Temperature above 190.....

I would assume you can't remove the thermostatic switch unless you remove the coolant first?
No need to drain the coolant. Remove the reservoir cap briefly to relieve pressure before replacing the thermoswitch. Remove the old thermoswitch and and cover the opening with the ball of your hand while you fiddle with getting the new one positioned. You'll lose a bit of coolant, and you'll have to bleed a radiator after you're done.

If the old thermoswitch is broken, by all means replace it. I would not replace a working switch with one rated at a lower temperature. It will not provide any material benefit, but it will make your fans run more often.
 
No need to drain the coolant. Remove the reservoir cap briefly to relieve pressure before replacing the thermoswitch. Remove the old thermoswitch and and cover the opening with the ball of your hand while you fiddle with getting the new one positioned. You'll lose a bit of coolant, and you'll have to bleed a radiator after you're done.

If the old thermoswitch is broken, by all means replace it. I would not replace a working switch with one rated at a lower temperature. It will not provide any material benefit, but it will make your fans run more often.
Ok, thanks. But if I just wanted to remove and test it in the kitchen, then I’d at least need to find a 22 1x5 plug, yes?
 
Consider this other bit of reality: on an X (without AC) as delivered, the likelihood of the fan running, ever, when the car is actually moving at speed and the ambient temperature of the air is less than 100°, is likely very close to zero.
Actually, I was surprised the mechanic freaked as much as he did when he heard the fans turn on. It was maybe the 2nd time I've heard them turn on myself, both times because the car was sitting and idling for 10 minutes. Even when driving on a hot day, 40 miles up the freeway, the fans haven't turned on that I've heard, and I've rarely seen the temperature gauge rise above 200.
It's possible, as a newbie who isn't a 'Master Mechanic', and is prone to believe things from people with more knowledge, that the bill was inflated a little for 'emergency' service that wasn't at all necessary. Possibly :)
 
Actually, I was surprised the mechanic freaked as much as he did when he heard the fans turn on. It was maybe the 2nd time I've heard them turn on myself, both times because the car was sitting and idling for 10 minutes. Even when driving on a hot day, 40 miles up the freeway, the fans haven't turned on that I've heard, and I've rarely seen the temperature gauge rise above 200.
It's possible, as a newbie who isn't a 'Master Mechanic', and is prone to believe things from people with more knowledge, that the bill was inflated a little for 'emergency' service that wasn't at all necessary. Possibly :)
They are a cheap part and they do fail. Having one on the shelf you have tested good would be a reasonable thing to consider.
 
They are a cheap part and they do fail. Having one on the shelf you have tested good would be a reasonable thing to consider.
I’ll yank this one out and bench test it, etc. It’s less than a year in-use from MWB from the looks of things, so there’s a good chance it can be saved. And remember - the original fan is still fine, apparently.
And you say just bridging the two leads on the switch will turn them on to test?
 
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I’ll yank this one out and bench test it, etc. It’s less than a year in-use from MWB from the looks of things, so there’s a god chance it can be saved. And you say just bridging the two leads on the switch will turn them on to test?
No, you don't bridge the leads of the switch. You bridge the leads of the connector that plugs into the switch.
 
Disconnect and bridge these two. Got it.
And while I had my head up in there, here’s a picture of how maybe you shouldn’t splice a ground into a white/black wire. I guess you’d call it a cold-twist-and-we’re-too-bothered-to-solder join….

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I've had my 86 X since 1989 & it always hovered around the 190 mark. In traffic it would jump slightly higher, but the fan would bring it back down quickly. that cycle continued as long as I was in traffic. Other than in traffic or idling for a while, the fan never comes on.

I sprung a leak behind the motor 2 years ago. I could see it was from the pipe from the water pump to the thermostat. I sourced a replacement pipe as I figured it had rotted & decided to refresh the system with new hoses, waterpump, thermostat, and complete flush with new coolant. I didn't like the thermostat I received from Vic's as it was smaller than the housing. I found the exact 1 I removed from Di Fatta Bros in MD. I don't know what the temp rating was.
After removing the old waterpump, I moved on to the pipe. SOB, the clamp on the thermostat side had broke causing my leak.... Too late now, I've already ripped in...

Got everything back together & proceeded to bleed the system. Went to turn the bleeder & it spun the whole thing off the radiator... I bought the "Texas Heat" aluminum radiator & temp switch. Direct bolt in & reused the OEM fan. Now my car is around 180, but I can't say exactly which thing, or all, did the trick.
I remembered, as suggested on this forum somewhere, I drilled a small hole in my thermostat to aid in the bleeding process. Theory is that it would allow trapped air past the closed thermostat with the engine cold & not running.
 
Well that is beyond shoddy. Baring the one wire and that ground is just stupid. Fixing these things is in your wheel house, get some shrink tubing and cover the bare wire and properly splice the black wire in. What is that wire for anyway?

