Ok guys here the deal. Last night while coming home from the movies my tempature guage shoots up and tops off at about 240 degrees, sits there for about 35 seconds and drops to normal operating tempature. While that isn't overheating it is way outside the vehicles normal operating tempature ranges. So when I get home I check under the hood real quick, nothing seems to be out of place so I go inside.

This morning I go out to look a little deeper. I start with the radiator which was about half full. Odd, checked it one week earlier and it was full. Theres no smoking, no puddles of fluid under the vehicle at any time, no overheating. The only leak to speak of is at the front of the intake manifold, and that is very small. By no means enough to leak a half a radiator in a week. Besides there'd be residue everywhere. So after a little more looking I found what appears to be a line of coolant along the bottom outside edge of my head. So what's this sound like? I want to say that it's a blown head gasket, but not sure. Luckily I can't find any traces of coolant in my oil.

By the way this is on a 1993 Chevy Suburban with a 350, if it helps at all.

It sounds like you've found the problem.  Depending on the leak, you can hold an emissions analyzer over your open radiator <where the cap goes> and get readings.

From what you describe, the thermostat stuck shut for a moment. This will quickly begin boiling off the coolant in the water jacket around the head.  No real biggy as long as it wasn't allowed to run for too long.

Check the oil and make sure  it isn't contaminated with coolant. The oil will look milky if it is. Coolant + Oil means the head gasket is blown.  If it's not, change out the thermosat. It will take you all of 30 minutes.



ETA. When you fill up the radiator. Add alumaseal. (Radiator sealant) It'll seal up any intake manifold leaks.

Thanks guys. I checked the oil first thing when I notice coolant around the head. No contamination noted. I need to run out and pick up some cooling system sealant.

Thanks again guys.