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Username Post: Cooling a Too Hot Engine        (Topic#331229)
iRt 
Forum Newbie
Posts: 37

Reg: 11-18-15
12-12-15 01:29 AM - Post#2594951    

I have a '92 Caprice and have driven GM RWD V8 cars for about 40 years. But today I am concerned with a vehicle I am sure is at the top of everyone here's list < intended sarcasm>, a 2000 Toyota Sienna (I know, I know).

This is my wife's car, and yes I know it's a puker for us lifetime Chevy users. Yes, I have been posting on a Sienna forum, but there's a big difference in thinking there: the Sienna folks seem to be of the "Toyota knows what they're doing and there's no way you can improve it" while the Chevy thinking is more "stock factory is just a starting point", and I'm in the latter group.

If you don't know this, Toyota really blew it with the 1mz-fe engine in the 1st generation Sienna's and the heads run so hot that it cooks the oil into a sludge. The engine is ridiculously hot when you pop the hood. It's just not right!

The cooling system seems to be 100% fine and the water temp gauge never budges from dead centre. I've never seen a car reach operating temperature as fast as this vehicle, but I'm also of the thinking that there's nothing "abnormal" about it, if you took it to Toyota I'm sure they'd say it was working the way it was designed to.

So I am looking at ways one could cool down the engine and want to get some ideas from people here.

I live in Hawaii and for decades drove cars with no thermostats. The main reason was to eliminate a part that could fail. I did notice that those cars always ran cooler, my thinking was that the thermostat restricted the water flow. Hop in a cold shower with the water just producing a small trickle and then crank the pressure full (still all cold water) and tell me which feels cooler (duh...).

So one thought is to take out the thermostat. I'm guessing that many people will say "no, the vehicle was designed to run with one". But I don't like this option as it will take longer to heat up and it's not variable.

I'm gathering that a lower temp thermostat (it's now 180˚) would do nothing as that only affects the time it takes to get to operating temp. O'Reilly does have a 160˚ one, would that do anything? I'm guessing no. Does a lower temp thermostat do anything once the car is warmed up?

Where I live in Hawaii has a very narrow temperature range, it's seldom in the 90's and seldom below 60˚.

Second idea: mount another fan on the front of the rad controlled with a toggle switch. Me likey.

'nother idea: the engine compartment is tiny, there's hardly any room around the engine... would a hood scoop help? Maybe a huge hood scoop? Would no hood actually be better? (not an option, just asking).

I keep thinking of heat sinks like you'd have on a big audio power amp...

Any comments or ideas?



 




gregvm 
Forum Newbie
Posts: 20

Reg: 05-25-11
12-12-15 04:34 AM - Post#2594955    
    In response to iRt

Thermostat will control the lower engine limit, cooling system capacity will determine upper limit.Also the computer is probably designed to run at high temps for emissions and won't like lower engine temps and will cause a drop in fuel economy(my GMC Envoy with a faulty cts dropped 3-4 mpg cause the ecu THOUGHT the engine was running too cold).
I wouldn't tinker with it.



 
iRt 
Forum Newbie
Posts: 37

Reg: 11-18-15
12-12-15 08:25 AM - Post#2594987    
    In response to gregvm

Thanks, I hear what you are saying and that's exactly what I would expect most people would say, however it is theoretical and I'm not sold that in real life it's true.

Who knows, maybe I will find out that I'm wrong and I welcome that as almost all my knowledge has been obtained by making mistakes (I'm thinking about the time when I was 12 and attached a 20' garden hose to a snorkel thinking I could swim at the bottom of the pool).

The way the engine was designed, the Sienna engine destroys itself, that's why Toyota sent out 3.something million notices out to owners and extended the warranties for 8 years (and from I understand didn't honor almost any of those extended warranties).

The difference here is that the Envoy probably had a well thought out system wheras the Sienna isn't. I would go with a slight gas mileage drop if the thing ran cooler and didn't need a $4000 cleanup routine every couple of years (along with synthetic oil changes every 2-3k mi). The added gas usage would be a bargain in the big picture.

But I do appreciate your 2 cents - thanks!



Edited by iRt on 12-12-15 08:44 AM. Reason for edit: know raison gibbon

 
gregvm 
Forum Newbie
Posts: 20

Reg: 05-25-11
12-12-15 09:59 AM - Post#2594997    
    In response to iRt

Also, the ecu controls the cooling fan turn on/off temp, so you may have to manually put a jumper switch to turn on the fans when YOU want them to turn on(and off). I see that oem t-stat is 180 and only a 170 is avail. That isn't going to make a whole lot of difference.



 
iRt 
Forum Newbie
Posts: 37

Reg: 11-18-15
12-12-15 10:06 AM - Post#2594998    
    In response to gregvm

Yes, I gather that using a lower temp thermostat won't affect things in the slightest once it's up to normal operating temperature, which in this car is almost no time at all.

