Overheated Issues

[drv2e30]

Hello,

I've been working on my Dad's 1997 Grand Am Gt on and off now for the last year. After a major overheat and cracked heater core I haven't been able to get it to stay cool. My Dad had the dealership diagnose the engine and said it was the intake manifold gaskets so I promptly replaced those to no avail, it STILL overheats!

I'm not entirely familiar with GM cars simply because I'm a BMW e30 fan (80's model 3-series), so I'm not sure about the flaws in the 3100 engine in terms of possible head failure, cylinder wall failure, or if the engine is iron or not. I was wondering if anyone may be able to shed some light on my problems with overheating because I've been scratching my head as to the main problem of the system.

As of now I've purchased two used heads that pass a compression check and are level that I plan to use on the engine. I'm only guessing that the engine's heads, head gaskets, or valve seals are to blame for this overheating issue.

If you have any questions please don't hesitate to ask.

Thanks,

Sean

Also on a side note, I've had idle issues with this engine before where it would just start climbing rpm's at idle. While still under warranty the dealership tried to determine the issue but simply said they couldn't figure it out and just replaced the TPS multiple times to no avail. Has anyone come across this problem before?

[Xidion]

Did you check the therm-stat?
Check to make sure that the radiator isnt pluged?
Is the water pump working like it should?

Check the IAC sensor for climbing RPM might have a problem there. I will check our SI on the web tomorrow for any information on the RPM problem and the overheating issues. I get off at noon so as soon as i get home ill let you know if i found anything.

[drv2e30]

I replaced the water pump, I removed the thermostat, and the radiator flows normally but I still flushed it.

Each time I tried to make sure the car warmed up and I bled the system, but it still overheated.

Sean

[Xidion]

Heres some Engine Overheating stuff

'Engine temp lamp comes on and stays on, or temp guage shows hot, or coolant overflows from surge tank onto the ground when engine is running'

1 Check for loss of coolant. Is there a loss?
Yes Step 2 No Step 3

2 Fill the system to specified level. Does engine still overheat?
Yes Step 3 No System Ok

3Check for kinked or pinched surge tank hoses, especially at the radiator.Does engine still overheat?
Yes Step 4 No Step 5

4 1.Relieve any kinks by rerouting hoses, 2. Replace the hose if need be. Does engine still overheat?
Yes Step 5 No System ok

5 Check for loose, missing or damaged radiator air seals or deflectors. Does engine still over heat?
Yes step6 no Step 7

6 Repair or replace any loose or damaged or missing radiator air seals or deflectors. Still overheat?
Yes step 7 No system Ok

7 Check coolant concentration, Still overheat?
Yes Step 9 No Step 8

8 Replace coolant if need be. Still overheat?
Yes step 9 No System Ok

9 Use correct pressure Cap Check system for loss of pressure. Is there a loss of pressure?
Yes Step 10 No Step 11

10 Repair any leaks Does system still overheat?
Yes step 11 No System Ok

11 Check for faulty ECT, Is the ECT Faulty?
Yes Step 12 No Step 13

12 Replace ECT. Does engine still overheat?
Yest Step 13 No System Ok

13 Check radiator for any air flow obstructions or bent fins. Is there air flow obstructions or bent fins?
Yes Step 14 No Step 15

14 1.Remove or relocate add-on parts that block air flow. 2. Clean out any dibris from the radiator core. Does engine still overheat.
Yes Step 15 No System Ok

15 Check for blocked passages in the cooling system. Are there any blocked passages?
Yes Step 16 No Step 17

16 1. Remove ubstructions. 2. Flush cooling system. 3. Refill coolant. Does engine still overheat?
Yes Step 17 No System Ok

17 Check for inop cooling fan. Are the cooling fans working?
Yes Step 18 No Step 19

18 Replace Cooling Fan. Does Engine still overheat?
Yes Step 19 No System Ok

19 Check Thermostat that is stuck closed. Is it stuck?
Yes step 20 No Step 21

20 Replace Tstat. Does engine still overheat?
Yes Step 21 No System Ok

21 Check for faulty water pump, impeller blades may be eroded or broken. Is the water pump faulty?
Yes Step 22 No Start Diagnostics over you missed something

22 Replace Pump Does engine still overheat?
Yes Start diagnostics over you missed something No System Ok

[blurredvision]

ok i have the same problem and the only way it dosnt over heat is if i keep the ac on. i had a leak coming from the back of my motor block, so i fixed that and had the same problem out a new water pump , ratator, thermostat, temp sensor, and so on but my dads a mechanic and he says u have to get all the air out of the coollent system for it to read right. you have to fill the car up and then force the air out of the block by squezing the hoses coming from the radatior and then start the car let it warm up and alow the thermostat to open and keep filling it then squize the hoses again till all the bubbles are out. turn the car back off and alow to cool and then repeat everything again intill you squize the slowly and no bubbles come out will the car is running and the hold in the gas around 2ooo rpms and fill the rest of the resivour up will holding the throttle and put the cap back on and then it should be fine.

