BG Auto: radiator and heating problems

[Taera]

A few months ago my truck was over heating and I ended up having to have the radiator boiled out and cleaned and I haven't had a problem since until today. My gauges were reading hot and my heat would go cold as the gauge would get higher. It would get to the far right then go back down to normal then the heat would get warm again. Then the gauge would start climbng and the heat would go cold again and when I got to work I could smell antifreeze. I don't know what the problem could be since I had the radiator cleaned completely this past fall. Also when my truck sits idle wiu the defrost going; itnever gets warm and keeps blowing cold air. Any help would be appreciated. Thanks.

02 chevy blazer automatic 120000 miles

[Elesirdur]

Hmm, the cold air is kind of strange. I doesn't sound exactly like the symptoms of a blown head gasket, though if you can get your engine pressure tested I would recommend it.

I'm presuming that your heater core runs off of engine coolant, so the lack of heat might be caused by air bubbles in your coolant system. The air bubbles won't carry any heat to the core, which would explain why there's little to no heat, or you suddenly get cold air.

That being said, air bubbles in your coolant could be caused by two things: leaks in the radiator or coolant lines, or a leaking or blown head gasket. As I write, I'm starting to think that the head gasket is the culprit, as it would also explain the variations in the dashboard temperature gauge (again, air bubbles don't conduct heat like liquid, so the temp sensor is getting funky readings). Get the engine pressure tested, or buy a block pressure tool yourself as they are cheap and the procedure is easy with someone to rev the engine while you read the device.

[Cadsuane]

Check the water pump, check the thermostat, check the monovalve for the heater core, check solenoids for fan vent louvers. Alternatively take it to a mechanic and forget about all of that shit because messing with engine cooling systems is a pain in the dick. It's probably a busted thermostat and if so that is potentially a DIY job. Dunno what the guy above me is blathering on about head gaskets for.

edit: on second thought, check if you're low on rad fluid and if that's the case, look for leaks. Water pump and thermostat are usual culprits. Low rad fluid can stop your heater from working properly and the antifreeze smell is probably the radiator boiling over.

[BIGSTIC]

Bad head gasket. The 4.3 is horrendous for head gaskets. Last company I worked for had a couple of them as fleet vehicles. Same symptoms as you are saying and it was always the head gasket. Think the company's bill was around $1200/ea but if you are mechanically inclined the parts are cheap and it shouldn't take more than a day.

[Stumblingdrunk]

have you checked your coolant level yet?

[Elesirdur]

Head gasket changes aren't that hard, especially in a vehicle with lots of space surrounding the engine. The only worry is that the head or block may have become warped due to improper cooling. If that's the case, then you have to get either or both machined to have a flat surface. I'm going to guess it's an OHV engine, not an (D)OHC, so keeping the cam in alignment shouldn't be a problem.

[Vacht]

Check the water pump, check the thermostat, check the monovalve for the heater core, check solenoids for fan vent louvers. Alternatively take it to a mechanic and forget about all of that shit because messing with engine cooling systems is a pain in the dick. It's probably a busted thermostat and if so that is potentially a DIY job. Dunno what the guy above me is blathering on about head gaskets for.

edit: on second thought, check if you're low on rad fluid and if that's the case, look for leaks. Water pump and thermostat are usual culprits. Low rad fluid can stop your heater from working properly and the antifreeze smell is probably the radiator boiling over.

srsly.

[Cadsuane]

Head gasket changes aren't that hard, especially in a vehicle with lots of space surrounding the engine. The only worry is that the head or block may have become warped due to improper cooling. If that's the case, then you have to get either or both machined to have a flat surface. I'm going to guess it's an OHV engine, not an (D)OHC, so keeping the cam in alignment shouldn't be a problem.

Realistically a failed head gasket is the sort of problem you typically write a car off for, because of what you mentioned and the fact that by the time shit like that starts to fail the car is old enough that it's not worth spending 4 digits on it anymore. And taking off a head is no joke, or at least it's not something an amateur with a handwrench can be fucking with. It's not a usual problem and I've gotta admit I didn't think to connect it to a coolant issue but since my backround is in diesels I sort of have an excuse. Head leaks in diesel motors usually means oil is leaking into the cylinders which causes runaways and total motor deaths unless you can shut it down before it self-destructs. Anyway, /thread, guy's been given good advice by multiple people.

[Shagoa]

Try looking at or replacing the radiator cap if it hasn't been done already. A lot of other great info in the other posts in the thread.

There's no leaks under the car when it sits? I've seen water pumps leak out of the seals, but usually this happens while the car is running. No white smoke while your driving? That's another good indicator of a blown headgasket. The smoke looks a lot like steam and smells like fireworks.

Ultimately, the best advice is to take it to a mechanic though.

[Titanss]

change the thermostat