I'm trying to avoid cutting into the factory wiring harness, but an override fan toggle switch is an option.

One thing I notice is that the amount of grille blockage in the vehicle seems extreme, the vast majority of the radiator has stuff in front of it, but it could be most of the air going through the rad is coming under the front.



 
bobb 
Super Senior Member
Posts: 5322
bobb
Loc: paradise
Reg: 09-05-03
12-13-15 01:09 AM - Post#2595136    
    In response to iRt

it is always better to run a thermostat. pics would help. if your near town i could look at it for you. have you checked the temp with a heat gun?

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
Bruces 57 
Frequent Contributor
Posts: 2373

Reg: 01-03-07
12-13-15 05:41 AM - Post#2595160    
    In response to bobb

Hello;
You might try a "water wetter" type chemical in your cooling system.Someone used to make a coolant called "40 below" which does do what it says. You may look at if there is any such thing as a high performance water pump for it. Also, if you have all antifreze in your system, living in hawaii you probly won't need that stuff, so you might consider draining and refill with just water! Save the antifreze, just in case.

Bruce



 
TAT_2 
"17th Year" Silver Supporting Member, and Official CT Grim Reaper
Posts: 35054
TAT_2
Age: 64
Loc: "UNDER THE BOARDWALK"
Reg: 10-29-00
12-13-15 06:05 AM - Post#2595163    
    In response to iRt

SOME OF OUR MACK TRUCKS HAVE A 5MIN RUN PERIOD AFTER THE IGN IS TURNED OFF TO KEWL DOWN THE TURBO.YOU MIGHT BE ABLE TO INCORPORATE YOUR ELECTRIC FAN TO RUN FOR A TIME AFTER THE IGN IS TURNED OFF TO GET RID OF THAT HEAT SOAK.

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65_Impala 
Very Senior Member
Posts: 3990

Reg: 12-29-02
12-13-15 09:30 AM - Post#2595198    
    In response to TAT_2

You first need to define the problem as more than "too hot". Have you got an actual gauge that reads temperature?

If the thermostat is 180* then that is fine. What temperature do the fans start operating at?


  • TAT_2 Said:
SOME OF OUR MACK TRUCKS HAVE A 5MIN RUN PERIOD AFTER THE IGN IS TURNED OFF TO KEWL DOWN THE TURBO.YOU MIGHT BE ABLE TO INCORPORATE YOUR ELECTRIC FAN TO RUN FOR A TIME AFTER THE IGN IS TURNED OFF TO GET RID OF THAT HEAT SOAK.



It's pointless to run the cooling fan if the coolant isn't circulating. All you do is cool the rad down.



 
bobb 
Super Senior Member
Posts: 5322
bobb
Loc: paradise
Reg: 09-05-03
12-13-15 10:23 AM - Post#2595205    
    In response to Bruces 57

never use just water. it will rot your engine from the inside out. there are other chemicals you can use that will lube the waterpump and prevent corrosion.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
iRt 
Forum Newbie
Posts: 37

Reg: 11-18-15
12-13-15 01:53 PM - Post#2595251    
    In response to bobb

Yes, antifreeze does 4 things that I know of: makes the boiling point higher, makes the freezing point lower, prevents the inside of the engine from rusting and lubricates the waterpump. Running a car on straight water would be like lubricating your bicycle chain with water - works for a few minutes but in a few days it's total rust.



 
iRt 
Forum Newbie
Posts: 37

Reg: 11-18-15
12-13-15 02:01 PM - Post#2595253    
    In response to bobb

I don't have a way of checking the temp other than the somewhat useless temp gauge. I'm just going by instinct - when you pop the hood it is ridiculously hot to me. But I think any Sienna would be like that, maybe even any aluminum engined V6 of the last decade or so. Anything for economy, even if it means you need to belong to the engine-of-the-week club.

There's no headroom for error in the engine, I call bluff on it's design. I'll be selling it as soon as possible and will continue to drive iron SB V8's that are viewed by most people as antiquated gas guzzlers but in reality are more economical than any Accord or Camry. What a con job people have been fed.

I don't need any more help with this, thanks everyone for your comments. Consider the vehicle pushed off a cliff where it belongs.



 
65_Impala 
Very Senior Member
Posts: 3990

Reg: 12-29-02
12-16-15 09:21 PM - Post#2596039    
    In response to iRt

This reminds me of the people who claim their electric motor is too hot because it burns to the touch. Well, an electric motor can run at 100*C all day so of course it can be burning hot to the touch. Without temperature data you just don't know what it's doing.



