The 95 has two sensors. A one wire sensor, to the passenger side of the thermo housing, that is for the gauge, and that's all it does. The one on the drivers side of the thermo housing should be a two wire, and that is the one the PCM pays attention to. PCM doesn't care about the single wire sensor. It has no idea what its doing.

 

Ok, issue seesm to be diagnosing itself.. Temp sensor will not effect flow.. Only temp
reading for pcm and/or guage. Flow is Flow !! what is temp diff between upper and lower hose?? T-stat will not go in upside down!! So if water pump is new (and plastic empellor is not cracked on spline, as i am sure you inspected that, and t-stat is new).. Sounds like a restricted radiator to me ..!! Flow is Flow ..

 

Plastic? I wouldn't run one with plastic...but that's just me. Too much opportunity for failure.

 

I thought it was the IAT, but long story short it turned out that when I rebuilt the engine neither I nor the machine shop thought to deck the heads or the block. This resulted in the head gasket giving way only when the engine was under low, moving maybe 2mm or so, but enough to cause blow-by. I finally found a radiator shop that could perform a carbon test on the coolant, and sure enough there were burnt hydrocarbons in the coolant.

I'm thinking if the OP doesn't have any coolant flow that there's a blockage in his system. It could be in the radiator, the block, or both.

 

I wonder about the fan clutch now. the fan may spin, but maybe it is not fully engaging, thus not spinning fast enough to cool it off & yes, check that a garden hose can spray thru the radiator fins all over unrestricted. Mine was time consuming to burp all the air out also. Does the upper radiator hose get too hot & full of pressure to squeeze with 1 finger & thumb when it over heats? If not, there is definitely a flow issue in the coolant system. If I am too cheap to buy a fail safe thermostat, I usually drill 3 5/32 holes around the flat part to allow SOME coolant to flow in the event of a meltdown. if your fan clutch is bad, this may be a great time to upgrade to electric fans. I used 2 from an old bonneville I had & it runs SUPER cool all the time. The fans barely have to come on at all. I think after that giant shroud was removed, there was instantly more air flow around the engine anyway, but I have a V6 so my shroud took up nearly 3 feet deep of space under the hood. Now I have TONS of room to stand in the engine bay to do stuff.

 

Guys,

I replaced the coolant temp sensor also, but no difference. The fan is spinning the right direction and the coolant is moving in the system, prior to the thermostat, just not after. Ran it to something nearing 225 degrees and no action. I guess I will pull the tstat and test it in a pot of water. Any other ideas, please send along.

 

Peshewa,

Thanks for the info. The issue I am having is that the upper hose is not pressurizing at all, nor heating up. I just put in a new tstat (stock), but forgot to test it first. I checked the flow across the fins with the hose and it looked good.

If you know where, off the top of your head, I can get a failsafe tstat, I would appreciate it.

 

Have a helper start the vehicle to idle the engine. Tell said helper to kill the engine, at which time observe how the fan reacts when the engine comes to a stop. The fan should immediately stop with the engine. Should the fan continue to rotate after the engine has ceased rotating, replace the fan.

 

Flow is Flow - I hear that. I had clean coolant at the tstat when I replaced it and I had clean coolant bubbling out of the sensor hole when I replaced that. I will check the fan clutch tonight and will likely put in a failsafe tstat tonight as well.

Incidentally, the pump had a metal impeller. I hand spun it when I pulled the tstat and there was movement in the coolant, indicating the pump was operating.

Lastly, I had not issue filling the radiator. Will update Monday with new tstat.

To the sensors, the passenger side one was a two prong as was the one on the driver side. Threw the parts store guys for a loop for a while, but got it finally.

 

Don't bother with the failsafe state. They are pretty much guaranteed to fail....... even under normal conditions. Your conditions are not exactly normal.....

You really need to check your radiator for blockage. Just because you see some flow there, doesn't imply that it isn't a problem...... need to check it with something like an IR thermometer, and see if the temp various dramatically from spot to spot. The 17 degree difference in temp between inlet, and outlet, suggest to me that your radiator is being woefully inefficient.