Thermostat housing temp sensor

[70barracuda]

So I am installing an electric fan in my Comanche, and I want to avoid using the radiator probe insert. I'd rather use an actual temp sensor in the coolant flow. I bought a simple switch and was going to put in the plug spot on my thermostat housing, but found out it's a very uncommon metric size. I thought about drilling out the factory plug and tapping it for my sensor but I'm worried that because it's steel the heat transfer won't work as it would with brass. Anyone have any insight to this?  I'm trying to find a metric to npt adapter but haven't found anything so far. Only things I've found with the thread are oil drain plugs. 

[Jeep Driver]

Drill and tap to 3/8npt.

 

 

The only one that works.

 

 

[omega_rugal]

does the "Y" style thermostat fit the 4.0? i need a water outlet that goes to the drivers side and bending the heater hoses doesn´t work well...

[Jeep Driver]

14 minutes ago, omega_rugal said:

does the "Y" style thermostat fit the 4.0? i need a water outlet that goes to the drivers side and bending the heater hoses doesn´t work well...

Yes.

[yxmj]

You can search the site to see.....But I have this setup in multiple jeeps Both 4.0 and 2.5

 

The best spot to install the temp switch is in the lower rad hose.

 

You will have to get a splice pipe with a bung that accepts the sender and run a wire from the splice pipe to ground.

 

I use a 195 T-stat and a switch from a Vette that turns on at 210

[yxmj]

Here is how I made my slice pipe 

-Chunk of exhaust pipe that has an OD same as the ID of my lower hose

-Weld in bung

-1/4" SS bolt

2 pipe clamps

Drilled the pipe out to accept the bung....welded the Bung in the hole.....welded the head of the bolt to the pipe.....Inserted pipe in hose....inserted sensor (switch) in bung...connected 1/4 bolt by 12 Gauge wire to batter -ve terminal.

Fan is set up as such.... +ve from battery runs to one side of a common relay .....relay coil is attached to keyed accessory terminal (only alive when key on).......other side of relay runs to +ve of fan....-ve of fan runs to tab of sensor (switch).....When the coolant that has run though the rad is hot enough....switch closes ....fan sees ground and turns on.

 

Like I said do some research.....Placing the switch in the t-stat housing will activate the fan all the time......you only want it  to turn on when the coolant is still hot after leaving the rad......on  90% of mine under normal highway conditions the fan does not come on at all.......But I am a cool Canadian 'eh

[Jeep Driver]

1 hour ago, yxmj said:

You can search the site to see.....But I have this setup in multiple jeeps Both 4.0 and 2.5

 

The best spot to install the temp switch is in the lower rad hose.

 

You will have to get a splice pipe with a bung that accepts the sender and run a wire from the splice pipe to ground.

 

I use a 195 T-stat and a switch from a Vette that turns on at 210

Why??

 

Lower is cooled coolant coming in. 

 

So your switch is lagging by about 40 degrees or more.....maybe 60 degrees. 

 

I want my switch to react to the temp in the head. 

 

 

[Ωhm]

2 hours ago, yxmj said:

-ve of fan runs to tab of sensor (switch).....When the coolant that has run though the rad is hot enough....switch closes ....fan sees ground and turns on.

 

Are you grounding the Fan motor through the Coolant Switch? Shouldn't the Coolant Switch control the coil side of the Fan motor relay.

[Jeep Driver]

1 hour ago, Ωhm said:

 

Are you grounding the Fan motor through the Coolant Switch? Shouldn't the Coolant Switch control the coil side of the Fan motor relay.

Should go without saying. 

[70barracuda]

I wasn't a fan of the in hose coolant bung adapter thing. It may work fine but seems like another spot for a leak to occur. I ended up drilling and tapping a new thermo housing I bought just like jeep driver did and should work great. Thanks!

[yxmj]

Do as you wish…..if I am wrong…..why does the factory put the switch in the rad? (on all MJ & XJ Zj Ect.) (or like some older units on the block directly beside the return lower hose.)    Just for giggles?

 

 The T stat housing sensor is for the gauge so that you get an accurate read of engine temp as it leaves the motor, prior to any cooling happening.

