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Thread diameter of water temperature probe
Posted: Mon Dec 01, 2008 11:42 am
by aldo
Good evening everyone.
I cracked the temperature probe. It happened because it never sealed very well, and has been over-tightened many times.
I see a replacement on ebay for $35, suitable for Perkins engines, it says the "Probe thread diameter is 5/8 UNF". Can someone tell me if that's the correct thread for my Dexta?
Posted: Mon Dec 01, 2008 8:14 pm
by Mervyn Spencer
Hi Aldo
I measured the probe nut of my Dexta and its diameter was very close to 14mm and the tread was certainly not coarse. I also have a new gauge that I bought from Sparex and its dia. and thread is the same. The Sparex part number is S.66874. The equivalent part numbers are 81718522 and 957E17365C for Dexta Super Dexta 57>4/62.
Good luck
Kind regards
Mervyn
Posted: Tue Dec 02, 2008 9:54 am
by aldo
Thanks for your reply Mervyn.
I bit the bullet and bought a new gauge from the local distributor, same price as the ebay one, same thread. 5/8 UNF, and it fitted just right. Same problem as the old one though -doesn't seat very well, so there is a small drip, and you need to tighten it really hard. I'm not going to that to the new one, that's how I broke the old one. Need to fix the problem, probably the seat on the housing is a bit corroded.
Posted: Tue Dec 02, 2008 11:09 pm
by Brian
Moved at Mervyn's request:
Hello Aldo
I measured both old and new bulb and both are very close to 36.5mm from the tip to the shoulder that fits against the housing of the thermostat and bulb. Strange that the previous buld got damaged.
Regards
Mervyn
Posted: Wed Dec 03, 2008 7:30 am
by aldo
Brian wrote:Moved at Mervyn's request:
Hello Aldo
I measured both old and new bulb and both are very close to 36.5mm from the tip to the shoulder that fits against the housing of the thermostat and bulb. Strange that the previous buld got damaged.
Regards
Mervyn
Overtightening, wiggling and jiggling, then getting it out again when I overhauled the cooling system (water pump rebuild etc), then getting it to reseal again, I finally cracked it somewhere. A strange sweet alcohol type of fluid came out of it. The new one fitted fine last night, put some silicon gasket stuff on the seat, will give it a final light tightening tonight and retest it. If the seal holds, I don't think I'll need to remove it for quite a few years.
Posted: Wed Dec 03, 2008 8:38 am
by Mervyn Spencer
Hello Aldo
Glad you have been able to get it right. As long as you did not decide to taste that sweet smelling alcohol might have got your temperature up.
Regards
Mervyn
Posted: Sun Dec 07, 2008 1:09 pm
by aldo
Just got it, you're right Mervyn, I meant to say sweet smelling, no I didn't taste it.