Aluminum radiator so you should have good cooling.
 
Well that is beyond shoddy. Baring the one wire and that ground is just stupid. Fixing these things is in your wheel house, get some shrink tubing and cover the bare wire and properly splice the black wire in. What is that wire for anyway?

Aluminum radiator so you should have good cooling.
The ground goes up into the light well / frunk. Will trace it this weekend and see what their plan may have been. There’s also a notch of the sheath missing in the other ground wire, so I’m wondering if they had two plans and one didn’t work out?
 
The ground goes up into the light well / frunk. Will trace it this weekend and see what their plan may have been. There’s also a notch of the sheath missing in the other ground wire, so I’m wondering if they had two plans and one didn’t work out?
I think they didn’t know what the hell they were doing. Just fix the effing wire and be done with it. It likely has a break at or near the termination for the ground. A continuity test would tell you what or where the problem is with some investigation.

Some shrink tubing over the wire to ‘heal’ it would be the appropriate action and should have been done when it happened, its not like he couldn’t get access to it.
 
I think they didn’t know what the hell they were doing. Just fix the effing wire and be done with it. It likely has a break at or near the termination for the ground. A continuity test would tell you what or where the problem is with some investigation.

Some shrink tubing over the wire to ‘heal’ it would be the appropriate action and should have been done when it happened, its not like he couldn’t get access to it.
I’ll test the fans for operative reliability and then make a decision on what‘s next. Idea being the shoddy wiring isn’t effecting operation, or parasitic battery draw etc. It’s easier to believe now why the ‘G’ light wire broke so easily…
 
No, you don't bridge the leads of the switch. You bridge the leads of the connector that plugs into the switch.
Hi from the correct thread this time. I tried this, but neither fan turned on. Any ideas?
Does the ignition need to be on? Something to do with the relay they inserted in the path? Blown fuses?

Edit: Fuse is good.
 
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Hi from the correct thread this time. I tried this, but neither fan turned on. Any ideas?
Does the ignition need to be on? Something to do with the relay they inserted in the path? Blown fuses?

Edit: Fuse is good.
Yes the ignition has to be on with an X
 
Remember these are analog gauges and analog sensors, what they show is relative. The engine could well be at 190 (or 220 for all we know) or not depending on its accuracy.

Yes if the thermostat is made to hold 190 then hopefully it will hold the engine close to 190 by introducing the ice cold water as needed to the engine to keep it at 190. 190 is not high, it is proper and correct for this engine.

The radiator and the fan can keep it at 190 in all but the worst conditions: at idle, just coming off the race course/highway/autox. Or perhaps Lost Wages :)

The radiator on an X in good condition has never been the thermal weakpoint in the system, yes it could be better but it is more than enough to dissipate the energy dumped into the coolant by the existing engine.
Reviving a previous thread…
So the other day I’m sitting at a drive thru for a little longer than normal, maybe 10 minutes by the time I took this photo of my raised temperature. Funny thing was, I didn’t hear the fans turn on, and the temp seemed too high for my liking. I was about to shut her down, but my order arrived.

I started to drive, and within a minute in fourth gear, the temp dropped back down quickly.

Question: this temp is too high to NOT hear the fans, correct?

Could it have anything to do with the higher rated radiator coolant cap I put on (up from that .5 thing)?

Or is it more likely the switch is failing, or a wiring problem with the fans (we do remember that WD splicing, yes?).

Whichever, I’d like to test it in the driveway without blowing the engine - how high would you let that temperature rise before shutting down?

I fully expected to hear fans at that temp, but didn’t, and the rising temp gauge would indicate something was amiss.
Here‘s the proof:

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I agree that the indicated temp reading (about halfway between 190 and 260 would be in the ballpark of 225) is "too high."

Under the conditions you describe, waiting in a drive-thru line, you should have had fan activation before reaching this temp.

The two most likely causes of this issue:

1. Air in system.
1a. Air and gasses in general have a horrible ability to transfer heat, as compared to liquids.
1b. Air in system tends to collect in the driver's side radiator tank, which is why the bleed screw is there. Too much air here will have the temp switch exposed to hot air and not hot liquid coolant, and thus not give the fan switch a true temp reading, so in essence it won't "know" that it needs to turn the fans on.

2. Defective fan circuit (wiring, relay, fuse, switch).

Both situations are easily tested and have been covered in hundreds of posts.

The easiest first test is with key in run, pull the leads from the fan switch and touch them together. If the fan runs, the everything (other than the fan switch) in the fan circuit is fine and now you concentrate on figuring out if the system is air-bound or the switch is bad. Switches do go bad but I'll bet a lot of good ones have been replaced.

The next thing is to bleed the system. A lot of air=smoking gun for the symptom of no fan operation. Which means you have to figure out why so much air is getting in, but that's a whole other kettle of fish.
 
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