 

To answer the 2 gents above…… think of this……my way if the rad is doing its job and cooling the water with just the air flow developed by moving…. and great if it is 60 degrees less…then the water re-entering the motor is cool…..no need for the fan to come on. (And it doesn’t)

 

(So you get the advantage of extra HP & fuel savings….no draw on your mechanical or electrical system.)

 

With the switch in the t stat housing the fan goes on too soon….. Basically it will turn on as soon as your T-stat opens and runs constantly the whole time…..because you are reading the temp BEFORE the coolant goes through the rad and has a chance to cool. If your rad is working and cooling correctly….why have the fan run when it is not necessary…..like I said on a hot day at 30 mph my fans do not turn on at all…..my temp gauge sits exactly where it should (the sensor in the T-Stat housing) and the 4.0 and especially the 2.5 gets to run without the burden of a mechanical fan or a constant draw on the alternator.

 

Like I said Google it (and search this site) you will see it is really quite common.

[Jeep Driver]

5 hours ago, yxmj said:

why does the factory put the switch in the rad?

Because the Efan is secondary. 

 

Not just here but on any Jeep site- Efans have a bad rap, primarily because guys do not know how to set up a primary Efan. 

 

The factory setup is fail in my opinion. 

Temp switch is in the rad because the Efan picks up where the primary mech fan fails. Temp switch comes on at what, 220? If your rad temp is at 220 you have failed. 

 

Primary Efans have to get ahead of the heat. 

 

My new engine has never seen beyond 200 degrees, fan cycles perfectly. 

 

Tstat will manage engine temp, it's your job to keep the radiator as cool as possible.

 

 

You, from the Great White North, however you have  yours set up, if it works for you, great. Those of us in the South in particular need to learn to manage heat. 

[omega_rugal]

On 5/10/2019 at 4:30 PM, yxmj said:

The best spot to install the temp switch is in the lower rad hose.

 

i want an explanation for that...

[JMO413]

The factory fan comes on when the coolant in the radiator reach's 195.

[yxmj]

JMO413

The factory fan comes on when the coolant in the radiator reach's 195.

 

Yes exactly……so if the T-stat is 195 and the switch is in the T-stat housing….the switch would activate and turn on the fan as soon as the motor reaches temp… why would you want to have the fan running all the time…..if that is your goal stick with the mechanical fan .

 

omega_rugal

i want an explanation for that...

 

That is simple I explained it above but I will do it again.

 

Let’s use your truck as an example….1988 2wd Short bed 4.0 Renix AX15.

 

For the sake of this description we are going to remove the mechanical fan and replace it with one single electric fan (I use stock XJ/MJ fans but an aftermarket will be the same).

 

We will assume a working 195° T-stat and a 195° N/O switch. And a moving truck.

 

First we install the temp switch in the T stat housing…….we drive and run the truck up to temp……Stat opens @ 195 and allows fluid to flow…Motor will heat the coolant beyond the 195° point ….switch closed completes the circuit and turns the fan on…..fan will stay on constantly as long as the motor is running now….it will only shut off when the motor is shut off and cools down.

 

Now we install the switch in the lower (return) rad hose as described. Motor is run up to temp….Stat opens at 195° and allows the fluid to flow…..water pump does its job and pumps the water through the rad and out the return hose past the switch….If the act of the water running through the rad with just the air flow of movement drops the temp below 195 (maybe as much as 60° as said above) the switch will not close and the fan will not turn on…..BECAUSE IT DOES NOT HAVE TO……so you now get the benefit of removing the mechanical fan (I do not have the numbers on HP or MPG gain but it would obviously be something as the motor is no longer working to turn the Mechanical fan or in the case of the constantly running electric fan the extra load on the alternator.)

 

And like I said at 60 MPH….my fans do not go on even when the temps are in the 90’s

 

Should the coolant in the return line be above the 195° mark the switch would close complete the circuit and turn the fan on until such time as the Temp should drop back down to the 195.

