Angry funnel eruptions whilst bleeding

[Jaypod]

Hello everyone! First post, first Bongo, first hiccup! Any advice is gratefully received

We bought our first bongo a week ago (2.5Ltr Diesel '95), drove it home, no problem. Drove it a day later and spotted the water temp climbing very quickly, only after a mile. Pulled in and popped the bonnet to find water spraying out from a pin prick at the bottom end of the top radiator hose (part 15-183: http://lushprojects.com/bongopartsmk2/c ... mgno=.html) - the dog-leg one

Managed to bandage the hole using a sanitary towel and some cord from the "Bongo toolkit" as a makeshift tourniquet and limped a mile home taking it very easy.

This weekend, drained and flushed the system and used all the fantastic advise given in the Mazda Bongo Bleeding YouTube vids.
See-sawed the system cold until no bubbles at the funnel end - all good.

Moved onto see-sawing the system with the engine running and straightaway there are huge kind of water eruptions at the funnel end. At no point do we let the expansion tank run dry or introduce any air at the funnel end and we just keep seesawing as it must just be trapped air right?

Well after about an hour of explosive seesawing (sounds painful) there is no change at the "angry funnel" end - surely this can't be air as if we turn the engine off and continue seesawing, its as slick as you like with no bubbles. I'm thinking there must be another fault somewhere as its so violent - almost like a heat swell or something working its way out as it doesn't look like air bubbles at all and nothing like it does in the YouTube vids.

Few more symptoms/clues hopefully..

- Rear heater blows hot air, front heater only cold
- Water temp, once up, stays at a constant 11 O'clock on the dial
- Radiator fans kick in when they should
- Bottom near-side radiator hose is continually cold
- If we switch off the engine, cap off the the bleed hose as per video instructions so as not to introduce any air, double check the water level is good in the expansion tank and replace its cap. Start the engine as normal, with a couple of mins we have coolant forcing its way out of the expansion tank overflow with crazy gurgling noises!?[/list]

Has anyone ever seen this? I'm quite anal when following instructions so don't believe I've missed a step and the detail in the vids is very good - any ideas people?

[MountainGoat]

Where about are you, your location would be helpful. There may be a member or two who are real experts at bleeding a Bongo Cooling System.

Tony

[Jaypod]

Hi Tony,

I'm in Somerset, near Glastonbury and Wells if that's any help.

Cheers,
Jay

[MountainGoat]

Haydn Callow one of the people in the utube video also lives in Somerset, with a bit of luck not too far from you. You could wait until he comes on the forum again or send him a PM. The chances are that he may discus your problem with you over the phone.

Tony

[Northern Bongolow]

dont run it anymore until you chat to haydn.

ive rung him, hes coming on now

[Jaypod]

Thanks guys, I'll do just that

[Northern Bongolow]

see above post ive just edited.

[haydn callow]

Have PM'd my phone No to you.

Thank Ady AKA Northern Bongolow for bringing this to my attention,

[sunnyjim82]

I'm no professional but sounds like you may have a blockage somewhere?maybe in rad or heater matrix or maybe a pooped thermostat?thats where I would start or as said pm one of the pro's!!

[swampy]

Few more symptoms/clues hopefully..

- Rear heater blows hot air, front heater only cold
- Water temp, once up, stays at a constant 11 O'clock on the dial
- Radiator fans kick in when they should
- Bottom near-side radiator hose is continually cold
- If we switch off the engine, cap off the the bleed hose as per video instructions so as not to introduce any air, double check the water level is good in the expansion tank and replace its cap. Start the engine as normal, with a couple of mins we have coolant forcing its way out of the expansion tank overflow with crazy gurgling noises!?[/list]


Hi Jaypod,
Having bled ours several times recently in an effort to get the fans working, (sensor problem) I think the clue here is that your bottom hose is always cold. This means the thermostat is not opening when it should (82 deg.). When bleeding you get the hang of having the right level in both the funnel and expansion tank. When the stat is closed and you are revving, then return to idle, you will get coolant flowing quickly back into the funnel, you then raise it up to stop overflowing, when the stat is closed this is more pronounced, as soon as the stat opens and the bottom hose warms up, this quicker flow dies down and reaches equilibrium.

Air escaping manifestes itself as bubbles, not this volcano effect, that's normal-ish. Also if your fans are kicking in before the stat opens, the temperature at the head on the 2 pin sensor (back of head RHS below glow plugs) is already at 96 deg, but the stat should have opened at 82. don't do this again until you have solved the problem.
Take out the stat and test it first on a pan of water on the heat with a thermometer, you shoud see it open halway at about 82 and fully by about 95 degrees. Also check it looks OK and the little hole is not blocked.

You may have a blockage somewhere, drain out the coolant again (after you've either refitted the stat if it works, or a new one, probably worthwhile now anyway - I'd recommend a genuine Mazda stat) and save it in a clean bucket, put a hosepipe in the expansion tank with the bleed tube unplugged and pointing downwards, run the hose for 10 minutes or so at a fairly low pressure to the flush the system, you should get the same flow at both ends. If it continually backs up in the tank, and flow out the bleed pipe is poor you may have a blockage, hopefully this will clear it.

When you've done all this, before you put mixed coolant back in, I'd suggest filling it with water only (with a flushing compound if you like), bleed again making sure the bottom hose gets hot. If it does and the fans don't come on, then refill with AF coolant, after draining again (when it's cooled of course).
Trouble with your temperature gauge is, it has a sticking point at 11o'clock, ranging from around 75deg. to 115 or more, so you're temp looks fine, but it obviously isn't. There are loads of threads re low coolant/temp. alarms (ask Haydn) and a temperature gauge mod which is very simple if you're handy with a soldering iron. This works very well.
The reason it's gurgling out of the expansion tank now is because the stat's not opening, so it's still got air. Hope that helps, good luck.

[swampy]

Sorry jaypod, just noticed you mentioned the front heater is cold, that may be the blockage, maybe your stat didn't open at all previously even though it seemed fine. When you drain it again you could try draining the heater as well and flushing, test the heater a couple of times when bleeding to make sure it's hot, if it doesn't the heater matrix could be blocked. Swamp.

[Northern Bongolow]

swampy has it spot on. the only thing i would add is that the obstruction is most likely to be air,(airlocked) so a physical blockage isnt always there to find.
the fans on and the bottom hose cold is classic airlock, or blockage.

[haydn callow]

Hoping to get to see Jaypod later to-day.

What I don't understand is ....if it is a blockage ..either physical or air....why does it keep erupting for a hour.....??? it must be getting the "erupting" air/gas from somehere....I will check what I can but my guess from seeing this in the past is combustion gases getting in via the head or h gasket.

The gauge did move to the HOT mark.
Only had it a week.
Did lose a lot of coolant.
When the bleed bung is replaced the Tank erups.

[westonwarrior]

It doesnt sound good

But at least you will be able to check it over.

hoping for the best but is this another story of a car sold with a disuised fault

[2sticks]

It would not surprise me if it was simply a classic case of
STEAM in the cylinder head.

With an open cooling system with no pressure, and probably
a very low concentration of anti-freeze, you could quickly
exceed boiling point and produce steam if you don't monitor
the cylinder head temperature with some accuracy.