cuisinartvette wrote:
I run a 160 in everything I own except the DD.

biggrizzly wrote:
Andy's recent thread about temp gauges has me wondering a bit.
I put new sensors in mine, both from Advance Auto. One in the water pump and one in the head. I think the one in the head is the one that feeds the PCM and the one in the water pump feeds the temp guage. I may have this reversed.
But since rebuilding the motor I can' seem to get my temps above 180 on a hotttt day and lately with the cooler temps here I can't get it much over 160 and I also have no heat.

I did install both a new radiator and a new ac condenser. Also had the fans programmed to come on earlier and installed a 160 thermostat. Is it possible the thermostat is stuck open?

I love the low coolant temps in the summer but damn its getting cold now.

CentralCoaster wrote:
Simple, if you want temps to hold above 160 you need a higher rated stat. It surprises me that 160 on an LT1 isn't enough to keep the heater working.

The cooling fans' "OFF" setting should be at least 10F or more above the tstat rating, which means the "ON" setting has to be even higher.

The LT1 cooling system is a different animal than the traditional small block, so the common knowledge there doesn't really apply.

CentralCoaster wrote:
Simple, if you want temps to hold above 160 you need a higher rated stat. It surprises me that 160 on an LT1 isn't enough to keep the heater working.

The cooling fans' "OFF" setting should be at least 10F or more above the tstat rating, which means the "ON" setting has to be even higher.

The LT1 cooling system is a different animal than the traditional small block, so the common knowledge there doesn't really apply.

jsup wrote:
black

jsup wrote:
Quote:

CentralCoaster wrote:
Simple, if you want temps to hold above 160 you need a higher rated stat. It surprises me that 160 on an LT1 isn't enough to keep the heater working.

The cooling fans' "OFF" setting should be at least 10F or more above the tstat rating, which means the "ON" setting has to be even higher.

The LT1 cooling system is a different animal than the traditional small block, so the common knowledge there doesn't really apply.

How is it different, I mean I get the reverse cooling but how is it drastically different in terms of how the physics of combustion change or not.

I've had a 160 and have had heating problems, the inside of the car just would not get hot. We went to a wedding in October, and it wasn't all that cold, and the car would not warm up inside.

The 180 is much better in that respect.

pr0zac wrote:
Quote:

jsup wrote:
Quote:

CentralCoaster wrote:
Simple, if you want temps to hold above 160 you need a higher rated stat. It surprises me that 160 on an LT1 isn't enough to keep the heater working.

The cooling fans' "OFF" setting should be at least 10F or more above the tstat rating, which means the "ON" setting has to be even higher.

The LT1 cooling system is a different animal than the traditional small block, so the common knowledge there doesn't really apply.

How is it different, I mean I get the reverse cooling but how is it drastically different in terms of how the physics of combustion change or not.

I've had a 160 and have had heating problems, the inside of the car just would not get hot. We went to a wedding in October, and it wasn't all that cold, and the car would not warm up inside.

The 180 is much better in that respect.

that cold water is hitting the head first instead of warmed water from the cylinder coming up to the head.. its like a diesel when its first started in the cold.

BillH wrote:
Don, Is the new radiator a stock one? If it is, I find it strange that a LT1 won't heat up regardless of which thermostat you have in it unless the fans are coming on early.
On a 30 degree day, mine runs at 190. I can pull it down to 180 by turning the fans on (manual switch).
If your temp gauges are correct and you're already at 180, a 180 thermostat will be open or opening plus/minus the tolerances.
Do you know exactly when the fans are coming on?
Before you switch the stat, I'd start the motor cold and see what temp the fans kick on at. While you at it, when you start to get some temperature in the radiator hoses, check both heater hoses (with your hand), turn on the heat and keep checking them.

You can turn the fans off by pulling the connectors at both relays, then see what temps you get.

I agree with the guys on a 160 in a standard small block not producing enough heat, I've had that happen. But not in a LT1 with the stock colling system.

BillH wrote: If it is, I find it strange that a LT1 won't heat up regardless of which thermostat you have in it unless the fans are coming on early.
On a 30 degree day, mine runs at 190. I can pull it down to 180 by turning the fans on (manual switch).

biggrizzly wrote:

Yes, it is a stock radiator, just a new one.
Off the top of my head I can't remember what we set the fans to, I'll need to go back and check that.
When I drove it the other day, it was around 35 dgrees outside and it never got above 160 until I stopped at a redlight. But as soon as I took off it went back down to around 150 or so. If the weather is warmer it will get up to around 180 but that was back in September on a 75 degree day.

biggrizzly wrote:
OK - I just gave it a little test in the garage. Primary fan came on at 180. It took almost 15 minutes to get it up to 180. My garage is at about 50 degrees right now ambient temps.

I wasn't going to wait for the secondary fan to kick in, because as soon as the fan came on at 180 the temps dropped right back down.

There was a little warmth blowing from the vents but hardly detectable even when the car got up to 180 degrees.

It makes no sense to me because as I see it, the thermostat should open at 160 correct? If it opens at 160 I have full circulation of coolant? or is there another controller that allows coolant into the heater core? or am I ass backwards here?

