Mysterious problem with cooling system

General discussion about our beloved Tercel 4WD cars
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marlinh
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Re: Mysterious problem with cooling system

Post by marlinh »

I believe you said you had an infrared temp gun. Did you check temperatures with it when your gauge was reading high?

Air in the cooling system will not bleed out when sitting.

Also, when you had weird things happen did you put full heat on inside the car and turn the fan on max. This is like adding another radiator into the system and would help cool down the engine if overheating is actually a problem. Also, when bleeding the system after changing a component, you should have heat on inside the car when running it.
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NWMO
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Re: Mysterious problem with cooling system

Post by NWMO »

Also, when you had weird things happen did you put full heat on inside the car and turn the fan on max. This is like adding another radiator into the system and would help cool down the engine if overheating is actually a problem.
I understand why this is the case and believe it to be true. However, I have noticed with my Terc that when I engage the dash fan to high heat, the heat gauge gets a barely noticeable bump UP. I'm sure the temp does not go up, but the gauge does for some reason.

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MotorLicker
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Re: Mysterious problem with cooling system

Post by MotorLicker »

Petros wrote:that would be pretty frustrating to have the temp gauge in the red the whole time. I would want to verify proper temperture with a separate gauge, just to be sure. that would spook me even if I knew for sure it was a bogus reading.
Yes, I had a knot in my stomach the entire drive. I'm thinking I'll pick up an aftermarket gauge today, fingers crossed it reads normally.
Petros wrote:Perhaps you got the wrong sender. swap back in your old one see if it goes back to the previous readings.
I'll try that once I get home this evening, this is the part I got http://www.opticatonline.com/part/beck- ... ure-switch maybe it was bunk out of the box? It acts like it's super-sensitive. When it reads normal temp/dead center the heater blows tepid-warm air. It used to blow very warm at this point.
Petros wrote:Yes, grasshopper. I explained it to you so you will have knowledge for next time. Everyone is a beginner at some point in their life. I do not think machinery is natural to the human condition, we have to adapt to it.
Hahaha excellent, thank you. I am here to learn!
NWMO wrote: However, I have noticed with my Terc that when I engage the dash fan to high heat, the heat gauge gets a barely noticeable bump UP.
I experienced this before I swapped out the sender. A few times, if I turned off the heater completely it would drop the temperature to dead center. This sounds similar to what was happening here (at least on the first page) viewtopic.php?f=4&t=11037&hilit=temp+sender

Would a good course of action be to get an aftermarket gauge and seeing how that works with the new sender? If it's crazy in the red I'll swap senders again. Is it a simple plug and play with aftermarket gauges?

Perpetually perplexed,
Shaye
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Petros
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Re: Mysterious problem with cooling system

Post by Petros »

if you are getting heat out of the heater, the temp gauge should show a noticable drop in temp. It takes about a minute or two to show, but it will drop a bit. That heat is coming out of the engine coolant, if the heat is going in to the passanger compartment, the temp has to drop.

If the gauge goes up, that does not make any sense. I do not think I have ever seen this happen with a properly working system. one of my diagnotic "tests" if the temperature is high, is to turn the heater on full. I should get heat out of it, and see the temp drop. if not, something in the system is wrong.
'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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MotorLicker
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Re: Mysterious problem with cooling system

Post by MotorLicker »

Petros wrote:if you are getting heat out of the heater, the temp gauge should show a noticable drop in temp. It takes about a minute or two to show, but it will drop a bit. That heat is coming out of the engine coolant, if the heat is going in to the passanger compartment, the temp has to drop.

If the gauge goes up, that does not make any sense. I do not think I have ever seen this happen with a properly working system. one of my diagnotic "tests" if the temperature is high, is to turn the heater on full. I should get heat out of it, and see the temp drop. if not, something in the system is wrong.
I understand that, and being in Vancouver I had the heat on nearly constantly just to stay warm. This has been going on for weeks, and like I said sometimes if I turned the heater completely off while it was running hot it would drop down to normal temp after a few minutes.

I knew that blasting the heat should drop the temp, but that is not what I was experiencing and I was watching very closely for it. Once I get the temperature gauge working I'll try that again though..
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MotorLicker
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Re: Mysterious problem with cooling system

Post by MotorLicker »

marlinh wrote:I believe you said you had an infrared temp gun. Did you check temperatures with it when your gauge was reading high?

Air in the cooling system will not bleed out when sitting.

Also, when you had weird things happen did you put full heat on inside the car and turn the fan on max. This is like adding another radiator into the system and would help cool down the engine if overheating is actually a problem. Also, when bleeding the system after changing a component, you should have heat on inside the car when running it.
Okay thank you, now it is all burped and happy. I think I followed this procedure the first time but not after doing the sender *d'oh*

I got it running well 'into the red' and pointed thhe IR gun all over the block/hoses

-upper rad hose ~
-lower rad hose ~
-thermostat housing ~
-right where the sender is ~
-next to the oil filter ~

I'm hoping this is normal operating temp. :oops:
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Petros
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Re: Mysterious problem with cooling system

Post by Petros »

I do not see any numbers shown.

the t-stat opens at 180 deg, upper hose and head should be a bit lower, lower radiator hose should be a lot lower.
'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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MotorLicker
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Re: Mysterious problem with cooling system

Post by MotorLicker »

Ah shoot, I have an extension that converts Fahrenheit to Celsius I think it made the numbers disappear in the post, sorry about that.

Upper hose - 180 F
Lower hose - 80 F
Block near temp sender - 205 F
Block near oil filter - 205 F
Thermostat housing - 200 F
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MotorLicker
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Re: Mysterious problem with cooling system

Post by MotorLicker »

And at the top of the head it was lower, I forget the approx number but it was below 180
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marlinh
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Re: Mysterious problem with cooling system

Post by marlinh »

Those temps look pretty normal.
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MotorLicker
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Re: Mysterious problem with cooling system

Post by MotorLicker »

marlinh wrote:Those temps look pretty normal.
Well that's a relief. Thanks for all the replies..

Guess it is the gauge after all (going to napa today to grab an aftermarket)

Cheers,
Shaye
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Re: Mysterious problem with cooling system

Post by BaileySims »

Is the temp gauge an interchangeable piece within the cluster? I've got a good one if it is.
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Petros
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Re: Mysterious problem with cooling system

Post by Petros »

those are all good numbers, and about correct at operating temperature.
'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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