2.5 TD 4WD first time overheating

[dobby]

Thanks for all the info. I will get a breakdown when I go back to the garage. The garage is ADS in Bristol and they seem to provide a good service.

Good luck, let us all know how you get on. ADS are mentioned on this post:

http://www.igmaynard.co.uk/bongo/forum/ ... &hilit=ADS

[bigdaddycain]

the coolant in the reserve tank was above my coolant alarm sensor. Yesterday, before I travelled home the coolant had dropped to below the sensor (i.e. Between LOW and HIGH on the tank) setting the alarm off, so I topped up with coolant.
Thanks Paul

And the Head had gone... ..... between high and low is not that much of a loss IMHO.... I would have thought the alarm would have warned you sooner.....

That's what i thought!

I'd have thought a gas sniffer test would have detected any trace evident in the expansion tank? I thought those tests are pretty conclusive and about a tenner per check??

[Northern Bongolow]

sorry i dont understand the debate here with the low coolant alarm.
the level dropped between the top and bottom levels,so the alarm triggered,how could it trigger earlier.

[mikexgough]

I was only saying that the small drop in coolant amount triggered the alarm only on the Sunday cold start up and (put me up against the wall for the theory) surely that small drop in coolant (which was not below the LOW mark in the header tank) and between the level parameters would not have damaged the head?........ nothing more......... I will get my coat...... which wall do I stand at and can I choose the firing squad....

[Northern Bongolow]

no firing sqauds on here (i dont think) just good debate,now you have clarified your point i understand entirely.
is it not good that the alarm has shown a low level,even if its within the parameters of the system as no coolant loss is acceptable.
the sensor is positioned 15mm i think, below the full mark just for this reason.
the only way it can detect at a different time/loss amount is if you position the sensor differently.
regards ady.

[mikexgough]

no firing sqauds on here (i dont think) just good debate,now you have clarified your point i understand entirely.
is it not good that the alarm has shown a low level,even if its within the parameters of the system as no coolant loss is acceptable.
the sensor is positioned 15mm i think, below the full mark just for this reason.
the only way it can detect at a different time/loss amount is if you position the sensor differently.
regards ady.

No worries.....but although there has been a loss of coolant (by whatever means) the level was between the expansion tank High & Low parameters...... so within "working" coolant levels......

what I don't get is how the head went......if the only coolant loss was only noted on the Sunday cold start via the alarm......yet is still within manufacturers coolant levels......unless something more sinister has happened causing an air lock and subsequently a false coolant level reading which for whatever reason the alarm would not pick up on just a thought

[Northern Bongolow]

your last paragraph is the key part of this.
in my opinion this is exactly what is happening up and down the land.small leak somewhere on the system.airlock goes to the head and sits there,holding the water level UP in the expansion tank.you think everything is rosey and off you go.

[haydn callow]

I really don't know what some peeps expect....the LCA (Low Coolant Alarm) does exactly what it says on the tin.....It detects ANY drop in coolant level that exposes the Tank sensor.
That is about 15mm below the tank FULL mark and a loss of about a cupful. Put the sensor higher and the alarm will activate sooner but may also give false alarms as you go round bends/up steep hills. It seems to work very well and the testmonial page within the webshop tends to back that statement. 3000 Bongos running around with one fitted and well over 100 reports of it saving the day.
That will do me.
One of the biggest importers/dealers will no longer sell a Bongo without a LC alarm.
Yes! even petrol ones....He had 3 recently "pop" a hose whilst changing/testing the cooling system. (pinprick holes)

[missfixit70]

your last paragraph is the key part of this.
in my opinion this is exactly what is happening up and down the land.small leak somewhere on the system.airlock goes to the head and sits there,holding the water level UP in the expansion tank.you think everything is rosey and off you go.

This why I fitted the High level add on to the coolant alarm, & it's worked a few times over the last week when I've had airlocks thanks to weeping hose joints on the silicon hoses, it's leaked a tiny amount then when it has cooled it must have sucked air in, no coolant drop detected or visible in the header, so even a visual inspection wouldn't pick it up. A few miles down the road Mason starts bipping (set quite low - just before fans are supposed to kick in), then the coolant alarm starts screaming in earnest as the coolant level rises & starts to be ejected form the overflow, temp gauge still well withing control range, pulled over, fans going full belt but doing nowt as the stat is still closed thanks to the airlock. let it cool for a bit in Aldi car park, then bled it to get home, where I pressure tested it & found that another replacement jubilee clip had gone on the bottom stat connection.
So I have to say a huge thanks to Mr Mason as well as Mr Callow, both alarms did what they said on the tin, & thanks to Ady for the pressure testing kit (that I never got around to making ) disaster averted.

[mikexgough]

your last paragraph is the key part of this.
in my opinion this is exactly what is happening up and down the land.small leak somewhere on the system.airlock goes to the head and sits there,holding the water level UP in the expansion tank.you think everything is rosey and off you go.

Hence why the low alarm may not notice a drop in coolant level, if the coolant is held up in the expansion tank by such an induced airlock.... Nothing wrong with the alarm at all and fitted numbers support this,it just could be fooled by this kind of scenario....

[haydn callow]

Drop in coolant level ??? it will pick this up.....
When most folks say "drop in coolant level" they mean drop in the level in the tank. That is what the alarm detects....No more and no less.
I give up.....!!!
It is NOT a airlock detector....high temp detector or anything else other than a Low Coolant (in the tank) Alarm.

Perhaps someone could start work on developing the "detects anything wrong" alarm or DAW Alarm

[mikeonb4c]

Perhaps someone could start work on developing the "detects anything wrong" alarm or DAW Alarm

Interesting point. Supposing there was an airlock in a bad place (say around the head area) so that a local hotspot might form and cause damage. How might this be detected? Would the coolant temp. rise. I'm not sure. Might the coolant boil locally, causing pressure build up and an overflowing header tank? Possibly. I guess a high level detector is then a good idea though I imagine coolant erupting from it only a short period after it overtops the high mark would warn you anyway.

You give up Haydn? Never!

[dobby]

I guess that a temp rise is the only pointer?

I think that this goes back to the well maintained and good heating system debate. I.e. if everything was 110% then there would be no leaks.

Haydn's post is quite right, it's a low coolant alarm though. It's sold as such and works as such. Saved ours last year when the core plug corroded (poor maintenance). But when a hose went and cracked the it wouldn't have had a chance as the system pressurised etc.

[mikexgough]

Drop in coolant level ??? it will pick this up.....
When most folks say "drop in coolant level" they mean drop in the level in the tank. That is what the alarm detects....No more and no less.
I give up.....!!!
It is NOT a airlock detector....high temp detector or anything else other than a Low Coolant (in the tank) Alarm.

Perhaps someone could start work on developing the "detects anything wrong" alarm or DAW Alarm

Personally with my theory (rightly or wrongly) I was not implying that the alarm did not work ........only that IF an airlock caused the expansion tank to keep the level within the High/Low parameters and above the trigger point as Northern Bongolow suggests that the alarm would not warn the user that the coolant level was low..... which it wouldn't as it would be within normal operating levels....

[haydn callow]

Give up ????
What I'm trying to get across is that the LCA does just that..
It does not detect punctures, rusty wheelarches or anything else it was not designed to do (including cylinder head airlocks).
Fit a cylinder head temp gauge if you want to go to the next level....Having a temp sensor in the coolant is not a lot of good if there is no coolant present to give it a reading.
Everything in life has it's limitations.