!!!!!!!!!!!!!!!!Overheating!!!!!!!!!!!!!!!!!!

[ianelvar]

Would it be helpful to know what the exact temp is? You can get a temp from the front and back of the block by reading the two sensors. I know the stock gauge isn\'t very precise, and there seemed to be some debate as to how accurate the PFC would be, but you can quite easily cailbrate the sensors using the following method:

Remove the coolant temp sensor (ECU) from behind the filler neck. Remove the coolant temp sensor (gauge) from the back of the block on the left hand side just by the oil pressure sensor.

Get a load of ice, and pack as much as you can into a pint glass, and fill with water. Place the sensor into the water as close to as many ice cubes as possible and leave it for a minute of two. If you have a thermometer place it right by the sensor and read off the temp. If not assume that the temp is probably 4 degrees.

Then take a voltmeter and measure the resistance of the sensor. If it\'s a two terminal one (I THINK the ecu one is) measure across the terminals. If it\'s a single, measure from the bit that srews into the block and the terminal.
Note down what you read off. Then repeat with boiling water. Ideally after that you should repeat with water at 50 deg. but this might be tricky without a thermometer... You can then graph the results and get a map of what resistance the sensor will read at different temps. It\'s exponential with a lot of sensors, so three readings are required really.

Then you can sit a multimeter on the sensors and measure their resistance as she warms up. You know it\'ll be accurate as you\'ve just calibrated the sensors yourself. I know it\'s a bit of a fiddle, but it would be some data that you can absolutely rely on.

I hope that might help a bit.

One other thing I did think of... Can you measure the pressure in the system while it\'s heating up? RS components probably sell a gauge that could be used to measure it for about £50. Just tee it into a coolant line. Measure the temp and pressure, and you\'ll soon tell if it\'s temps rising that are actually causing the pressure build-up.

If you do get somewhere with that, and you want to get some further data I have a box which should be able to datalog temp and pressure if it\'s set up right. PM me if I can help with anything.

Good luck :Thumbs-up

[Rixio]

Wow some detailed info there bud...thx for that! Im not actually going to do anything with the car for the time being because 1) Sh!tty weather 2) cba & 3) cba...might muster up some energy on monday :o

[Grizzly]

I think at this stage you may be best off putting it all back together as it was and let the Engine guy have a look.

TBH i don\'t think this has anything to do with Gauges or Temp Sencers etc this is a Coolant system fault and a big one. To over pressurize a 0.9 bar cap like that takes a fair bit and there isn\'t alot that will make an RX7 overheat that dramaticly.

[ianelvar]

Sh!tty weather 2) cba & 3) cba...:o

Lol. Fair enough.

TBH i don\'t think this has anything to do with Gauges or Temp Sencers etc this is a Coolant system fault and a big one. To over pressurize a 0.9 bar cap like that takes a fair bit and there isn\'t alot that will make an RX7 overheat that dramaticly.

A totally fair point, but I\'m not suggesting it\'s gauges at fault, just trying to invent a way to gather some more info on the problem in a scientific manner.
The method of calibrating and reading the sensors directly might be useful to someone else in the future, so I think it\'s valuable to share the knowledge.

Hope all goes well, anyway. May the goddess of all spinning, orbiting things smile upon you lol

[Rixio]

Iv just got the point that im tired of it. Iv run out of energy/patience...specially the weather being as it is. I think as soon as i get the keys to the new house i can work on it all day & night because its a heated garage.The car is back together so to speak apart from the strut & filters so not much to do on that front...

Im trying to sell lots of bits and peices to get some cash organised so i can get the car to the builders & let him check it out, but without an income it may be abit difficult :o

[ianelvar]

It\'s a harsh problem you\'ve got, but I know the feeling. I\'ve got an MR2 that has a problem with oil draining back to the sump when it\'s sat for more than an hour, and no-one can work out what is causing the problem. The result is that it sounds like somone has emptied a bag of spanners into the engine when you start it, and it\'s goes through big ends like they\'re going out of fashion! It\'s been at the latest garage since febuary.
My rex project has been carried out largely while I\'ve had no income, so I can sympathise there too. It\'s moving on now that I\'ve got some money coming in, but it\'s still hard.

