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Water temp?
http://classiccamaroclub.mfatw.com/viewtopic.php?f=5&t=4150		 Page 1 of 2
Author:  78 Camaro [Mon Oct 27, 2014 9:45 am ]
Post subject:  Water temp?
On the way to work this morning i noticed that the temp gauge wasn't working (has the gauge package that shows 40-120c). It sat at 40 (bottom of the gauge) but usually it sits around 80 when warmed up. Just wandering what could be the issue / solution? Could it be the temp sensor? (not sure where this is located?)

Was working great on Sat morning, here's what happened since...
I changed the oil and also cleaned up the engine bay with a bit of degreaser and a rag - wonder if i knocked a cable out of place or something?
Did some welding on the exhaust on Sunday - forgot to unplug the battery :( - Maybe i shorted something out? All the other electronics seem ok, but maybe?
Also unscrewed the bottom dash panel (under the steering wheel) to check some wires - maybe i knocked something there?

My initial thought is the temp sensor - any other thoughts as to what it could be? Where abouts is the temp sensor - any way it can be checked? Would be a strange coincidence if it failed the same time as all the going on - so thinking (and hoping) it's just a wire? Geekily, i like seeing stats like the temp :geek:

Thanks in advance!

Ray
Author:  3rdGenmalc [Mon Oct 27, 2014 10:12 am ]
Post subject:  Re: Water temp?
I think the temp. sender is in the passenger side head between plugs 6 & 8.

How to test;
http://www.madelectrical.com/workshop/w ... auge.shtml
Author:  78 Camaro [Mon Oct 27, 2014 10:15 am ]
Post subject:  Re: Water temp?
Thanks for the quick reply Malc :thumbup:

I've been researching while i can this morning and found:

http://www.thirdgen.org/forums/cooling/ ... olant.html

"The coolant temp sensor sends coolant temp to the ecm. This is located on the on the front of the intake above the water pump. The coolant temp switch turns on the cooling fan when the coolant reaches a certain temp. This switch is located on the pass. side head in between the #6 and #8 spark plugs. Can be a pain to get to. The sensor screwed into the bottom of the plenum is the IAT sensor(intake air temp sensor). It sends air temp readings to the ecm. "

I guess i can start with
Quote:
The coolant temp sensor sends coolant temp to the ecm. This is located on the on the front of the intake above the water pump.
I'll locate that, check the wiring (hoping that's all it is). I'll also take a look now at the link that you've posted about testing it. Fingers crossed for it just being wiring :?

Cheers...
Author:  78 Camaro [Mon Oct 27, 2014 10:22 am ]
Post subject:  Re: Water temp?
Ok so according to the engine wiring diagram: ('87 tpi) http://austinthirdgen.org/mkportal/modu ... wiring.gif

On the bottom left of that pic the coolant temp sensor has a yellow wire from it, going into the ECM.

According to this:
http://www.thirdgen.org/forums/electron ... grams.html
Quote:
The sensor in the drivers side head between 1&3 spark plugs is solely for the gauge. There is a sensor in the intake coolant crossover by the thermostat housing that gives the temp to the ECM which grounds the green/white wire on the relay to turn the fans on.
So it looks like there are 3 sensors...
1) Pass side of block, between 6&8 - should go to fan relay
2) Drivers side of block, between 1&3 - should go to gauge
3) Top of block, by coolant jacket - should go to ECM
Author:  z28stu [Mon Oct 27, 2014 11:14 am ]
Post subject:  Re: Water temp?
Mornin Ray
Just before you get carried away with your multimeter etc and asuming the coolant systems still full ???
On your drive home do you get decent hot air from the dash heater ???
If not check all engine bay coolant hoses are hot as it could be as simple as a stuck open stat :think:
Hth
Stu
Author:  78 Camaro [Mon Oct 27, 2014 11:37 am ]
Post subject:  Re: Water temp?
Hi Stu,

Thanks for that tip - i'll check for that on the way home today. The water coolant was full on Saturday after i did the mini service (ran out of time to do the spark plugs). Didn't use the car on Sunday and no signs of a leak when i left this morning, so i'm assuming it's still full but will double check before i leave. I usually get warm air through the car the when driving, was a mild morning so didn't have the fan on, but will check to see how it is on the way home.

Will report back...

Cheers!

Ray
Author:  78 Camaro [Mon Oct 27, 2014 12:11 pm ]
Post subject:  Re: Water temp?
Ok, so found this http://www.austinthirdgen.org/mkportal/ ... _part1.gif

And it shows that the coolant temp gauge should be connected directly to a temp coolant sensor, avoiding going through the ECM (makes me feel a bit better already - was worried that the fans wouldn't kick in if it was getting hot, as they would be seeing a null reading). Need to find the dark green wire according to the above link. Wiring appears to follow the same format as the '79 Camaro, i remember wiring that up and it was also a dark green wire, routes straight to the gauge via the factory loom. The sensor on the Camaro though is on the Pass side of the block, between the last 2 cylinders, closest to the firewall. According to the other links, the Firebird gauge sensor should be on the drivers side between 1&3. When i was changing the oil, i do remember that near the oil filter there was a connector and it had some muck on it and the wires, so gave it a blast of degreaser and wiped it down. I think i may have either loosened it, or maybe the wire was fragile and it broke the copper strands. hmm :think:
Author:  78 Camaro [Mon Oct 27, 2014 7:45 pm ]
Post subject:  Re: Water temp?
Ok, so when i got back to the car i located the dark green wire that runs to the drivers side block, around cylinder 1-3. Was a bit difficult to see as there is a small aluminium plate that keeps the heat away from the headers. Anyway, i followed this wire to what seemed to be the point where it plugged into the sensor on the block. Then... i moved and jiggled the wire and connector around a bit. Then, i hoped and prayed. I started the car, hoped and prayed some more, about 5 minutes later... the temp gauge started to rise :D After 10 minutes and on the motorway, it sat at 70 deg c like always, man was that a relief!!

Very happy and slightly embarrassed but i couldn't be more thankful for all the quick replies and help and that it's working. I learnt a bit about the cooling system, Malcolm's info about the sensors (via the link he posted where he's been given quite a commendation by the author :thumbup: ) and hopefully this thread now helps other people that run into any needs for info about the cooling system. Appreciate the help as always!! Thanks :D :thumbup:
Author:  3rdGenmalc [Mon Oct 27, 2014 8:09 pm ]
Post subject:  Re: Water temp?
You moved and jiggled the wire, could need a new connector soldering on.

The temp sensor is on the block driver side front, fan switch pass. side head towards the rear.

None of this is controlled by the ecm.
My ecm is long gone and the cooling fan system works just fine.

What you saw in the link I posted is my old 305 motor, Mark doesn´t update that often. :lol:

Check out his other electrical parts and tips. :thumbup:
Author:  jon_buss [Tue Oct 28, 2014 9:35 am ]
Post subject:  Re: Water temp?
Glad you got it sorted!

Suggests I may also have a slight problem, my gauge always sits around 50ish (just above the 40 mark) when the engine is warm. Never seen it get higher than that other than when I was short of coolant due to an airlock (following heater matrix change). I thought that was normal until I read your post!! Twin electric fans are pretty much always running on mine after a run (until I turn the ignition off anyway so I assume it must be a switched live rather than constant live). Was thinking about getting a 180 degree thermostat, may have to move that forward on the list of jobs to do!

Going to have to look into that myself as well now :eh:
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