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Hi Neil, it might be worthwhile popping a photo or two of the engine in the thread…it could be that you have an earlier head or something like that. On one of my engines someone has fitted a “bellows thermostat” head on a later engine, and butchered the bottom of the deep thermostat housing to make it fit above the later model timing case and 9 hole water pump…
Quote:
Originally Posted by S3ute
I just had a look - this time on the vehicle, not the parts book! It is not actually on the thermostat housing, it is on the cylinder head, just below the thermostat housing! And it possibly may not exist on early 7:1 heads although this does not seem to be the case in the parts book. Pre-chassis suffix 'C', as there was no standard temperature gauge, there should simply be a plug.
Matt,Quote:
Originally Posted by drfish
Hello again and thanks.
I’m in the city shopping with the frau but soon heading home.
I will take another look at the motor when I get home and also take a photo.
Cheers,
Neil
John,Quote:
Originally Posted by JDNSW
Thanks again.
When I was looking at the engine yesterday afternoon - especially in that general area - I simply didn’t note any trace of a sensor unit or blanked off hole etc. My sense was that there was nothing there.
Anyway, I’ll be back home later and will have another probe. All seems a bit odd.
Cheers,
Neil
Hello again.
I took a girl's look at the engine after I got home and may have solved the mystery of the sender - there doesn't appear to be one.
This is the otter switch that is on the left hand side of the thermostat.
Attachment 182054
The next three photos are of the right hand side of the head - I believe the hex nut in there is where the temperature sender should have been fitted but wasn't.
Attachment 182055
Attachment 182056
Attachment 182053
This seems to further clear up some of the mystery of the origin of the truck - early on in my ownership (about 12 years ago) when I checked the serial number I discovered that the engine wasn't the original that it left the factory wearing. Not unusual given the vehicles then age - 1975 model - but did make a bit of a mockery of the PO's claim at the time that it was in excellent original condition.
When I got it there was a U/S heater fitted but no hose attachments to the engine which had puzzled me a bit. Once I worked out that the engine wasn't a Series 3 original but likely came from a 1969 Series 2 the explananton for the missing hose connections became a bit more obvious. I think the same applies here - the temperature gauge didn't work and rather than being a faulty voltage stabiliser more likely it was connected to the otter switch.
To be honest I have only ever driven the truck less than 100 metres since it arrived all those years ago - basically the distance from the street to my workshop. Hence not enough to have accurately diagnosed what did and didn’t work before it was stripped down.
Whatever. Most of what didn't work then has subsequently been rectified and this latest hitch is just another small part of that journey.
Cheers,
Neil
G'day Neil,
The "Otter UK" thermostat is indeed a switch that is normal open (NO) and closes at approx. 130 deg F. If you clean off the dirt their will be a letter and numbers like M54 stamped on the metal frame. That would indicate it will close a 54 deg C or 129 deg F. The numbers will change depending on what temperature it snaps closed at as each one is individual. The bowl the thermostat sits in is filled with a small amount of oil that covers the bottom of the bi-metallic thermostat and used to conduct the heat from the coolant to the bi-metallic thermostat. I have repaired a lot of these!. They are a pain to adjust.
Yes it controls the choke warning light.
Chris
Yes. That hex plug on the side of the head below the thermostat housing is where the temperature sender goes.
Hello again.
Did a bit more fiddling around with the old and new engine harnesses today and took the opportunity to take a look at the otter switch set up. Seems that someone in the past did indeed extend the wire for the temperature sender in order for it to reach the otter switch - thereby guaranteeing that the gauge was never going to work properly.
The new harness has the sender wire in the right place to access the correct sender - due to arrive in the coming week - on the RHS of the head before the rest of the harness passes behind the thermostat housing to the alternator.
That leaves the question of where in the new harness is the wire sourced that is meant to connect to the otter switch and choke activated sensor switch. It isn’t part of the engine harness which has only two branches to connect the temperature and oil pressure sensors. Hopefully it will turn up somewhere or other as a stray white/blue trace wire.
Still puzzling over where the wires might be for the reversing lights - they don’t seem to be in the rear chassis harness and don’t officially appear on the wiring diagram in the workshop manual. I did order the reversing light extension harness but I think that is just the section of harness that connects the reverse light switch on the back of the gear selector back to the main loom.
Bit of a way still to go….
Cheers,
Neil
Most Series 3 did not have a reversing light. I just had a look at the owners manual for a 1981 S3 - the wiring diagrams in this manual do not mention a reversing light.
Worth noting that the vehicle the manual came from (which contributed the cab and some other parts to my 2a) actually did have reversing lights ex factory - and a recent improvement ot my 2a has been to use the switch and gear lever mount from it to fit a reversing light to the 2a.
My truck did have the factory reversing lights fitted to it including the crappy switch fitted into the back of the gear change mount - not sure if they were actually working when I bought the truck some years ago as virtually nothing else electrical did when it arrived.
As noted the usual Series 3 wiring diagrams don’t generally show the reversing lights but I’ve no doubt wiring them up won’t be a huge challenge. The more immediate challenge is to work out whether Autosparks has actually made allowance for them somewhere in the new harness and where that might be. As mentioned earlier, I included the reversing light extension as one of the thirteen bits of harness in the order but I’m still to determine whether that component is just the wires from the switch to the main loom or is meant to also go back to the lights themselves.
Much may be made clearer when I get the main harness out of its package - started with what should have been easier peripherals including the rear harness, engine harness and battery/solenoid/starter leads. When the instruments come back from testing and refurbishment and are refitted in the dash binnacle I’ll braven up to the challenge of getting the main harness sorted out - I’m thinking that much might be clearer in terms of where the other upgrade items might fit.
I’m presently procrastinating over a pot of tea before finally taking to the left side of the tub to start hacking out apertures for the second tank filler, hose etc. Nice to get right, but likely easy enough to stuff up if you’re not careful.
Cheers,
Neil
