Overheating after radiator change

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PNWtercel
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Overheating after radiator change

Post by PNWtercel » Tue May 22, 2018 9:03 pm

The other day my old radiator finally started leaking out of a crack that was developing in the top of it

I changed the radiator and now the car overheats

The coolant in the reservoir bubbles and stream and coolant come pouring out

I have tried numerous times to make sure I have all the air out of the cooling system

Anyone have a suggestion?

The new radiator came from a parts car and appears to be in good shape

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: Overheating after radiator change

Post by Petros » Wed May 23, 2018 12:23 am

welcome to the forum,

sorry to hear about your troubles. if you allowed the engine to overheat because of the previous leaky radiator, likely the head gasket is compromised. I have found these engines are very sensitive to being overheated, even if it never gets into the red zone on the temp gauge you may have broken the head gasket seal. this will allow combustion pressures into the cooling system. pull the spark plugs and inspect them carefully, the #1 or #2 likley will be "wet" with coolant. A compression test may show front cyclinder with low compression, but sometimes it does not show up with the relative lower pressrues of cranking the engine, but only leaks with the higher pressures of combustion.

Typical symptoms of compromised head gasket: oily residue in radiator, brownish "chocolate" sludge in the motor oil, white steam exhaust on start up, low compression in front cylinders, or high pressures in the cooling system, head gasket needs to be replaced.

also, put in a new quality thermostat while you are at it. unless you know it is fairly new, these items wear out and can cause severe damage to your engine if you do not catch it in time. buy only a US made, or Japanese thermostat, qulaity ones are in the $16-$20 range, stay away from the cheap $4.99 ones made in a communist factory in the orient. not worth the risk, many are junk right out of the box.

it is a big job, but not costly and can be done in a day if you have all of the parts and tools necessary.

if you need a new head gasket, follow this procedure here:

viewtopic.php?f=7&t=6059
'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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splatterdog
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Re: Overheating after radiator change

Post by splatterdog » Wed May 23, 2018 12:33 pm

Examine the radiator fins closely and did you see any deposits inside the rad?

Don't believe Petros about a singular overheat taking out head gaskets. T4 #1 had two huge overheats while I had it and it spent it's whole last summer running hot and still made it to almost 400k, still running but extremely tired. That hot summer was due to a rad that looked OK at first glance, but wasn't transferring heat sufficiently. None of my builder engines are sitting around because of head gaskets. For me it's always valve job or #3 piston/rod.

But, if it bubbles over right away on a cold engine you have a large combustion leak. If it's after warm up, suspect the "new" rad. Of course you should make sure the fan works.

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splatterdog
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Re: Overheating after radiator change

Post by splatterdog » Wed May 23, 2018 12:37 pm

Almost forgot. Good pressure cap? You need pressure to raise boiling point..

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Petros
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Re: Overheating after radiator change

Post by Petros » Wed May 23, 2018 2:08 pm

splat makes a good point. if it runs hot after warm up, and the temp comes down when you turn on the heater full, that means you have limited cooling capacity. could be plugged up rad or one with mineral deposits on the inside from someone using tap water rather than filtered water in the cooling system.

if your head gasket is bad enough to over pressure the cooling system, usually that would show up with a compression check.
'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)

xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: Overheating after radiator change

Post by xirdneh » Wed May 23, 2018 3:15 pm

i'm betting its a clogged radiator
several times I have had tercel blow headgasket right after over heating
I have also overheated a few that did not blow the gasket
so ya never know
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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ARCHINSTL
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Re: Overheating after radiator change

Post by ARCHINSTL » Wed May 23, 2018 11:58 pm

Two notes on radiator help, following on what splatterdog, Petros, and xirdneh wrote:
viewtopic.php?f=7&t=10496&hilit=radiator
viewtopic.php?f=7&t=6915&hilit=radiator
Tom M.
T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"
"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

PNWtercel
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Re: Overheating after radiator change

Post by PNWtercel » Fri Jun 01, 2018 9:01 am

Thanks for all the replies

It turned out to be a air bubble stuck in my cooling system

I thought that I had definitely got all the air out but I didn’t
All is good now

Except my radiator fan seems to run constant?

As soon as I start the car it turns in and continues to run

It didn’t used to do that

Any ideas?

I will be looking into it today to see what is going on

The temperature gauge has never worked for me it always just slowly builds to hot and stays there

rocketscience
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Re: Overheating after radiator change

Post by rocketscience » Fri Jun 01, 2018 9:59 am

Concerning the fan running, test the switch at a cooler temp with a multimeter to see if it failed open, no continuity, they are normally closed and activate the fan when open or when you pull the plug off. Other options would be a bad relay which operates the reverse of most relay because of the close normalled switch. An easy way to check that and the wiring would be to pull the plug off the switch and jumper it, if it still runs either the relay is bad or the wiring is damaged.
Last edited by rocketscience on Fri Jun 01, 2018 10:20 am, edited 1 time in total.

rocketscience
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My tercel:: 1983 4WD SR5
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Re: Overheating after radiator change

Post by rocketscience » Fri Jun 01, 2018 10:15 am

To test the relay activate it with 12v, it should be open. with no voltage it should be closed. I think the wiring diagram in the fsm actually shows it backwards.

xirdneh
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My tercel:: 87 tercel 4x4 wagon w/reringed engine, 83 tercel 4x4 wagon w/salvaged engine and 4.1 Diff's
Location: seabeck, washington, USA

Re: Overheating after radiator change

Post by xirdneh » Fri Jun 01, 2018 1:51 pm

make sure the plug is all the way on
also some of those switches look almost alike but work in opposite manner
if you are reusing your old switch that would not be the problem
but if you switched switches it could be
Love those Tercell 4x4 wagons but they sure suffer from road noise.

gnarnold
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Re: Overheating after radiator change

Post by gnarnold » Mon Jun 04, 2018 10:35 pm

Hey guys remember the nightmare radiator episode I had a year or two back
viewtopic.php?t=9786&start=45
It went out not to long ago couldnt figure out the problem i so I just mounted a manual switch .and while I was at it since tbe key cylinder housing was worn so bad that it didnt matter how many different cylinders i exchanged. It woukd shut off whike driving .so I installed a push button ignition..works good exceot when i forget to put the key in to unlock the steering wheel,before I start it up and go .ahhh yes the stories .....giod times
I used to laugh at the man with a pinto :lol: , until I became a humble servicer of a tercel :|

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