Good morning. Last wekend in installed my l92 headed lq9 in my 87 regal. After getting running, i noticed that the coolant temp is sitting rught around 204 at an idle. Rasie the idle to 11 1200 rpm and it dropps to about 185. It has two ram charger cooling fans that work properly. I have the cylinder head bleeders hooked to the radiator,but i notived on the factory trucks that there is is a bleed on the rad to the pressurised overflow bottle and the foward wp outlet hose is also connected to the pressurised bottle. I cant drive yet due to an error with the drive shaft. Anyone else have this prob? I haf to fill the block thru the upper rad hose neck.no matter how long it sits and idles it dosent go above 206 degrees. Do i need to be worried?

 

Sounds like the temp sensor isn't fully contacting fluid until RPM causes full contact (air pockets). Have you run the engine up to temp @ least twice & then added fluid each time after engine completely cools?

We usually fill, run for just a couple minutes (not up to temp), then shut down for 20 minutes or so. Fill radiator & half fill overflow tank. Second time start, run up temp, shut down to complete cool down, then fill any missing fluid in radiator & overflow tank. After third start & fill, no more fluid should be needed.

 

These cars run 230 ish stock with the AC running. 205 is way way normal and even doing good depending on how you look at it. Proof? Fans don't even come on in a stock tune until 220+ degrees.

 

Do I need to add the bypass like the factory has with the bottle and the rad bleeds?yes I have heat cycled the motor a few times and added coolant on each cooldown. Interesting though is that I have a dakota digital set up and the sensor is in the rr cylinder head and it reads 40 degrees cooler than the computer temp reading. Coolant temp sensor for computer is new also,no change.

 

My reply was relative to the fact that there was a drop in temp w/ just 2-300 RPM increase/no fans. Makes no sense for temp to drop unless there are air pockets or engine hasn't yet been brought up to operating temp. Reply had nothing to do w/ what temp is normal for stock LS engine. Would have been good to know that you heat cycled & filled.

As long as front steam vent on heads goes to a high spot within the coolant circuit, it's OK.

 

in my first post i said the temp dont move off 206 degrees there by saying it has been up to operating temp. the bleed from the cyl heads goes to roughly to the same spot it would where it would be on a stock truck,mid way down on the pass tank. thinking of trying to use a bypass like the factory does from the rad to the larger heater core hose without the pressurized bottle like the factory does cuz it seems that there is no coolant movement with out these bypass ports. anybody else try this?