oil changes - most at dealerships, but some at other quick lube places. The seller indicates dino oil was likely used although the last oil change was supposedly hybrid oil. 5W 30 is recommended in the manual. Two issues I wanted to note: 1) the valve cover gasket is leaking in case that impacts oil choice votes. 2) In the oil filler "neck" area, I noted the metal "baffle" has a hard carbon-like oil coating that most folks on the mechanical board didn't find concerning, nor did a reputable shop that I had inspect the car. But I can't help but wonder if perhaps I should look at an oil that might have better cleaning power than others.

I'm partial to Mobil. So am thinking:
1. Mobil 1 5W-30 full synthetic
2. Mobl 1 5W-30 High Mileage - full synthetic
3. Mobil Super 5000 synthetic blend
4. Mobil Super conventional

Years ago, folks claimed switching to full synthetic could cause oil leaks and I think this is the origin of the Mobil1 1 HM version that supposedly has additives that help swell seals to avoid leads. Any issues with using straight Mobil 1? Consider the HM version? Go with a blend (considering conventional has likely been used in the car since 2005) to be on the safe side yet still get synthetic qualities, or just stick with a good quality conventional like Mobil Super and be mindful of the 5k change intervals.

TIA in advance oil gurus for any and all input!
 
I've always been confused by synthetic blends. They seem neither here nor there. Is it simply an attempt to address a price point between conventional oils and more expensive full synthetics? In other words, if I don't mind spending more, should I go for the full synthetic or are there any actual benefits to the blends?
 
GSCJR said:
Normal.

One of the best vehicles I ever owned was a 2003 Highlander, it's not fussy, just pick an oil. Enjoy the truck!
Click to expand...
Appreciate that. I was indeed concerned about the oil coating at first. I've never seen that before. Good to know you liked your 2003. I've been impressed so far. Purred on the highway all the way home today!
 
Others may disagree, but with one valve cover already leaking, starting now with a full synthetic oil could cause more leaking. The last leak you want is a rear engine seal. I'd still go with a high mileage blend.
 
Toyota's 3MZ 3.3L V/6 is one of the best engines Toyota has ever produced, easily in the top 5.
I have always used 5w-30 M1 in mine and it only burns about 1/2 qt between 5k mile oil changes at 200k miles. The black crusty substance on the oil fill baffle is not a problem. I think that they might have come that way from the factory because mine has always had it.
I disagree with those that claim switching to a synthetic oil will cause oil leaks. There is NO rational reason why it would. There are many threads in here on this topic and most people (and experts) agree with me on this. I consider this an "old wive's tale".
On an older Toyota you want to keep a close eye out for cooling system leaks because a major overheating event could kill it. The weak points in the cooling system are the plastic thermostat housing (cracking), an upper left hand corner radiator leak (hard/impossible to see), and the valley pan seal leaking. Just watch your coolant level closely because none of these leaks are catastrophic and none of them leak coolant into the crankcase. Use only Toyota Super Long Life 50/50 pre-mixed pink coolant (a proprietary HOAT).
Some people feel that having a timing belt is a disadvantage, but I personally don't. Just have the timing belt, water pump, and idler pulleys changed using OEM parts every 100k to 110k miles and it should last 300k+ miles easy. I have only had mine changed once, it is about due for another soon, but I'm not too worried about it because I personally know people who have gone over 200k miles on the original parts (but I don't recommend that you do this).
The 5spd automatic transmissions are solid, just do a fluid drain and fill every 30k miles (don't flush it) and it shouldn't give you any problems, and it is easier to change than the oil. Use only Toyota T-IV fluid.
 
Any of those you listed will be fine. Regular oil changes at the proper interval is much more important than the brand of oil used.
 