 
Stinky 
Senior Member
Posts: 1590

Loc: Whitewater, CO
Reg: 05-25-01
12-17-15 02:53 PM - Post#2596163    
    In response to 65_Impala

On a Toyota...usually....I don't know about yours, the t-stat is actually a T-valve. When closed, the coolant goes motor to w-pump. When open, it goes from rad to pump. If you look at it, it has a flapper on the bottom, that goes over the hole, from the block, when it warms up.

On an old-world Chevy, the water-pump dead-heads and does not by-pass (other than through the heater-hose).

This really adds to shortening the warm-up time (which is good for emissions and mpg).

As mentioned, if you lower you temps to much, it will kick your computer in to a warm-up fuel-mixture (richer), in short, your computer will put on the electronic choke (it actually does something to electronically alter your fuel-air ratio).

That said, you could turn on your rad-fans all of the time. Which would, theorectically, lower it to the T-stats pre-set temps....tis would be for if you were driving in the city. If on the road, then IMHO, you would not gain anything.

You gage in possibly not much better than an idiot light....you don't really believe that your motor is running at the same temp all the time do you? But, I am guessing that your gage is set to indicate temps at a certain point on the gage, when w/in what the factory has determined what the normal operating range should be, as normal and I bet that that is a range of about 30 degrees (about 200-230) Also, a Toyota usually has the T-stat on the intake and measures the temp coming in to the motor.



Edited by Stinky on 12-17-15 03:16 PM. Reason for edit: No reason given.

 
KShortell 
Senior Member
Posts: 4034
KShortell
Loc: Chesapeake, VA, U.S.A.
Reg: 04-14-01
12-18-15 12:47 PM - Post#2596351    
    In response to Stinky

My Uncle David and his wife had a Toyota Sienna. In fact, they were part of the class action lawsuit against Toyota for what they referred to as their "Sienna sludge van". It really was an engineering defect.

So, it would appear that the only solution is to somehow add additional cooling capacity, either via more airflow, a larger radiator, or BOTH.

I'm not familiar with the underhood layout of the Sienna, but my memory of seeing them in the road suggests that it was tight. You might really be limited as to options.

Either way you slice it, any solving or improvement with regard to your problem will definitely be a "custom build".

Good luck!

Semper Paratus
FL05-03 Home Page
Stock is not a dirty word...


Edited by KShortell on 12-18-15 12:50 PM. Reason for edit: No reason given.

 
skip57 
Forum Newbie
Posts: 53

Reg: 09-24-14
12-21-15 07:42 AM - Post#2596843    
    In response to KShortell

Lets go back some years and think (remember) when the cats were getting so hot that were setting the grass and cars on fire. The yoda four cly the cat is right up front so here is your furnace.

As for your T stat due to your location (an island) it works for you. T stats for the rest of us allow for quicker warmups, restrict the flow to allow the rad. to work and cool the coolant.



 
DanTurbo 
Forum Newbie
Posts: 7

Reg: 12-20-15
12-28-15 10:52 PM - Post#2598349    
    In response to iRt

Had the same problem. My car overheats when the AC is on even when Im not driving. I've been using just water but looks like I'd better spend a few dollars on some antifreeze.



 
CowboyTrukr 
"7th Year" Silver Supporting Member
Posts: 3908
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
12-29-15 11:41 PM - Post#2598618    
    In response to DanTurbo

The jug does say antifreeze/coolant. Not only does it lower the freezing temperature to around -45 degrees, it also takes the boiling point up from 212 for plain water to 265 for a 50/50 mix. That is vital to the health of the engine. The plain water can vaporize in the engine, creating pockets in the engine where no liquid is in contact with the metal. Eventually, the water will boil and create steam pressure that will exceed the pressure rating of the cap.

Greg

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5Larry7 
"14th Year" Gold Supporting Member
Posts: 1924
5Larry7
Loc: Dallas, TX
Reg: 05-17-04
12-30-15 01:04 PM - Post#2598737    
    In response to DanTurbo

Using just water will rust the engine, unless it is aluminum. But even for aluminum, using a 50-50 mix is better than water.

'57 210, 327 cid, Holley MPFI, 700R4, A/C & more.
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Jim Terrill 
Forum Newbie
Posts: 3

Reg: 03-18-17
10-18-17 07:24 AM - Post#2711235    
    In response to iRt

Reference cooling:
I have had a couple of cars with heating problems. The 55 chevy (350 ) with an air-conditioner. I use a thermal temp. sensor to prove the hot spots. The car runs fine now with a 160 deg. thermostat.
I installed an external fan but seldom need it except in town driving in hot weather ( 90deg.+). I believe you need a thermostat.
The other car is a 56 Thunderbird with a 312 eng. It always seemed to run hot. I put a 160 deg thermostat in it and with the external temp. sensor I found the temp. was normal even though the ga. showed very hot, almost pegged on H. With no AC on this car I do not worry about it anymore.
Hope this is helpful to you



 




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