ive had this problem forever and just now fixed it by following everything i just said

[drv2e30]

I tried double checking all the hoses and pushed out as much air as I possibly could and I used the bleeder valve that was on the engine. As far as I can tell I believe there is something possibly wrong with the cylinder heads. I've gone through the diagnostic testing for the car, following chilton's repair manual, and found nothing out of the ordinary. The fan is functional, the temp sensors are functional, the hoses aren't clogged, the radiator flows, and the water pump flows (creates pressure when cold). Though the car still overheats.

Sean

BTW: the heads are aluminum and the block is iron right?

[blurredvision]

well i really dont know what to tell u besides everything i already said you can keep trying to get the air out but there will still more in there im still trying to get all of it out and used the bleader. so is everything circulating out in the system. see i put a hose and was filling it up and took of the hose goin to the water pump off and then started the car to see if the water was flowing threw the system and then went from there. and does the fan work all the time or only when the air is on?

[drv2e30]

The fan is always on when the engine hits the temperature sensor's temperature. There has always been a steady flow of coolant from the system and like I mentioned earlier, the system does create pressure when cold.

Sean

[Xidion]

Are you sure you have enough oil in the car? are you sure your not running lean all the time?

[drv2e30]

I certainly have enough oil in the engine and I haven't had an increase in fuel nor a distinct signal as to the engine running lean. Each plug has been removed for further inspection and has yet to return fouled or obviously soiled.

I did pull the front head today, and upon further inspection I have to believe that the head gasket was leaking. Cylinders two and four had an orange/rust color to them with caked on dust on each valve. However, the sixth cylinder had a grey color to the exhaust valve indicating a standard burn without coolant present.

So I believe I have confirmed the coolant leak, but I am going to test the level of the block on the cylinder head mating surface tomorrow.

Does anyone know if the block is iron?

Thanks,

Sean

[rixGAphx]

The block is iron, and is stout as hell.

-Rick

[drv2e30]

Excellent! That's what I was hoping for, I'm concerned with warping and I'm guessing the heads are shot.

Sean

[drv2e30]

Are 3100 heads all compatible? I originally had a front head that was stamped 25B however I have a replacement head that has 222. It appears to be a bit more sleek but has the same bolt patterns and fits well.

Sean

[rixGAphx]

They are 'compatible' to the point that everything lines up.

Even old iron 2.8 heads (with carb!) are 'compatible' with 3.1 for alignment, except that the 2.8 had parallel valves so there's a pushrod/valvecover issue with them.

3.1 heads have always had 'canted' valves.

But the 3.1 aluminum heads were introduced in the late '80's, for FI'd engines with OBD-I engine 'puters.
There have been casting changes over the years, and maybe a port or two added specifically for OBD-II sensors.

There are several Internet Sales sites for re-manufactured heads, and they list the various head numbers for the vehicle application.
Google 'cylinder heads' and look around.
If you can't decipher, mebbe just e-mail one of them.

Hope that helps.
-Rick

[4kQuad]

How bad is the raditor cap?

Cold cap will not seal, and expalin the no pressure.

have you checked the temp sending unit to make sure it is right?

[drv2e30]

I had a pressure gauge on the overflow bottle and the pressure was reading fine.

I've been calling around to head reman shops and everyone is saying the heads I have are slightly incompatible. One guy said that the new heads are off of a later model 3.1 liter and have slightly different intake ports with a gasket mounting hole that has been moved. I'm hesitant to continue because I've already mounted the stupid thing.

The correct casting number for the engine is 245-03769
and the new heads I have are: 245-07487.

Any thoughts?

Sean

[drv2e30]

Well I have been able to determine that the heads are able to be bolted on but have a few changes that folks at head shops are saying will throw off the computer and will not bolt on.

First off the intake manifold side looks kosher, but the intake manifold gaskets wont line up in all of the holes. Second, the compression is higher with larger valves and slightly bigger exhaust ports.

So I'm at a loss.

Sean

[drv2e30]

Well I've gone on gut feelings and the heads work wonderfully!

The engine actually sounds a little bit deeper, almost as though I put an exhaust on. Oh and when you give the engine a bit more throttle it simply sings with a vibrant tone that is new and all to its own.

Sean