High RPMs on freeway. Toyota 4 cylinder longevity

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More and more I find myself having to speed up to keep up with modern cars. My 1991 Toyota Previa is geared way too low for my comfort. 5th gear is around 3700rpms at 70mph. I’m nearing 4000rpms at 75mph. Do you guys think my concern about this vehicle’s longevity is unfounded? I just have this paranoia that the engine is going to blow up or become a big oil burner running those rpms for so long on the freeway. I put red line oil in it to appease my paranoia. Do you guys think this engine can last for a long time? The engine is a jdm engine with unknown miles, but was in spotless condition when installed. Been running it for a year now with no problems. It’s a 2.4 liter 4 cylinder. I know modern cars like the Honda Fit spin fast also, but those are smaller 1.6 and 1.8 engines. I think smaller engines would work better for those rpms
 
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Originally Posted By: Kurtatron
More and more I find myself having to speed up to keep up with modern cars. My 1991 Toyota Previa is geared way too low for my comfort. 5th gear is around 3700rpms at 70mph. I’m nearing 4000rpms at 75mph. Do you guys think my concern about this vehicle’s longevity is unfounded? I just have this paranoia that the engine is going to blow up or become a big oil burner running those rpms for so long on the freeway. I put red line oil in it to appease my paranoia. Do you guys think this engine can last for a long time? It’s only got about 100k miles on it now. I am hoping it can last another 100k.

It would be interesting to see what the oil temperature is after running near 4k rpm for a while, but I suspect it will highish but still in the range of good, especially with redline in it.
I don't think that 4k rpm will make an engine an oil burner, but an oil burner will burn more at those rpms. What's your mileage at 75? You will get far better mileage at 65 so maybe that's incentive to slow down a bit.
 
I can’t slow down without feeling like a menace in these parts. I am already on the slow lane, getting passed by big trucks running 70.
 
It's a Japanese 4 cylinder engine, they are made to rev. It will be just fine at those RPMs. In fact, every Honda 4 cylinder engine I've driven ran more efficiently in the top end, they have almost no low-end torque and need to be revved.

Keep the oil full and changed regularly and you won't have any issues.
 
Originally Posted By: jeepman3071
It's a Japanese 4 cylinder engine, they are made to rev. It will be just fine at those RPMs. In fact, every Honda 4 cylinder engine I've driven ran more efficiently in the top end, they have almost no low-end torque and need to be revved.

Keep the oil full and changed regularly and you won't have any issues.


+1
 
Do you guys think an oil analysis would be worth looking into? Would low wear numbers indicate anything? Or is it just a shot in the dark as far as determining high rpm effects.
 
Originally Posted By: Trav
I don't think so I know it can with no problem whatsoever.


Don't run yourself down.

Perhaps you mean "I don't think;I KNOW it can, with no problem whatsoever."
 
My Nissan's engine is named HR16DE, HR means High Revolution. I think Japanese inline-4 design is for them to be high rev because they tend to be underpowered.
 
It's a 26yr-old vehicle, and you're wondering whether it'll last for long around Detroit? Keep oil in it, and worry about your ball joints, bushings, and rust.
 
First of all, I covet your vehicle - I always loved those Previas, especially the early ones ('91?) with the 5-speed manual. They have the reputation here as being one of the most durable minivans of all time. (The other longevity champs are mostly RWD as well.)

I didn't know the Previa was geared that low - those revs sound really high. The engine is the 2.4 l, correct? Is it automatic? If so, are you sure it's shifting into 4th (O.D.)? (I just reread your post - you mentioned 5th gear, so your van must have coveted manual, and obviously you're in high gear.)

By comparison, our '90 MPV (2.6 l w/ 5-speed manual) ran at 2500 RPM @ 100 kph (62 MPH), which extrapolates to about 2800 @ 70 MPH, and 3000 RPM @ 75 MPH.

Our '97 MPV (3.0 l w/ 4-speed auto.) runs at about 2250 RPM @ 100 kph.

Our '09 Mazda 5 (2.3 l w/ 5-speed manual) runs at about 2700 RPM @ 100 kph.

