Engine Oil Question

I’m wondering if I should run thicker oil on my up coming trip.
My Taco has almost 500k miles and running strong . It does run hotter when it 90 degrees and above with the AC running . My trip is a 4 hour road trip in 90 degree + weather . Would it be worth trying to run 10w40 and see if it helps out .

 

In theory it should protect parts better once it’s hot, yes, excessive viscosity isn’t good either though.. you’ve seemingly been doing something right with that kinda mileage lol

 

I wouldn't change a thing you have been doing for the past 500k miles.

As a matter of fact ...what kind of oil have you been using to this point?

 

When was the last time you changed the coolant? I would look at my cooling system before changing the oil. Clean out your rad cooling fins with a power washer and something like simple green and new coolant.

 

500k? we should be coming to you for advice.

 

10W-30 Synthetic and STP Oil Treatment, thats all !

 

Euro 0w40 oil is what I'd use. Better oil and will flow better for the occasional cold day, if there are any in California.

 

0W-20 is all that needs to be said.

 

have you back blown the radiator with compressed air? With that kinda of mileage I wonder how much dust and bugs are in your radiator fins.... I have a kubota tractor, and it will start running a little hotter in the summer heat, and ill blow out the radiator fins and it will run much cooler for a while. Have you ever done a water pump on the truck with that many miles? Not sure if it would help on not but my 2 cents.

 

oh... have you ever had the thermostat changed? and i always go with toyota parts on water pumps and thermostats.

 

Don't use oil additives, some can actually hurt the lubrication/viscosity properties of the oil.

https://youtu.be/CAGT5inQScE?si=2jMYAKeOXWAUFx1J

Run the factory reccomended oil viscosity and grade in a high quality oil and you will have no issues.

 

500K is impressive. I'm on board with other's—keep on changing the oil just as you have. We all can hope to do as well.

 

Change out that coolant. When was the last time you did the waterpump, thermostat and a flush of the liquid system?

Sometimes, for shits and giggles of cleannnn oil, I will change the oil for regular interval, then do an Italian tune-up and proceed to change to oil again, maintaining the 5k interval.
230k on the clock, I might lose ~4oz a change.

 

If he is asking, it is likely he didn’t put most of those miles on his truck. Or, he hasn’t driven far in hot weather in a long time.

How much hotter? Does needle move close to HOT? I just drove from San Diego to Flagstaff, and back. AC was on most of the time. I am usually in 195 temp range, but went up to 205 on the trip. Yet my needle never moved past halfway. Since I only had 3K on the oil, I didnt change the 5/30 syn oil I had in it. Using UltraGauge to monitor temps.

I will add my ATF temps topped at 210, and very briefly up the steep grade on I8 into SD county. This was much better than the 230 temps I reached on my Tx trip last year in similar weather. I upgraded my trans cooler to the slightly larger

$58 Hayden 679 Universal 11” Rapid-Cool Add-On Transmission Cooler to Enhance Cooling (not for direct replacement of the factory unit)

Hayden 679. I will note the ambient temp was about five degrees warmer on the Tx trip, but I had noticeably stronger headwinds the second time around.

 

I bought the truck brand so yes I put all those miles on . I use 5w30 the recommended . Never changed weight other than using high mileage synthetic now . Changed oil ever 2500 miles .
Couple years ago I seen the temp climb with pulling even the smallest incline if the incline is long enough with the AC on . Changed water pump , thermostat , radiator, fan . After that it was still doing same thing . Took to my mechanic and he sniffed the rad fluid … no emission . So I’m at the point where I’m thinking she just got miles on her and that’s the way she going to run now . Normal operation with outside temp under 90 she runs normal .

 

What’s happening with transmission temps? I think even with a transmission cooler the first stage of cooling is integrated into the radiator.

In theory, the transmission could be driving up the coolant temperature. In practice, I really don’t know what I’m talking about and it’s possible this effect would be minimal. There are a lot of smarter people here who could probably say one way or another.

 

Not sure about the temp of the Tranny. I dont have a way to see that. I am on spot with getting a tranny service every 50k miles. I did have a converter shutter for many years. Thought my tranny was going out . Tranny never went out nor did the tranny shutter get better or worse. Took it to the Tranny shop year and half ago and of course they said replace it. My last ditch effort was to put some converter shudder fix in with my last tranny service. Couldnt believe it but the shudder has stopped and has not come back. knock on wood . Never had issue with shifting.

 

Get you a scangauge or ultragauge so you can see what actual coolant and trans temps are, the gauge on the dash isn't all that "smart" it just kinda sits in the middle if coolant temp is anywhere in the operating range.

 

You should do a write up on the major repairs and services you have had to perform over the years to keep her right.

500K miles sure is impressive. Hope I can do the same with mine.

 

High mileage trucks I tend to look between the rad and condenser for build up. Usually there's tons of old mud trapped and restricts air flow.

Just gotta take off the upper rad cover, 10 odd clips.