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Radiator riddle?
Posted: Fri Jun 05, 2015 9:21 pm
by Chaosengineering
I was under the impression that the reason the radiator caps were different colours was because one was a pressure cap (yellow expansion tank) and one was a standard cap (white radiator only marked).
However my radiator has a steel overflow pipe on the neck and has a white "radiator only" PRESSURE CAP too. So that's a pressure cap on rad and expansion tank?
Can anyone clarify please
Re: Radiator riddle?
Posted: Fri Jun 05, 2015 9:44 pm
by francophile1947
You have a non-standard radiator fitted. Standard radiator doesn't have an overflow.
Re: Radiator riddle?
Posted: Fri Jun 05, 2015 10:32 pm
by Simon Jones
Yep, it sounds like it's not an original radiator. If the overflow isn't already blocked up then it needs to be done to prevent any opportunity for coolant to escape, or air to get it.
These are the correct caps and even though the rad one has 1.1 bar on the sticker, that's the working pressure rather than point at which it releases pressure.

Re: Radiator riddle?
Posted: Fri Jun 05, 2015 11:12 pm
by Northern Bongolow
Chaosengineering wrote:
However my radiator has a steel overflow pipe on the neck and has a white "radiator only" PRESSURE CAP
out of interest what pressure has it got marked on the cap. and is the rad all metal construction.
Re: Radiator riddle?
Posted: Sat Jun 06, 2015 7:31 am
by Chaosengineering
Radiator pressure cap has 1.1bar on it along with white sticker and rad use only on. Appears the rad is of brass construction.
If I block the overflow pipe I do have a plain rad cap that would then fit it.
Re: Radiator riddle?
Posted: Sat Jun 06, 2015 8:12 am
by Simon Jones
The cap with red and white sticker is the correct one for the Mazda radiator and should not have a spring loaded washer (as the expansion tank cap has). You want non-vented cap on a non-ventable radiator fitting so blocking the pipe should be fine.
Re: Radiator riddle?
Posted: Sat Jun 06, 2015 9:57 am
by Gasy
Hi
I new I had got mine crossed over months ago when I did the flush and rusty tee
Just been out and swapped them to correct positions now ( top up rad to neck, don't want to risk a bubble , if you do it )
But my red and white rad cap does have a spring and washer inside
Any way thanks for the post
I new I'd put them on wrong
But didn't realise the difference
Cheers
Re: Radiator riddle?
Posted: Sat Jun 06, 2015 12:04 pm
by rita
The man from Mazda he say...
Radiator cap KL0115205
Expansion/header/degas tank KL0115205
Re: Radiator riddle?
Posted: Sat Jun 06, 2015 12:22 pm
by Muzorewa
Isn't the KL0115205 just for the expansion tank - isn't the rad cap a WL0115205 if that's different?

Re: Radiator riddle?
Posted: Sat Jun 06, 2015 12:59 pm
by teenmal
Gasy wrote:Hi
I new I had got mine crossed over months ago when I did the flush and rusty tee
Just been out and swapped them to correct positions now ( top up rad to neck, don't want to risk a bubble , if you do it )
But my red and white rad cap does have a spring and washer inside
Any way thanks for the post
I new I'd put them on wrong
But didn't realise the difference
Cheers
Yes you have the correct caps, both caps should be the same,you will find that Mazda/motor factors etc stock them as the same cap for both radiator and expansion tank.
Re: Radiator riddle?
Posted: Sat Jun 06, 2015 10:48 pm
by Simon Jones
teenmal wrote:Yes you have the correct caps, both caps should be the same,you will find that Mazda/motor factors etc stock them as the same cap for both radiator and expansion tank.
Mazda have two different part numbers and that is because they are two different parts:
Only the expansion tank cap has the large spring loaded pressure relief valve underneath. They are physically interchangeable but will not work correctly if the wrong way round.

Re: Radiator riddle?
Posted: Sun Jun 07, 2015 10:48 am
by teenmal
You will find that Mazda/motor factors etc stock them as the same cap for both radiator and expansion tank.
For example AVA Leisure and The Bongo Fury Shop.
(just a bit of useless information)
