Originally Posted by
napalm
Okay so, I don't know jack shit about autos. I've browsed around the internet trying to find a decent, well-populated auto forum to try and post this question, but all of the sites I found weren't very lively. I'm hoping maybe one of you knows a thing or two and could help me out.
Anyhow, the truck I'm driving is a 1991 Chevy K2500 4WD. The truck has been sitting in the driveway for a long time, and got used maybe once a month or so. I know that it is past due for an oil change based on time, but not miles. It also hasn't had the radiator fluid flushed in recent memory, if that's worth anything.
So anyhow, after an extended period of little use, it's become my primary driver. A few days ago I started her up, took a load to the dump, drove 2 hours on the freeway to get my lost cellphone from a lady, drove around town, and everything was fine. Later that night I was meeting someone for dinner and I noticed the check gauges light come on and sure enough, the temperature was all the way "HOT."
I turned the heater on, and it did nothing but blow cold air. Once I pulled over, the truck did the cliche steaming from under the hood thing for a while, so I got picked up. After dinner I got dropped off at the truck and I drove it back home from that spot taking my chances on melting the engine. I figured the problem would be the thermostat, since this has happened before. So, I got a replacement yesterday and did the switch. The person at Schucks (which has the worst fucking staff I have ever encountered) insisted that I use this O-ring and wrap it around the new thermostat, instead of using a gasket. It's an awkward connection and I don't think it's right, but there is nothing leaking, so it must have done the job. I did notice the old thermostat was covered in a thick layer of orange-colored radiator coolant.
I figured that would have fixed the problem, but alas, it's still doing the same thing. I've done some reading online and I think the problem MAY be either a blockage in the heater core, or a bad water pump. One other piece of information that I can offer, is that while it does the whole overheating/blow cold air out of the heater thing, occasionally when I'm driving and it's overheating, the temp will drop down again and the heater will blow hot air for a second, and then it will go back to it's old routine. That tells me something is wanted to work, but just can't quite do it. From what I remember of high school auto maintinance class (a joke) the coolant is stuck in a closed cycle and isn't contacting the heater core. Also, I've checked the coolant and oil levels, and they're both normal.
So, does anyone have any recommendations as to where I might start trying to repair this? I don't have any extra money to throw around so I'd prefer to try and do this myself, but if it's over my head I'll go ahead and blow the money. Thanks for the help...