'94 Camaro, 3.4L V6, 160k miles. I replaced the thermostat about 2 months ago, and flushed the radiator. Didn't have any issues. Now, two days ago, in a heavy downpour, I notice my temp gauge is spiked. The temps aren't labeled too well, but normal operating temp is at the 1/4 mark (195°) and the red-line (full) is 260°F. I didn't notice any problems this morning, but I wasn't really looking. Had BAD problems yesterday afternoon.

Symptoms:
1) Temp gauge was all over the place. Generally 1/2-3/4 regardless of speed- same temps on the highway as in stop/start traffic. Maybe a little better on the highway, but not a large difference.
2) Turned on the heater full bore. Blew cold air. A few seconds of warm air, then cold again.
3) I turned the A/C on. No change. (Blew very cold air, no surprise there.)
4) At one point, sitting on a hill by a stop-light the needle was at 3/4. Upon accelerating, the temp just plummeted quickly to about 1/4 then rose back up.
5) The temp plummeted again, this time dropping slightly below normal operating temperature.
6) The engine is running rough as hell. Almost like a bad cylinder, but not quite that bad. Kinda feels like it's stumbling over something. This makes me think it might be a bad impeller?
7) I just changed the thermostat 2 months ago; I took it out last night and it tested fine on the stove.
8) Water pump's 15 years old and has 160,000 miles on it. No leaks.
9) Coolant level looks good, was a little low in the resevoir, and topping it off made no real difference.
10) There's a high pitched whine coming from the engine that I *think* is the water pump, but I'm not sure.

I was convinced it was a water pump problems and have started disassmbling my engine, but am now stuck, as I can't get the power steering pump bracket loose. First question is: is this even the water pump; should I cut my losses and start putting it back together, or just change the pump now that I've gotten this far into it? Follow up is: I've removed four bolts and a nut from the power steering pump bracket, including one I had to take the ignition coils off to get to. How do I get the pump to swing free?

 

You but a pully puller and pull off the power sterrting pully, they are cheap,a dn this will save oyu a LARGE headach. Make Sure your antifreeze is not missing. If you blew your intake manifold gasket, antifreeze will leak into the oil pan. If this hapens your oil level will rise and the oil will turn a chocolatemilk color. this thins oyu oil adn causes tour engine to run like **** because the oil will not lubricate the engine.

 

There's no indication of any oil in the coolant, or coolant in the oil, so the gaskets should be OK.

Oh, and I found another nut on the power steering pump bracket buried in the back on the bottom, I couldn't see it around the wiring harness. Unfortunately, I'm having difficulting *reaching* it around the wiring harness, but that's another issue entirely...

 

When the temperature spikes and drops and spikes and drops like that it means there is air in the system. 160k on a water pump is just unbelievable. I've gone through 2-3 and I'm at 220K. I'd say your water pump is probably the culprit here but I'll also say that your coolant level is low. When you fill your radiator after this swap out do the following. Fill the radiator full, then wait a minute as the air runs out of the system you'll notice bubbles coming up. Then just keep putting more and more in until no bubbles come up. Then fill it to the top and cap it. Start the engine. Run for 10 seconds. Shut it down. Take the cap off and check the level again. Careful openning the cap as there may be pressure built up. If your radiator is truly full your coolant will either be at the same level it was before you started the engine or it'll be higher or gushing out when you open the cap. So when you open the cap just keep downforce on the cap so you can clamp it back down quickly so you don't spill coolant all over. It won't be hot obviously just trying to help you not make a mess. Otherwise running the engine for 10 seconds should force a good portion of the rest of the air out of the block and into the radiator. Top it off again and your good to go. At that point if the temp spikes again after your repair you can eliminate the possibility that it's low on coolant. If the temp still spikes then you're likely looking at a blown head gasket. Hope this helps.

Thanks,

Tom

 

As Tom said, get the air out. Heater not working indicates either you have air in the heater corelines or the heater core is plugged up. I would go ahead and change the pump. I've never seen how the power steering is hooked up on a 3.4, so I'm not sure what your seeing.

 

Before I checked the thermostat, I tried adding coolant. After running the engine, the level at the radiator was still right at the top, and was cold, but the overflow tube was registering a little below the "full cold" mark even with the engine overheating. There is certainly pressure in the system when the engine's hot, I can hear it hissing around the radiator after I shut the car down, and the cap spurts out coolant if I loosen it. The radiator does *not* sound normal.

Is there a check valve in the overflow tube, or does that drain back into the cooling system? The level didn't change when I drained the radiator last night. I couldn't add another quart directly to the radiator, so poured it into the overflow tube. Not sure if that did any good or not.

 

The overflow tube sits lower than the radiator cap, so I don't see how water would go back the cooling system.

 

Well, I got the pump out. Doesn't appear outwardly to be anything wrong with it. A bunch of water came out when I broke the seal. With all the WD40 and antifreeze splashing around, I can't say for sure that it's a sign of leakage, but the weep hole under the bearing has a small drip, and the area around is dry.

 

Got the pump replaced and everything put back together- much to my relief, the car started up just fine I'm still watching for leaks, but it's so wet, it's hard to tell.

How do I bleed the air from the system? I left the cap off, and bubbles are coming up, but the level isn't going down.

Edit: lol, missed two key steps. One was to wait for the thermostat to open! Two is to get a beer
Seems to have worked- temps are a little high, but there may still be some air pockets or other problems. Right now, I'm on leak watch. The little rubber tube coming off the pump leaked until I adjusted the spring clamp and added a 2nd pipe clamp, but that's about it.

Thanks everyone!!!!