Changing Temp Sending Unit- Help (1 Viewer)

[flaa1a]

Had a little time this afternoon so thought I would change the temp sending unit real quick. The stock one is not hooked up and I want to hook it backup. As ususal, it took longer than usual and was not an easy job....as easy as I thought it should be anyway.

A some point the PO had unhooked the stock sending unit and put after market one in. The wire for the stock one is hanging right there and I thought I would pop the existing sending unit out and screw my new one in from Cruisercorps....

My 40 is a 72 with a 77 2F in it. So the unit from CC should work as it is for a 9-72 and up.

Long story short. As you can tell from the picture the "stock" one is too big to fit in the union that screws into the top of the engine..

Is this something that I can get easily at an Auto store....CRAP!!!

 

[bsevans]

The stock sending unit on my '78 has 16mm straight threads. If in fact '72 and up are the same, then I would measure the thread diameter of the new sender to determine if you have the wrong unit. Judging by your photo, you recieved the same unit as I have in my '78. The second photo shows my factory unit and the VDO temp sender for the VDO temp gauge I have.

 

[flaa1a]

I am pretty sure that the unit Cruiser corps sent me is the right one. I do not think the union nut is the same. The stock unit won't even start to fit in the union nut (on the left).

I wonder how the temp sender units differ from the early years to the late years? Are the earlier years (pre 9- 72) a little smaller in diameter?

 

[FJmoneypit]

Autozone

I just swapped mine out, 2/76 FJ40. I still had the original factory one which turned out to be bad. I picked a replacement up at autozone (had to special order, got it in 2 days). It looks like the PO used a adapter to install the aftermarket one. You need the factory adapter and your new one should screw right in. A lot of the aftermarket gauges/senders come with multiple adapters for differeant applications, maybe one of those would work if you could find one.

John

 

[Bigcity25]

So the problem is the thread size? Not the length of the wtsu itself?

 

[flaa1a]

Problem is that the diameter of the stock TSU is bigger that the aftermarket one that was in. I just went to Lowes and got a brass bushing....

Basically, the existing one is a 1/2 to 1/8 and I needed a 1/2 to 3/8......

I am getting ready to go out and give it a whirl.....

Randy

 

[FJmoneypit]

Did it work?

Were you able to install it?

 

[flaa1a]

Yes it did work.....But the temperature guage is not working!

The sending unit wire is hot (tested) and the unit itself is installed with no leaks....

When the key is off the needle is all the way on the HOT side. When I start it up the needle goes down to the cold and stays there and never moves ......until I shut it off and then it goes to the hot again....

I will keep working on it....

Randy

 

[Bigcity25]

So my experience with the truck and engine not matching is a polarity issue. I had to match the cluster year with the wtsu. Since I have a 70 fj40 the 82 2f apparently has different polarity. Mine would do the same with the wrong wtsu in it. Did you ground out the wire with the battery on? It should go straight to cold or hot( I don't remember) but that can give you and idea if the gauge is working ok. Also if I recall I used plumbers tape on the threads if the wtsu. Did you just get this truck? Is fluid flowing correctly?

 

[flaa1a]

WTSU installed

I did put teflon tape on it and just read that you're not supposed to....is that right? Still does not work.....any ideas guys? Should I take the tape off? I am positive it will leak without it. The teflon tape is around the threads of the WTSU only and not on the base of it where I assume that the water is actually touching it.

It does peg on the hot when the key is off and when I start the 40 it slowly falls down to the cold....but stays there......shut if off and it goes back to hot....

Could be a polarity issue as suggested. If there is one thing I suck at (actually there are many) it is electirc stuff. How would I check that Big City?

Thanks guys!

Randy

 

[Bigcity25]

It could be polarity, I know that the connection for my wtsu is the a round vs a blade type. Yours still looked like it was hooked up parallel not perpendicular. Not sure if that's the issue though. I am with you about polarity. I am not very good with electricity. Are you sure coolant is flowing around? Did you recently change coolant? Did you burp your system? Trapped air in your system. I know coolerman on mud is a big wiring guy. Might be able to pick his brain. Wish I could help you more.

 

[caladin]

hmm

I think I remember pinhead or Coolerman saying that the stock unit
grounds to the block an that' why not to use teflon tape.

Try starting it up and running a wire from the side of the brass fitting to a good connection on the the engine block see if it goes down. if it does your teflon tape is probably causing infinite resistance and thus is pegging the meter to max heat.

Cal-

 

[flaa1a]

I am almost postive that ihave read at least once not to use tape.....but it will leak without it....is there another option for that ........instead of tape?

 

[spotcruiser]

Liquid thread sealer from any automotive parts place.

I am almost postive that ihave read at least once not to use tape.....but it will leak without it....is there another option for that ........instead of tape?

 

[flaa1a]

will get that!

 

[kurtnkegger]

You need to get a '71 wtsu, and install it in your 2F engine. My guess is your cluster is the original and the meter, and the sender don't communicate...or you could get a newer meter...either way, they need to match up to work, you can't mix the two...

 

[subzali]

You need to get a '71 wtsu, and install it in your 2F engine. My guess is your cluster is the original and the meter, and the sender don't communicate...or you could get a newer meter...either way, they need to match up to work, you can't mix the two...

x2. Best bet would be to get a pre-9/'72 temp sender. I'm not sure if there are differences in the gauge that would keep a later model gauge from working in your earlier instrument cluster.

 

[flaa1a]

I am not questioning you guys...but I bought the one that I did because the engine was a 77 2F.....I guess that is not what I needed...

Is there a rule about things that you buy to match you engine and things you buy to match your actual rig?

 

[kurtnkegger]

No, but the sending units send information differently for earlier, and later models. Since you still have an early model gauge cluster, you need an early model sender. If you want to keep your later model sender, then you need to install a later model gauge. But, like Matt previously stated, I'm not sure if the gauges will interchange in the cluster. It would probably be much easier to replace with the earlier model sender...

 

[Bigcity25]

No, but the sending units send information differently for earlier, and later models. Since you still have an early model gauge cluster, you need an early model sender. If you want to keep your later model sender, then you need to install a later model gauge. But, like Matt previously stated, I'm not sure if the gauges will interchange in the cluster. It would probably be much easier to replace with the earlier model sender...

X2 that's what I had to do with mine. Match the wtsu with the cluster, no issues since I did that. I have to make sure when getting parts what part of my rig is this for and how it interacts with my cruiser. It's been a big learning experience. But a fun one at the same time.