yellowy/header tank and sorting it all out

[rapiddescent]

I had a look at the header tank and I couldn't see the level without using a high powered torch - even then, it's hard to tell what level its at. It doesn't overheat and I was only looking because the coolant alarm has been tripping when starting (I park on a steep incline) When I bought it, i did notice that it was a bit yellow (but it isn't dark brown like some of the pics on here).

1: What makes the header tanks become so non-transparent? and how do I fix it.
2. It looks like it has a bit of brown gunge at the bottom of the header tank. What's that?
3. I was expecting to see a brightly coloured fluid inside, it's hard tell what's in there. It looks like water.

I think it's time to check it in for a full coolant change - is there anything else I should ask for while it's being done?

[missfixit70]

There's a theory that any that are discoloured have overhaeted to some degree in the past, I don't agree that is necessarily so, plastics can discolour with age & depending what's in them, look in a lot of older vehicles & you'll see the same thing.
Brown sludge may indicate that you hav incompatible coolants mixed in it, or if it is just water (worryingly) it could be rust.
Full chemical flush, backflush the rad & check for full flow, check all hoses & pipes thouroughly, possibly do a pressure test on the system to check for any leaks, fit a new thermostat -preferably a mazda original - if you don't know if it's been changed.

[Triple/R]

I had a look at the header tank and I couldn't see the level without using a high powered torch - even then, it's hard to tell what level its at. It doesn't overheat and I was only looking because the coolant alarm has been tripping when starting (I park on a steep incline) When I bought it, i did notice that it was a bit yellow (but it isn't dark brown like some of the pics on here).

1: What makes the header tanks become so non-transparent? and how do I fix it.
2. It looks like it has a bit of brown gunge at the bottom of the header tank. What's that?
3. I was expecting to see a brightly coloured fluid inside, it's hard tell what's in there. It looks like water.

I think it's time to check it in for a full coolant change - is there anything else I should ask for while it's being done?

I do'nt think header tanks are particularily pure white--they seem to be more of a golden colour---what would concern me if they was really dark brown towards the bottom of the tank as opposed to the top -- thats my thoughts anyway.

[mikexgough]

I had a look at the header tank and I couldn't see the level without using a high powered torch - even then, it's hard to tell what level its at. It doesn't overheat and I was only looking because the coolant alarm has been tripping when starting (I park on a steep incline) When I bought it, i did notice that it was a bit yellow (but it isn't dark brown like some of the pics on here).

1: What makes the header tanks become so non-transparent? and how do I fix it.
2. It looks like it has a bit of brown gunge at the bottom of the header tank. What's that?
3. I was expecting to see a brightly coloured fluid inside, it's hard tell what's in there. It looks like water.

I think it's time to check it in for a full coolant change - is there anything else I should ask for while it's being done?

1: probably age......... this is a Japanese Owner/Spanner's tank


2: possibly mixed coolant like 2 different types.... or hopefully......just old coolant....
3: get it changed ....... flushed and rinsed through and change the Thermostat while the coolant is drained...... use a branded coolant ...... there are certain type numbers out there and gets a bit techie for most folks...... just remember ......when it is changed keep some of what the system has been refilled with for top ups.... don't mix it...

[mister munkey]

A discoulored header tank is a possible pointer to previous abuse but one that a majority of us manage to live with.

Suggest a replenishment & flush to be on the safe side but the tank will remain stained. Have a search on here for finding the Lolly Stick measurements you need for a DIY coolant dipstick in the meantime.

[rapiddescent]

that's excellent advice - mine does look more yellowy-old-plastic rather than brown from a head gasket failure. I'm more used to being able to see a clear blue level of coolant in other vehicles. Also, not sure if relevant, but it's been pretty cold here. -18'C a few weeks ago and it's about -4'C when I checked it 45 mins ago.

[missfixit70]

For a coolant dipstick jusy mark a line 20mm up a lolly stick or unvarnished chopstick, so the water stains where the level is, then stick the dipstick in the header vertically until it touches the bottom.

[pjbowers058]

For a coolant dipstick jusy mark a line 20cm up a lolly stick or unvarnished chopstick, so the water stains where the level is, then stick the dipstick in the header vertically until it touches the bottom.

Should this be 2cm ?

Regards Paul.

[missfixit70]

yep 20mm I meant

[blobber]

I might be wrong here, but didn't I read on here in "days ot yore" that discolouration is caused by the type of coolant used in Japan?

[rapiddescent]

Is it true to say that if there had been a previous head problem, the entire head reservoir would be stained brown? Mine just has a bit of a layer at the bottom - it isn't sludge, the torch just made it look like that last night. I think it's just old coolant or a mix of coolants in the past. It didn't smell of oil.

[mikexgough]

your probably correct in your thinking..... discolored through age and coolant changes....... Jap coolant comes in many colours, blue,green,yellow,red for starters...... their coolant is OAT based like the G12+ we have here like Comma Red or Caprlan Red. Now some Bongos can/do get topped up with the same colour coolant on arrival/first year or so in the UK by unsuspecting folks...... Now Blue Jap coolant.....wont play nice with the other children in the coolant family as it causes sludge and gelling....... as your coolant is a little discoloured it kind of hints and suggests that some G11 blue stuff has been added, if your lucky it was maybe just a tea cup full...... but please as soon as you can get your coolant changed.
Ask the garage, if your not doing it yourself......to put a coolant flush in......then flush throughly after.....change the thermostat and replace the coolant with 5 litres of the coolant of your choice......
never recommend a brand as many have their own choices and preferences and it blurs any threads with my coolant is better than yours kind of rubbish........... for me I use a G12+ Red coolant(one of the above mentioned).....

[rapiddescent]

it's booked in - thanks for the advice!

The mechanic (on the phone) also mentioned that the coolant alarm might have been sounding because the coolant mix has got less than 50:50. This would certainly make sense because it looked very clear. Clearly, coolant is very important in a bongo - but for me, because it is so cold here (and I'm a skier, so it sits in an artic climate!) it's even more crucial because one frozen pipe and that would be it.

Luckily, I've not been driving it in the cold weather much - opting instead for another vehicle that happens to have snow tyres...

[missfixit70]

Alarm could also have been sounding if you've got incompatible coolant mixed in, causing electrolysis on the screw probe/s, whip them/it out & clean it off or replace the screw if it's too bad.

[rapiddescent]

I'm very very lucky. It turns out that I had no antifreeze and the chaps at campercraft said it was a miracle that I didn't lose my engine. Basically, luckily for me, I was in my mountain biking gear and had the window open and the heaters on full, also, I was a bit early so was taking my time - I took a slightly wrong direction and ended up coming over the hill from PowMill, past knockhill race circuit to Kelty in a full blizzard with about 12" of slush on the road. The radiator pipes where frozen up but they think that the combination of the slush underneath and the heaters on saved the day.

no air coming though to the header and it looks like everything is OK. phew!