Heater matrix acting more efficient than my rad?

merlin2002 · June 23, 2011, 12:17:17 AM

Hi peeps
Some of you have now met me and my erm ..... Interesting car lol!

Well just thought I would get some feedback on this from the more knowledgeable people on rx7 than me!
I\'m pretty sure a water seal has a leak in one of the housings
Points to note!
No White smoke on start up or while driving
If I have the heater in the car set on hot and fans on using ac button, this cools down engine somewhat amazingly! If left to do it will, temps go up and up and up!!
I loose quarter to half a pint of water very journey!

New thermostat fitted
Refitted ast
New rad.....ebAy dodgy one ( do these flow badly?)
New antifreeze and flushed till crystal clear!
I have bleed the system a number of times, antifreeze does have a few small bubbles which feel as if coming from rad rather engine ( I say feel as I could feel a vibration in pipe when air was coming up) this didn\'t want to stop!

My thoughts are this could the rad be flowing badly? Causing water loss due to localised boiling due to air pockets? And this is why heater matrix cools engine better?

Yes i grasping at straws.... But once back from holiday I have to decide what I am going to do about this engine!

On a up note I\'ve probably done around 1000miles with it like this!

Any thoughts or free engines appreciated lol
Rob

philiwily · June 23, 2011, 12:34:51 AM

Whats it like with the heaters on cold and the aircon on?

merlin2002 · June 23, 2011, 06:54:35 AM

Keeps it cool unless i give it some! Ie 80-85 with on hot brings it right down between 70-80 unless I give it some

philiwily · June 23, 2011, 08:21:56 PM

If you are sitting at idle do both the fans come on with the aircon off.

P.S. have you gave any thought to resending the AST removal cap

merlin2002 · June 23, 2011, 09:28:19 PM

if im honest I havent noticed this! im even wondering if the pump is iffy? as i have changed the thermo switch to a FC one.
AST removal back in post tomoz, kinda hard to get to post office this week, but will tomoz as have full staff at work!.....to your NEW addy lol

philiwily · June 23, 2011, 11:25:02 PM

It was the thermo switch I was wondering about but could still be a relay so worth having a look.
Taking the pump off for a look would be worth while as I changed a water pump on a Astra last week and the impeller was just a stump.
Do you know what temps the fans are set to come on, on your PFC (if you have one).

Can\'t believe I done that Ebay thing, I bought other stuff and its totally AWOL.

merlin2002 · June 25, 2011, 12:19:20 AM

No PFC for me yet

had a try tonight with a/c button off and number plate removed from bumper to aid air flow.
got 16 miles then sat at some traffic lights for a few mins and temp went up to around 90 then got to where i was going parked up and it it 100 with no fans on!
so I chucked on the A/C swicth to cool her down wich it did so easily down to around 75.
I have changed the thermo switch to the FC one so the fans should be coming on earlyer....I gona check wiring from thermo switch tomorow afterwork...fingers crossed

cyman · June 25, 2011, 12:28:11 AM

if you have fitted an fc thermoswitch it makes the fans come on at around 93 deg instead of 107 deg of fd one then they switch them off at around 87 deg.

i think if you just put the thermoswitch wire to earth that will make fans come on so its easy to check

merlin2002 · June 26, 2011, 01:45:54 AM

Ive done some extensive wiring investigation today it would appear that the fan switches work oppersit to how most people think....on the RX7 there is 2 therm swtches one that switches them on and one that changes speed of fans.
the actual thermo switch is earthed to start with, so unlpluging sensor turns fans on!

My fans come on at just over 100 and then go off when temp falls just under, me thinks he seals are defo gone as I hit these temps just sitting on my drive.

Another interesting point to mention is that I didn bother to top up my coolant today and once I swicthed off the car there was no boiling rumberling noise and the pressure release cap didnt release fluid back in to overflow tank.....

Im thinking perhaps getting a PFC and setting fans to come on at 85/90 is this feasable? as this could help my poorly engine last a tad longer lol till winter time for rebuild or engine?

Rob

cyman · June 26, 2011, 10:47:10 AM

if your fans arent coming on until over 100 then you dont have an fc switch or its faulty

Nik da Greek · June 26, 2011, 11:07:24 AM

Quote from: merlin2002;771614I
Im thinking perhaps getting a PFC and setting fans to come on at 85/90 is this feasable?

Yes :Thumbs-up

Dr Hoo · June 26, 2011, 11:11:41 AM

Are you using the same radiator cap you have always used, or the one you got with your new rad?

merlin2002 · June 26, 2011, 11:31:41 AM

It\'s defo got an fc switch on her, also new rad cap from work!
Hmmm power fc lol

Dr Hoo · June 26, 2011, 12:11:22 PM

Quote from: merlin2002;771674............. also new rad cap from work!

I was thinking along the lines that the coolant wasn\'t being pressurised and hence would boil at 100degc.

I saw this many moons ago on an Astra where the bypass spring in the cap was goosed so the system could never pressurise and would just over heat like a Bi_ch!

cyman · June 26, 2011, 12:36:18 PM

Quote from: merlin2002;771674It\'s defo got an fc switch on her, also new rad cap from work!
Hmmm power fc lol

well ive got an fc swithch and it makes the fans come on at exactly 93 deg and turns them off at 87 deg it does it everytime at these temps checked many times on the commander. im guessing yours is faulty or you are taking measurements from a dif place to the standard temp sensor.

also i didnt think you can make changes to fan settings on the commander i thought it had to be dont on pc connected to the ecu???