Can any solve the mystery of the faulty temp gauge

Hay buddy check my link think we have the same sump plate angle with cooling thins ..this may ne the reason we are looking for I posted a link of my one so you can see if it's the same as your one

 

Yes that’s the one !

 

Mike, you may remember a few TE ago I asked you to check on why I was having the problem. You kindly used your magic gizmo to check everything and couldn’t find a fault so I think we thought it was a duff sender. Replaced sender and the story continued

 

I think the sump plate has to be the problem to much of a coincidence surly.... we both fitted the same one and have the same problem .it felt like some sort of light weight metal to me like aluminium or something maybe its not giving a good earth connection )and its a painted surface)...or the cooling fins are cooling the oil in that area ...but a doubt that as the heat would go up when idling surly ...put the old sump on see if it works ...I will but only just changed oil ..

 

As a quick test, just wrap some bare wire round the body of the sender and earth it. See if that makes the gauge behave.

 

Will do in my next big run out thanks

 

Well …Dipstick sender arrived from Heritage. Did the boiling water test using existing wire from gauge and separate earth. All good reading about 10 deg less than my yoghurt thermometer
Connected it all up and idling for 4 minutes crept up to 50….after 10 minutes 55 then maxed out at abut 65. Sump sender would hardly have registered in that time 50 at max.
So it seems that the problem was either the earth from the sump or just its position in the sump.
Out of interest should the dipstick sender sit about 1 “ from the sump bottom ?

 

On a type 1, it sits where it sits. Don't be tempted to saw a bit off the end

Won't really get up to temp sat sitting idling. Take it for a blast!

 

Will be doing later.
As sitting were it sits , the grommitty bit slides up and down ( there is a tightening screw though) should I adjust it so it is the same length as the original dipstick.
Side issue, seemed to get the same reading even when I switched the wires.

 

Yes, you need to tighten the screw up. My dippy bit is about 6 1/4" long to the tip. Matron.

Get the leads round the right way. One terminal will be earthed to the dipstick tube. A 2-way automotive connector goes on the terminals nicely, so you can unplug the dipstick lead.

 

Thusly. The yellow blob marks the "live" connection.

 

May sound daft …but how do I know the right way, no instructions and no difference on the terminals

 

On mine, the copper-coloured output terminal is stamped "G", for "gauge".

 

Ill

Swapsie. ? Mine may be worth oodles

 

You can check which is which with your meter.

 

Did so, 50 mile trip with a lot of Welsh hills, got to a max of 90 which probably is more like 95-100……( temp not speed ! ) is that about right
Now it’s working I’m worrying more

 

Very good.
Some long stretches on a motorway will tell you more about the engine temps.

 

If you only drive your bus on single carriageway A roads or lesser, it can never get really hot. Basically using the 1970's road network.

A good belt along the M4 past Swansea and theres some long fast hills that will show you what a warmed up oil temperature looks like, or M5 north up the Severn valley ..

 

90* is fine. Need to get the oil over 80* anyway to boil all the muck off.

 

Thanks for the update glad you got it working definitely the earth on the "special " sump plate we both have...I will try a separate eart on my sump sender or even a new sumo plate before I go the dipstuck route...funny you said you worry more ...I am like that with the presure gauge