Ha! Yea I have been around for awhile.
Overheating after 10 minute drive
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Correct
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Cold hoses tells me the system has air in it, or the water pump is not circulating. Do the heater hoses not warm up? I second 95wagon's recommendation to remove the water pump cover and try to spin the impeller by hand. Make sure it's tight and does not spin.
One easy test is to pull the radiator hoses, then use a garden hose and try to push water through the radiator. If it doesn't flow, there's your problem. The 1996 cars were very prone to clogging due to the stopleak GM put in them.
One easy test is to pull the radiator hoses, then use a garden hose and try to push water through the radiator. If it doesn't flow, there's your problem. The 1996 cars were very prone to clogging due to the stopleak GM put in them.
What is
I will check the shaft later today.
Thank you
Robin
What is this Stop Leak that GM put in?
I will check the shaft later today.
Thank you
Robin
Ditto all this.
And, since you have to drain the system again anyway, consider junking the radiator and hoses as well. (rads clog, hoses deteriorate, heater hose plastic tee fails with time, flow restrictor in the heater inlet line can clog). Better all new plumbing at one go than only partial,or you're just waiting for the next failure. And flush like crazy, preferably with knock sensors removed (i admit i have failed at this step). 3 decades of sediment and goo.
PS cool license plate!
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OP has already paid a shop to replace waterpump, thermostat, coolent, and heater core..Before disassembling anything and voiding any type of warranty..take it back to them and see what they say?
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Assumtion The car was not overheating prior to waterpump, thermostat, and flush..Just blocked heater core..
Seems most people (as well as I) believe that all these GM products was/is caused by the "improved" new dexacool antifreeze and previously leak stop put in on the assembly line...Turns coolant into Alabama red Mud after 5ish years..
Only two items I have found that cuts it loose at all..Best is Thermo cure by evapo-rust and a few days of driving..Man it stinks!! And 5 to 10 flushes to get most of the junk out. (Red clay)..of course it can't be freezing outside...
In eight minutes, the little 3/8 line to coolent tank, one of the heater hose is no longer comfortable to hold IR gun say 141 degrees, same as water pump.
After 10 min, thermostat open, scan gauge says 190...driverside radiator tank reads 160, same for one heater core, same as 3/8 coolent line...Passenger tank around 110...(note, this is outer surface of lines/tank with ir gun)..above 140 degrees it is uncomfortable to hold.
One can not see the waterpump drive coupling, nor impeller without voiding warranty.
I think you have no water pump flow...drive coupler, no/slipping impeller..
Blockage or stuck thermostat would not stop all flow...take it back to the shop that I'm sure you paid good money too..My two cents..kev
Seems most people (as well as I) believe that all these GM products was/is caused by the "improved" new dexacool antifreeze and previously leak stop put in on the assembly line...Turns coolant into Alabama red Mud after 5ish years..
Only two items I have found that cuts it loose at all..Best is Thermo cure by evapo-rust and a few days of driving..Man it stinks!! And 5 to 10 flushes to get most of the junk out. (Red clay)..of course it can't be freezing outside...
In eight minutes, the little 3/8 line to coolent tank, one of the heater hose is no longer comfortable to hold IR gun say 141 degrees, same as water pump.
After 10 min, thermostat open, scan gauge says 190...driverside radiator tank reads 160, same for one heater core, same as 3/8 coolent line...Passenger tank around 110...(note, this is outer surface of lines/tank with ir gun)..above 140 degrees it is uncomfortable to hold.
One can not see the waterpump drive coupling, nor impeller without voiding warranty.
I think you have no water pump flow...drive coupler, no/slipping impeller..
Blockage or stuck thermostat would not stop all flow...take it back to the shop that I'm sure you paid good money too..My two cents..kev
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Not sure how the gauge would go back down with no water pump flow.
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..How about sliping impeller?
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Maybe. That's possible.
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That why we share thoughts!!...Nobody is perfect..(I'm close, ...that is a lie..lol)..blocked coolent thru radiator is the normal cause for that Scenario or fan...I just have to go off what he said..
Drove a 69 400 firebird convertable 900miles with semi block radiator and heater running full blast in the summer..But he has no heat also.
Drove 1969 427 vette for 450 miles with locked up clutch fan removed. Good except stop and go in Montgomery...
Can only go on what is told.
Drove a 69 400 firebird convertable 900miles with semi block radiator and heater running full blast in the summer..But he has no heat also.
Drove 1969 427 vette for 450 miles with locked up clutch fan removed. Good except stop and go in Montgomery...
Can only go on what is told.
Does the coolant always flow through the heater core, regardless of the interior heater being on or off?
After the thermostat opens, does the coolant then flow through the rad and heater core?
Is it true that this motor flows in an opposite direction then most? Someone mentioned this to me.
The car overheated on a lengthy highway run, that's what started all of this. I wasn't driving, so I don't actually know what happened. The gauge is certainly an issue through this investigation, as well as sufficient flow through the rad.
