Confirm my research please - heater related.
 

Car - 1978 280Z, no A/C equipment.

Ok, so after extensively searching out & reading about heater problems, I think I have reached a conclusion. Most of the posts are on the S31 body

Problem: When driving, once engine temp comes up to normal operating temps, you can smell a bit of antifreeze in the interior. On cooler days a little foggy patch appears just above the right side of the dash defrost vent. I haven't found coolant leaked into the interior yet, nor any leaked on the ground so It's got to be a small leak.

My conclusion: Leaky heater hose connection, leaky water cock, leaky core. Won't *really* know until I can take a look. Is there a way to inspect without pulling the dash? Does the S30 have the rats nest of vacuum lines I've read about the S31 having?

Thanks!

The heater control valve is of course under the dash where the hoses come in from the engine. If you can fit in a 2' square box it will be easy. Otherwise it is harder than installing the engine/trans. There are 2 different style valves one of which is n/a. There is a guy on one of the other sites that sells rebuilt ones for $150 and that's cheap. The hoses are available from blackdragon. Some posts on using other configurations are shown on hybridz.org.
You have to find the leak before you start because replacing the heater core is even harder. Good luck with all that!

Thanks! Under the dash I go when I find time to spend a day in the garage ~

JM

except the smell it looks like normal... when it's cold your car gets colder than the air and the fan produces fog
then if you've been using air con before you could have a strange smell of humidity
have you tried to use only water with no coolant to see if it really changes something with the smell?

Yeah, stuff some paper towels under there and drive for a cople days before you start. You might just have some wet debree accumulated under the cowl.

Haven't tried that the water thing. I don't have A/C installed. It is definitely warm antifreeze smell. I'll get under the dash with a flashlight and see if I can find any damp spots behind the dash. A previous owner replaced ALL the carpet so if could be simply leftover from a prior problem and I just need to clean a surface or something.

JM

What is an S31?

I meant S130.

JM

You don't need to take the dash out on an S30. Remove the fan assembly, the front console heater controls & all mounting bolts, control cables & heater hoses from the heater box. Once the heater box is loose go through the front console opening to remove the top plemum from the heater box. Once the top plenum is removed the box should slide out from behind the dash & into the passenger foot well.