I've had my LY6 in and running now for a couple of months and hadn't noticed until now that I don't have any heat coming from my Vintage Air system unless I am parked and idling with the engine temp up around 195. There are a couple things I don't understand: 1 - I have two temp senders, one for the ecm which is located in the driver's side head toward the front and one in rear of the passenger side head for my speedhut guage. The two of them vary by 10-25 degrees at all times but I 'm not sure if the speedhut guage is reading correctly. The temp will hit the preset value and turn the fan on via the ecm but my passenger side sender is still saying its running at about 170 degrees.
2 - I have a stock chevelle big block radiator which seems to be too big because my lower radiator hose never gets hot. I wouldn't think there is such a thing as having a radiator that is too big as long as the thermostat is doing it's job. I've tried changing thermostats and had no change. My water pump is for a 2010 Camaro that came right from GM along with the factory thermostat. I'm sure there is no air in the system because I built a surge tank and mounted it at the highest point in the system with the steam vent dumping into it and the pressurized cap is on it. I also have a 3/4" outlet from the surge tank tee-d into the heater hose closest to the thermostat.

When the outside temp is below 60 degrees, the car runs at 140-160 when driving according to the speedhut guage otherwise it runs a little warmer when the outside temp goes up.

It seems like I'm running without a thermostat or some type of bypass which I can't figure out.

Any ideas??? Any information would be greatly appreciated! Thanks!

 

Could be the Thermostat is stuck open ?!?

You say that sitting idling.. the temp will raise to 195 ? but once you start moving it drops ? Sure seem like the Thermostat is not closing to keep the engine in it operating range. The factory Thermostat should be a 195 and should keep it in range.

try Blocking part of the Raditor with some cardboard or something and then drive around. .see if it heats up and stays up in the 195+ range.

 

Yes, when idling it seems to warm up properly and the fans will cycle on and off and run where it should but when I get moving it cools off very quickly. It does seem as if the thermostat is stuck open but two in a row is hard to believe. Would it have anything to do with the "failsafe pin" that is in the thermostat?

 

Hey i'm having the same issue my heat only seems to work when its warmer outside and my temp gauge is @ 180...did you ever figure this out

 

Since the heater hose connections are ahead of the thermostat it does not make any sense that you don't have heat, except for either a stuck stat, or a partially plugged heater core. Have you checked the temp on the incoming and outgoing hoses to the heater? If you have a vacuum controlled heater valve make sure it is opening freely. If the core is partly plugged you may still have an air pocket there.

 

I haven't driven the car in a couple months now that the temperature has dropped and there is salt on the roads here in Wisconsin. I don't think the thermostat is regulating the temperature like it should because my temp on the drivers side head sending unit (just before it goes back to the radiator to be cooled) would only get to about 167-172. When this is the case, the passenger side head sending unit is telling me that the coolant temp is about 130-138 which would coincide with the heater only blowing luke warm or even cool air. The thing I don't understand is that at an idle everything is fine and it gets to 192-198 and stays there without changing but as soon as I start moving and getting air flow through the radiator the coolant temp drops significantly and starts to blow the cool air.

Is there some sort of bypass that I don't understand or maybe isn't working properly? I don't know what to try next.

 

Get rid of the T-fitting going to the heater hose from the tank. If my understanding is right of this setup, you're allowing coolant to bypass the thermostat. Do you have any decent pictures of this cooling system setup?

 

I agree. You should try something different at the heater hose ports. They are so close to the thermostat that not only could they be bypassing coolant, they could be affecting the temperature used to drive the thermostat open/closed. Something to try anyway. Do you have any photos of your setup?

 

Did you route your steam line down to the area near the heater hoses?

 

Yeah, The smaller (5/8") one should be the outlet port from the pump (pressure) to the heater core and the larger 3/4" hose is the return from the core.

I think you said you have a Purge tank tee'd into this ? maybe try removing this setup..? where else did you connect the purge tank too ?

can you provide any pictures of your setup and any more details of what you have for a setup ?

BC

 

I'll get some pictures tonight and try to get them posted right away. It's actually the same setup with tees and surge tank as the pickups would be.
My steam vent is now routed to the top of the water pump on the outlet.

 

Here is the current setup that I have.

 

Where does the small hose from the front of the surge tank go? the one that is near where it's teed into the heater line?

Also before you upload photos, you may want to resize them. You can search for the microsoft powertoy "image resizer" which makes it easy. It's not available for newer versions of windows, but you can find alternative programs that do the same thing. It allows you to right click any image or group of images on your computer and resize them to a convenient size for web sharing.

 

It goes to the radiator which I took the guts out of the radiator cap and it is now just a sealed cap and the only pressurized cap is on the surge tank.