[Rixio]

Sorry for the wait on this but i was waiting on various bits & now finally getting somewhere with it!

Well this was the apparrent cause of all this crap over the last 7 months...heres the pic...its the size of a 5p piece. For those who dont know, this is the front plate of the engine block, the bit thats broken is the outer lip of the water seal housing groove.

So its another £2000odd for another rebuild for another year...when will it end:2Rolleyes

[TwistedHumour]

Sorry to hear mate!  

Theres only one way to cheer yourself up after bad car news - buying more goodies

[Martiny]

Oh dear  :- (

I think its my turn next...

My car pushes water out the overflow, but the weird thing is, it usually happens only after I turn the engine off???

[Grizzly]

You can usaly tell if its got a Bad Seal or Groove if the Pipes go hard whilst being  still on Cold start.

Do you have a PFC? if so watch the temp when you shut down it may be that you have a dodgy rad/Thermostat or something causing it to get a bit hotter than Normal then when its shut off the temp rises and it boils over.

[MillSpeed]

Oh dear  :- (

I think its my turn next...

My car pushes water out the overflow, but the weird thing is, it usually happens only after I turn the engine off???

This could well be your AST cap. When you shut the engine down the temp of the (now stationary) coolant is going to rise due to the fact that heat is no longer being removed from the system via the radiator. Perhaps if the AST spring has weakened with age, when the engine heatsoaks and the coolant expands, the pressure is enought to force large amounts of coolant past the cap and down into the overflow tank. Do you get any associated boiling noises when you shut down?

EDIT: Jusr re-read your post from the previous page. Did you get around to fitting an original AST after? Cos like you said some of the aftermarket items have cap seating issues. Still think it\'s worth checking the cap, in particular the seal and the little return valve.

[teabagger]

Sorry to hear mate!  

Theres only one way to cheer yourself up after bad car news - buying more goodies

I know that one. Though in my case it was more like:

"My engine needs rebuilding"
"Sure, would you like anything else; porting? 3mm Seals"
"Nope, just a straight rebuild please"
"Sure?"
"Oh sod it, go on then"


Need some new treads as soon as I get it back too. And I thought women cost a lot to keep...

[shaunwil]

Sorry for the wait on this but i was waiting on various bits & now finally getting somewhere with it!

Well this was the apparrent cause of all this crap over the last 7 months...heres the pic...its the size of a 5p piece. For those who dont know, this is the front plate of the engine block, the bit thats broken is the outer lip of the water seal housing groove.

So its another £2000odd for another rebuild for another year...when will it end:2Rolleyes

At least it will have a bit of closure to it. All the stuuf thats been done to it will make it like brand spanking when the engine is back in one peice.

Can you please pass my Db meter onto kev, if he hasn\'t rung you already. He needs it to test his new exhaust setup.

Shaun

[Rixio]

Okidoky, Kevs around here pretty often so will do

Bit of closure hehehe...you dont know the half of it yet Shaun! Anyways best leave that for a propper conversation!

But yep absolutely everything is or will be brand new now

[Martiny]

This could well be your AST cap. When you shut the engine down the temp of the (now stationary) coolant is going to rise due to the fact that heat is no longer being removed from the system via the radiator. Perhaps if the AST spring has weakened with age, when the engine heatsoaks and the coolant expands, the pressure is enought to force large amounts of coolant past the cap and down into the overflow tank. Do you get any associated boiling noises when you shut down?

EDIT: Just re-read your post from the previous page. Did you get around to fitting an original AST after? Cos like you said some of the aftermarket items have cap seating issues. Still think it\'s worth checking the cap, in particular the seal and the little return valve.

Well Clive sent me a used AST cap, no difference.

No I havent tried a Std AST yet.

I have only std ECU.

Yes I get bubbling noise!   :- ((((((