What color is your radiator fluid? (plus other topics)

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What color is your radiator fluid?

[quote author=Rich link=board=2;threadid=11820;start=msg107855#msg107855 date=1077298304]
The overheating problem is compounded by the fact that the factory temp gauge is designed to lie. Once the engine is at normal temp the gauge sits in the middle, even it if continues to get hotter. The engine has to get really hot before the gauge moves up to the red zone. This behavior can mask an engine that, due to cooling system problems, is running hotter than it should.

I know from 200 - 226 degrees my temp gauge sits in the middle. I don't know how hot it would have to get to move up from the middle. One of my projects is to determine why the coolant gauge is so nonlinear and modify it so that it more accurately reports engine coolant temp.

Rich
[/quote]

Wow, this blows my mind! :o I've always relied on my gauge for accuracy and I refer to it regularly while I drive. If it is inaccurate, I'm wasting my time and potentially taking temperature risks I wouldnt othewise take!!! >:( We really should find a way to defeat this function. If it is in place to prevent people from rolling into the dealer with dumb questions, then it is also preventing people from rolling into the dealer until they really overheat! Seems like bad logic to me? ??? If this feature cannot be defeated from the factory setup I can see myself getting an accurate gauge and adding it in somewhere sometime around YESTERDAY! Man that makes me itch!!! >:(
 
What color is your radiator fluid?

I have a few questions..with simple answers. I plan on flushing/changing my radiator fluid soon.

Q1. When i go to the Toy Dealer..do i just ask for "toyota red" fluid? or is there a specific part/type # i need to ask for?
Q2. How much of the fluid do i need to get? and how much $$ is it?
Q3. I know i can use distilled water to flush the system..how many times do i have to flush (ie. how much distilled water do i need buy in gallons)?
Q4. Should I use a 'cleaner' to flush system also? if so..what type.


[glow=red,2,300]JUST FOR THE RECORD...[/glow]Junk dont be mad..but, I did do a search..and it kicked back like 20,000 responses/topics! ???

If anyone gets upset that i am asking these questions...AGAIN....please see my avatar and 'think happy thoughts' :D

later..
JOE
 
What color is your radiator fluid?

Last fall I removed the coolant temp sensor, placed it in a pot of water on the stovetop, and measured the change in resistence as the water heated up. The chart below shows that the curve flattens out around 200 degrees. The shape of the curve is typical for a thermistor. This shows why the gauge parks in the middle at higher temps. When I get the ambition I will repeat the test using oil and a high temp lab thermometer so I can heat the sensor beyond 212 degrees.

With the incomplete data one question that remains is what is the mechanism for pegging the gauge during overheat. It is possible that curve changes shapes at very hot temps, beyond what I could achieve in a water bath.

The only other observation I have is that my gauge was still in the middle when the coolant overtemp ac cutoff kicked in, which is supposed to occur at 226 F.
 
What color is your radiator fluid?

When my ac cut out I wasn't aware of the safety circuit. The guage was ever so slightly elevated. It was a little stressful until I tried it some time later.

It would seem that from your chart the culprit is the sending unit and not the guage. I haven't looked at it but I'd think that a different sending unit with a similar resistance at 190 deg could be found that has a more linear response to the temperature change.
 
What color is your radiator fluid?

[quote author=- S.A. - link=board=2;threadid=11820;start=msg108613#msg108613 date=1077480799]
I have a few questions..with simple answers. I plan on flushing/changing my radiator fluid soon.

Q1. When i go to the Toy Dealer..do i just ask for "toyota red" fluid? or is there a specific part/type # i need to ask for?
Q2. How much of the fluid do i need to get? and how much $$ is it?
Q3. I know i can use distilled water to flush the system..how many times do i have to flush (ie. how much distilled water do i need buy in gallons)?
Q4. Should I use a 'cleaner' to flush system also? if so..what type.


[glow=red,2,300]JUST FOR THE RECORD...[/glow]Junk dont be mad..but, I did do a search..and it kicked back like 20,000 responses/topics! ???

