LS cooling issues

1-tonmudder

1-tonmudder

Doin my part to stir the pot.
Joined
Apr 17, 2005
Location
Greeneville TN
Ive been workin on a LS swap in my wifes 88 YJ.Finaly got it cranked tonight and it runs good but is gettin hotter than I think it should.The temp gauge only gets to about 160 and the elec fan,thats operated by the ECM,doesnt come on.The top of the rad and top rad hose is to hot to touch but the bottom hose is cool.My thinkin is that if its got air in the system it would keep the temp sensor from reading right and thats why my fan is not comin on,or the thermostat is stuck shut.I ordered a new thermostat that will be in tommorow and want to know whats the best way to bleed the coolin system when you dont have a bleeder screw?? Or is there something Im missing???
 
Leave the cap off, let it come up to operating temperature, and once it burps it should be fine. You'll see it suck a bunch of coolant down through the system and just fill it up. My truck runs at 198 degrees or so with a factory 195 thermostat. The thermostats fail to open, so they won't generally get stuck shut.

What fan harness are you running and where is the sensor for the coolant temp gauge? I'd guess it's on the driver's side head above #1 spark plug like stock.
 
And where did you connect the hose for the steam tube.
I like to install a fitting into the radiator for it but you can also get a 10 "temp gauge" adapter on ebay that splices into the upper hose and then you can put a barb in that. With it done that way its nearly impossible to get an air lock.

Buckeye Performance Inc.
828-779-2242
 
Croatan_Kid said:
What fan harness are you running and where is the sensor for the coolant temp gauge? I'd guess it's on the driver's side head above #1 spark plug like stock.
Click to expand...
Im usin a stock harness that was moded by jims perf.The temp for the ecm is in the stock location and the jeep gauge sending unit is in the back above #8.I have adapted the SAE temp probe to fit in the metric hole in the head and not much of the probe is in the coolant so that might be some of the reason for the gauge not reading correct.

novacayne75 said:
And where did you connect the hose for the steam tube.
I like to install a fitting into the radiator for it but you can also get a 10 "temp gauge" adapter on ebay that splices into the upper hose and then you can put a barb in that. With it done that way its nearly impossible to get an air lock.

Buckeye Performance Inc.
828-779-2242
Click to expand...
I "T'd" it back into the heater hose.
Hokie_YJ said:
Did you fill the block through the water pump outlet? I remember reading where several people had cooling issues like this and pulling the top hose and filling the block that way solved them.
Click to expand...
I filled the traditional way,I stayed up till about midnight last night googling it and read where that was the prefered way to fill.I also read where some had to rev the engine to get the coolant pushed thru to the TS.

My thermostat will be here after 1 today.Im gonna change it,refill the correct way,and try again.
 
I got it all worked out now.My thermostat didnt come in so I pulled the old one and took a heat gun and heated it to see if it was workin.TS opened and closed correctly so I reused it.Before I put it back in I removed the bypass in the ts and drilled the hole out a couple of drill bit sizes bigger.Put it back together and filled it by usin the top rad hose and by the time the AF had backed up in the hose the rad was about full.Put the hose back on and started it up and its working right,the fan cycles on and off like it should but the temp gauge doesnt read above 160 so Im gonna have to address that.
 
I'm thinking you're right about it sticking out a little and not reading right. I did the same thing with the Cummins engine you sold me way back when and got a 3/4 NPT adapter to get the temp probe to fit and it never reads above about 175 in the dead of summer, even though I know it's up to operating temperature.

I'm sure you can get a metric threaded sensor.
 
I like it :huggy: I'd think that would solve your problem.
 
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