Heat soak

[ianelvar]

My FD gets relly hot after I turn it off. So much so that the fans come on if it\'s left for a few mins, and the key turned to the on position again. It stays hot for ages if the bonnet is left down after switch off, even with the fans going!

Unless I prop the bonnet open and leave the fans going after I switch off I\'ll get the coolant buzzer when she\'s retarted. No sign of seal failure, starts first time, every time, hot or cold and with no sign of smoke.

Have tried nearly half a dozen AST caps.

Are they generally like this, and why is my coolant ending up in the expansion tank?!

[Jimjitsu]

is you expansion tank over filling?

[ianelvar]

Yes, it sits full the whole time!

[Rixio]

Sounds like a water seal failure if the expansion tank is filling up everytime. Do a champagne test...

First thing in the morning turn the car on when cold and leave the filler cap off

If you have bubbles rising from the filler neck you have combustion gasses in your coolant...

Therefore...

Rebuild im afraid

Good luck - HTH

Rixio :Thumbs-up

[Jimjitsu]

Sounds like a water seal failure if the expansion tank is filling up everytime. Do a champagne test...
 
First thing in the morning turn the car on when cold and leave the filler cap off
 
If you have bubbles rising from the filler neck you have combustion gasses in your coolant...
 
Therefore...
 
Rebuild im afraid
 
Good luck - HTH
 
Rixio :Thumbs-up

beat me to it

[oldone]

Whats the milage and age on that motor Ian ?........will be at Dodd\'s tomm after 5ish,..be good to see ya if you are around...:cheers

[ianelvar]

I really hope not. Did the bubbly test, came out fine. Pipe\'s don\'t pressurise prematurely, no smoke, easy starting, so I\'m pretty confident it\'s not seal failure. And it only happens when I switch off and don\'t open the bonnet to loose the heat. Can drive hundreds of miles and she\'ll be perfect. My other FD has really bad seal failure, so I\'ve seen the symptoms. Finger crossed it\'s something simple!
Would changing the AST and pipes leading to the expansion tank help maybe?
I was wondering if the heat making the coolant expand pushes it down into the tank, and a dodgy pipe or AST is letting in air when it cools and contracts?
Oldone - Somewhere around 10K for the mileage. I\'ll be around later on, would be great to catch up. I\'m No. 8 Bullsdown close if I don\'t manage to catch you at the garage. See you later on.

[Rixio]

Iv got a Alloy AST if you want to replace yours...doesnt sound like its a pipe cos theres no puddle...hmm tis a strange one

[RemarkLima]

Have you done the champagne test when it\'s warm, mine wouldn\'t bubble at all until it had warmed up and the thermostat had opened.

I went through loads of things, new rad, new alloy AST, loads of AST caps, Mazda AST\'s... Hoping it wasn\'t but if I let it heat up then tons of bubbles came out

Also no water would come out of the overflow unless I kept topping up before I set off a few times in a row, then the expension tank must have been overfilled but only after I shut off.

The pipes wern\'t going stiff, but the system must have been overpressurised as it split the rad then a couple of days after fitting an alloy rad it split the AST. Then I\'ve gone onto borrowed time and used a bottle of:
http://www.kalimex.co.uk/section.html?secpath=01.03.&pgid=2

You have to follow the instructions to the letter, but *touch wood* it\'s sorted my car out until I can get a new engine sorted.

I hope it\'s not, but it seems the water seals can go only a little and only get exhaust gasses into the coolant and not the other way round

[ianelvar]

Have you done the champagne test when it\'s warm, mine wouldn\'t bubble at all until it had warmed up and the thermostat had opened.

I went through loads of things, new rad, new alloy AST, loads of AST caps, Mazda AST\'s... Hoping it wasn\'t but if I let it heat up then tons of bubbles came out

Also no water would come out of the overflow unless I kept topping up before I set off a few times in a row, then the expension tank must have been overfilled but only after I shut off.

The pipes wern\'t going stiff, but the system must have been overpressurised as it split the rad then a couple of days after fitting an alloy rad it split the AST. Then I\'ve gone onto borrowed time and used a bottle of:
http://www.kalimex.co.uk/section.html?secpath=01.03.&pgid=2

You have to follow the instructions to the letter, but *touch wood* it\'s sorted my car out until I can get a new engine sorted.

I hope it\'s not, but it seems the water seals can go only a little and only get exhaust gasses into the coolant and not the other way round

Thanks for the info Really hope it\'s not seals though.....

Rixio - Thanks for the offer. I might well take you up on that. For the moment I\'ve got a spare AST I can pressure test, so I\'ll give that a go before I go alloy.

As always, thanks for your thoughts.

[Hayward North]

Shame ya aint closer, you could have poped down and i could have tested it for Hydrocarbons in the coolent system.
The test kits ate only about £35 so if ya wanna be sure go perchase one.
Like i say shame ya aint closer.

[RemarkLima]

I do hope it isn\'t either, hopefully a pin hole leak or somewhere on the expansion bottle tube sucking in air instead of coolant.

But if you fancy a read of my saga have a look here:
http://www.mazdarotaryclub.com/forums/showthread.php?t=41790

As said mine turned out to be bad, but have made a seemingly good fix for now. One of my dad\'s mates apparently done a season drag racing with this stuff in a boinger, so it\'s good some good reviews!

[ianelvar]

Steve - cheers. Guess I can pick up a tester from an ordinary motor factor? Hadn\'t thought ot that.

I\'d often wondered about the \'block weld\' type stuff. Seen plenty of posts on the yank site raving about it, but you never really know till you try it!
I\'m sure I\'ve read through your post before when I was diagnosing my silver one.

I\'m tempted to have a go, but judging by the way it pressurises 5 secs after turning on I think it might be too far gone. Thanks again :cheers

[RemarkLima]

It is a real PITA to "apply", you have to flush all your coolant, and keep flushing it with water so that you\'ve just got water only in there.

Then get it up to temp, open the filler cap (lose loads of water in the process), top it up, add this gear then leave it to idle for 40 minutes of so, maybe a bit longer if you can.

Then drain all the water out and leave the system empty overnight (at least 4 hours) so it can cure in the air, the flush out the remaining, fill back up and you\'re good to go apprently.

As said, seems to have sorted me out and needs to be the seal up as I had no joy with the K-Seal stuff (which mixes with coolant), I\'ve not tested in full anger as of yet, but happy so far.

I guess the only way to be sure is to do a HC test on the coolant and check for exhaust gasses.

[ianelvar]

Hmm, interesting. I think I\'ll do it on silver and see if it works. I\'m most interested to see what it\'s like when you come to dismantle the engine after using the stuff.