I had read somewhere that Toyota reckoned that their engines ran at maximum efficiency at about half of redline, and at one time geared their cars accordingly, such that the engine would spin at half redline @ 55 MPH.

Be aware also that analogue tachs tend to read high - the actual RPMs may be 10% or more lower than indicated. Do you have a ScanGauge you could compare to?

What oil grade does Toyota spec for the Previa? It's too old for xW-20, so I would guess they spec'd 10W-30 down to 0 F, and 5W-30 below that, correct? I think you'd be fine with a stout 10W-30. Others here, far more informed than I am, can recommend a thick 10W-30.
 
Originally Posted By: khittner
It's a 26yr-old vehicle, and you're wondering whether it'll last for long around Detroit? Keep oil in it, and worry about your ball joints, bushings, and rust.

What he said.
 
It’s my camping vehicle. Thankfully for that reason I don’t have to worry about rust. I don’t go camping in the winter. That’s one of the reasons I wonder about the high rpms, because that’s all it sees really.
 
Originally Posted By: Number_35
First of all, I covet your vehicle - I always loved those Previas, especially the early ones ('91?) with the 5-speed manual. They have the reputation here as being one of the most durable minivans of all time. (The other longevity champs are mostly RWD as well.)

I didn't know the Previa was geared that low - those revs sound really high. The engine is the 2.4 l, correct? Is it automatic? If so, are you sure it's shifting into 4th (O.D.)? (I just reread your post - you mentioned 5th gear, so your van must have coveted manual, and obviously you're in high gear.)

By comparison, our '90 MPV (2.6 l w/ 5-speed manual) ran at 2500 RPM @ 100 kph (62 MPH), which extrapolates to about 2800 @ 70 MPH, and 3000 RPM @ 75 MPH.

Our '97 MPV (3.0 l w/ 4-speed auto.) runs at about 2250 RPM @ 100 kph.

Our '09 Mazda 5 (2.3 l w/ 5-speed manual) runs at about 2700 RPM @ 100 kph.

I had read somewhere that Toyota reckoned that their engines ran at maximum efficiency at about half of redline, and at one time geared their cars accordingly, such that the engine would spin at half redline @ 55 MPH.

Be aware also that analogue tachs tend to read high - the actual RPMs may be 10% or more lower than indicated. Do you have a ScanGauge you could compare to?

What oil grade does Toyota spec for the Previa? It's too old for xW-20, so I would guess they spec'd 10W-30 down to 0 F, and 5W-30 below that, correct? I think you'd be fine with a stout 10W-30. Others here, far more informed than I am, can recommend a thick 10W-30.


Thanks haha. I have pretty much exactly what you mentioned. It’s a 91 5 speed. It’s specced for a 10w 30. I use redline 5w 30. Would that be a problem?
 
Originally Posted By: Kurtatron
Do you guys think an oil analysis would be worth looking into? Would low wear numbers indicate anything? Or is it just a shot in the dark as far as determining high rpm effects.


A string of UOAs can be useful for nailing down the best OCI and seeing trends in your engine.
 
Even if it running at those speeds would lead to a shorter engine life (which I doubt), what else are you going to do, run at 50-55MPH on the freeway?
 
You need high rpm you are moving a minivan(box) and its underpowered.

Its lasted this long.. why would it suddenly blow up?
 
Originally Posted By: Kurtatron
Do you guys think an oil analysis would be worth looking into? Would low wear numbers indicate anything? Or is it just a shot in the dark as far as determining high rpm effects.

Kurtatron,

while the BITOG crowd would like to see OUA just for fun, I think in the past you complained about money problems.
so i would say no analysis, just plain look at the dipstick and smell.
and for the oil instead of redline use walmart's supertech or any oil on sale (check the BITOG sales section).
...and I have been passed at 90+ by a semi... somewhere in Michigan...

all the best and be safe.
 
Slow down. Let them go around you. Plenty of trucks out there governed to 62 MPH and you can hook up with one of them. Fast traffic needs to do the work, not the slow guys ...
 
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