If anyone gets upset that i am asking these questions...AGAIN....please see my avatar and 'think happy thoughts' :D

later..
JOE
[/quote]


1 and 2. Toyota Red or it is also called Toyota Long Life Coolant, I called around and prices ranged from $12 to $20 /gal at the local Atlanta dealerships, the closest was the cheapest, at $12 it is only about twice the price of standard coolant, witch is not to bad, I also got a new thermostat and gasket wile I was there, I should have had better forethought and had it tacked on to my order from Dan, you will need to buy 2 gallons (you will have a quart or so left over)

3 I bought 10 gallons of distilled for .58/each at wally world draining the radiator and block drain plug gets out about 2.75 gallons, but the total capacity is closer to 4 gallons I back flushed mine with a garden hose and a Prestone heater hose "T" for a long time trying to get some of that gray sludge out (a few to many step #6's and and almost no sleep the night before left me dozing in the drivers seat engine idling hose hooked up, wound up getting flushed for over an hour) then filled it 3 times with the distilled and running the engine for a wile (have to open the thermostat to let the fluids mix) hoping to get the majority of the tap water back out

4 I tried the prestone radiator flush it did very little, I would not bother

on a better note my radiator did not look as bad as I was expecting from the look of the overflow and cap, there was a very thin coating (like the thickness of primer) of the gray stuff but not enough to worry about

considering how unsuccessful the flush was at putting a dent in the deposits I did have I would recommend a few distilled water “fill/run to operating temp/drain” cycles only, (let engine cool before refilling with room temp water engines do not like sudden uneven cooling, they will crack/warp) I was weary of tap water and the flush chemicals but I wanted to try to get some of that junk out turns out that I did not need it and if I did they would not have done much :doh:, and it was a lot of work trying to get them back out :slap:

I did a few experiments with the deposits in my overflow bottle nothing short of mechanical action would remove those gray deposits, I tried soap and water and vinegar and water neither did much
 
Re:What color is your radiator fluid?

I'll be interested in seeing a curve like that excellent information from Rich that takes it up to an overheat situation. Rich, it would be great if you kept it hooked to the guage during the test so you could see if the guage has a proper reaction since that's really the end game question.

As to mfrs routinely creating water temp guages that are false readings, I wouldn't be so quick to judge. I read what I believe was the same article and it dealt with oil pressure guages, so I'm wondering if there was a mixup? Oil pressure varies by age and type of oil, as well as some variance between identical aged engines. I recall the article calling out BMW about is as several BMW club members from somewhere had noted it and were threatening a class action suit or something like it.

Anyhow, good data. My guage does move a bit and I may put more load on my 80 than anyone here on a routine basis due to our overweight towing all summer and the mountain passes. Mine will go up a needle width on really tough passes and my cooling system is in top shape. I've owned it since new and have personally done all maintenance work on it. One consideration might be that if your vehicle has had mixed or old coolant in it the temp sender has a layer of sludge on it that reduces variations a bit.

DougM
 
What color is your radiator fluid?

It should not have to be done, but another alternative is to install an aux. temp gauge with real numbers. The stock sensor should be kept as there is input to the engine control module from it. I installed a Greddy that allows an alarm light to come on at any temp I set it for. Also, I wired in a piezo buzzer just in case. Finding a location for the aux. gauge sensor can be a problem. First, I made an adapter for the block drain hole and this worked well until the block needed flushed. Then CDan came up with an idea for installing it closer to where the water went back into the radiator.
It's a pain to remove as the alternator bracket has to come off the block to get to the lower bolt, but then it's just a simple drill and tap.

Bill
 
What color is your radiator fluid?

Joe the part number for the coolant is 00272-1LLAC If they want more than about 13 bucks a gallon they are porking you. :rolleyes:

Bill, have you fired up the engine with the modified water housing installed yet? That job is next on my plate of to-dos. I am searching for the best possible 2 inch gauge for this. Any recommendations?


D-
 
What color is your radiator fluid?

[quote author=cruiserdan link=board=2;threadid=11820;start=msg108678#msg108678 date=1077495903]
Joe the part number for the coolant is 00272-1LLAC If they want more than about 13 bucks a gallon they are porking you. :rolleyes:[/quote]

Dan..thanks for the heads up :D
[glow=red,2,300]I DEFNITELY DO NOT WANT TO GET PORKED![/glow]
later..
joe
 
What color is your radiator fluid?

Dan,

No, never fired it up yet. I was pondering putting a LARGE alternator on so I might have to remodify the water housing or fab a new one.

