Jason248

So this morning i woke up and was going to put the temp sending unit (just installed cluster with guades rather than lights ) in and then swap my leaf springs.

after i installed the s/u i started it and watched the guage work like a charm, the issue came when the temp got right up to the red line...

ive changed the thermostat, radiator cap and upper radiator hose because i found a leak.

i dont know what to do next, i see no leaks.

any ideas?


PS- i apologise if this reads out funny but im posting on my cell phone...


-Jason

BuckB91XJ

Sounds like the T-stat might be stuck shut. Sometimes they are bad new off the shelf.

(Eckks-Jay)

Is the fan clutch working?

Jason248

i believe the tstat is working because i left the cap off and started it and once it hit like 205 it seemed that it opened and coolant flowed into the adiator and it overflowed the radiator and i shut it down.


i dont know hot to check the fan clutch. all i know is that when the engine is on its moving

Mike1998XJ

Run it with the cap off again but have someone hold the throttle at 1500-2000 rpms. The coolant won't overflow and you can keep adding to it.

Jason248

unfortunatly i dont have anyone that can help me out right now

Mike1998XJ

Stick a piece of wood under the throttle on the intake manifold that will hold the rev's up.

Jason248

I did what you said, and was able to get about another half gallon in, but it still holds at like 240 - 250 and just stays there, i can feel the difference in the upper radiator hose ( heat ) when the thermostat opens. Im starting to wonder if its a bad pump but it doesnt seem to be leaking out of the bottom of it and im not hearing the bearings scream.

Im definitely confused

Mike1998XJ

OK, so now we know you have enough coolant in the system.
The fact that you were able to add coolant might make this irrelevant but just for kicks...
Did you know that the thermostats can be installed backwards. Could it be that?
As the engine temp hits 195-210 does the top radiator hose heat up? (OOPS, I guess you said it does)
Does the hose start to pulsate as the thermostat opens in this temp range. If not the thermostat is sticking closed.
Do you have a friend who has an IR gauge or multi-meter with a temp probe? If so, measure the temp on the thermostat housing as the engine heats up. See if that number is close to the number on the new gauge you installed.
So when it "overheats" (assuming the gauge is working correctly) it is when you are parked at idle correct? And the mechanical fan is running all the time right?
When you worked on the engine did you flush the system with a hose? Flushed in both directions? Did you also flush through the heater hoses by taking them off? Flush through the long hose first.
When you filled the system did you have the heater on hot and the fan on high? If not remove the cap crank the heater on and see if you can add more coolant while revving the motor again.
Also, did you flush the radiator in both directions while you had it apart? I can't rember if you said you put in a new radiator or not...
Answer these questions and perform these tests and if you don't hit the nail on the head we will at least be closer by process of elimination.
One last question... was it overheating before you did all this work?
Mike

Jason248

im about to flush the system within the hour, and put in fresh coolant, the thermostat was installed correctly, but ill be taking it out to flush the system regardless. I will be flushing the radiator as well. i dont have an IR guage or a meter a temp guage, so i was thinking about just leaving the cap off and sticking a thermometer in there and seeing what the temp is as it warms up. sound cool?

Also i assume it was overheating before hand, but again before i had a cluster with only a light, which never turned on. all i did is one morning swap out the cluster and temp sender, and temp sensor. start it up and watch it go up to 240-250 ish.


again thankyou for all the help so far

Mike1998XJ

So when you change from a light to a gauge do you have to change the sender on the back of the head? Are these the same? Your locale parts store could tell you if the part numbers are the same. If they aren't maybe the gauge isn't getting the correct input?
Just thinking out loud.
Why don't you google "engine coolant flush" before you do it. I bet you find a few things that might have been left out here.
Mike

Jason248

yeah the two parts are different, you can look it up on advanceautoparts.com and it shows the two different ones, i tried leaving the old one in and no dice, didnt work. so i installed the one thats listed as ( with guage ) and its working now, as for the coolant flush, i called a guy i know whos a shop formen and he said to do it the old fashioned way and flush it with a hose, run water through the engine and let it poor out, and run water through the radiator and let it poor out. So im giving that a shot right now.

Mike1998XJ

Yep, and do it in both directions on the block. the radiator and the heater hoses feeding the cabin heater. When you flush the heater flush from the longer hose first then alternate.
Good Luck
Mike

claygrassmann

did you try burping the system?

Jason248

well i have it parked at work, and have only been working on it when ive had time unfortunatly, but today is when i get to give it a shot.

i usually just run it with the cap off and squeee the upper hose to burp it.

what is the best way?