Help. I have not heat at startup?

**Red97LT1** · 11-15-2006, 04:39 PM

My car has gotten to where in the mornings(35 degrees) when I heat the car up for 15 mins,the heat is only warm coming out of the vents. After the car has run for 30-40 mins it is really hot. I have had the radiator flushed,thermostat replaced and the whole heater hose/line assembly replaced because it needed it. I have been told that the only thing left to replace would be the heater core. What I don't understand is,if the car doesn't get warm in the morning when first started,then gets really hot after awhile,how can it be the heater core? Seems to me that I wouldn't get any heat at all??
97 Camaro Z28

**mahoney1** · 11-15-2006, 05:03 PM

You dont have a problem its called getting cold outside, so it takes longer to heat up!

**BlackLT1Z28** · 11-15-2006, 05:12 PM

Yeah, it will take awhile for the car to heat up. That completely normal, for any vehicle. The car is heated from the engine, so when the engine is cold, the air will be cold. The heater core extracts the heat from the engine coolant, so when the coolant is cold, the air will be cold. That's why when your engine is overheating in the summer, you can help cool it off by turning on the heater.

**Red97LT1** · 11-15-2006, 05:15 PM

I don't think that's the problem. Last year after 10 mins the air was hot.Now it's warm.

**mahoney1** · 11-15-2006, 05:24 PM

then go to a garage and have them look at it!

**Orcus79** · 11-15-2006, 05:25 PM

Could be a blocked core, try giving just it a flush.

**Red97LT1** · 11-15-2006, 05:59 PM

My first post says what I have had done already. I have had the system flushed twice to no avail. I may just go ahead and replace the core,everything else has been replaced.

**BlackLT1Z28** · 11-15-2006, 07:20 PM

What type of thermostat are you running? And make sure you have a proper mix of water and coolant.

**Hi-Po** · 11-15-2006, 11:13 PM

Originally Posted by Red97LT1

My car has gotten to where in the mornings(35 degrees) when I heat the car up for 15 mins,the heat is only warm coming out of the vents. After the car has run for 30-40 mins it is really hot. I have had the radiator flushed,thermostat replaced and the whole heater hose/line assembly replaced because it needed it. I have been told that the only thing left to replace would be the heater core. What I don't understand is,if the car doesn't get warm in the morning when first started,then gets really hot after awhile,how can it be the heater core? Seems to me that I wouldn't get any heat at all??
97 Camaro Z28

While 30 to 40 mintues seems too long... i assure you your car is ok. Everything sounds fine. Like said above.... it takes time to warm up.

**SSTODD** · 11-16-2006, 07:24 AM

The bigger the engine the longer it will take, a 4cyl or 6cyl will make heat quicker than a V8. Make sure you don't have a cold thermostat either for that weather. 180 or 190 is cold enough.

**Red97LT1** · 11-17-2006, 12:37 PM

Thanks for the replies. I replaced the Heater core yesterday and this morning everything seemed fine.

**DaddySS** · 11-19-2006, 03:29 PM

Originally Posted by Red97LT1

My first post says what I have had done already. I have had the system flushed twice to no avail. I may just go ahead and replace the core,everything else has been replaced.

Checking the flow of the core is easy, hook a hose to the inlet and see what volume comes out of the outlet. There is a TB about LT1 cores getting clogged and a specific flush method. I am betting your core is clogged. When the engine begins to warm up in the morning feel the two hoses, if one is hot and one is cold it is the flow through the core.