Second water temp sender tip installation question
 

Could anybody help me with ideas for installing a second temp guage sender tip? My stock temp guage gets squirrelly every few weeks and I want to check up on it when it gets weird, so I need a second place to get a reading with the cheap aftermarket guage I picked up.

One of those old school thermostat covers with a tap in it would be nice, I found this picture with a search:

https://www.rx7club.com/forum/attach...hmentid=123711

Anyone know where you can get one of these?

Or if there are any other good ports in the cooling system?

Thanks!

Ray

Ray, That looks like a small block Chevy housing.

Ray, check the Archives, I believe there are a couple of detailed threads on gauges in there.

Thanks Doc, I did look in the archives and there were about a half a dozen threads I could find, but none on putting a second temp sender in. Lots of discussion about guage types, etc, but the pic above was the only one I found that would easily allow a second sender to be put in (although that wasn't the point of the thread I took it from).

In fact that Tstat cover with the tap in it would be the perfect solution, if I could find one. Small block Chevy you say? Is that metric or are all themostat sizes the same? Should be easy to find if so.

Thanks
Ray

Ray, the sizes vary but most are similar. My observation is just that refeering to the Chevy. If no-one chimes in with what they have used than you could always take the one off of yours and go down to the local Napa and see if you can match one to what they have on the shelf. But remember you have to account for the radiator hose size and the angle at which the nipple points also.

This should get you in the right direction.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/water-temp-install-question-447073/

Thanks Doc, that's the thread I got the photo from, a guy named Jeff20B. But I couldn't find anything in the thread or several other similar ones about installing a second water temp sender.

Are there any other holes in the cooling system that I could tap into?

Jeff20B said that thermostat cover was "old school rotary", is this the set up they used on the 3's, cosmos and rpu's?

Anybody got one for sale?

Thanks
Ray

RX-3, RX-4, REPU, Cosmo. Some of the later ones were undrilled. By '79 they were still aluminum (or maybe pot metal) but the option to install a guage was no longer available. They changed the casting. Then by '81 or so they went to steel.

I just installed a guage fitting in the back of an iron waterpump. I'll soon see how well it works. It's the same car but different engine and different guage.

The chevy idea seems plausible. Someone should compare the angle, size, hole spacing etc.

I had an idea about mounting an additional water temp sending unit. Would the following work? My engine has a 1983-1985 rear iron that allows for the beehive oil cooler. I have changed to a front mount oil cooler and thought that maybe I could fab something up to utilize the section of pipe what supplies water to the beehive. Since I would have to block this anyway, why not use it for a second water temp sending unit.

Will this work or does it need to be closer to the waterpump?

If this doesn't work then I think to oldsschool gooseneck is a great solution.

I put mine in the threading used by the engine block heater. Its located on the block under where the AC pump would be on the drivers side. Its a hex head. You will also need a secound gauge for this as the factory one won't be able to handle 2 senders. I'm running Autometer at this time.
http://memimage.cardomain.net/member...9_175_full.jpg
http://memimage.cardomain.net/member...9_178_full.jpg

Ray, There are a few places you could use.

^^^ John's above.

2. Also that side of the engine but in the middle is a drain plug, Remove and use the hole.

3. on the back of Water pump is a temp sender for (the choke?) It can be pulled out and a bushing put in to adapt it to the correct thread, The bushing can be bought in a pack from sunpro, Their $20 guage also works OK.

4. a couple places sale an adapter that you put inline with the top rad hose and then has a place for the sender.


With you being all stock #3 will not work for you.


Sunpro
http://www.sunpro.com/product_detail.php?pid=16338
http://www.sunpro.com/product_detail.php?pid=16294

I picked up the sunpro guage at Pep-boys, and the adapter kit at autozone.

Any idea what this thread is for the hole? I can tap it to 1/8 NPT, but will I need to drill first or is the hole 1/8 BSPT and easy to tap?

Thanks.

Not sure of the size, it was the same thread and pitch as one of the sender adaptors that came with my Autometer gauge!

it probley wasint... just like the place behind the waterpump isint the same.. its close and can be forced it and it will seal up(good thing brass is soft) but they are not the same as what comes in the kits :)

The bushing that comes in the sunpro metric kit is the same as the WP spot.

If you find out that it is 1/8 BSPT and your sender is 1/8 NPT Napa sells an adapter for that.

I dotn think so. You have to use 3/8 pipe tap

Nope, I just used the bushing and was ready to go. It fit fine and run in perfect.

I think it was the

• M12 X 1.0 to 1/8" NPT

Wow thanks for the help, esp Jeff, John and Matt for the excellent ideas. It's nice to have options! I really like that old school thermostat cover, it just looks cool, if anyone has one available or knows where I could get one please let me know.

In the mean time I'll hook it up in one of John or Matt's suggested locations, and yes it is one of those cheap-O Sunpro guages, should work just fine.

The tap and/or adapter should be the easy part, given the details you guys gave. I'll do it this weekend and let you know how it goes, including the best adapter.

Ray

One serious problem I have with the old school thermostat housing is it places the sender above the thermostat. If it ever sticks closed, the engine will overheat and not register the full temp rise on the gauge.

Ahhh, too much work Ray. Just get a Steiger adapter and be done with it.
http://img.photobucket.com/albums/v3...inished040.jpg
steigerperformance.com

Yup I feel the same way with my Steiger adapter. But then again I hardly drive my car and the thermostat is new. On the other hand, when my fan's fuse blew because of a short in my wiring, I got instant warning by my gauge hooked up to the adapter and not by the stocker.

Maybe I'll put in all four, the rad hose, the thermostat cap, the preheater port and the drain plug, see if I get different readings. And a guage cluster on the driver's side roof pillar, like in the Fast and Furious. Then I'd really find out if the stock one is working right or not.

But if you had to put in just one until you got the money for the other guages, which spot would you chose and what are the advantages?

Right now I'm kind of liking Matt's drain plug idea because it should give a reliable engine temp and it's easy to get to (I still have the A.C. in place). But would it really give reliable engine temps??

Then I could add the one on the thermostat cover just because it look cools and I'd have all those guages on the driver's pillar.

But if you had to do just one, which would it be?

You can order the metric conversion kit from Jegs.com! Same kit for $8.99. Go to jegs.com and search for CP7573. Shipping is higher though. You can also order it from the above site. I went to Discount and Autozone today and the folks there didn't know crap about this. :(

Just ordered through Actron.com. $17.08 total with shipping. A good bit cheaper than jegs.com.