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Following on from here:- http://www.mazdarotaryclub.com/forums/showthread.php?t=67195
 
Possibly a bit of a ramble, but bear with me, I do have a question or two at the end!!
 
I\'ve replaced most of the coolant hoses now on my 92 fd3s after having three of the originals spring substantial leaks in quick succession - all whilst driving and only by a mixture of good fortune and decent observational skills have I avoided an overheat because I\'ve been able to switch off very quickly each time...
 
Needless to say, I\'m a bit paranoid about the cooling system now, even though all 3 hoses that failed had good reason for doing so

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• Had been nicked with pliers or similar close to the hose clip (by someone working on the car previously) and had failed where it had a fairly deep chunk taken out of it
• Was rotten - once removed it was obvious the hose was as weak as anything where it had failed
• Standard hose clip had been replaced by a Jubilee which had been overtightened, causing the hose to split internally and eventually all the way through

I\'ve carried out the champagne test at the cap by the thermostat, and was relieved to see no bubbles at all going from a cold engine all the way through to the fans cutting in, just a tiny bit of foaming when the coolant was properly hot.
 
To monitor against future failures, I\'ve plumbed a 0-15psi "fuel" pressure gauge into the cooling system using a t-piece in the hose to the rear of the throttle body, but the results aren\'t quite what I was expecting...
 
Cold start & left at idle
 
From cold (0psi) the reading rises quite gradually as the coolant warms up, peaking at around 12psi, at which point there is a sudden drop in pressure (back to about 3psi) and then the process repeats - pressure rises slowly (couple of minutes) to around 12psi and then drops back quite suddenly. Does the same before and after the thermostat opens. Would this be the (0.9 bar) AST pressure cap in operation, releasing pressure to the header tank?
 
Driving
 
On the road it\'s a different story however, the coolant pressure seems to rise and fall dramatically with engine revs. For example, accelerating from 1500rpm to 5000rpm would see a fairly static pressure reading of perhaps 6psi suddenly shoot off the scale and peg the needle. The speed at which the needle hits the peg would suggest the system could actually be hitting 30psi+!!! As soon as the revs are reduced the pressure drops back to sensible levels.
 
Obviously as the revs increase the water pump is spinning faster, but would that be expected to cause such a massive pressure increase?
 
Any suggestions for possible problems to investigate would be very welcome. I can\'t help feeling these sorts of peak pressures are way too high and would go some way to explaining why the cooling system has seemed to be finding the next weakest link via which to release pressure...
 
Thanks
Mark

Cheers mate, I\'ll not start panicing just yet then!! :Laugh

Thanks Si.
 
Checked the coolant level at lunchtime (by removing the main pressure cap) and it had dropped a bit again.
 
The header / overflow tank (with the dipstick) is still on max though so it doesn\'t seem to be pulling extra coolant through from there when needed as I thought it might? Is there anything I should check that might be preventing this from happening?
 
Took about half a pint to top up, no obvious signs of leakage but could still be purging air I guess??

Well I tried Mazda yesterday, the hose is in stock in Europe but they can\'t price it or sell it to me until Mazda UK "add it to the system"!! :2Rolleyes
 
Was advised to call back next week to see if the system has been updated by then...
 
So yesterday afternoon I removed the hose and cut the damaged end off - it had holed under the hose clip - looked like someone had caught it with pliers previously when removing the clip and taken a chunk out of it.
 
Fortunately there is just enough length left in the remaining hose to refit it without it being under tension or kinking, so a quick refil of the cooling system, a couple of goes at bleeding it and all seems
 
Will keep a close eye on both the hose and the water level over the next few days, but it got me to work this morning without expiring in a cloud of steam so that\'s a good start!!

Yes I\'m going to get price and availability from Mazda and see how they compare to the cost of the SFS 5 piece silicone ancilliary set - which does appear to include the one I need.
 
The SFS set is £66 off ebay although the sellers feedback suggests it will take a good couple of weeks to arrive..

It\'s this one I need... Any recommended sources?
 

Hi All,
 
any suggestions for where to get a lower heater hose from (the short curved one below the ABS unit that goes from the heater pipes protruding from the firewall to the engine)?
 
I assume Mazda can supply one for £silly and I\'ve also looked online and found this http://www.sfsperformance.co.uk/prod_carkits.asp?make=mazda 5 piece "ancilliary" hose set - anyone know if this would include the one I need?
 
Alternatively I guess I could find an "old school" motor factor and root through their hose collection to try and match up something very similar...
 
Thanks
Mark

Thanks Chaps, yes it was indeed "simples"!
 
Only slight complication was the moulded bracket had split on one of the covers so I had to remove the cover and epoxy that bit first.
 
Also straightened up my front number plate at the same time so the front end looks much sharper now - amazing what a difference some pretty subtle adjustments makes :yes

Hi All,
 
had my car a couple of weeks now and starting to compile a to-do list.
 
Hopefully starting cheap and easy (well I can dream!) the headlight covers don\'t align with the bonnet and wings very well when closed - as below they are slightly raised at the outer edges and too low towards the middle.
 

 
Ive had a quick look and there did seem to be some adjustment to the screws on the sides of the lamp unit that are accessible when raised, but they\'re already pretty much at the limit of adjustment - is this where I should be trying to adjust the alignment?
 
The alignment and shut lines of the wings, nose and bonnet all look good, so I\'m hoping that only the lights need tweaking??
 
Thanks
Mark

 

No worries, I\'d rather understand the figures correctly and I think you\'re right - I\'ve got 2 graphs too and the green figures are 258.8 and 305.4 which makes more sense.
 
Question is then - what the hell are the yellow figures??!! :xconfused

Well I did think that 25 hp was quite a small amount to lose in transmission losses, that\'s why I quoted the wheel hp originally as that\'s what the dyno actually measures..

Less than 10% loss does seem low but WGT are very experienced in dynoing these cars so I would expect there to be some logic behind the conversion figures they use??

Anyway the car feels nice and quick and more importantly to me is delivering the power really progressively and from quite low down so it\'s really driveable - which it wasn\'t pre-mapping so I\'m more than happy for now :burnout

hey dude quick question you were mapped at 280 RWHP what was it at the Fly and what mods are fitted?
 
Cheers
 
Kris

Kris, it made 280 at the wheels, 305 fly on WGT\'s rollers.

As far as I know the car is stock other than a WGT exhaust, twin mushroom filters, HKS hard pipes and a Power FC..

That would have been good, but.... you\'re Longton Staffs and I\'m Longton Preston, so not quite so local!!
 
I didn\'t realise there was more than one!! I\'ll have to revamp my sig now!
 
:cheers

Hi, no t\'wasn\'t me. Didn\'t have an rx7 to put a bonnet on a couple of weeks ago!!