no heat

[falconmanconvert]

my 09 tahoe heat guage only climbs to about 175. the dealer replaced thermostat but that didnt help. he also said it had a air bubble in it. where do I go from here?

 

[MO Viet Vet]

Does sound like an air bubble and the dealer was paid to refill after the thermostat so they need to fix it.

 

[falconmanconvert]

dealer claims he got the air out but it seems like it is back, so I wonder where can the air be coming from?

 

[MO Viet Vet]

I call bull$hit. Make them look at it again and tell you how it creates air in the system.

 

[bladenbullet]

tell them to make sure your gauge is reading correctly....a thermostat isn't the answer to everything and may not have been the problem to begin with...air isn't that hard to remove from a cooling system...and I doubt 2 thermostats would leave you reading the same temp either way....

 

[falconmanconvert]

the tahoe is going back to the shop on friday,i told them to pressure test the cooling system and test the cap,also told them to test the coolant for exhaust gases, i am concerned about a head gasket, i just bought this 2 weeks ago so the dealer is getting the bill

 

[bladenbullet]

did the dealer you bought it from agree to you bringing it to someone else for the repairs?..

the cap wont affect temperature....only boiling point of the coolant...

 

[falconmanconvert]

same dealer,different location, the service manager told me abad cap will also reduce the temp of coolant when outside temp is coldbut i swaped caps with my 2006 1500hd and nothing changed in either vehichle

 

[bladenbullet]

well that's an interesting theory....the cap allows the system to build pressure in order to prevent boiling....every pound of pressure raises the boiling point 3*F (15# = 45* increase in boiling point along with the minor addition of a few degrees with coolant)...the pressure is the result of heat and expansion...

the actual coolant temp needs to be compared to the gauge reading to confirm proper gauge operation before they play anymore...

I know you titled with "no heat"...are you actually getting poor heater output or just commenting on the gauge reading?...

 

[rockenthebowtie]

I agree with bladenbullet have compare scan tool CTS data to IPC gauge reading.. also have the preform a sweep test on the gauges of the IPC with the scan tool to see if it may be hanging up causing a false reading

 

[falconmanconvert]

well I took it in friday, they idled it in the shop for half an hour gauge went to 210 ,so I climbed in and we test drove it the temp fell to 165 and stayed there then they replaced the thermostat again, same result,now they think it has an after market radiator that doesnt have the restrictor in the side tank allowing the coolant to flow through to fast he said gm has a service bulletin out about aftermarket radiators, by the way my temp gauge is off but itsrunning cooler not warmer

 

[rockenthebowtie]

Sorry the part about the temp gauge, I'm not sure if I understand.. the temp gauge is showing a lower or higher temperature then actual ECT. ?

 

[falconmanconvert]

temp gauge is showing higher than actual so my problem is worse than I thought

 

[bladenbullet]

I think we're all getting a bit confused here...if the thermostat is new and presumably closing below its prescribed temperature then the engine should be able to maintain that temperature unless it has magically found a way to make combustion without heat or dissipate heat in the absence of a cooling system circulating in the radiator...regardless of the radiator size or equipment...

when you say the gauge is showing higher than actual temp how is that being determined?....what is the gauge showing?...what is the actual?

please feel free to embellish like crazy....it feels like we're only getting partial information here....

 

[rockenthebowtie]

Ok got it, i that case remove the surge tank hose from the radiator and visually inspect the radiator tank nipple that feeds the surge tank. If the radiator is missing the surge tank restriction orifice there will be an increased amount of coolant flow to the surge tank. Excessive coolant flow may induce low ect temperature and may even set a dtc P0128 ECT BELOW THERMOSTAT REGULATING TEMPERATURE

If the radiator surge tank restriction is missing, the radiator needs to be replaced with the proper replacement radiator

 

[bladenbullet]

wow....ya learn something new every day....

would it be possible to add a restriction in the hose or nipple to avoid a replacement radiator?...

 

[falconmanconvert]

sorry for confusing everyone,but its hard not to when i am myself. as for the temp readings, the computer in the tahoe was reading 10 to 15 degrees colder than the gauge, the service mgr. didnt think it could be fixed by restricting the hose to the expansion tank

 

[bladenbullet]

need to get an actual coolant temperature reading to know which sender is readign the correct temperature....then correct the differential in readings....then work on correcting the temperature problem if it actually exists....

 

[falconmanconvert]

brought it back from the shop last night and the temp gauge read 210 so the new radiator did the trick

 

[MO Viet Vet]

Ok got it, i that case remove the surge tank hose from the radiator and visually inspect the radiator tank nipple that feeds the surge tank. If the radiator is missing the surge tank restriction orifice there will be an increased amount of coolant flow to the surge tank. Excessive coolant flow may induce low ect temperature and may even set a dtc P0128 ECT BELOW THERMOSTAT REGULATING TEMPERATURE

If the radiator surge tank restriction is missing, the radiator needs to be replaced with the proper replacement radiator

Nice job. Had never heard of this. Assuming gets ya in trouble. Really, though ElGuapo, that was a great call. eace: