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Old 09-28-2009, 08:53 AM   #1
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Default Quick question about coolant temps. and the t-stat...

Alrighty, I did some driving around after the re-route yesteray. Driving around surface streets the temp gauge was 11 0'clock and up to about 12 when sitting. Well, once I git the freeway and was crusing ~3,500 rpms, the temp gauge dropped to about 1/3 up from cold...then it would go up to about 11.....then drop to 1/3 again. At one point when accelerating over 5,000rpm, the temp gauge dropped to the minimum mark on the gauge.

I can only think of two things.. airbubble in the system...or...I managed to put the t-stat in backwards. If it's air, it should burp it out in a few warm up/cool down cycles.

Thoughts?
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Old 09-28-2009, 08:58 AM   #2
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put the front of the car on jackstands, so the rad orifice is the highest point, then start the car and squeeze the rubber hoses to pump the air out. It sounds to me more like its open though if its not maintaining temp.
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Old 09-28-2009, 09:11 AM   #3
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Thanks for the idea...simple, yet it didn't even cross my mind.
Though the idea of the t-stat staying open is not one I like...I don't want to dig around back there anymore...and the t-stat is brand new. Also, even when the temp. gauge shows low, the heat coming out of the vents feels.....toasty.

I give it a week before I take the t-stat out.
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Old 09-28-2009, 09:36 AM   #4
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I think you have bubbles.
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Old 09-28-2009, 09:38 AM   #5
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Quote:
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I think you have bubbles.
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Old 09-28-2009, 09:41 AM   #6
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yeah gauge shouldn't move past 11 o clock if all is working well.
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Old 09-28-2009, 09:43 AM   #7
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Don't make me break out the MSPaint skills to show the various ranges of temp before and after the re-route
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Old 09-28-2009, 09:45 AM   #8
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Quote:
Originally Posted by Doppelgänger View Post
Don't make me break out the MSPaint skills to show the various ranges of temp before and after the re-route
Where is the heater line return plumbed? If its not re-circulated through the mixing manifold I'm going to come through the computer and bitch slap you.
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Old 09-28-2009, 09:59 AM   #9
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Don't make me break out the MSPaint skills to show the various ranges of temp before and after the re-route
Can you do it when you're drunk again?
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Old 09-28-2009, 11:06 AM   #10
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Heater line cometh from the spacer and returns in it's original location.
Also, I walked out to the car just now and noticed a small trail of water coming from under the car......dammit. Well, all questions/answer are null and void until I completely seal the cooling system. Took over two hours of sitting to release about 8-10oz of coolant. I'm hoping the clamp on the hose at the waterneck needs some tightening.
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Old 09-28-2009, 11:19 AM   #11
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Quote:
Originally Posted by Doppelgänger View Post
Alrighty, I did some driving around after the re-route yesteray. Driving around surface streets the temp gauge was 11 0'clock and up to about 12 when sitting. Well, once I git the freeway and was crusing ~3,500 rpms, the temp gauge dropped to about 1/3 up from cold...then it would go up to about 11.....then drop to 1/3 again. At one point when accelerating over 5,000rpm, the temp gauge dropped to the minimum mark on the gauge.

I can only think of two things.. airbubble in the system...or...I managed to put the t-stat in backwards. If it's air, it should burp it out in a few warm up/cool down cycles.

Thoughts?
Dude you really need to get a real gauge in there

11 o'clock on the factory gauge = 160° to 230°F
<11 o'clock = cold
>11 o'clock = ****

You need to check your hydra setup for your cooling fan. Your coolant temperature may match your cooling fan hysteresis. Might need to raise the activation temp.

If you can't maintain 190° you are running too cold and probably have extra fuel enrichment. At best, it wastes fuel and causes poor performance. At worst it removes oil from cylinder walls.
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Old 09-28-2009, 11:27 AM   #12
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where is the temp sensor in relation to the thermostat? Which reroute is this again?
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Old 09-28-2009, 12:17 PM   #13
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Custom re-route. T-stat is on spacer on back of head, temp. sensor is also on spacer right next to the hearter core feed.
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Old 09-28-2009, 12:39 PM   #14
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Quote:
Originally Posted by Doppelgänger View Post
Custom re-route. T-stat is on spacer on back of head, temp. sensor is also on spacer right next to the hearter core feed.
please confirm that the CLT is on the engine side of the thermostat.
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Old 09-28-2009, 12:53 PM   #15
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Ummm yeah...like...duh.
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Old 09-29-2009, 10:48 AM   #16
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OK, more details and information...

Last night, the radiator hose to the hard pipe popped off...interesting. Is it overheating? Hmmmm. So once I got home and lifted the front of the car up, checked all my nuts, bolts, clamps and fittings (I did manage about 1/2 turn on the two bolts holing the rear assembly in place) and refilled the coolant. This time I left the car running about about 45min to make sure it was well burped.

So this morning I charged up the lappy toppy and plugged it in to monitor themps on my way to work. Car warmed up with no problem, despite the temp gauge showing it was not nearly warmed up. Well, while driving the temps went up and down between 82*C and 87*C. I managed to find some stop-and-go traffic to sit in to see what would happen. Temps up to 90*C and the fans kicked on, temps drop to 88*C after the fans were on for less than a minute. All seems normal so far. Then I got a chance to go directly from the sitandshit traffic to romp-through-the-gears open road. A couple 1-4 pulls resulted in no change in temps... started at 87*C and went up to 89*C after acceleration and withing a minute they were back down to 85*C.

Conclusion? Temps via the Hydra seem perfectly normal even with the tamp. gauge having a mind of it's own. I did have to extend the temp gauge harness to get it to the new location. I extended each wire one by one to ensure I didn't cross any up. So i'm a little baffled as to why the ECU sees normal readings. I don't know much about the wiring, but I was under the impression that out of the three wires, one was power, one was ground and one was signal to the ECU. But now i'm starting to wonder if one is power, one is signal to the ECU and one is signal to the temp gauge.
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Old 09-29-2009, 11:08 AM   #17
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There is no power lead. The temp probe is a thermistor, aka resistor of variable resistance related to temperature. The leads are (1)to sensor ground (2) to gauge (3) to PCM. More resistance = colder. Maybe you have a bad connection on the lead to the gauge. Did you solder and shrink the extension harness?

On my car
(1) sensor ground Black/Red
(2) dash gauge Violet/White
(3) PCM Red/Blue

(1) and (3) are side by side, on the side of the connector with the harness clip
(2) has no other pin next to it

Code:
    (1) (3)
      (2)
Check your wiring, it's likely you'll find a fault there or at the main ground strip. If you find the sensor FUBAR, I probably have some extras in the garage.

Last edited by Ben; 09-29-2009 at 11:21 AM.
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Old 10-02-2009, 08:28 AM   #18
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Ah ha! Voctory is mine!

Even after I rewired the extension and made sure all wires connections were nice and tight, I was still having the issue..although the needle spent less time on "C". So thismorning before I left work, I had idea. I thought about how the spacer is now sandwiched between two gaskets..which act as insulators and maybe the sensor needs a ground. I mean, in stock forum the bolts holding the neck to the head act as grounds and with the spacer the bolts don't. So after grounding the spacer to the head, the temp. gauge worked perfectly normal on my way to work today. Finally. I win.
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Old 12-14-2009, 01:30 AM   #19
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How did you ground it? A wire with two ring terminals or something? I'll be having the same problem...
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Old 12-14-2009, 03:15 AM   #20
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Hey,Your not runnig my spacer...Cant be the same problem.
(G)
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