Usually I find help just lurking this site, now I have to ask! Thanks in advance for any thoughts...

Last fall my '97 STS (101,000 mi.) overheated to the point where the engine shut itself down. I didn't see the temp needle until it was all in the red. Turns out my water pump failed, so we replaced the pump and some other bits - problem solved.

Ever since then, the car is very hard starting *most* of the time, and clearly it was a perfect starter before this incident. Interestingly, when completely cold, it usually fires right up. Otherwise, it cranks for up to 10 seconds before firing up, sometimes starting lumpy, and eventually smoothing out, and all seems perfectly well. I'm not sure where to start tinkering.

I thought perhaps it was simply a plug issue - I replaced the plugs, which were in real need anyway, but no change. I would otherwise continue to suspect an ignition issue - possibly coils and/or wires, but these are a bit expensive to experiment with

The only other real insight that might add a clue to the informed: When the car overheated, I tried to start it back up once the temp had come down, just to see if it was still mechanically sound. There was a loud POP, and smoke came from under the hood!! By the time I got the hood open, I could see no sign of what had popped. I tried again shortly thereafter, and it ran seemingly fine, but obviously the needle started climbing quickly enough, I figured out what was going on. I have no idea if this pop could be related to my current issue, but thought I'd describe this event, in case it makes light bulbs go off in the more experienced minds.

Thanks in advance again, I hope someone can share a clue with the clueless!

 

I just found Stealth's helpful tip on another thread to READ THE OVERHEATING FAQ. New here and didn't notice - very interesting stuff there - am going to read through in depth.

I fear head gasket, etc., now as I surely smelled the sweet aroma of coolant in the engine bay, and my "check coolant level" warning has alarmed twice in the last week or two (only to go away, I presume due to thermal expansion). Of course it could also be a first-year-med-student issue - once I learn all about cancer, I think every itch must be a tumor

I'll report back if I can find anything, in the meantime, any other hints are appreciated - sorry i didn't dig through the FAQ first (great FAQ too, guys).

 

Being far too cheap for a fancy Coolant pressure test kit, I built my own. I'd like to see if anyone can tell me if there is any reason my fabrication will not work.

I pressurized the overflow hose into the reservoir. I hooked a gauge up to it, and pressurized it using 30PSI inlet pressure until i reached 15PSI. I see no reason it should not hold pressure, nor be a reasonable place from which to pressurize the system. I first want to make sure my method is sound (see pics below) because...

It doesn't hold pressure at all. I have no leaks in my apparatus, having tested to 40PSI with the hoses capped.

Are there any other reasons that my cooling system will not keep pressure, or is this a pretty clear indicator of a problem? I imagine the latter, and am sad at the thought.

Here is a pic of my pressure tester installed, non-pressurized. I built it using two pneumatic Tee-pieces joined together with good amounts of thread tape. A simple air pressure gauge on one end of the top Tee, and a air compressor valve on the other end. Then you just hook this Tee up to another Tee made for the through hose, and voila! easy peezie.