Temp Gauge issue

[Beach-Burban]

Originally Posted by FirstOwner69

This won't help you at all, but...
Boy, does that bring back memories. We lived in Fullerton from 1968 through 1971. We had a '65 Impala SS with a 327 in 1968 and made a couple runs up to Yosemite. The Grapevine is the only place we ever boiled over.

Great place for a trial run!

Well Jim...the "Grapevine" made an impression that you will never forget...kind of cool in a way. I appreciate you sharing that memory!

Woody

[custom10nut]

Well, after researchIng the sending units that are supposed to be the “Right” one, I ordered one from Auto Wire (on the Suggestion of another board member), and when I opened it, I noticed that it has no Teflon thread sealant on it like the last two that I’ve tried.
I read in one response, that the sender shouldn’t have any sealer on it in order to work correctly, and this makes perfect sense. What does not make sense is why would Delco and other companies put the Teflon on their senders?
I haven’t had a chance to put my new sender in yet, but I’ll let y’all know how it works out.

[Beach-Burban]

Originally Posted by custom10nut

Well, after researchIng the sending units that are supposed to be the “Right” one, I ordered one from Auto Wire (on the Suggestion of another board member), and when I opened it, I noticed that it has no Teflon thread sealant on it like the last two that I’ve tried.
I read in one response, that the sender shouldn’t have any sealer on it in order to work correctly, and this makes perfect sense. What does not make sense is why would Delco and other companies put the Teflon on their senders?
I haven’t had a chance to put my new sender in yet, but I’ll let y’all know how it works out.

custom10nut...I read the same thing, but I also read that as it's NPT, the threads cut through the Teflon and make contact anyway??? The one I removed didn't have any Teflon on it so I didn't put any on the Auto Wire one either...and just made sure that it was tight enough to not leak. Two things I've heard through the years about Teflon when it comes to water tight fittings: First, Teflon is not a sealant...it's main purpose is to act like a lubricant? Second, if something leaks even with Teflon, just give it time and minerals and such will collect at the leak...sealing itself. Although personally I have found both of these to be true, I have zero "insider knowledge" that guarantees that either of these statements are 100%.

I hope you get the results that you are looking for...I'm still trying to figure out what my results are telling me!?!?

Woody

[HO455]

Originally Posted by custom10nut

Well, after researchIng the sending units that are supposed to be the “Right” one, I ordered one from Auto Wire (on the Suggestion of another board member), and when I opened it, I noticed that it has no Teflon thread sealant on it like the last two that I’ve tried.
I read in one response, that the sender shouldn’t have any sealer on it in order to work correctly, and this makes perfect sense. What does not make sense is why would Delco and other companies put the Teflon on their senders?
I haven’t had a chance to put my new sender in yet, but I’ll let y’all know how it works out.

Please let's put the Teflon Tape myth to bed. I have installed hundreds of senders in my career and never once did I find one that worked incorrectly due to pipe thread sealant. And as further proof please go to my earlier post in this thread (#28) and follow the link to the post I called out there is a pdf. That PDF is from a gentlemen who besides plotting resistance readings on several brands of senders to show how the different manufacturers senders vary in resistance, he also debunked the teflon tape/pipe sealant myth.

[tdangle]

Very easy to probe the Teflon tape doesn't affect the readings. Install it with tape and check the resistance between the housing of the sending unit and engine block. It will read 0 ohms. if the tape isolated the sending unit the gauge would read cold all the time. Don't believe me? Unhook the wire to the sending unit and run the engine, your gauge will read cold.

[custom10nut]

I wasn’t trying to deny or confirm anything about the Teflon. I was just making an observation
I just hope this sending unit is the correct one.

[Beach-Burban]

Got back yesterday from another "Grapevine" road-test...and the results are indeed "very telling"! Bottomline is: my radiator needs an old fashion boil-out, rodding...or core replacement. The block and head water passages might need some "descaling" as well. It's my intention to stick with the copper/brass original style 4 core, which is why I'm going to a friend recommended shop, as they actually work with your radiator instead of the quick "scrap and replace with new junk" approach. I hear a lot of pros and cons regarding aluminum radiators...but I'm not sold on that idea (yet).

Temperature gauge results:

Photos one and two: my normal around town and freeway temps when fully warmed-up.
Photos three and four: my "new" normal freeway temp with just a slight grade.
Photos five and six: Going up the Grapevine!!! Truth is, right before I hit the summit, the gauge was kissing 250 (no photo), but over the summit on the down side, it did back off to the 230ish range!
Photo seven: The recovery tank was doing it's part on this drive, where it wasn't needed on the last one (without knowing the numbers). My fresh green coolant is now a rusty brown color, but I still didn't lose any coolant and the motor did not "act" as though it was over-heating...but I can tell things are going in the wrong direction!

I stopped at the bottom of the grade and had a "Dave's Double" at Wendy's...and sat for a while. When I finally started it back up, the radiator started guzzling up the coolant from the recovery tank...but no more than it expelled into it (as far as I can tell?). Nothing significant to report on the way home, but of course, my "new" normal freeway temp stayed in the 230 range. I stopped for a while at my best friend's house when I was about an hour from home...and got stuck in traffic (an accident) when I left, but things stayed pretty much the same at the slower speeds. Off the freeway and in beach city driving conditions, the "new" normal stayed around 220ish, so a stop at my friend's repair shop confirmed what I already suspected...dirt/rust/debris clogging the radiator is the prime suspect. A flushing will be the first step, but it's doubtful that this will be a cure...but when it's all sorted out, I will once again compare the readings between the Stewart Warner mechanical gauge and the factory gauge utilizing both of the electrical sending units (TS6S and American Autowire). Report will be coming...but don't hold your breath...it's going to take me a while!

Woody

[Beach-Burban]