I guess I'll just go get a 180 to see how it behaves. It can't hurt.

jsup wrote:

Isn't the standard t-stat 195?

biggrizzly wrote:
OK - I just gave it a little test in the garage. Primary fan came on at 180. It took almost 15 minutes to get it up to 180. My garage is at about 50 degrees right now ambient temps.

I wasn't going to wait for the secondary fan to kick in, because as soon as the fan came on at 180 the temps dropped right back down.

There was a little warmth blowing from the vents but hardly detectable even when the car got up to 180 degrees.

It makes no sense to me because as I see it, the thermostat should open at 160 correct? If it opens at 160 I have full circulation of coolant? or is there another controller that allows coolant into the heater core? or am I ass backwards here?

I guess I'll just go get a 180 to see how it behaves. It can't hurt.

biggrizzly wrote:
Dan, I agree on all your points and understand the operation of the system pretty well. I just have a hard time understanding why the 180 coolant running through the hoses at idle isn't enough to get me warm air. The air that is blowing is not cold AC air but its not heat in my opinion.

Last week my wife and I drove the car to an event in the evening and it was colder than a witch's tit. It took a while for the car to comfortable and the heat wasn't coming from the heater is was coming from the exhaust system.

biggrizzly wrote:

....and it was colder than a witch's tit.

dan0617 wrote:

Blade, maybe there is enough difference in an LT1 from a sbc but if the roads were dry I could go shoot you a video as long as you want (literally hours) of my temps never going above 180 with my 180 stat during normal driving, and that is with stock radiator and stock cooling fan. Stock AC condenser is still in place too.

CentralCoaster wrote:
On mine it uses vacuum from the a/c control head to open or close the valve. I think it's set to always allow a little bit of flow to keep the heater core from rotting out.

CentralCoaster wrote:
On mine it uses vacuum from the a/c control head to open or close the valve. I think it's set to always allow a little bit of flow to keep the heater core from rotting out.

Your a/c controller doesn't use vacuum though.

biggrizzly wrote:
OK - I just gave it a little test in the garage. Primary fan came on at 180. It took almost 15 minutes to get it up to 180. My garage is at about 50 degrees right now ambient temps.

I wasn't going to wait for the secondary fan to kick in, because as soon as the fan came on at 180 the temps dropped right back down.

There was a little warmth blowing from the vents but hardly detectable even when the car got up to 180 degrees.

BillH wrote:
Quote:

biggrizzly wrote:
OK - I just gave it a little test in the garage. Primary fan came on at 180. It took almost 15 minutes to get it up to 180. My garage is at about 50 degrees right now ambient temps.

I wasn't going to wait for the secondary fan to kick in, because as soon as the fan came on at 180 the temps dropped right back down.

There was a little warmth blowing from the vents but hardly detectable even when the car got up to 180 degrees.

On a 50 degree day, 15 minutes is about right. My Lt1 takes over 5 min. to get to 100.
Kicking the fan on at 180 is really low, means your fan will run a lot in the summer.
If it was mine, I'd reprogram to 195.
I don't even hit my manual switch at stop lites unless I see 205.

To see if the heater control valve is working, warm up the engine with the heat off, touch both hoses going into the core. One warm, one cold? - The valve is closed. Turn on the heat, both hoses warm?- the valve has opened.

Note: my LT1 will blow very hot air at 160.

pr0zac wrote:
or you could try to flush it for free..

jsup wrote:
To be clear, the valve is before the input to the heater core. If you feel the hoses and it's a different temp, only proves the heater core is clogged, nothing about the heater control valve.

You have to feel the hoses on each side of the valve, not of the core.

Actually, only touch the output side of the HCV and see if it warms up.

I'm 99% sure that will be the problem. Either the valve or the control for it. Like I said, for the winter bypass it and deal with it in the spring.

If it's the valve, it's easy, if it's the control, it's more complicated. Don't know if it's electrical or vacuum activated.

BillH wrote:

OK, where is the valve on a LT1?

pr0zac wrote:
i am almost certain there isn't one of those valves on an lt1. my trans am did the same thing would get to 220 and wouldn't pass ANY heat out of the vents. cold air would come out.. you could hear the hot/cold flapper move... no heat.. flushed it and now it works prefect.

BillH wrote:
OK, here's the correct shit. There is a "Heater flow Control Valve". It's a check valve in the inlet heater hose.
It's located in the heater hose where it's clamped to the fenderwell about 8 inches from the heatercore nipple.

It's interesting that after I posted about checking the heater hoses, I pulled the FSM. Under "Insufficient Heating", the diagniosis runs:
Warm up to normal opp. temp.
Temp lever to full hot, blower on high.
Put hand close to lower hose, it should be hot.
Put hand to lower hose, it should be cooler.

Note that water always circulates thru the LT1 heater core.
When the A/C is on the airflow goes thru the evap. and bypasses the heater core because the temperature mix door closes it off.

CentralCoaster wrote:
On mine it uses vacuum from the a/c control head to open or close the valve. I think it's set to always allow a little bit of flow to keep the heater core from rotting out.

Your a/c controller doesn't use vacuum though.