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Just be careful putting the new sensor in. When I was doing that on my new radiator, it actually busted through the side of the radiator. I found out the replacement radiator was actually about a half inch less thick than the original one. Had to send the replacement radiator back and buy a new one from another vendor.
I ordered the Standard Motor Products sensor/switch thing p/n TS329 and... it doesn't fit in the hole on the Denso 221-4101 radiator. It fits the hole on the OEM radiator I removed, and the OEM switch/sensor thing (89428-33010) fits the hole on the Denso rad, but the aftermarket switch/sensor doesn't fit the hole on the aftermarket rad . Seems just enough too big diameter on the sensor to seat far enough for the threads to catch.
Anyone have a recommendation for the switch/sensor that DOES fit the Denso rad? I'd hate to have to keep buying and returning until I find one that fits. But if I do I think I'll try the Beck Arnley one next. Partsouq recommends a Taiho p/n LS112 or Tama p/n LS112 (same p/n for different manuf??) as an OEM replacement.
(Also bought the Gates high pressure power steering line seen in the pic)
Oh no. So much for replacing a radiator being a simple job. I guess the good news is that you're not paying $85/hour for a mechanic to run into these issues. Who could have guessed?
Oh no. So much for replacing a radiator being a simple job. I guess the good news is that you're not paying $85/hour for a mechanic to run into these issues. Who could have guessed?
So many great posts in this thread!
Yeah these kinda set backs add extra aggrevation to the job for sure!
Found out how to test the ECT switch to see if it works or not before spending more money buying others to find one that fits the Denso radiator. Now if I only had a 9v battery for my tester!
Found out how to test the ECT switch to see if it works or not before spending more money buying others to find one that fits the Denso radiator. Now if I only had a 9v battery for my tester!
Early on after getting my '91, an especially trendy topic on this site (BTW, from being here for a while, it is interesting to see how popular repairs come and go) was replacement of the ECT sensor, on top of the engine, near the right coil, which is similar but different from the switch you're talking about here.
But it similarly has a bench testing procedure, with a plot of temperature vs. resistance. I was younger then, dreaming of these stories of better MPG, free healthcare, free student loan payoffs, foolish enough to believe the hype, so I bought a new sensor. By the time I had the old one out, the new one was going in no matter what I found.
The punchline is that the original one tested exactly to spec, there was no change at all in how the car performed with the new sensor, and eventually the forum moved on to talking about ECU capacitor replacement as the favorite repair du jour of the day. (I did that one too, and even though I was not facing major problems, it did help fix some minor issues I did not even know I had)
So great job on posting the bench testing procedure just so people can make a more informed decision. Keep going!
No experience doing this but I can read and watch YouTube so I THINK I'm doing it right. But my results are perplexing. Turn my multi-meter to the 200 ohm setting. No noise and the display is a 1 on the left side of the readout. Touch the leads together and I get a tone and some numbers (I don't think the numbers are important but the tone means continuity). Connect the leads to pins in the connector on the room temperature switch. Still have a tone - which it should because there should be continuity below 181 deg F. Then I dangle the sensor end of the switch into boiling water (i.e. more than 199 deg F) and there is no change. Still have a tone. So, I think, proof of a bad switch. Then I try the new switch (since I have all this stuff out and set up might as well see how it works) and I get the exact same results. I readjusted the leads several times to make sure there wasn't some inadvertent contact. Retried both the old and new switches several times. Always the same. No change in continuity when being dunked in boiling water.
What am I doing wrong?
Based on the test procedure I'm assuming that a correctly operating switch would open (i.e. no continuity) when it senses the coolant temp above 199 and thus turn on the aux fan. When the coolant drops below 183 it would close and turn off the aux fan. I read other threads I believe that said their aux fan would run constantly because of a bad switch. I guess that would be a bad switch in the always open way (thus the fan never shuts off). But mine, if it is bad, is bad in the always closed way meaning the fan would never come on regardless of how hot the coolant was.
I took the damn switch to O'Reillys to see if they would test it and tell me if it was bad or not. They don't test them. The old me would have bought a new OEM switch by now and carried on with the rest of it. But now I wanna know if this switch is bad or not!
... Turn my multi-meter to the 200 ohm setting. No noise and the display is a 1 on the left side of the readout. Touch the leads together and I get a tone and some numbers (I don't think the numbers are important but the tone means continuity). Connect the leads to pins in the connector on the room temperature switch. Still have a tone - which it should because there should be continuity below 181 deg F. Then I dangle the sensor end of the switch into boiling water (i.e. more than 199 deg F) and there is no change...