Today practically all oil is at least a synthetic blend, they pretty much have to be so they can meet the stringent specifications that are used today and honestly have been shifting that way for a long time now. With the older vehicles it's a bit of truth to that, mostly due to it being older and the materials used for seals and gaskets. Synthetic oils have molecules that are the same size in unison but conventional has ones that are both large and small, over time the larger ones shear down and basically thins out the oil and you lose viscosity. With the larger molecules they are prone to not leaking whereas the synthetic can seep through cracks. It's not that they cause new leaks, they just find them more easily.

For your application any synthetic can go 5k with ease.
 
As Lubener said any one of those oils in your list will be fine, even WM SuperTech. There isn't much difference these days for a daily grocery getter.

I quit using conventional oils in the 1970's when Mobil came out with the first Mobil1, the "leaker". That would include my 1958 Ford and 1970 MGB back in that era. The only things that get conventional oil, now a blend, are my OPE.

And as one member noted, the black, crusty, material in the oil fill hole is something added by Toyota.
 
wag123 said:
Toyota's 3MZ 3.3L V/6 is one of the best engines Toyota has ever produced, easily in the top 5.
I have always used 5w-30 M1 in mine and it only burns about 1/2 qt between 5k mile oil changes at 200k miles. The black crusty substance on the oil fill baffle is not a problem. I think that they might have come that way from the factory because mine has always had it.
I disagree with those that claim switching to a synthetic oil will cause oil leaks. There is NO rational reason why it would. There are many threads in here on this topic and most people (and experts) agree with me on this. I consider this an "old wive's tale".
On an older Toyota you want to keep a close eye out for cooling system leaks because a major overheating event could kill it. The weak points in the cooling system are the plastic thermostat housing (cracking), an upper left hand corner radiator leak (hard/impossible to see), and the valley pan seal leaking. Just watch your coolant level closely because none of these leaks are catastrophic and none of them leak coolant into the crankcase. Use only Toyota Super Long Life 50/50 pre-mixed pink coolant (a proprietary HOAT).
Some people feel that having a timing belt is a disadvantage, but I personally don't. Just have the timing belt, water pump, and idler pulleys changed using OEM parts every 100k to 110k miles and it should last 300k+ miles easy. I have only had mine changed once, it is about due for another soon, but I'm not too worried about it because I personally know people who have gone over 200k miles on the original parts (but I don't recommend that you do this).
The 5spd automatic transmissions are solid, just do a fluid drain and fill every 30k miles (don't flush it) and it shouldn't give you any problems, and it is easier to change than the oil. Use only Toyota T-IV fluid.
Click to expand...
These tips of what to watch out for are great. Thanks so much. I will print this out and include with my owners manual and be sure to give those items a good look as I explore the car over the next few days.

For the hard carbon deposits on the "baffle" in the oil filler neck, it really doesn't look like some sort of factory coating but rather oil that has baked on over the years on top of that plate and also around the sides. I'm not sure it is a factory coating because it is somewhat non-uniform - you can see uncoated patches around the coated ones as if the baffle was pristine to start. Unless... it was a poor factory coating to start with. Either way, it really does look to be of oil origin and not any sort of enamel etc one might expect Toyota to apply. I try and get a better picture today and get it posted.
 
I really appreciate all this great advice and information. Would choosing a product with enhanced oil sealers/conditioners be advantageous like the M1 HM or the Valvoline mentioned? From what understand all oils have some amount of seal conditioners (although I'm not sure of this).

Finally, wondering if someone can address my question as to the purpose/origin of these synthetic blends. I always thought of them as being here nor there, neither full synthetic or full conventional, and maybe just addressing a price point between conventional and synthetic. Do different manufacturers alter the proportion between synthetic and conventional in these blends? Are there advantages, or pros and cons, especially as to my application? I'm not trying to overthink this, but really want a better understanding in general.
 
NissanMaxima said:
I've always been confused by synthetic blends. They seem neither here nor there. Is it simply an attempt to address a price point between conventional oils and more expensive full synthetics? In other words, if I don't mind spending more, should I go for the full synthetic or are there any actual benefits to the blends?
Click to expand...
Member Norman (above) didn't suggest any synblend. He suggested a high mileage synblend.
 
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