Cracked Head Leaking Head Gasket?
Alright guys I have a question, and hope to get some help here. I have 1989*Chevy truck, brand new GM Good Wrench 350 long block assembly roughly 2-3,000 miles on it. Topped off with an Edelbrock Performer TBI intake, new 195 degree thermostat,holley TBI, and all new sensors. The problem at hand is this, i just replaced my thermostat because I noticed she wasn't getting up to temperature, and that fixed the cooling problem. I lost some coolant changing the thermostat, and went to top it off and bleed the air out of the system. no matter how hard I try, I can't get the air out of the system. It's not the usual big air bubbles I'm used to. The air bubbles are more like a "Jacuzzi", small bubbles that wont stop coming up through the radiator and seem to foam up. I just replaced my oil with no signs of coolant, and I don't notice anything coming through the*exhaust. Another problem I feel is related to this, is a rough idle. When I first ran the engine for roughly 1,500 miles my idle was strong, no surging. But I took the truck up to the mountains, a good 150 mile drive, and returned with a surging idle. I started replacing sensors, one by one that were from my old engine, thinking they had there last straw after the 200,000 miles they suffered on the last motor but there was no change. When I first start the truck in the mornings, she has a strong steady idle for the first five minutes exactly. Then after that five minutes has past the idle starts to go up and down varying RPM's at no specific fluctuation range, this will continue while in gear, but no as noticeable, but it is slowly getting more noticeable now. My theory, is that I have a small leak in my*head gasket, small enough to only let gasses past, and not allow any coolant to pass through. And the reason my idle starts to freak out after five minutes, is because, of the expansion of the steel once warmed up, allows the gasses to pass. What do you guys think? has any body had a similar problem?