New Temp Gauge sensor LEAKING!!!!

TX641D · Nov 30, 2010

:evil:

I am REALLY frustrated. I hope its just pilot error, but i have one heck of a coolant mess in my garage and i don't understand what i'm missing.

I ordered a new 12V gauge kit from the part store on this site. The temperature gauge sensing unit that was included in the kit looks like this:

The larger compression fitting that was included does not fit inside the hole in the block where the sensor goes. So, I took the larger compression fitting off...put the sensor in the hole and tightened down the smaller compression nut into the hole. IT LEAKS LIKE A RIVER!!!

The old one will no longer completely seal the hole...so i have a slow leak still going in the garage....I guess until all the brand new coolant drains from the tractor.

Ideas???

JMOR · Nov 30, 2010

(quoted from post at 22:25:06 11/30/10) :evil:

I am REALLY frustrated. I hope its just pilot error, but i have one heck of a coolant mess in my garage and i don't understand what i'm missing.

I ordered a new 12V gauge kit from the part store on this site. The temperature gauge sensing unit that was included in the kit looks like this:

The larger compression fitting that was included does not fit inside the hole in the block where the sensor goes. So, I took the larger compression fitting off...put the sensor in the hole and tightened down the smaller compression nut into the hole. IT LEAKS LIKE A RIVER!!!

The old one will no longer completely seal the hole...so i have a slow leak still going in the garage....I guess until all the brand new coolant drains from the tractor.

Ideas???

Vito · Nov 30, 2010

Where was the guage made or need I ask.The last couple that bought were junk.I sucked it up and bought Stewart-Warner guages for the 981.

Vito

TX641D · Nov 30, 2010

The kit was purchased from Yesterday's Tractor. The box the actual gauge came in says "Sparex" part number s.61525 which replaces C3NN18287A.

That doesn't tell me where it was made though.

awhtx · Nov 30, 2010

The cylinder head should have a seat machined into it for that tapered flange to seat against. I have had to really crank down hard on the nut to get it to seal and not leak. I've cranked down so hard that I thought I was going to round off the corners of the brass nut. ALWAYS use a flare nut wrench to tighten the nut. You may have to remove the battery tray to get a good grip on the nut. Also, check the seat inside the head to insure there is no rust or debris on it that could cause an incomplete seal.

TX641D · Nov 30, 2010

JMOR: That gauge and sensing unit must be the wrong one for my tractor then, even though the part numbers from YT are correct for their description of a 12V gauge set for 4 speed 601 series tractor.

There is NO way that larger fitting can be used on my tractor. The hole in the block is not big enough.

JMOR · Nov 30, 2010

"That gauge and sensing unit must be the wrong one for my tractor then,.."

I'll second that.

TX641D · Nov 30, 2010

Even with the nut clamped down tight, there is 1/8" of slop left....you can hold the cable and feel the fitting wiggle around in there. I may just go buy one from Ford/NH tomorrow. Waste of money from Yesterday's Tractor for the gauge I got from them. Disappointed.

awhtx · Nov 30, 2010

My bet is that you don't have the nut tight enough. I just went out to the storage room and looked at a spare 172D head that I have and it most definitely has a seat machined into it for the temp sensing bulb to seal against.

TX641D · Nov 30, 2010

Thanks!

I just went back out there and pulled the old unit out and held it up against the new one. The sensor head from flange to tip are equal in length. So.....I think you are right (as usual!). I don't have a flare nut wrench, and will have to go pick one up tomorrow.

I'll reserve any more judgements til I give it another try as you have suggested. Perahps i'll have a bit more patience then too!

awhtx · Nov 30, 2010

You cannot get enough torque on the nut with an open end wrench- a flare nut wrench is absolutely, positively the only way to tighten it.

GlenIdaho · Dec 1, 2010

I had the same problem with an after market temp gauge. The flare on the bulb is not the same specs as the original and the nut has a hard time seating it unless you really crank down on it. I also used a tap to clean the threads and a shotgun wire brush to clean/polish the seat. No leak, but then I decided to refurbish the original unit and put the after market one on the shelf.

36 Coupe · Dec 1, 2010

Buy a US made flare nut wrench set.The imports break.Ive had my flare nut wrenchs since the 50s.If you ever replace a brake line you will need them.

Scott in SC · Dec 1, 2010

I’ve got exactly this issue going on right now with my 971 and a new SW temp gauge. With the fitting tight you can feel movement in the sensing unit cable running to the gauge head. I picked up a nylon washer from Lowes, and plan to install that over the probe when I return from out of town. I figure that will seal between the machined taper in the head, and the taper on the probe.

juniur · Dec 1, 2010

go to napa and buy an adapter fitting that has the seat in it it will have the same thread as the nut on the bulb .

LarryT · Dec 1, 2010

The head has a standard pipe thread. That's why they use the adapter. And That is why I use OEM or if I am going to put an aftermarket on the tractor I use an electric with the correct adapter. Those are your only options, LarryT

Dean · Dec 1, 2010

TX:

There's lots of good advice below.

I will add that you should verify that everything remaining of the old bulb sensor has been removed from the cylinder head.

I had a similar problem several years ago and found that parts of the old sensor renained in the head preventing the new bulb from seating.

Tightening, of course, had already ruined the new bulb by the time that I discovered this.

Dean

awhtx · Dec 1, 2010

It is NOT a standard pipe thread. It is a standard straight thread- 5/8"x18 tpi.

TX641D · Dec 1, 2010

I appear to have been wrong. Right part from YT, poor execution by me. After following advice from awhtx it appears to have tightened up. I haven't filled with new coolant yet, but it appears obvious that it sealed up properly.

thanks!

Jim In NY · Dec 1, 2010

I had the exact same promblem with my '61 2000 134cid. And I'm posting to say that the heads are not the same as what is supplied as standard from YT and other gauge/sender manufacturers !!!! I posted a coulple of years ago about this and after nothing surfaced; and with only one YT'er commenting likewise as to what I had found what I did is simular to what Scott is thinking. I wrapped teflon tape around the area between the probe and the small nut quite a few time and inserted it and it tightened down nicely; and without any leaks for two years now, either hot, cold and just sitting for long periods. Another YT'er had the same problem (archives) and i advised likewise and he had success too ! One theory is that perhaps there are some heads out there that were manufactured in Canada and require diferent connections in order to snug -up without being loose and leaking. Scott's idea RE: a nylon washer just might be the fix alltogether, but teflon tape done the trick for me and at least one other individual on YT. No matter what, the heads are not all the same and there are some odd balls out there just the same. Hope this helps. Jim

Jim In NY · Dec 3, 2010

How are you making out with your temp sender leak
?????

TX641D · Dec 3, 2010

thanks for asking, Jim. awhtx was correct, the nut was just not tight enough. I bought flare nut wrenches and tightened it down hard and it sealed right up. I have a MUCH bigger leak problem now

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New Temp Gauge sensor LEAKING!!!!

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