Hi, i was hoping someone can help me out with my winter truck. I had heat problems with it last year, and had the heater core flushed by a local shop since it was nuts cold outside and i didnt want to do it myself. Anyways, the heat worked great for winter. I drive it a little here and there in the non-winter months, and drive my GTO instead. The heat doesnt work at all again, coolant up to the right level, and the truck after 20 mins or running is in the normal range on my gauge in the truck, it blows absolutely zero heat. I also did not notice any leaks of coolant inside the truck, or under the hood anywhere.

After the truck has been running for about 20 mins and up to temp, both heater core lines are cold, and feel like there's no pressure there at all. I'm not sure if the heater core ALWAYS has coolant running through it, regardless of what the HVAC is set to inside the truck?

Is there anything else i should check? There is coolant at the front most line when i pull it off, and the coolant is warm (towards the front of the truck, at the water pump), but still bone dry at the heater core at both lines. I can try flushing it myself, but i dont see the point, if there's no coolant going to it in the first place.

ANY help would be greatly appreciated, thanks in advance!!

 

how old is your thermostat ? dose your truck reach running temp ?

might wanna check it

 

Off the top of my head, i think its around 170 or 180 after idling (about 50 degrees outside, hood shut). I never replaced the thermostat, but the engine NEVER gets anywhere above 210, never overheats.

It's about 1/4 of the way up the gauge.

 

When the engine is at operating temperature, (very close to 200F) if both heater hoses are cold at the heater core, either the core is clogged, or it's low on coolant. When the coolant level gets low, (2 or 3 quarts) the first symptom is no heat.

Provided the cooling system is full, coolant flows through the heater core whenever the engine is running.

 

Are you saying there's no coolant in the lines when you pull them off at the core nipples?

If that's the case, you should make sure there's no clog at the manifold {near thermostat}.
I have never heard of that happening but I suppose it could. Even weirder would be if the hoses were plugged.
If that was the case, the heater core wouldnt have a chance of being clear, i would think.

 

I had this happen on my 2000. I was told it was happening because of the orange coolant. I flushed and drained it then started using the green stuff. 5 years later and it hasn't clogged again.

 

You're asking for trouble using ethylene glycol in a system designed for Dexcool. If you maintain the cooling system properly by flushing it every 3 years or 36,000 miles, mix the Dexcool 50/50 with distilled water, keep the system full, and make sure the body grounds are good, you won't have problems.

http://www.ricksfreeautorepairadvice...-wrong-coolant

 

I can only tell you my experiences. I've put at least 100,000 miles since switching to the green stuff and no issues. I have it flushed and filled every fall.