Is my thermostat not working?

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Joined
Apr 22, 2007
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163
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Location
Carpinteria, CA
Hey all,
I finished putting my engine back together about two weeks ago and I am still trying to work out a couple of the bugs. I always keep an eye on the temp gauge because im paranoid of
overheating. All seemed great, the temp hovers around 1/4 to half on the gauge. I have noticed that recently it stays on or sometimes a little below the cold mark occasionally
making its way up to just below the 1/4 mark. I have to believe that it is getting hotter then this right? I am driving at normal speeds in 75 degree weather. At first I thought maybe the
temp sensor was bad but it seems to work a little bit. I did replace the t-stat and all of the coolant hoses while I had it apart. I checked for a good connection at the plug as well. Any
ideas? I just ran it for a while and the rad. hose to the t-stat doesnt seem to be pressurizing. Also the idle seems to stay high for a lot longer than normal. Are these indications that the thermostat is not functioning? Has this happened to anyone here before? Thanks againfor the help. Oh yeah, 88 62.
Thanks,
Paul
 
did you replace the "o" ring in the top of the thermostat housing?
 
and even if you did it might have gotten buggered up, I have done this myself....

did you replace the "o" ring in the top of the thermostat housing?
 
yeah its got a new rubber oring gasket. It seems as though the t-stat might be working. I drove it to work this morning and when I got there I checked to see if there was pressure in the hose between the t-stat and the radiator and it was pressurized. Does that mean that the t-stat is working? Should I be focusing my attention more on the temp sensor. I guess that it wouldnt hurt to replace the temp sensor anyway. Does anyone know if the temp sensor tells the TPS to idle down after its warm? It seems as though it idles high for a longer period of time then usual. I am at work for another two days so I am unable to do any major work to try to figure it out. I will see what you all think and go from there.
Thanks again,
Paul
 
Classic temp gauge not working....go after market

Edit...I take that back......check the sensor...when I had mine reading low it was that.....when they read high (with the gas gauge moving around also) it is the Gauge.

Also did you burp the system?
 
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Im not exactly sure how to "burp" it. I have searched and I came up with a couple of posts that I started to read but got interupted with the duties of my job. I took off the top heater hose and tried topping it off from there but it was full. This is after I ran the rear heater until the air was hot. I also parked with the front PS on an incline to get the rad cap to be the high point and the coolant seemed to be all the way to the top there as well. I will continue to search for "burping the cooling system" unless someone has a good link handy they could throw my way. I think im still a little unsure how the TPS knows when to kick the idle down after it warms up. I will keep trouble shooting as time permits.
Thanks,
Paul
 
Im not exactly sure how to "burp" it. I have searched and I came up with a couple of posts that I started to read but got interupted with the duties of my job. I took off the top heater hose and tried topping it off from there but it was full. This is after I ran the rear heater until the air was hot. I also parked with the front PS on an incline to get the rad cap to be the high point and the coolant seemed to be all the way to the top there as well. I will continue to search for "burping the cooling system" unless someone has a good link handy they could throw my way. I think im still a little unsure how the TPS knows when to kick the idle down after it warms up. I will keep trouble shooting as time permits.
Thanks,
Paul
DAnimal has the setup...let me shoot him a pm

Have you checked for any codes yet?
 
I will check it with the FSM on tuesday when I get home.
Thanks,
Paul
 
Did you turn your rear heater on as well? The 60 has it mounted under the passenger front seat and the 62 has it mounted under the armrest. They have seperate pipes going to them from the firewall and can hold alot of air.

Do the same thing you did before with the heater on but also turn your rear heaters on.
 
DAnimal has the setup...let me shoot him a pm

Have you checked for any codes yet?

I dont have a code reader so im not sure if there are any codes.

Did you turn your rear heater on as well? The 60 has it mounted under the passenger front seat and the 62 has it mounted under the armrest. They have seperate pipes going to them from the firewall and can hold alot of air.

Do the same thing you did before with the heater on but also turn your rear heaters on.

Last night I turned the rear heater on and ran it for a while. then I popped off the top heater hose and it was full of coolant. Do I need to have the rad cap off?
 
Im not exactly sure how to "burp" it. I have searched and I came up with a couple of posts that I started to read but got interupted with the duties of my job. I took off the top heater hose and tried topping it off from there but it was full. This is after I ran the rear heater until the air was hot. I also parked with the front PS on an incline to get the rad cap to be the high point and the coolant seemed to be all the way to the top there as well. I will continue to search for "burping the cooling system" unless someone has a good link handy they could throw my way. I think im still a little unsure how the TPS knows when to kick the idle down after it warms up. I will keep trouble shooting as time permits.
Thanks,
Paul

Should just be able to run with the rad cap off and the heater selector all the way hot, let it run up to operating temp and add coolant if it goes down, let it cool with cap off and make sure it is topped off before putting cap back on.
:cheers:
Edit : And the rear heater on also
 
I dont have a code reader so im not sure if there are any codes.



Last night I turned the rear heater on and ran it for a while. then I popped off the top heater hose and it was full of coolant. Do I need to have the rad cap off?

You do not need a code reader...check your fsm..it will tell you how.....5 minutes is all it takes:grinpimp:
 
The way I "burped" the coolant system. Both heaters turned to hot, heater fans on. Radiator cap off, system full of coolant / water mix. Run engine unitl thermostat cycles and you have hot air at both heaters, continue to run engine and top off coolant / water mix. Make sure temp stablizes... Best to let truck run a while like this...20+ min. Top off coolant overflow bottle. Install radiator cap and go drive truck for 20 min or so giving it plenty of gas....go up hills, go down hills... plenty of throttle. Monitor temp guage. You keep the heaters going while driving.... Come home, let truck cool off and then check coolant. Do not open radiator cap with warm or hot engine.

LC has two heaters, plus plenty of hard line and soft heater hoses...... easy to get air in the system.
 

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