 

And before any one asks this one…..A 195° T-stat does not mean you motor is constantly running at 195°…..they run hotter than that …..195° is just the temp that the stat open up and allows full circulation of the coolant.

 

https://jeep-manual.ru/index.php?page=100

https://www.wranglerforum.com/f210/anyone-running-electric-fans-sensor-questions-1928378.html

https://grassrootsmotorsports.com/forum/grm/cooling-fan-sensor/39133/page1/

https://forums.corral.net/forums/general-mustang-tech/288712-electric-fan-those-who-put-temp-switch-lower-radiator-hose-inside.html

http://forums.turbobricks.com/showthread.php?t=270950

https://www.dieselplace.com/forum/63-gm-diesel-engines/20-6-2l-diesel-engine/829130-electric-radiator-fan-sensor-temp-lower-hose.html

http://www.fuelly.com/forums/f10/coolant-fan-temperature-switch-5252.html

 

 

[yxmj]

17 hours ago, JMO413 said:

The factory fan comes on when the coolant in the radiator reach's 195.

 

17 hours ago, omega_rugal said:

 

i want an explanation for that...

 

Sorry.....somehow these were supposed to end up in the reply above......

[Jeep Driver]

It's no wonder so many of you have problems. 

 

You really don't understand how it works. 

[omega_rugal]

well mine has no thermostat, it was MIA before i got the truck, got rid of the mech fan, the efan was missing ever since i got  it, i installed a plastic fan on the waterpump pulley, no overheating problems since then...

[yxmj]

16 hours ago, Jeep Driver said:

It's no wonder so many of you have problems. 

 

You really don't understand how it works. 

 

Well anyone who has read this thread as well as the attached links will be able to judge for themselves who really understands how it works.

 

Your answers that have nothing to back them up but you saying "Because I said so"

 

Thanks for being an example of my signature

 

[Jeep Driver]

12 hours ago, yxmj said:

Your answers that have nothing to back them up but you saying "Because I said so"

 

Thanks for being an example of my signature

 

Quote

It is the same when you are stupid……..

 

 

Do not insult my intelligence and my integrity. I have no reason to lie to anyone, if I tell someone something works, it works because I know for a fact it works. 

 

 

Yes, because I said so. 

 

You are wrong, much of what I read (elsewhere in particular) is wrong. 

 

 

 

 

 

As to having something to "back it up", see here-

 

 

Unedited. 

 

 

[WahooSteeler]

36 minutes ago, Jeep Driver said:

 

 

 

Do not insult my intelligence and my integrity. I have no reason to lie to anyone, if I tell someone something works, it works because I know for a fact it works. 

 

 

Yes, because I said so. 

 

You are wrong, much of what I read (elsewhere in particular) is wrong. 

 

 

 

 

 

As to having something to "back it up", see here-

 

 

Unedited. 

 

 

 

 

I should stay on the sideline but I just can't any longer. Jeep Driver, you insult people's intelligence on here ALL THE FREAKING TIME!!! Yes, it is clear you are highly knowledgeable about Jeeps and have an above average knowledge of mechanical workings. You were not born that way, you learned what you know. The majority of members here are doing just that.....learning. But almost every time someone engages you or debates you, you dismiss them as ignorant or uneducated. You are not just blunt and direct, you are rude. Granted, the written word on forum posts, emails etc does not always properly convey the attitude, tone or intent of the speaker's comments. But after awhile, if it looks like a duck, walks like a duck and sounds like a duck, then it's a duck! You may remove the "u" from duck and insert an "i" and that it is you Jeep Driver! And nowhere on this thread has anybody suggested or insinuated you were a liar in any shape or form. Get over yourself. 

 

Rant over................

[Jeep Driver]

12 minutes ago, WahooSteeler said:

 

 

I should stay on the sideline but I just can't any longer. Jeep Driver, you insult people's intelligence on here ALL THE FREAKING TIME!!! Yes, it is clear you are highly knowledgeable about Jeeps and have an above average knowledge of mechanical workings. You were not born that way, you learned what you know. The majority of members here are doing just that.....learning. But almost every time someone engages you or debates you, you dismiss them as ignorant or uneducated. You are not just blunt and direct, you are rude. Granted, the written word on forum posts, emails etc does not always properly convey the attitude, tone or intent of the speaker's comments. But after awhile, if it looks like a duck, walks like a duck and sounds like a duck, then it's a duck! You may remove the "u" from duck and insert an "i" and that it is you Jeep Driver! And nowhere on this thread has anybody suggested or insinuated you were a liar in any shape or form. Get over yourself. 

