Another temp gauge questions.... to tape or seal? (Page 1/2)
dayv27 OCT 29, 11:00 PM
'm running into a similar issue of gauge not reading correctly as has been posted earlier this week. During the heat, I'd see 185-200' all day on the freeway. Now that it's not getting above 80' outside, I went for a 60 mile drive and never got about 130'. I ordered this:
https://www.fierostore.com/...l.aspx?id=99&s=51404

and am hoping this helps. My question with this is the argument of teflon tape vs. high temp thread sealer? Is one more recommended than the other?

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I dated a girl in high school purely because she had a fiero.

olejoedad OCT 30, 08:21 AM
It is a tapered plug, no sealant is required.

However, a very small amount of sealant can be used.

Remember that the sensor grounds to the engine through the threads.
theogre OCT 30, 08:42 AM
Any pipe dope/paint sealer will work.
White "Teflon" paint get at nearly any store that doesn't fully dry out is good to clean if have to remove a sender/sensor for any reason. Example: need to replace head or intake and want to save senders etc. You often don't have to clean 100% either. wipe most and add fresh and done.
RectorSeal and others that dry out works but large pain to clean after. You must clean them 100% before reinstalling whatever.

Any sender ground thru the case the tape can have problems. Beside how you use it, Many versions of tape and some maybe work ok other cause bad connection to ground. So isn't recommended.
Most sensor for ECM/PCM doesn't care because doesn't ground thru case but tape can be a pain to clean as said above.

If you read any threads w/ my posts that dash gauges lie to you and why... Replacing a sender often doesn't help and finding true root cause can hours to days to never find a cause.

And that's if the dash lies... Many likely didn't scan ECM or try to other methods to check the coolant temp or oil pressure when that gauge lies.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 10-30-2021).]

eti engineer OCT 30, 09:29 AM

quote
Originally posted by dayv27:

'm running into a similar issue of gauge not reading correctly as has been posted earlier this week. During the heat, I'd see 185-200' all day on the freeway. Now that it's not getting above 80' outside, I went for a 60 mile drive and never got about 130'. I ordered this:
https://www.fierostore.com/...l.aspx?id=99&s=51404

and am hoping this helps. My question with this is the argument of teflon tape vs. high temp thread sealer? Is one more recommended than the other?





Teflon tape is not meant to be a sealant. It is only for making sure the threads don't gall as you tighten things down. It is more like a lubricant. Definitely go with the sealant.
theogre OCT 30, 09:51 AM

quote
Originally posted by olejoedad:
It is a tapered plug, no sealant is required.

However, a very small amount of sealant can be used.

Remember that the sensor grounds to the engine through the threads.

Wrong. Many also claim Brass parts in iron/steel parts can "self seal" know nothing.

All Taper Treads, this case NPT used in all US Plumbing, need sealer and No mater what metal types or material that a joint carries.

Sealer is not only Sealer but also a proper Lube so the thread will tighten right and won't have Galling problems.

Note: MANY senders and sensors have pre applied sealer. When true, you don't need to add sealer the first time used. (These sealers are made to pre-apply on a part and not available to the general public.)

Do Not over tighten tapered treads. If sender/sensor doesn't break, the thing they go into can and often easy.
Most go tight in the middle 1/3 of threads. If force into upper 1/3 or 1/4 then often will cause problems. If can't get tight like that, likely some fool installed old part wrong and cause problems. Very easy when part go into aluminum whatever but cast iron can have same problems.
olejoedad OCT 30, 11:56 PM


Seriously, do you have ANY real world experience, or did you just read stuff?
dayv27 OCT 31, 01:59 PM

quote
Originally posted by olejoedad:



Seriously, do you have ANY real world experience, or did you just read stuff?



Is this for me? (OP) ?

No. I don't really have any real world experience as a mechanic. I read here, I watch videos, and I try to make sure I'm doing it right before I do it. I'm trying to learn and not screw things up. I'd like to get real world experience with this car, but at the same time I don't want to "John Wayne" it and have it go south because I thought I knew what I was doing.

If this was directed at someone else, could you please clarify?
pmbrunelle OCT 31, 03:34 PM
I never tried to seal NPT threads without tape or dope.

In theory, there's a spiral leak path at the root/crest of the thread form.

NPT dryseal tightens the tolerances of the root/crest diameters to eliminate that path.

I did not know that non-dryseal NPT could work without sealant. Maybe it's one of those things that often works in practice, but not with the parts at their tolerance limits.
Blacktree OCT 31, 03:42 PM
I prefer to use paste sealant instead of teflon tape. My concern is that a piece of the teflon tape might break off and find its way into someplace it shouldn't be. Realistically, the chances of that are pretty slim. But I'd rather not risk it.
olejoedad OCT 31, 05:26 PM

quote
Originally posted by dayv27:


Is this for me? (OP) ?

No. I don't really have any real world experience as a mechanic. I read here, I watch videos, and I try to make sure I'm doing it right before I do it. I'm trying to learn and not screw things up. I'd like to get real world experience with this car, but at the same time I don't want to "John Wayne" it and have it go south because I thought I knew what I was doing.

If this was directed at someone else, could you please clarify?



Not aimed at the O/P, squarely aimed at the post above mine.