99 Grand Am 3.4

Ok...here it goes

I just rebuilt the top half of the engine (new heads, gaskets (intake and head), pcv valve, egr, all vacuum lines, coolant sensors (level and temp.), new upper intake, water pump, thermostat 2X. All parts from the store (not dealer) at about $600. I tried bleeding the system for coolant and NOTHING! No pressure in the hoses from the radiator, fans won't turn on, and the bleeder it deffinatly working. Does ANYONE have an idea, had the car for 3 months and afraid to drive it. I hard wired the 2 fans to run through the sunroof fuse (there isn't a sunroof). and still no pressure. I covered the basics. Any clue? Its a 3.4 engine with 143,000. Don't know what else to do, i'm lost. :runaround:

So are you saying that its overheating? Even with the fans rigged, it is overheating?

Was that coolant level sensor in the coolant reservoir? Did you replace the whole reservoir? If it's not holding pressure the first thing I would check is the reservoir cap (~$5 at parts store). I had similar symptoms on my 2000 Alero 3.4 v6. Turned out to be the coolant reservoir itself, not the cap. It just would not hold pressure. Cap is supposed to hold up to 15psi before venting. I was able to figure this out by squeezing the upper radiator hose near the thermostat - when cold it should be easy to squeeze, when engine is up to temp (after 10-15 min drive) it should be much firmer (like a basketball). Try this: place a clear plastic water bottle with about an inch of water in the bottom down next to the coolant reservoir, near the cap. (Gatorade bottle works great for this). Stick the overflow hose down in it. Overflow hose will hold bottle in place. With engine cold, you should be able to squeeze the upper radiator hose w/o any bubbles forming in the gatorade bottle. On mine, even though everything looked AOK, even with a new cap, the pressure was somehow leaking right out thru the overflow tube. I've heard of this on several Aleros/Grand Ams 99/00's, I'm beginning to think that the plastic reservoir warps with age so that it just doesn't seal to the cap. $40 for new reservoir (or grab one from the junk-yard). Hope this helps.

yes with the fans rigged it over heats, i service the coolant like usual, and i bleed the system, see it come out, close everything off. I have replaced the resevoir cap and the unit itself. I have done everything i could think of even replace the hoses...i changed the radiator and it still does it. If i drive it just a block, i see the temp gauge rise above 220 and i shut it off. and if it idles it stays at a constant 215. It does this with water, green antifreeze, and dexcool. No leaks in the engine, and the engine runs beautifully. Just won't accept coolant........:mad:

Coolant sensors for the "low coolant" light is on the resevoir, and the Temp. Sensor is located right above the thermostat, under the vacuum lines.

Does your heater work? If you turn it on max temp, you should get really hot air out of it; otherwise the lines may be clogged.

Fans are supposed to come on in low-speed mode @220 degrees and high-speed @230 degrees. Fans also come on when A/C is on. If fans come on when you turn on the A/C, the fans/relays are probably OK. I've seen the temp gauge get up to almost 3/4's before fans came on. I'm just saying that if your water pump is working, it's not the end of the world if the temp gets up over 220... Some people switch to a 180 degree thermostat just to keep things cooler.

However, if no pressure builds up in the cooling system when engine is hot, there is a leak, and you will have problems because coolant will boil at a much lower temp when it's not under pressure. About the only place where air pressure alone can leak out is the coolant reservoir∩ everywhere else you will probably get liquid coolant leaking out. Does it eventually boil-over (out the overflow hose)? I would turn the heater on high, run it 20-30 minutes, see if pressure builds up in system, if not look for steam or liquid coolant leak. It's going somewhere...

interesting you should see some kind of pressure in the upper radiator hose,
does the upper radiator hose ever get warm or hot?

- did you put the belt on correctly?

I had a similar problem with my 2000 GA 3.4 V6.. ended up after all said and done.. that the bottom feed of the coolant reservoir tank was warped from an overheating once and the pressure never could stay. Even though the hose was clamped on tight it still was enough to not hold any pressure. Once I replaced the reservoir it fixed all that. Doubt it's what you're in the middle of.. but that's what I had to deal with in that similar scenario.

interesting you should see some kind of pressure in the upper radiator hose,
does the upper radiator hose ever get warm or hot?

- did you put the belt on correctly?
good call, if you did not get the correct length and failed to wrap the belt around the Water Pump this seemingly could happen although it should be quite obvious

will opening your cap too soon when the car is warm mess up the reservoir tank... cause after that happend it wont hold coolant, spits out of the overflow, new cap, t-stat, water pump, coolant temp sensor, heater core