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-   -   Should I be able to see coolant moving? (http://www.jeepforum.com/forum/f8/should-i-able-see-coolant-moving-1520281/)

Turtle71 05-07-2013 08:49 PM

Should I be able to see coolant moving?
 
I noticed recently, that my temp gauge is creeping closer to the H than it ever has. That being said, this is probably the warmest weather I have driven it in since getting it on the road. Still feeling uncomfortable with the gauge reading I decided to change the thermostat. Ran it without radiator cap to burp it and did not see any "flow" when looking in the radiator. Temp gauge went really close to the H again so I decided to shut it off. Should I be seeing movement of the coolant?

Turtle71 05-07-2013 08:58 PM

Here is a pic I took while stopped at a light. It does get slightly closer to the H than this pic shows. Like towards the end of the green line.
http://i1233.photobucket.com/albums/...ps5465abd7.jpg

DYontheForum 05-07-2013 09:00 PM

Quote:

Originally Posted by Turtle71 (Post 15403648)
Here is a pic I took while stopped at a light. It does get slightly closer to the H than this pic shows. Like towards the end of the green line.
http://i1233.photobucket.com/albums/...ps5465abd7.jpg

You're almost outta gas!

Turtle71 05-07-2013 09:24 PM

:pThats the only gauge that doesnt work. I replaced the sending unit and float but it seems to be something else. Will have to track that down later though.

Anyone know if I should be seeing the coolant move when looking inside the radiator?

Jack61 05-07-2013 09:38 PM

If you still have the stock radiator with the cap in the middle then yes you should see some coolant movement once the thermostat starts to open.

VooDoo2 05-07-2013 09:49 PM

Replace the thermostat. Problem fixed.

Turtle71 05-07-2013 10:03 PM

Quote:

Originally Posted by Jack61
If you still have the stock radiator with the cap in the middle then yes you should see some coolant movement once the thermostat starts to open.

Mine has the cap on the drivers side. I believe the earlier models had it in the center.

Turtle71 05-07-2013 10:04 PM

Quote:

Originally Posted by VooDoo2
Replace the thermostat. Problem fixed.

Not sure if you caught it in my first post but I just replaced the thermostat. Are you saying that the new one is bad?

VooDoo2 05-08-2013 12:19 AM

Missed it BUT did you test it in some hot water? Ive had one fail right out of the box before due to swarf/rust on the shaft. Ive also seen mechanic's put them in upside down and they wont open. Check for an airlock too. If all else fails remove the top pipe and make sure water is pumping out. Could be a blocked radiator, bad waterpump. In AU we generally wont run them as it doesnt get that cold here to need it.

jeepdaddy2000 05-08-2013 04:37 AM

First thing you will want to do is check the actual coolant temp. You can do this either with a candy thermometer or with an IR gun.
If the coolant is too hot, then you need to look at the thermostat (bad or backwards), radiator (plugged or blocked) hoses (lower collapsed), bad radiator cap (won't hold pressure), or you may need a shroud.
If the temp is good, then you have a problem with the gauge or sending unit.

Matt1981CJ7 05-08-2013 05:23 AM

It could also be tuning causing abnormally high combustion temps, like a lean mixture, or too little advance, etc....

If you haven't tried it, yet, connect manifold vac to your distributer. It will make the idle noticeably cooler.

Matt

Turtle71 05-08-2013 07:36 AM

Thanks for the tips guys!:tea: I will test out your suggestions when I get a chance. Im also going to try and check the sending unit. Any additional ideas are appreciated so keep them coming.

Turtle71 05-08-2013 09:19 AM

I havent been able to try the other things yet, but I did a quick test on the sending unit. I read on another thread to do this. I removed the wire going to the sending unit and touched it to a ground. This made the temp gauge peg out on the hot side. Does this mean the sending unit is bad, or is it functioning properly?:confused:

SLO_Ken 05-08-2013 10:07 AM

Quote:

Originally Posted by Turtle71 (Post 15405508)
I havent been able to try the other things yet, but I did a quick test on the sending unit. I read on another thread to do this. I removed the wire going to the sending unit and touched it to a ground. This made the temp gauge peg out on the hot side. Does this mean the sending unit is bad, or is it functioning properly?:confused:

That tells you that the gauge is working properly. The sending unit is basically a variable resistor that changes its resistance based on temperature. Higher temp = lower resistance.

The following link is courtesy of John Strenk
http://home.roadrunner.com/~john.str...eQuickTest.htm
Check out tests 6 and 8.

Turtle71 05-08-2013 11:15 AM

Quote:

Originally Posted by SLO_Ken (Post 15405722)
That tells you that the gauge is working properly. The sending unit is basically a variable resistor that changes its resistance based on temperature. Higher temp = lower resistance.

The following link is courtesy of John Strenk
http://home.roadrunner.com/~john.str...eQuickTest.htm
Check out tests 6 and 8.

Ah, gotcha. Thanks. I will have to get a hold of a voltmeter and test the sender next.

On a side note. I checked the previous thermostat that I changed out by heating it in a pot of water. It said 160 on the back so I assume its a 160 degree thermostat (I replaced with a 195). Sure enough it started opening right before the thermometer I was using got to 160.

So far that shows that the gauge and the thermostat are not causing this. Sending unit test is up next.


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