MEASURED HOW? WHERE? WITH WHAT TOOL(s)? At idle in the driveway, or after a 3-hour highway run?the engine temp will not get over 155 degrees. I put 3 different thermostats in it. The last one came from GM. They were all 195 degree thermostats.
Since all the cylinders are "reasonable" and all within a few percent of each other, you can pretty-much rule out compression problems.I have taken the compression test (All cylinders 128 - 135) I am running out of ideas.
Sure, I'd like the pressure numbers to be higher...but I've seen gauges that read 20 psi off from true. I'm the only person I actually know of that's ever tested the gauges of my compression testers to see how accurate they are. Altitude and cranking speed make a difference, as does cam timing. Forget the compression pressure, at least for now. I think GM official spec is 100 psi or better, and within 25% of each other.
If the engine runs, it should build temperature at least in summer.But I have tried about everything I know to get the engine temp up.....no heat in the winter months makes for cold driving. Could the injector be the culprit? Bad regulator? defective poppets?
Replace the fuel pump. The check valve has failed.The fuel pressure leaks down back to the tank. But holds when I clamped off the supply line.
I am not convinced that ANYTHING is "good" or "bad" on the cooling system until you tell me how you're verifying engine temperature.It is also not the temperature sending unit. Coolant temperature matches gauge. and I have put a new coolant temperature sensor in it also.
There's heaps of possibilities.There is only one possibility.
I had a P-O-S Honda Civic that needed cardboard in front of the radiator in the winter.try putting a sheet of cardboard in front of the radiator and see if the temp comes up while driving
I built City Buses that had "shutters" on the radiator to block air flow in cold weather.
Yup, this is valid especially as a test procedure--if the radiator air flow is blocked-off, the temperature MUST rise...or either your temperature testing method is faulty, or you've done a poor job of actually blocking the air flow. Ideally, the cardboard goes directly against the radiator--which means you're likely going to have to cut the cardboard to get it to clear the sheetmetal of the rad support/hoodlatch brackets, etc.
Agreed.I'm wondering how you verified the coolant temperature
Yup.and if you made sure you have the correct temperature sender.
Yup.one thing that I've seen for not building much heat is the fan clutch being seized and spinning at full engine RPM all the time instead of locking up only when hot.
Have you verified the temp probe/Fluke meter by dropping the probe in boiling water?I put a temp Probe with my fluke digital meter in the radiator.
Have you verified the IR Thermometer? They're notoriously inaccurate, largely because they rely on "emissivity", and different materials have different emissivity.I also tested it at the tstat neck and the heater hoses with an IR Thermometer.
Little heat, PLENTY OF AIR FLOW? Or poor air flow?they all matched the temp gauge, 155 degrees. I have little heat blowing through the vents, with heat on. But a blend door is key to heat in the vehicle, but irrelevant to engine temp.
Again...tested/verified HOW? The fact that it doesn't change summer/winter either could mean you have mild winters, or perhaps your test procedure is lacking. Does it take longer to get up to temp in the winter? How cold is "winter"?engine temp is still 155....summer and winter.
"Combustion" is a thousand degrees, more-or-less. Combustion temp has damned little do do with coolant temp. Engine load makes a difference, as does engine RPM.Frankly, I think somehow it running rich, is the problem with it not getting hot enough. (Richer mix = cooler combustion / Leaner mix = hotter combustion).
Huh? You mean you're eventually going to have a laptop computer-based scan tool? Good. Sooner is better.I am putting together a computer to check the data with to see what it looks like.
Huh? Please explain how that's possible--sooty plugs destroying the ignition module due to "back feeding".I would imagine with the soot you mentioned the plugs are sooty. You need 8 new ones before you end up back feeding the spark energy to the ICM and kill it
Fan clutches engage at approximately 170 degrees air temperature. This typically means 190+ degrees of coolant temp in the radiator. Since your engine is only running 155 degrees, the clutch should not be engaged at any time after engine startup. Is it? Does it turn freely when you shut off the 155-degree engine and give the fan a spin?
Start the engine from cold. Put your hand on the upper radiator hose. It should be cold until the engine achieves thermostat rated temperature. When the thermostat opens, the hose should get suddenly hot. Does it? If it gets hot gradually, the coolant is bypassing the thermostat. Are you buying the CORRECT thermostat? You've never mentioned a part number.
You're not drilling stupid holes in these thermostats...are you?
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