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Hello everyone. I've searched and found a bunch of threads unfortunately it looks like most no longer have images hosted and the ones I found with pictures all involve the digital hvac control.
Fast facts:
93 Vette - with the manual heat/air control not the digital 'set the temperature' version.
Can direct airflow out any of the vents.
Can set blower to any speed.
AC works as designed.
When setting adjuster to heat there is a noticeable decrease in total air volume coming out of the vents - it just doesn't heat up.
No anti-freeze present in cab nor any anti-freeze smell.
I've read about checking the heater hoses but unfortunately I'm not familiar with the hoses in a vette and I haven't been able to find a picture to indicate which hoses I should be checking. Every hose I touched was sufficiently hot that I would not want to grab hold after 5-10 minutes of idling. I understand their is a blend door that needs to be verified but I'm confused about where that is located. Any and all help is appreciated.
Sorry, No hot air can equal a nightmare.
Rain/ fog no way to defrost. Cold climents. Just keep it home.
Stage 1 pull the PS seat. C4's are very compact/ constricted. Could even test any phobias.
It's a tedious process. Not hard.
If you turn down the volume.
Sorry, a reference vid.
Which part ? Post a picture of that area if you can.
I'll take a picture this evening. However, the two vertical looking ports in your yellow circle are not there on my vette. I marked up your photo for quick reference. That piece is relatively smooth. I'll get a picture of my vette this evening.
I'll take a picture this evening. However, the two vertical looking ports in your yellow circle are not there on my vette. I marked up your photo for quick reference. That piece is relatively smooth. I'll get a picture of my vette this evening.
That part that is circled in yellow is the blower module for the fan which is used in the C68 or automatic system. Its not there on a manual system cause the fan speeds are controlled a different way.
Don't know if there is a plate where the module would be so you can look in but probably not. So you are going to have to determine if the blend door is moving another way.
The heater hoses are the ones running under the surge tank and should be hot. They actually get hot before the larger radiator hoses get hot due to the thermostat being initially closed.
That part that is circled in yellow is the blower module for the fan which is used in the C68 or automatic system. Its not there on a manual system cause the fan speeds are controlled a different way.
Don't know if there is a plate where the module would be so you can look in but probably not. So you are going to have to determine if the blend door is moving another way.
The heater hoses are the ones running under the surge tank and should be hot. They actually get hot before the larger radiator hoses get hot due to the thermostat being initially closed.
I never knew that, then again I have never seen a later C4 with manual HVAC. Just goes to prove the old adage that you really do learn something new everyday.
I never knew that, then again I have never seen a later C4 with manual HVAC. Just goes to prove the old adage that you really do learn something new everyday.
Turns out I'm blind there is a plate there. Popped it open and I verified the blend door IS moving as expected. I also verified both of the big hoses are getting hot. Coolant level is good. What do I check next?
Turns out I'm blind there is a plate there. Popped it open and I verified the blend door IS moving as expected. I also verified both of the big hoses are getting hot. Coolant level is good. What do I check next?
Thanks for the ongoing assistance everyone.
Damn, I was betting that would be your issue. If you have access to an IR temperature gun I would check how hot the heater core is getting just to rule out a circulation issue. The decrease in airflow is weird, maybe someone has an idea on that.
I realized my hoses look different than in the picture above. So I moved the reservoir out of the way to look at the hoses coming out of the fire wall... Look what I found. A dirt bag dealer who disconnected and bypassed the heater core and sold the car in July.
So setting aside for the moment I'm going to sue him. My guess is this means the heater core is shot and needs replaced. I have found write ups for that but where can I find a diagram/writeup on how the hoses should be run to reconnect the heater core to the system (after I replace the core of course).
That sucks. I don't know if you will have any luck with a lawsuit as the dealer will claim ignorance unless the heater was claimed to work.
A C4 is basically built around the heater core, so replacement is a PITA.
As far as the hose routing goes this may help.
The problem with the heater core really has not been confirmed. It's assumed it's leaking, but it may just be plugged. Maybe it can be flushed put which would be nice.
I guess the only way to find out if it is leaking is to connect it up and watch for leaks which may not make some people happy going in that direction.
The problem with the heater core really has not been confirmed. It's assumed it's leaking, but it may just be plugged. Maybe it can be flushed put which would be nice.
I guess the only way to find out if it is leaking is to connect it up and watch for leaks which may not make some people happy going in that direction.
maybe try with low pressure air first instead ? ...
"Never tried it, but you can take a bike innertube, cut it so you now have a rubber tube with two open ends and a valve in the middle. Use hose clamps to attach the ends of the tube to the heater core pipes. Pump it up so it's nice and fat then leave it for several hours. If it's lost air, you have a leak. "
09-29-2022, 11:44 AM
93 no heat
