temperature gauge irregular reading

[davelou]

Hi all, not been on this for some time..

All has been well with my bongo untill today, I've had water issues in the past, new head ect
Whilst driving home today i noticed my temperature gauge had dropped to cold after around 8 miles?? I pulled over straight away and the gauge moved back to near normal? I cheched for leaks none, and no loss of fluid,still the same as the last few months?? I'm getting the impression of a air lock as if i rev the engine the gauge goes to zero but if i take my foot off it goes to near normal??

The only thing i did different was yesterday i removed a glow plug to check the length.. could this make any difference or just a coincidence?
Any thoughts?
Regards Dave

[missfixit70]

I'd suspect you dislodged the temp sensor connection above the top hose.

[davelou]

Can you point me in the right direction to see what it looks like please?

regards Dave

[missfixit70]

18-510 here - http://www.lushprojects.com/bongopartsm ... no=.html#5
under the drivers seat front right hand side of the head above where the top hose exits the engine, one wire going to it, it's screwed in vertically& you'll only see the top bit with the flat connector, but it looks like this - http://www.mazdabongo.com/display.products.php?pId=429
Could be the wire's about to break & needs remaking, it does get a bit hot down there.

[Northern Bongolow]

just to the right of the 1st glow plug. single wire to the sender top.

edit kirsty wins again

[davelou]

Thanks . Do you think that would be possible? Seen as there is no obvious loss of fluid? The cable looks intact but i havent checked it yet?

Regards Dave

[missfixit70]

Wouldn't have said it if I didn't think it was likely, check it then you'll know check your heaters are blowing hot & check there's no puddles, but it sounds like a leccy fault to me. Increased revs = increased vibration
Is it an unmodified gauge? ie it sits at @11 0clock once it warms up then never moves normally? Have you got any other alarms or gauges on the cooling system?

[davelou]

Sorry for doubting your wisdom as we all know you are normally right. i'll check it in the morning. it is a normal gauge and the only one fitted.

Regards dave

[missfixit70]

I don't always get it right, can only make suggestions with remote diagnosis
The standard gauge will tell you nothing useful until it's too late, it sits there from @ 55 degrees up to @ 110 degrees C, by the time it starts moving it's probably too late. You can modify the gauge for the cost of a resistor & less than an hours messing about with a soldering iron, or you can get various gauges/alarms fitted that'll give you a bit more info, as well as the low coolant alarm of course (no vested interest before anyone starts), there's a factsheet in the members area & loads of info on the forum including recent discussions on fitting cheap digital gauges from ebay.
I am not trying to scaremonger, but we had a bongo at Looe that had probably been running for quite a while hotter than it should, with a slow gradual coolant loss, but the standard gauge wasn't moving, despite the rad fans being on a lot of the time (not normal unless ac is being used). The gauge was then modified, a TM2 temp gauge/alarm & low coolant alarm were fitted, it was found to be running very close to the upper limits, a good 10-12 degrees hotter than it should This bongo had also been towing a folding caravan, still not sure if disaster has been averted yet, investigations ongoing, but some improvement with a new Mazda stat & leaks sorted, but it wouldn't have got that bad if the driver actually knew what what was going on long before & it reduces the chances of it becoming a very expensive fix IF things do go wrong.

[davelou]

Update on the above issue...

As usual Kirsty was the first to reply and her theory was correct as per usual!!!

Many thanks for the input

Regards Dave

[missfixit70]

Excellent news Love a simple fix, what was it, loose connection or wire needed remaking?

[davelou]

I just cut the old connector off and replaced. Happy days

[Northern Bongolow]