 

Rant over................

If that's how you feel, that's fine by me. 

 

[WahooSteeler]

33 minutes ago, Jeep Driver said:

If that's how you feel, that's fine by me. 

 

 

I would expect that reply from you no doubt. 

 

Just watched the video. So let me get this straight.............since you posted it on YouTube, that makes what you say factual?? All you did was rant the same stuff you already said on your posts. I'm no mechanic by any means, but I'd argue that your "test" of idling in a garage is not a real world example. Truck is not under load and being driven in 90+ degree heat. To be clear however, I am not debating what you or yxmj are both trying to say. I am not taking sides. But if you're the engineer that Jeep/AMC/Chrysler should have hired 30yrs ago, why is your belt squealing? Why haven't you re-engineered that yet? You've got the whole round fan on a square box problem figured out by putting half moon cutouts on your fan shroud, holy $#!&, why couldn't Jeep figure that out? 

 

Again, I am not debating your opinion on the subject. I am commenting on, what I consider, your aggressive and abrasive attitude. Look, I generally appreciate people that are direct and straightforward, I like knowing where they stand or what they think without playing games or having to read between the lines. You POTENTIALLY have a lot to offer here. But IMO you are more concerned with proving you are right about something instead of simply sharing your knowledge. And when trying to prove yourself, you more often than not insult the other party.  

[Jeep Driver]

2 minutes ago, WahooSteeler said:

 

I would expect that reply from you no doubt. 

 

Just watched the video. So let me get this straight.............since you posted it on YouTube, that makes what you say factual?? All you did was rant the same stuff you already said on your posts. To be clear however, I am not debating what you or yxmj are both trying to say. I am not taking sides. But if you're the engineer that Jeep/AMC/Chrysler should have hired 30yrs ago, why is your belt squealing? Why haven't you re-engineered that yet? You've got the whole round fan on a square box problem figured out by putting half moon cutouts on your fan shroud, holy $#!&, why couldn't Jeep figure that out? 

 

Look, I generally appreciate people that are direct and straightforward, I like knowing where they stand or what they think without playing games or having to read between the lines. You POTENTIALLY have a lot to offer here. But IMO you are more concerned with proving you are right about something instead of simply sharing your knowledge. And when trying to prove yourself, you more often than not insult the other party.  

It's real simple-

 

You (anyone) asks a question. Question is answered- Here, this works......

 

You, anyone else, are free to take it or leave it. 

 

If you are going to challenge me by essentially stating that I'm being misleading to others..........you better be prepared. 

 

 

What I stated in the first reply works, I have proven that it works. 

 

 

 

 

As for the belt, I stated that the engine is coming out, I'm replacing it. The truck has not left my driveway in two years, I'm not spending money for nothing. 

 

 

 

 

Maybe if you and others spent more time learning rather than 'feeling'...........we'd all be better off. 

 

 

 

 

 

Here's one of the guys I learn from-

 

 

 

 

[WahooSteeler]

Jeep Driver, you don't get it and never will. Your YouTube video backs up what I'm saying because as you say in the video, "people are just effing idiots and I'm (you're) tired of dealing with their bull$#!&". Just because YOU say it works does not make it the end all be all. A square peg is not always the solution to filling a square hole. You rarely if ever are open to other approaches to solve common problems.

 

I don't give a crap about "feelings", I'm talking about common decency and respect. I read most of your comments on here because, believe it or not, I AM trying to learn AND I respect your knowledge. But you have no patience for those that either don't understand the topic or potential solution, especially if they question you with something else they read, heard or experienced. I, along with most on here I believe, are not looking to have our hand held. But you show very little, if any, respect to others and what they do or don't know. Again, it's called common decency.