cylinder head sensors

[MondoBongo]

Well I have had a brief scan and cannot find any info on these posted already so, apologies if the answer is already here and I have missed it,...

Hello, I am in need of anorak help,.. I believe this is the place to seek it ...

The chap who is fiting my new cylinder head has asked me to provide him with 2 replacement sensors which screw into the drivers' side of the head. Having asked around a bit no-one is sure what these are and I was advised by a very nice man to put some pictures up here and seek assistance..

The first of these is shown in situ, I believe it is a one-pin connection, and it is located near the front of the head near the cambelt (I think !)



The second is again on the drivers side, more towards the rear of the head, and this image shows the hole where it goes (just above the mole grips)



Below is the second of these sensors, broken, on my desk.



If anyone can advise me what these are called, what they do, and where I may be able to get them from I'd be very grateful !

damn those pictures ended up small.

Yours

Technophobe.

[dandywarhol]

The single pin one is the coolant gauge sensor. The 2 pin one is also a coolant sensor but supplies info to the ECU

Try some of the supliers on the homepage - bongobits for example

[MondoBongo]

cheers !!

[missfixit70]

This thread may help too (to confuse ) http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=29687

[MondoBongo]

Well I've read that thread a few times now and you're right, I'm very confused.

We seem to be mostly back to normal now following No 2 cyclinder head replacement. I have one of Haydns audible coolant loss alarms fitted, also a bunch of new hoses, and I am pretty determined not to have to do a cylinder head no 3. !!

I am taking my bongo back to my mechanic, when he's recovered from the flu, and there are only a couple of things left to do,

- add antifreeze. He didnt do this when he replaced the head, said to monitor for any coolant loss first.

- replace one or more glowplugs that seemed to have gone down when my head melted.

There is still something not right though... which is that the radiator fans come on when the ignition is turned on, and stay on all the time. Both of the sensors mentioned above, on the side of the head, have been replaced, and I even got one of those engine compartment £50 sensors, which I tried changing today but this made no difference.. (so I have a brand new one of those to sell if anyone needs one...I can't return it)..

BUt as to why the rad fans come and stay on, I am clueless. My mechanic may be able to work it out, he's pretty good, but any help that anybody here could give me will be gratefully received.

[Simon Jones]

Is it definitely the rad fans that are coming on, as opposed to the scavenger fan at the front of the engine? As mentioned above, the rad fans are activated by the rear sensor via the ECU. The scavenger fan sensor is by the handbrake & if you disconnect the wire to this, it will turn the fan on, so check for a loose connection here.

[The Great Pretender]

The single pin one is the coolant gauge sensor. The 2 pin one is also a coolant sensor but supplies info to the ECU

Try some of the supliers on the homepage - bongobits for example

I often lay awake at nights wondering why Mazda didn't fit a tee where the coolant sensor is with an automatic air vent, make sense?

[MondoBongo]

Nope its definitely the radiator fans. I changed the sensor near the handbrake but it made no difference. I'm a bit technically challenged (mentally), but am I right in saying that, having changed both of those sensors on the side of the head, and one of them supplies info to switch the rad fans via the ecu, that it is now sounding like there is a dodgy connection in this circuit somewhere, or a break in it, or there's something majorly up with my ecu ?

[rita]

Nope its definitely the radiator fans. I changed the sensor near the handbrake but it made no difference. I'm a bit technically challenged (mentally), but am I right in saying that, having changed both of those sensors on the side of the head, and one of them supplies info to switch the rad fans via the ecu, that it is now sounding like there is a dodgy connection in this circuit somewhere, or a break in it, or there's something majorly up with my ecu ?

Hi,when your head melted its probably knackered the sensors and jiggered that part of the ECU operation.

There is a Bongo Specialist in Scotland I believe its Dunfermline,that has encountered this on a few of his customer's cars after overheating.

If possible it would be worth while getting your ECU checked.

[dandywarhol]

Any chance you've got the A/c turned on?

[Grahame at work]

MondoBongo,

If you have a break in the wiring it will certainly set your fans on all the time.

Grahame

[MondoBongo]

Any chance you've got the A/c turned on?

Is that a joke ?

[missfixit70]

Nope, if the a/c is on, it triggers the fan/s

[MondoBongo]

well I wasnt sure.. sorry...

Anyhow I checked and it was definitely turned off. We never to my knowledge have used it anyway.

Sounds to me that its a break in the circuit somewhere or the ECU is broke. I hope to have it back with my mechanic this week, I'll run those theories past him...

[MondoBongo]

Hello,, my issue rumbles on..,.

Just to recap, our bottom rad hose went on the motorway a month or two ago. Rapid (unnoticed) coolant loss led to overheating, causing a cracked head. Head replaced, 1 and 2 pin sensors on side of head replaced. Numerous hoses replaced (not broke but probably due to ...), coolant loss alarm fitted...

Our Bongo is now running but with a couple of minor niggling things which neither I and our regular mechanic seems ot to be able to figure...

Rad fans come on when ignition turned on.

One or two glow plugs seem to be down.

Now, we seem to have gone through more glow plugs than one might expect over the 5 or 6 years of our ownership. From what I have been able to gather on here, the ECU governs the operation of the glow plugs, also the rad fans, so I thought it could be that this overheating has damaged our ECU, or it was dodgy before (re glow plugs) or both.... so i managed to gat a 2nd hand ECU from a 'working' vehicle from a reputable bongo bit dealer.. Tried this out this morning and no difference whatsoever. Which I guess may be because this replacement unit has the same fault as our existing one, or may be because the current problems (rad fans, glow plugs) are not caused by the ECU. Question is, I can understand if the glow plugs got boiled with the engine, they can be replaced, but why are my rad fans on all the time ?

Also, low coolant alarm now seems to activating at unusual times for worrying lengths of time, since antifreeze was added (cold level is at max mark) ... !! Just to confuse me even further I guess.

Any advice deas or theories gratefully received,,one does like to solve a problem but my sanity is being a bit compromised (this is now the third cylinder head on our Bongo),, also if anyone is in need of a 2nd hand (but possibly working !) ECU and/or new, but not needed, engine compartment/scavenger fan sensor, well, I'm your man.