Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

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mikeservations
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Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

Post by mikeservations » Thu Sep 05, 2019 11:56 am

I swapped out the instrument cluster on my 87 T4 DLX to a 83/84 SR5 to gain the tach. The temp gauge needle on the original cluster would generally sit just below the temp symbol in the middle of the gauge (horizontal on that gauge). However, on the temp gauge needle on the SR5 cluster seems to generally sit towards the upper end of the temp symbol in the middle of the gauge (vertical on this gauge). Are there different temperature ranges for these two different clusters? Or does this perhaps indicate an issue with the gauge, connection, or sender? I need to pull the cluster again anyway to replace a dead bulb in the door indicator and double check the speedometer needle to make sure it's fully seated (it's bouncing and chattering on this SR5 cluster first thing in the morning when the ambient temperature is cold and then seemingly working fine later in the day when the ambient temperature is considerably higher).

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Petros
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Re: Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

Post by Petros » Thu Sep 05, 2019 10:44 pm

there should not be different temp ranges, as far as I know the senders are the same, and of course the engine interals are idential, so no reason to have different temp gauge. you may be able to adjust the location of the needle, but first you may want to verify actual operating temperature with an after market temp gauge (they are cheap to buy at any auto parts store). Operating temp is very important that is is accurate, you need to protect the head gasket. So best to verify the temperature independant of the factory sender and the stock gauge. you may just need a new thermostat, best know for sure before you swap out the gauge.

that problem with the speedo is from wear on the moving parts. it is free spinning needle with a metal bar on the back, and the other end is a magnate the spins with the speedo cable, in very close proximity the metal on the back of the needle. when they get a bit of wear, they will make very breif contact, it happens first when it is cold out, once warm the parts change size slightly and than the contact goes away. mine does that, I have just lived with it for many years. it has not caused a problem...yet. I do not think there is any easy way to fix it without taking it all apart.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
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mikeservations
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Re: Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

Post by mikeservations » Fri Sep 06, 2019 10:54 am

Thanks for the info Peter! I appreciate the quick and detailed response.

I wanted to add a few more details -

The temp gauge in the SR5 cluster moves around a lot - much, much more than the gauge in the original DLX cluster. In my 15-20 minute commute home late yesterday afternoon, I saw the needle periodically climb up to the top of the temp icon and then later drop to the middle or below it, but not in a consistent way (i.e., not just when idling or not just when climbing a hill). Once or twice the needle even wildly jumped up and then promptly back down to below where it started. The radiator fan is definitely coming on (checked that when I pulled up at home) and the coolant level hasn't changed. Does the erratic needle behavior maybe suggest a dirty connection or loose wiring on the SR5 cluster?

I also noticed the needle in the SR5 temp gauge moves freely with gravity when the cluster is not installed and I can tilt it with my hands. None of the other gauges (tach, speedo, fuel) do this. Is that normal for the temp gauge needle or does it indicate an issue with the gauge?

Regarding the speedo needle, I noticed in the morning yesterday that it wasn't just bouncing and chattering but also occasionally losing any traction and dropping back down to zero or 10-15 mph when I was going closer to 30 mph. I didn't notice this happening when I was at higher speeds (<45-50 mpg), and there was much less bouncing/chattering at higher speeds as well. I'll double check but how the needle is seated but it certainly seems like it could that be the speedo gauge is well worn and there's not much to be done.

Last night I swapped back in the original cluster so I can take a closer look at the SR5 speedo needle and replace the door indicator light in the cluster frame. The temp gauge in the DLX cluster was back to normal - slowly warming up and then sitting just below (to the left) the temp icon. I brought along an infrared thermometer gun, and after my commute home (when it will be warmer), I'll check the temp on the radiator hoses.

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Re: Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

Post by Abletobecain » Fri Sep 06, 2019 3:23 pm

My temperature gauge behaves the same way that yours does. Mine's an SR5 cluster as well, swapped into a DLX. It'll just jump around like it's changing 100 degrees in an instant. I don't believe it. I'm putting in an aftermarket gauge as Peter suggests this weekend.

I've messed with 3 or 4 of the SR5 temperature gauges now and the needle on all of them floats with gravity as your describing. I don't know if that's how they're supposed to operate or not so...

My speedo was off about 15 MPH as well after I swapped the temperature gauge out. There's some adjusting deal-e-o's on the back of the speedo that got me down to about 10 MPH. I noticed that the needle just went waaaay below zero so I just pushed it up to zero when I was parked and still no go...now it just doesn't move until I hit about 10 MPH. I was just going to accept it but if there's a fix, I'd love to know about it too.

My clock also went out when I swapped the temperature gauge...haven't tried to diagnose that one yet but I noticed that my key buzzer went out as well.
1977 BMW R100S 1WD ("Brunhilda"/Summer Fun)
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1983 DLX Tercel Wagon 4WD ("Charlie"/Daily Driver)
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1985 SR5 Tercel Wagon 4WD ("Lucky"/Project)
1983 SR5 Tercel Wagon 4WD ("Cadaver"/Parts Car)
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Re: Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

Post by Petros » Fri Sep 06, 2019 10:53 pm

sounds like a bad contact in the gauge. I think the DX temp gage is the same design as in the SR5 cluster, might see if it can be swapped out without risking damaging it.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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mikeservations
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Re: Difference in temperature gauge ranges from 2nd to 3rd gen clusters?

Post by mikeservations » Mon Sep 16, 2019 11:34 am

Thanks for the replies and info. I checked the temperature on the radiator hoses with the infrared thermometer gun after driving home on a warmer day last week and nothing was above 195 F, so paired with the swapped-back-in DLX temp gauge behaving normally, it seems like there is something amiss with either the contact or the SR5 temp gauge itself.

The design of the temp gauge on the 87 DLX cluster is different from that on the 83 SR5 cluster (horizontal versus vertical) so the swap Petros suggests may be more than I'm up for, but over the weekend I pulled another SR5 cluster (out of another 83). I'll try swapping that one in to see if it behaves any different. It seems like I may end up with the same results that Abletobecain notes when swapping in the SR5 cluster in a DLX, but it's worth a shot (and only $20 spent on another cluster to test out).

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