? Water cooled van overheating

[meggles]

This is the story so far:
Gauge shot up, appeared to be overheating. New thermostat fitted. Couple of wires were looking dodgy so temporarily insulated with tape (as a safegaurd). No oil in water and vice versa. Owner drove away and then(Quote)

sat happily at halfway for about 3/4 of a mile, then red
light flashed and needle shot up - seemed to come down when i whacked
the heating on full, but that could have just been a coincidence...!
no steam coming out of anywhere as far as i could tell, but really
want to get to the bottom of this!

[T'Onion]

start by making the dodgy wiring all good again

[Mocki]

if its not the wiring at fault, its got a airlock id say

[meggles]

This is gonna difficult to describe:
Done the air lock thingy and got some air out. All seemed OK for a short while then the fault returned. Bled again and same result.
When engine had cooled a fair bit I turned ignition on and light flashed, and flashed, and flashed...... needle went over to extreme right of gauge. Turned off, then back on and all was normal. Then ran engine for a while and all OK. Turned off then on again and light appeared to go through it's 2-3 second checking phase and then turned itself off. Then it started again with check and then off again, this carried on for several minutes. Needle moved toward right when light was on and then back towards left when light went out. There may have been a difference to sequence when I moved wiring harness in glove box (not sure about this 'cos it doesn't make a difference now - may have been coincidence). Also it appears the problem may have occured after Halfords fitted a stereo but not certain about this.
One time when the gauge went over to max the engine was definately NOT overheating.
I took plug off level sensor and side of thermostat housing and fault stilll occured.
hope you can understand what I mean.
BTW, the wires which are a little taped up are definately NOT shorting.
Hope you can help, elec's are a nightmare for me. I am now sure it's electrical in view of the fact it occurs on a cool engine!

[meggles]

Well! This seems to have got everyone stuck. Brilliant advice in the first place. spot on in fact! I reckon there was
1) an air lock
2) an electrical fault.
Cured the air lock but am I right in thinking it's probably an electrical fault now. If so, what is the likely culprit.
I realise it's difficult diagnosing from a distance. Any ideas most welcomed
Thanks#
BTW, I have tried WIKI and can't find anything which helps, or am I being thick?

[Grun]

meggles wrote

There may have been a difference to sequence when I moved wiring harness in glove box (not sure about this 'cos it doesn't make a difference now - may have been coincidence). Also it appears the problem may have occured after Halfords fitted a stereo but not certain about this.

Working on the principle of what was last disturbed........ in the fusebox is a Coolant level Control Unit '43'...... on earlier models (don't ask how early)...... the same unit is up behind the dash (Instrument panel or whatever modern folks call it)). Could it be something as simple as this little unit being pushed out of firm contact with its socket. It is common to both the level and temperature systems but in a complex way. Looks just like any other relay.
Now the man that really knows how all this electrickery works is AngeloEvs, and I have kept a copy of his previous posts on this subject, together with his superb photos which I could no doubt send as attachments to you at an email address, or I could upload the photos to Photobucket and put them on the forum. (They really should be wiki-ed... with the text).
Mike

[ojsmith]

Thanks for the help today keith - and good job of explaining the problem! Im glad it isnt looking like being something massively serious - sounds like we will get to the bottom of it, and hopefully in time to get away this weekend!!

[ojsmith]

This is what the wiki has to say on the subject:

syncrosimon

There are two other causes for that little light to blink that I have experienced. 1. An electrical short circuit. This happened to me when an ill fitting battery was shorting on the battery lid. The red light would flash intemitently and the temp gauge increase in temp very quickly whilst shorting. 2. The main wiring harness multi pin connector to the dash pod comes a little loose. on later models this can also sound the buzzer of doom when nothing else is wrong, but should also effect other dash led's by making them not work. A gentle wiggle should correct, on my lhd you can reach this plug from the driving seat by sticking your hand up underneath, i cant remember if this is the same on a rhd.

Hope this may be of help as it is not always the obvious.

The engine wont be overheating if the needle doesn't say it is. The fan should come on when the needle is a needles width to the right of the little red light. (assuming that the gauge is working) The temp needle should start fully to the cold left side, then rise over about 4 miles to the middle, where in normal conditions it stays rock steady. Ticking over for long periods will require fan action such as in your traffic jam to cool the engine, but should be shown in a slight rise in the needle position. When the fan comes on you should be able to see the needle drop, a gentle rev to get the coolant flowing round faster at that point will cool the engine down faster. or you can put your heater on full for a time. This will keep the engine cool even if your main fan isn't working

Mocki

you need to remember that the light takes its signal from the temp sender for over heating, AND from the level sender in the headertank for low coolant, the rad fan is connected to neither of these and has a seperate sender switch in the rad itself, so is totally independent...

also check connections in the electrics box in the engine bay, where there is yet another junction for the gauge and the red light of confusion.....

Header tank cap check

just something to check with the cap screwed tight on the bottle when the coolant is cold blow/suck on the take off pipe. you should not be able to blow into the system or suck out. if you can your cap is faulty it needs to seal so the coolant can pressurise and not boil! non sealing will cause fluid loss and so can cause the fault you have with no apparent coolant loss!

[meggles]

Multi plug to dash comes loose? Halfrauds recently fitted a radio? Hmmmm! Brain working overtime!!!!!! Along with relay in fusebox? Plenty to go on then!
Could we not wire the fridge up to the cooling system? (Gotta keep laughing I suppose).

[meggles]

Thanks for the help today keith - and good job of explaining the problem! Im glad it isnt looking like being something massively serious - sounds like we will get to the bottom of it, and hopefully in time to get away this weekend!!

Thanks for help today? No problem, just wish I'd sorted it for you. This is what 80-90 is all about.
Very nice van by the way, especially without the elephant!
Grun: Sent you email. Thanks for that, it's arrived by e trickery! You're a star.

[doodlebug]

When my water cooled engine was over heating i took it to a local garage and they told me that it was due to some faulty switches but they didn't tell me which ones

[fried chicken]

Last summer I did 200 mile round trip, home leg 100 miles & 1 mile from home, gauge went up, light on with no warning, the water pump had given up. Just to give you something else to think it may be.

[ojsmith]

Last summer I did 200 mile round trip, home leg 100 miles & 1 mile from home, gauge went up, light on with no warning, the water pump had given up. Just to give you something else to think it may be.

does that give you an intermittent problem though, or does the needle just shoot up? the problem in this case is that the needle and red light are just crazily random!

[meggles]

Thinking that an aftermarket Water Temp Gauge would help warn of overheating, although not sort the gauge and red light problem of course. Anyone got any links re fitting one? (sorry, Please).