You would have to have your gasket go that is around the t-stat, my t-stat appears to have gone out and I do not smell any coolant. Although if you have a pump going out it will leak out very small amounts of coolant at first which will lead to small air pockets which will make the temps fluctuate. I had a water pump go on me this summer on the el camino and I must have missed the signs because I got back from cutting grass and was loading the mower back into the bed and saw a huge puddle of coolant on the ground(not a good feeling), luckily I was only 15 min from home and was able to top it off before I left and it just started to get warm when I got home.
BTW those cast iron pumps are heavy

 

I guess I will keep an eye on the water pump. I don't see any coolant yet. I don't drive it much this time of year anyway.

 

You might try wiping the area with a paper towel or your finger to see if you can find any residue from coolant.

 

What can happen is the water pump bearing goes bad and starts leaking very slightly therefore the odor of coolant. When it cools down, it can suck in air via that bearing and therefore introduce air into the system causing temperatures all over the place. As mentioned, the water pump bearing will get worse real fast. Now with the large black belt cover on the pump, you may not be able to see the leak. Anyway, keep digging till you find the source of the coolant as its going to be a real issue, real fast.

 

And it sucks when they go out completely, at least on these new cars you dont have to take all the accessories off the front of the motor and then dig out a 25 lb hunk of iron out of the engine bay. It took me about 4 hours to do the el camino during the say and less than an hour for my camaro at night, the biggest hitch is trying to find all the screws so look at your new pump to see where they are located.

 

Borrow or buy a cooling system pressure tester. Auto Zone and Advance Auto Parts will loan them to you.

Do a pressure test when the coolant is COLD. Any external coolant leaks will show up fast. Don't exceed 15-18 PSI when testing.

 

Well today I think I seemed to see a little liquid on the hose at the nipple on the top of the surge tank. If this was leaking ever so slightly, would it cause the fluctuating temps? Still can't see any fluid anywhere else.

 

Yes. Look on the ridge along the edge of the tank and you will probably find a trail of coolant. Next, once its cooled down totally, remove the rubber line and see if you have a crack in the nipple tube itself. If so, replace the tank. You will most likely not be able to replace it. Air getting sucked into the cooling system at that point or any other will result in issues.

 

Well, I removed the rubber line, no crack. Cut off 1/4 inch of hose and reattached. Took it out and still fluctuating temps. Only gets up to 207 degrees and back down to 198. What issues from air getting in? It still runs well.

 

The fluctuating temps are probably from air-pockets that are in the system. They probably got in due a leak somewhere. Remember that when the coolant heats up, it expands and hopefully into the tank. When it cools down again, it'll suck the coolant back into the radiator. Now keep in mind that if there's a leak, air is lighter than coolant so it'll suck in air first. If the coolant got out, there should be some evidence of that. In the case of the nipple on the tank, the nipple itself is known to crack and you would see it. Not a crack on the rubber tube. When it cracks, you will probably (not always) see a line of dried or wet coolant running along the horizontal edge of the tank which is what I found on mine, when mine cracked.
Saying all this does not mean this is the cause yet. You could still have a bad bearing on the water pump or there could be worse issues such as head gasket possibilities. The loss of coolant location needs to be identified. If the water pump is starting to go, it may be leaking and drying up quickly, before dripping onto the belt and floor. If the head gasket is doing it, there's a exhaust gas test kit for the coolant available for like $45 from Napa. Its absolute for head gasket issues into the coolant system. If the head gasket lets go into the lubrication system, you'll see light colored swirls in the oil.
Since you were smelling it in the engine bay, I'm thinking leak of the water pump or one of the hoses, tank or similar...the usual suspects.

 

OK, I'll keep searching for the leak. I don't think it's a head gasket problem though. The oil and the coolant look fine.

 

Just keep in mind, if the head gasket had issues with exhaust gasses getting into the coolant, you'll get overheating, bubbles and the definitive test is the test kit. You won't know it otherwise although there may be other symptoms. Others are better experts than me for sure. If a head gasket leaks, does not automatically mean you'll see it in the oil...Just had this happen to somone's Scion. Blown gasket between #2 and #3 cylinders on that car, overheating and losing coolant, but oil was good.

 

I'm holding out hope there isn't a head gasket problem! Wouldn't that affect the car's performance?

 

I would imagine there would be some impact but I would think you wouldn't be smelling coolant in the engine bay, rather out the exhaust.

 

If it is a small leak then you would not notice a loss in performance but you would almost certainly be overheating.

 

Found the leak! As simple as new worm hose clamps. Apparently the original GM clamps wern't hoding tight enough. New clamps and problem solved.

 

Where was the offending clamp/hose?

 

Replaced both clamps on bottom nipples of surge tank. Was ever so slightly leaking from there. Tank is good, new clamps, good to go.