Water temp gauge

[Martiny]

The thermostat plays a part in an open system, because it is the very thing that has opened the system. If that part were to fail or be partially faulty, you are not reading the ENGINE temperature.

Actually, once its opened, do you think it STAYS open? No way, it will be constantly opening and closing to try and keep the temperature constant.

What you guys are reading is the RADIATOR temperature, not the Engine temperature. Well, I dont care what the radiator temp is, I care what the ENGINE temp is, thats whats going to cause the damage.  

No, sorry, I dont get it, and I think I give up now, someone needs to explain it to me perhaps face to face with a piece of paper or something.

[RobbieRX-7]

http://www.rx7club.com/showthread.php?t=247152

[nikp]

No way, it will be constantly opening and closing to try and keep the temperature constant

Hi Martin, surely you\'re not suggesting that a thermostat will fully close in an up-to temperature engine, are you? The thermostat starts to open at 80-81 degrees, and as such, as long as that temp has been reached, will always be partially open.

I\'m sure you know that - I\'m sure it\'s just the way it\'s been written! :p

[Fish]

Justin, a bit off topic and not meaning to be horrible, but is there a reason for your posts always being in bold?

Fish

[Martiny]

Hi Martin, surely you\'re not suggesting that a thermostat will fully close in an up-to temperature engine, are you? The thermostat starts to open at 80-81 degrees, and as such, as long as that temp has been reached, will always be partially open.

I\'m sure you know that - I\'m sure it\'s just the way it\'s been written! :p

Well, I agree it wont be fully closed, I guess the temp has to go down quite a bit for it to do that.

If I can make an analogy - if I wanted to measure the temp in my house, I could put a sensor outside the house, in the path of an open window, so I measuring the temp of the air coming out of the house.

Now, what temp will I see if my wife closes that window?

-- what will you see when the thermostat fails? Or are they 100% fail safe?

[Martiny]

http://www.rx7club.com/showthread.php?t=247152

 Good one, Robbie, that backs up exactly what I have been saying. The throttle body coolant tap makes more sense, it "sees" nearly the same temp as the engine, and the coolant, I think, is circulated there regardless of thermostat being open or closed.

[Jono FD3]

So basicaly the thing your saying is, to get a perminant acurate reading you have to situate the sensor where the stock unit is???

What if you get an adaptor made that screws in to the standard fitting in the block that allows you to put the stock and auxilary sensors in (like the oil pressure T pieces)

Jono

[nikp]

Well, if you want an accurate reading, why don\'t you just use an electric gauge that pulls the signal off the standard sensor? That\'s probably eaisest!

I\'m ok - I have two! I have the stock sensor reading through the apexi commander, and a secondary sensor plumbed into the top rad hose. So I can compare my temps together. I can tell if the thermostat is healthy or sticking, I can identify if the fans are working and i can generally monitor the health of the whole coolant system!

[nikp]

If I can make an analogy - if I wanted to measure the temp in my house, I could put a sensor outside the house, in the path of an open window, so I measuring the temp of the air coming out of the house.

Actually, i don\'t think that\'s a good anology. I think it would be better desribed as:

If you have a multi story house (Say 2 or 3 floors) and you have your homes central heating thermostat located on the ground floor - you have an \'after market\' heat sensor on the floor above - they\'ll read different temperatures, but they\'ll go up and down at similar rates, but not necassarily at the same time period.

Actually, this is exactly what I have at home!

[allstaruk]

I\'m with martiny,l the gauge needs to measure the engine temp not the radiator temp, I have recently ssorted out an overheating problem on my car which was caused by a dodgy thermostat. My gauge is tapped into the thermostat housing which meant that I was reading the radiator temp not the engine temp so all the readings were comming up fairly normal while the engine was getting extreemly hot.

If you put the gauge in the rad pipe or themostat housing you have to take the risk that the thermostat may break and you won\'t know and it will destroy your engine.

Unless you have a power FC aswell and then you can use it to moniter the engine temp and then the gauge to measure the radiator temp allowing you to see if the thermostat is working.

[Martiny]

Nik, yes that is a better analogy.

Allstar, thanks for the support, I felt I was drowning there for a while. A better than stock solution would be a better gauge using the stock sensor, or at least the stock sensor location.

:-)

[nikp]

A better than stock solution would be a better gauge using the stock sensor, or at least the stock sensor location.

Yup, pretty much what i said. And what the Apexi Commander does too! There, everyones happy.... aren\'t they!?

[nikp]

Actually, you can actually do some jiggery-pokery with the standard gauge to linearize it, so it moves when the temps move. Quite a pain in the butt operation to do though!

[nikp]

Here are the instructions on how to linearize the stock temperature gauge for the FD for anyone who is interested.

I\'ve currently uploaded it to my own web site, but if people are interested in this, it may be worthwhile uploading it to the MRC website with a sticky thread.

Hope this is of interest to people.

[allstaruk]

If your not using a power FC then you can plump a gauge into the standard water temp mount, making the one on the dash redundandt its a bit of a pain to get to but it is a standard gauge mount so should just screw in.