Nice work. So far the only rookie mistake is thinking that O'Reilly's would have any idea at all how to test that part.
Comments on the above:
"1 on the left side" - that sounds odd. Usually everything on the display means something. A "1" does not make sense to me. I'd try to figure out what that means.
Even with a continuity check / tone, the numbers usually indicate resistance, so that may be meaningful.
199 is pretty close to 212*F. Due to the heat capacity / thermal mass of the switch, it may take some time (e.g. a couple of minutes) for it to reach the 199*F trigger point. Also there will be some tolearance / variability in that number. So I would let the switch sit in the pan for longer and see if it makes a difference. I doubt anything would be harmed by fully immersing it, other than the risk of melting the leads insulation on the edge of the pan.
I'd look for bubbles on the bottom of the pan to indicate 212*F rather than the thermometer. The bubbles will also increase heat transfer, making the switch warm up faster.
Well, a successful test! Thanks for suggesting leaving it in the water longer. I was expecting it to affect the continuity within a few seconds. Not the results I wanted but a successful test nonetheless.
Hooked up the old switch and held it in the boiling water for a full 5 minutes. Readings on the meter went from 1.0 down to 0.6 and the tone was consistent.
Hooked up the new (but doesn't fit the rad) switch and held it in the boiling water for just about a minute. The readings went from 1.0 UP to about 1.5 then the tone stopped - i.e no continuity.
So my findings are that I did indeed screw up the OEM switch when removing it and now I need to find a replacement that fits the Denso rad. Not great but at least now I know for sure.
By a "1" on the left side of the display I mean this thing which, if I understand the book correctly, means "overrange". As soon as I touch the leads together or connect them to the pins on the switch the readings come up on the right side of the display as seen in the picture in the previous post.
10-4 on the photo of the "1 ." Not a common way to show over-limit, but yes that indicates the measurement is out of range, so greater than 200 Ohms in this case.
Glad it was just the extra time needed for it to come up to temp. Great job on the testing. I always like to understand exactly what failed, and try to replace parts only when they really need it.
With the new found confidence that the aftermarket switch works like it's supposed (and the original one does not) I gave making it fit another shot. Lubed the sensor with a little bit of coolant (not sure if that really qualifies as lube) and gave it a firm push and a twist into the hole on the radiator. It popped in. So it stays now. Gotta torque it to something like 5.4 ft-lbs (65 in-lbs) and I'm gonna run it.
And while it's not cooling system related, I did get the power steering pump pulled tonight so I can fiddle with that replacing gaskets and whatnot, install the new acv and put the new high pressure line in before proceeding with the timing belt service. And then reinstall the radiator, hoses, etc... I read a thread on pulling the ps pump that said getting the 2 bolts out of the back side is easiest done from underneath with a long extension to a 14mm socket. I had to use my impact wrench with a long extension to get the lower bolt to budge but after fighting with the upper bolt for a long time from underneath I got back up top and used my 14mm long handle ratcheting wrench on it and had success getting it out. I haven't had any problems with the alternator so I'm hoping I can just clean it up and it'll be fine. It's pretty well coated with what I guess is atf and dirt right now.
Glad ya got the sensor in the radiator, at least ya know that one is good. That alternator would scare me though. Looks like the PS fluid has been leaking on it for a while. Seeing how you're gonna have it off anyway when you do the T-belt, you should take it and have it checked, even though it's still working now. I had an alternator that went bad which had alot less fluid on it then yours, I was still able to see the copper inside. Also, be careful removing the plug off the back cuz with all the fluid it might have deteriorated a bit and might crack when squeezing it.
Glad ya got the sensor in the radiator, at least ya know that one is good. That alternator would scare me though. Looks like the PS fluid has been leaking on it for a while. Seeing how you're gonna have it off anyway when you do the T-belt, you should take it and have it checked, even though it's still working now. I had an alternator that went bad which had alot less fluid on it then yours, I was still able to see the copper inside. Also, be careful removing the plug off the back cuz with all the fluid it might have deteriorated a bit and might crack when squeezing it.
02-07-20, 06:59 PM
. Seems just enough too big diameter on the sensor to seat far enough for the threads to catch.