These are the temp gauges I run.

http://www.greddy.com/products/product_detail.asp?catidx=8&catname=Electronics&prodtype=36&prodtypename=60mm%20Electronic%20Warning%20Gauges&productidx=1598

Unfortunately, the warning gauges only come in 60MM (approx. 2 3/8") I think. If you decide to get one just make sure you get all three pieces. One datalink can control more than 1 gauge IIRC so if you get more than one gauge you just need the gauge and the sensor. My EGT gauge is from Apexi

http://www.apexi-usa.com/meters_elgauges.asp

which is also a very good gauge and also is the same warning type. Same 60MM deal though. Greddy does make 52MM electronic gauges

http://www.greddy.com/products/prodtype.asp?catidx=8&catname=Electronics

which would be around the size you want but I don't think they would be the warning type.

Oh, and as far as I know, all the warning gauges are metric.

Bill
 
What color is your radiator fluid?

[quote author=Photoman link=board=2;threadid=11820;start=msg108661#msg108661 date=1077490612]
It should not have to be done, but another alternative is to install an aux. temp gauge with real numbers. The stock sensor should be kept as there is input to the engine control module from it. [/quote]

Bill, looks like you have a good setup for an auxillary water temp gauge. Note that the factory setup uses two separate sensors for the dashboard gauge and the coolant temp input to the engine ECU.

Rich
 
What color is your radiator fluid?

Rich,

Thanks, I was not aware of the two sensors. You do mean on a 1FZ? Any idea where they both are located?
At first, I made an adapter to fit the block where the stock sensor is located. It was an odd thread so I could not find any aftermarket adapters that would work. I ended up using a hydraulic hose fitting, welded on a bolt head, and drilled an tapped it for the Greddy sensor. Then I got worried about the ECU and removed it without trying it.

Bill
 
What color is your radiator fluid?

Bill,

On a 97 1FZ, drivers side of engine block, from front to back, there are three coolant temp sensors in this order: 1) Dashboard Gauge, 2) AC Cutoff, 3) ECU.

Rich
 
What color is your radiator fluid?

[quote author=Rich link=board=2;threadid=11820;start=msg108987#msg108987 date=1077556524]
Bill,

On a 97 1FZ, drivers side of engine block, from front to back, there are three coolant temp sensors in this order: 1) Dashboard Gauge, 2) AC Cutoff, 3) ECU.

Rich
[/quote]

So, if I am reading this right, one would have to modify only the dashboard gauge to get accurate readings right? Are you saying that there are three gauges that all input their own data separately of one another or that they average all their data together and that is why the dashgauge is so vague?
 
What color is your radiator fluid?

Thanks Rich!

Turbo
Rich may be able to explain it better but I will give it a shot. The front (toward the fan) sensor/thermister basically just works the temp gauge in the dash. As you can see from the chart Rich posted, the resistance from the sensor/thermister does not vary much from 190-210; hence the gauge does not move much in this range.
Think of the center sensor in the block as just a switch. At 226F it just shuts down the AC compressor. Has nothing to do with the gauge.
The third sensor probably is just like the first except it is wired to the ECU (not the gauge) so it knows for example - the temp is very cold - the engine must just have started - I'll richen it up and kick up the idle.
My interpretation.
The three sensors are located in a row under the intake.

Bill
 
What color is your radiator fluid?

Thanks Bill, that makes perfect sense, thanks. So, out of curiosity, has someone done the oil bath readings so we can continue charting the graph farther than possible with the water bath?
 
What color is your radiator fluid?

[quote author=landtank link=board=2;threadid=11820;start=msg109396#msg109396 date=1077600310]
I wonder if the third is more linear and true to the temp and could be subbed in to the first slot?
[/quote]

Terrific thought! I think the first thing for figuring this out is to test if the third sensor is more linear and then I guess if it can be spliced into the gauge or into the front sensor? Any electrical engineers out there or someone who can advise? Seems like a terrific idea but I am still really wondering what happens with the stock sensor past the degrees measured on the graph.
 
What color is your radiator fluid?

The ECU temp guage is probably a V-ref type sensor, as opposed to a grounding thermister like most guages are. The guages usually send 12V to the sensor through the guage and then measure how much goes to ground. The ECU sends a voltage out, usually 5V, and measures how much comes back thorugh a reference wire. You can't just splice in. Even if you could, I would NOT add another guage to the ECU sensor as you do not want the ECU to misread the engine temp.

I'm not sure if Toyota does it this way, but most everybody else does.
 
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