Need brainpower!!

[scotv]

Hello new to this forum but not new to wrenching. Got a heating problem on a 94 Yukon 230000 miles. New radiator, new heater core new temp switch, new temp sender, new 195 termostat. The problem is motor will not get to operating temp ever. I have even blocked the radiator with cardboard. Thermometer shows water temp at 150 after 10 mile drive.( removed t-stat housing, stuck thermometer in intake) What do I need to do???

 

[Jounier11]

so you are saying that?? your truck overheats or does not get hot enough my truck gets 135F and that's it not hotter at all.

 

[scotv]

The truck will NOT get up to operating temrerature,195 degree t-stat, been thru 5 different t stats with no change. Only time the gauge goes up into operating temp is around 3000 rpm.

 

[lesterl]

Try a different brand of stat, you keep getting crap stats...... You do have the belt routed right?

 

[scotv]

After 5 t-stats from 5 different parts suppliers, I dont think the stats are all bad??? It has been suggested that I use genuine AC Delco t-stat Dealer didnt have one in stock waiting on # 6 stat to come in.

 

[lesterl]

I have had good luck with Stant Superstats from advance auto parts. that being said my last few other ones had weak springs and the stant spring was really stiff.....

Did you get a failsafe stat?

Put it in the right way?

Is your upper hose getting crumbly on the inside?

With the old one out does it appear to seal good? Hows the spring pressure?

 

[Tufong]

Mixture of antifreeze to water is wrong go get a Mickey Mouse tester for the right mix mine didn't get over 125 in winter but ran norm in summer

 

[SouthJerseyTahoe]

You probably have air in the system. An airlock condition will cause underheating and overheating at the same time in different parts of the system. When its cool, drain the entire system, disconnect the upper radiator hose and fill it SLOWLY through the radiator. Works even better if you fill the engine without the thermostat. Old tech trick is to wedge aspirins under the thermostat to hold it open when you fill it and they dissolve as it heats up. It helps to jack up the front of the truck too but I dont find it necessary.