My next steps are;
To get the rad pressure and flow tested
Replace the temp sender and temp sensor
After the thermostat opens, does the coolant then flow through the rad and heater core?
Is it true that this motor flows in an opposite direction then most? Someone mentioned this to me.
The car overheated on a lengthy highway run, that's what started all of this. I wasn't driving, so I don't actually know what happened. The gauge is certainly an issue through this investigation, as well as sufficient flow through the rad.
My next steps are;
To get the rad pressure and flow tested
Replace the temp sender and temp sensor
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Take off the radiator cap and make sure the coolant is moving through the radiator. Make sure you warm the car up first, or else take the thermostat out.
Hey Nosirrah, I would start with basic's...
Your heater core will heat up before thermostat opens, that is why you have heat fast.
After the stat open, water flows thru radiator.
the 2nd gen LT1 is reverse flow thru heads first to aid in cooling of combustion chamber because of higher compression ratio.
1. verify stat is opening, don’t care if new. (Pull stat and boil on stove to see if opens and closes)
2. make sure water flow thru engine and heater circuit.
3. you can test resistance on temp sensor based on water temperature
4. With the engine running, the bleeder screw will be pushing water out of small hole, a good stream of water.
5. there is a heater hose restrictor in the middle of the heater hoses, just below your alternator attached to fender. Check to see if plugged.
6. If you have IR heat gun or FLIR to check heat thru engine and cooling system.
7. Its hard to tell if water pump drive coupler is stripped, or broke visually, but you will not have water flow. Which would mean pulling water pump.
8. If truly overheating, clogged radiator, unless you know it has been changed.
Your heater core will heat up before thermostat opens, that is why you have heat fast.
After the stat open, water flows thru radiator.
the 2nd gen LT1 is reverse flow thru heads first to aid in cooling of combustion chamber because of higher compression ratio.
1. verify stat is opening, don’t care if new. (Pull stat and boil on stove to see if opens and closes)
2. make sure water flow thru engine and heater circuit.
3. you can test resistance on temp sensor based on water temperature
4. With the engine running, the bleeder screw will be pushing water out of small hole, a good stream of water.
5. there is a heater hose restrictor in the middle of the heater hoses, just below your alternator attached to fender. Check to see if plugged.
6. If you have IR heat gun or FLIR to check heat thru engine and cooling system.
7. Its hard to tell if water pump drive coupler is stripped, or broke visually, but you will not have water flow. Which would mean pulling water pump.
8. If truly overheating, clogged radiator, unless you know it has been changed.
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Other tips...
Some premium thermostats come with a tiny pre-drilled hole to bleed the air. Fancier ones have a brass ball in the hole to allow more air than water to pass.
This is a "Hypertech" brand made for the LT1. Look carefully at the brass "bead" at the 11 o'clock position. It's actually loose and allows air to pass easily.
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When I replace a thermostat on any older V8, I always, either buy one with a bleed hole or drill one. 1/16" drill bit is enough. I learned this lesson early in life wrenching. And works great to make sure the LT1 bleeds all air. The brass bead isn't necessary. But that marks that you would drill the hole in that ring.
I'm really leaning toward a thermostat issue here. I had one fail 1/4-open which causes all kinds of weird symptoms. Overheating on long drives but the fans catch up while idling.
Lack of heat is weird though, I think I still had heat with the thermostat issue, so that could be another unrelated problem. For example, maybe the restrictor failed internally. That plastic is really brittle and can fail in a clogged state.
Some premium thermostats come with a tiny pre-drilled hole to bleed the air. Fancier ones have a brass ball in the hole to allow more air than water to pass.
This is a "Hypertech" brand made for the LT1. Look carefully at the brass "bead" at the 11 o'clock position. It's actually loose and allows air to pass easily.
When I replace a thermostat on any older V8, I always, either buy one with a bleed hole or drill one. 1/16" drill bit is enough. I learned this lesson early in life wrenching. And works great to make sure the LT1 bleeds all air. The brass bead isn't necessary. But that marks that you would drill the hole in that ring.
I'm really leaning toward a thermostat issue here. I had one fail 1/4-open which causes all kinds of weird symptoms. Overheating on long drives but the fans catch up while idling.
Lack of heat is weird though, I think I still had heat with the thermostat issue, so that could be another unrelated problem. For example, maybe the restrictor failed internally. That plastic is really brittle and can fail in a clogged state.
Mentioned no heat at the beginning, so thermostat stuck open is the thought. From what I am reading items changed water pump, thermostat, heater core and then before or after system flush. Someone mentioned pulling rad cap off, well if true Impala those don't have a cap on the rad, tank only at least mine doesn't so really can't check flow that way. Two things come to mind, the replacement pump could have the wrong impeller installed yah never know, and if a shop did the work possible rag or paper towel ('s) could have been left. Yes, yes that could (cough, cough) happen. If going to drain the system just pull off the lower hose and look for crud setting inside rad. One other thing to check did they install the coupling?! Next thing is take it back to the reputable shop an ask what gives.
Just my 1 cent worth.
Just my 1 cent worth.
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