Another radiator fan dilima

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Eyeball
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Another radiator fan dilima

Post by Eyeball » Mon Feb 25, 2019 9:39 am

So a few weeks my radiator fan stopped working.. I checked the fuses,which were all good. I put power to the fan which kicked on. I check to make sure I was also getting power to the fan switch which check out and the fan does kick on when I unplug the radiator fan switch.

I changed out the relay also and when putting the new one in, when the relay is barely in contact it will kick the fan on which was odd but plugged in nothing.

So I started replacing a few things, the radiator (which was leaking) with a 2 row radiator from a local outfit which fit very nicely. At the same time I changed the thermostat with one from Tama Enterprises Co. Which Napa carries and costs $26. To top everything off I changed out the radiator fan switch with one from my newly acquired 87' tercel. It kicked on a few times but noticed yesterday it stopped. Today I bought a brand new fan switch from Napa, which I thought was the ticket. It was not.

What am I missing here?.. Also the bottom hose is hot so the thermostat is opening. Any help is appreciated, it isn't getting hot which is nice.

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NWMO
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Re: Another radiator fan dilima

Post by NWMO » Mon Feb 25, 2019 10:48 am

Eyeball wrote:
Mon Feb 25, 2019 9:39 am
What am I missing here?.. Also the bottom hose is hot so the thermostat is opening. Any help is appreciated, it isn't getting hot which is nice.
Eyeball,

If it runs the fan with the sensor disconnected and isn't running hot, I would have to wonder if your new radiator, etc. is efficient enough to cool without the fan right now. It appears you are in the northeast, winter temps may be enough to keep things cool and it's not warming up enough to cycle the fan.

Chris
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Petros
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Re: Another radiator fan dilima

Post by Petros » Mon Feb 25, 2019 1:22 pm

the only thing that should matter is that you do not over heat when it is stopped and idling. It will not kick on if the temp is within the normal range. It sounds like it is working, you did not indicate that it ever gets hot.

the system is fairly efficient when everything is working properly, so the fan will not come on much, usually only when stopped and idling for more than ten min. if your heater is on and running, that may be enough to keep it at normal operating temperature and the fan will not come on at all.

Also, if the car is moving you get enough cooling air flow through the radiator where it will not come on at all.

Just keep and eye on the temperature all the time, if it gets in the upper half of the gauge without the fan coming on, turn on your heater fan, and than check everything over again.
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Eyeball
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Re: Another radiator fan dilima

Post by Eyeball » Mon Feb 25, 2019 4:49 pm

NWMO wrote:
Mon Feb 25, 2019 10:48 am
Eyeball wrote:
Mon Feb 25, 2019 9:39 am
What am I missing here?.. Also the bottom hose is hot so the thermostat is opening. Any help is appreciated, it isn't getting hot which is nice.
Eyeball,

If it runs the fan with the sensor disconnected and isn't running hot, I would have to wonder if your new radiator, etc. is efficient enough to cool without the fan right now. It appears you are in the northeast, winter temps may be enough to keep things cool and it's not warming up enough to cycle the fan.

Chris
I would suspect the same however it does get (sometimes) just right above the middle mark on the temp gauge, that is when it use to kick on so something seems a miss for sure and it has climbed higher then that. Today I was feeling my lower radiator hose and upper of course and the lower was ice cold with the upper being almost to the point of burning bare skin. So I ditched the thermostat completely for now. My heater was also somewhat cold even after flushing the heater core! Also I am in the Pacific northwest.

I test lighted again today, weak light on the fan switch pigtail,, however mutimeter shows 14v's :shock: .

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Re: Another radiator fan dilima

Post by Petros » Mon Feb 25, 2019 5:03 pm

just above the middle mark on the gauge on the dash is usually where the fan turns on (on mine, it comes on when the needle reaches the top of the little thermometer graphic, but that may not be the same for everyone).

the upper and lower radiator hoses should have different temps. the lower hose is the cooled coolant (after it has run through the radiator), when it is sucked into the engine by the coolant pump through the lower hose. The upper hose is the hottest part of the system, where it goes back into the top of the radiator to get cooled. That is normal operation.

not a good idea to run it without the thermostat, it also serves to direct flow to the heater core before the t-stat opens. it makes the coolant in the heater core the hottest available during all driving conditions. there is a double action to the t-stat, the main control valve, and the disk on the end of the spring to control the flow to the heater core. if the t-stat is stuck closed, than removing it is your only option, but if it is working normally than it should be in place so you can properly diagnose the system. if it is not doing its job, you will not be able to tell if something else is wrong with the system.
'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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Eyeball
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Re: Another radiator fan dilima

Post by Eyeball » Mon Feb 25, 2019 7:21 pm

Petros wrote:
Mon Feb 25, 2019 5:03 pm
just above the middle mark on the gauge on the dash is usually where the fan turns on (on mine, it comes on when the needle reaches the top of the little thermometer graphic, but that may not be the same for everyone).

the upper and lower radiator hoses should have different temps. the lower hose is the cooled coolant (after it has run through the radiator), when it is sucked into the engine by the coolant pump through the lower hose. The upper hose is the hottest part of the system, where it goes back into the top of the radiator to get cooled. That is normal operation.

not a good idea to run it without the thermostat, it also serves to direct flow to the heater core before the t-stat opens. it makes the coolant in the heater core the hottest available during all driving conditions. there is a double action to the t-stat, the main control valve, and the disk on the end of the spring to control the flow to the heater core. if the t-stat is stuck closed, than removing it is your only option, but if it is working normally than it should be in place so you can properly diagnose the system. if it is not doing its job, you will not be able to tell if something else is wrong with the system.
Yep that's where mine would always turn on also. And i already took the tstat out and drove it up in the mountains to find some snow. So driving 40+mph the car is now running pretty much ice cold with the temp sensor bottom'd out. Now up in the hills climbing less then 20 it was below the middle mark and heater was as hot as it's ever been. Then in the snow unleashing beast mode, it got above the middle mark and sure enough the fan kicked back on like normal! So I believe it has to do with the tstat or something associated with it, but to get 2 bad in a row seems unlikely to me.. :?

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Re: Another radiator fan dilima

Post by ARCHINSTL » Tue Feb 26, 2019 12:33 am

@ Eyeball - check out this recent thread on thermostats - an eyeopener:
viewtopic.php?f=4&t=14042&p=105810&hili ... at#p105810
Tom M.
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Re: Another radiator fan dilima

Post by xirdneh » Tue Feb 26, 2019 8:47 am

When car is idleing you should be able to pull the plug off and fan will run. If not some thing is wrong in the wireing or fan motor is bad . Bad fuse somewhere.
I installed the wrong sensor once and fan ran as soon as engine started . That switch worked the opposite of the correct switch.
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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Re: Another radiator fan dilima

Post by Eyeball » Thu Feb 28, 2019 11:21 am

ARCHINSTL wrote:
Tue Feb 26, 2019 12:33 am
@ Eyeball - check out this recent thread on thermostats - an eyeopener:
viewtopic.php?f=4&t=14042&p=105810&hili ... at#p105810
Tom M.
This is a pretty informative thread! So I put some cardboard in front of about half the radiator which helped a little the other day. Then stopped at the local Napa and figured out the tstats I bought were 180 temps and the lowest one they sold was a 160 however it's made in Israel.. But I put it in last night right before dark drove around and got some decent heat, and of course got a leak at the gasket :oops:! So I took it out and saw the stat was open ,threw it back in and am running right below half temp gauge. So we will see how this turns out. I appreciate everyone helping out!

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Re: Another radiator fan dilima

Post by Petros » Thu Feb 28, 2019 10:31 pm

it helps a lot to use some sealant around the edge of the thermostat to help hold it into place while you get the nut on it and tighten it down.

it is easy for it to shift, and than cause a leak of your costly new coolant if you do not effectively "glue" it into place so it will stay in place while you tight it down.
'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)
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Re: Another radiator fan dilima

Post by ARCHINSTL » Fri Mar 01, 2019 12:38 am

Petros wrote:
Thu Feb 28, 2019 10:31 pm
it helps a lot to use some sealant around the edge of the thermostat to help hold it into place while you get the nut on it and tighten it down.

it is easy for it to shift, and than cause a leak of your costly new coolant if you do not effectively "glue" it into place so it will stay in place while you tight it down.
What - he - wrote !
The placement of the elbow-to-block and keeping the thermostat aligned is the most awkward in my experience (granted, limited to Morris Minors, Singers, an S10, and a '46 Ford V8 flattie *. The latter had two water pumps and two thermostats which were costly to replace for a 16-year old back in 1956 (so I ran without, which, of course, was a dumb mistake) ...
* While OT, those flatties were forever subjected to vaporlock which was solved by tinfoil and wooden clothespins on the fuel line, which I 'membered to use on my '88 Dodge/Mitsu 2.6 a "few" decades later, believe it or not!
Tom M.
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Re: Another radiator fan dilima

Post by Eyeball » Sun Mar 03, 2019 10:24 pm

160 degree thermostat seems to be the ticket for me, radiator fan now kicks back on when it should (after idling for about 8 minutes or so) other then that it stays well under half on the temp gauge.

Conclusion: I believe the 2 previous tstats I purchased were bad, with the top hose being so hot and the lower hose being ice cold. It was also causing my temperature to rise to nearly red at times. Which also cause my frustration with the fan switch but now everything is new, so that is the positive out of it.

160 t-stat 👍

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Re: Another radiator fan dilima

Post by slimdude85 » Mon Mar 04, 2019 1:50 pm

Petros wrote:
Thu Feb 28, 2019 10:31 pm
it helps a lot to use some sealant around the edge of the thermostat to help hold it into place while you get the nut on it and tighten it down.

it is easy for it to shift, and than cause a leak of your costly new coolant if you do not effectively "glue" it into place so it will stay in place while you tight it down.
I've got a coolant leak at the 'stat housing. I surmise it is due to this very issue. I never even thought it could have been due to the 'stat shifting. Could one hold the 'stat in place with a screw driver or needle-nose pliers (through the coolant neck opening) instead? Sorry 'bout hijacking the thread, by the way. Didn't want to start a new thread to ask a question about a recommendation from a different thread.
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Re: Another radiator fan dilima

Post by xirdneh » Mon Mar 04, 2019 5:18 pm

i am betting something else is wrong
should run right with 180 thermo
160 probably will not put out good heat in the cab
could have a leaky head gasket
my current driver has a 190 thermo and temp gage never goes above half
and i get tons of heat
only drawback is during 90 degree weather engine will ping now and then when starting off from dead stop
one last thing. 4 years like this and have never added water to radiator. its always at the top
Love those Tercell 4x4 wagons but they sure suffer from road noise.

xirdneh
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Re: Another radiator fan dilima

Post by xirdneh » Mon Mar 11, 2019 5:22 pm

clogged radiator?
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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