Assorted 2001 Alero Issues

[Surfnbiker]

The car is a 2001 Alero 3.4L Coupe. Owned since new (imagine that!)
Having a few issues to run by you guys and girls.
In order of frustration, this one comes to mind first.

Lately the car has been running warmer than usual especially in traffic. As a result I've turning on my AC to get the fans to kick on, ironically that cools the engine down nicely.

Now here's where it get a little strange, about six months ago, the temp gauge starts intermittently not registering anything, but the fans will kick on right after start up. The catch is when the temp gauge does read something, the fans won't kick on even when the engine starts getting hot.

So, I replaced the temp sender, and that remedied things for a time, as far as giving me a consistent temp reading, but the fans would still not ever come on except for when I have the AC on.

Now, however, it's back to it's old ways again. Intermittent temp readings, fan won't come on if temp gauge reads, will come on if it doesn't read. I've noticed some coolant on the floor of the garage, and it seems to be coming from around the thermostat neck.

Regular checks of the oil show no evidence of coolant in the crankcase so I'm hoping it's not the dreaded manifold leak. Just for a point of info, I do, on occasion, add coolant to the system. So any info on that situation would be appreciated.

Second, I've dealt with passlock fiasco myself, and here's where it stands now. After intermittent bouts with the system, it seems we are at an impass. The security light stays on all the time, but I (knock on wood) haven't had a "no start, wait ten minutes with the key on" situation in about a year. Although I'd like to get that light off, incase we try to sell the car, not to mention that it's flat out annoying.

Lastly is a question about ECMs. There a couple of outfits on eBay that sell used ECMs. They claim that when you purchase them, you provide your VIN # and they will "Flash" it for you and you can just plug it in and go. Does any one have any info, opinions, horror stories, etc...?

Thanks for taking the time to read my tale of woe.

[Iflylow]

When the computer cannot detect the engine temp, it will turn the fans on, just in case the engine is hot. When the AC is on, both fans run. When the AC is off, only one fan will run, unless the temp gets high enough, then both fans will run. Do both of yours run with the AC on? I suspect a fan or fan relay failure.
About Passlock: It sounds like you are in "fail-enable" mode. The computer has decided the Passlock system has failed, and you now have no Passlock protection. The light is on to let you know Passlock is inop. Read the article in the second post here: http://www.automotiveforums.com/vbul...asslock+bypass
It explains how Passlock works, and should help your diagnosis of the problem. BTW, the bypass method in the first post works great, and isn't as hard to do as it sounds.
As for buying a ECM and having it flashed, maybe. I thought they were able to be flashed only once, which was done at the factory. A dealer can usually flash a new one for you, I know. Drive there, change ECMs in the parking lot, and have them come out and do it. It should only take 20 minutes or so total.

[Surfnbiker]

Thanks Iflylow,

I will check on the fans, and probably change out the relays, just to eliminate them as a possibilty. I'll keep you all posted, but I welcome more info as well!

Thanks again

[BNaylor]

Both cooling fans are supposed to turn on in low speed mode when the engine temperature reaches 220 degrees and around 230 degrees turn on in high speed when the A/C is off. With A/C off what does your temperature gauge read. Is it over the half mark? Initially with ignition to OFF if you disconnect the ECT - engine coolant temperature sending unit and then start engine both fans turn on in approximately 5 seconds so the cooling fan relays may be good so you may be wasting time there. You may have another problem or even a PCM issue.

Also, has the engine coolant ever been replaced and the cooling system flushed? I hope you don't still have the original Dex-cool coolant since it is only good for 5 years or 150K miles, whichever comes first.

As to ECM/PCM module flashing or re-programming by those vendors on EBay that is common practice and reliable. Part of the cost of the ECM so normally they are good deals versus buying new and having a GM dealer flash it. I've never had one (dealership) do it for free and the charge can range from $40-$80 at the stealership. All they need is the VIN number and year. Also companies like DHP re-program PCM modules but I would not go that route unless you plan on modifying your Alero. See link below.

Click here

Note: With a DHP PCM the cooling fans turn on at 180 degrees so you never have to worry about temperature creep up with the A/C off.

Also, since the cooling fans turn on with A/C on then you are wasting your time with changing out the cooling fan relays.

[Surfnbiker]

First off, thanks for the reply,

If we're going at highway speeds with the A/C off, the temp will be just below the halfway mark. Around town it will hover around the halfway mark, but once you get into some traffic it will go over the halfway mark.

Originally, before all these issues, it stayed put well below halfway, in all conditions.

Yes I have had the system flushed in the past, but not recently.

Okay, I'll forget about changing out the relays since the fans come on with the A/C.

I guess from the sounds of it I'm left with the PCM then?

Thanks again.

[BNaylor]

How much higher than half? Use the gauge needle as a guide. A thermostat could cause a similar issue. However, since you mentioned you see visible signs of coolant leaking probably best to resolve that issue first. Hopefully you do not have bad LIM gaskets. Were they ever replaced with the revised ones?

[Surfnbiker]

I believe the highest I can recall seeing the needle go is halfway between hot and the halfway point, before we turned on the A/C, which brought it down to "normal" operating temps.

As far as the LIM gasket, does that present itself solely as an external leak, or, does it leak into the crankcase, my question being: wouldn't I see evidence of coolant in the oil? No, I've never had the LIM gaskets replaced.

I intend on replacing the the thermostat, if for no other reason, at least it will fix the leak.

Thanks again for your responses.

[BNaylor]

That is on the high side. We've never had it on our Alero go one needle mark above the half mark on the gauge even with A/C off. But our LIM gaskets were replaced with the revised GM ones about 3 years ago.

Also, be sure to carefully inspect the area of the cylinder head and LIM at the thermostat area. Some members had leaking via the LIM bolts and even a cracked LIM. The thermostat could be the issue so it would not hurt replacing it although it is a PITA to replace. At least cure the external leak since a loss of pressurization in the cooling system will cause the engine temperature to rise.

On LIM gasket symptoms it varies. You can have engine oil and combustion by-products in the cooling system (looks like sludge), coolant in the crankcase, an external leak only or just a simple unexplained loss of coolant via the intake system and being burned in combustion.

[Surfnbiker]

Okay, upon further inspection, I do believe that the it is the intake NOT the thermo housing that is leaking. That coupled with the presence of "sludge" in the expansion tank, confirms my fears that the LIM gasket need to be replaced.

I can see on both the front and the back of the engine, where the intake meets the heads is leaking for sure, on both banks.

I know there's a link for the replacement process on this board, so I'll try and find that. In the meantime, are there any pit falls, specialized tools, etc... that I might want to be aware of?

[BNaylor]

Here is the link. Be sure to use the FelPro aftermarket brand LIM gasket kit. People are experiencing failures with the revised GM gaskets. Good luck and let us know how the repair goes.

Click here

[Surfnbiker]

Thanks for the link. I feel confident that this is the issue I'm having even more so now that I've read it. I appreciate all the great info you've provided and will definately post my results.

[Surfnbiker]

Okay, so I finally relaced the LIM gaskets this past week end. I'm happy to say that all and all in went really well. I started Saturday morning and was able to take my wife out to dinner Sunday night.

I started by draining the block by pulling the drain plugs on both sides of the engine. Man that rear one was tough! Then I started the tagging and disassembly process. Cleaned all the gasket areas. I used the new metal Fel Pro gasket kit, which included the oil pump drive seal, which was nice. While I was in there I replaced the thermostat, and the fuel rail O rings, and since it was so easy to get to them when half the motor is torn down, I replaced the plugs and wires as well. Good thing too, because the outboard plugs look like they had been dipped in powdered sugar. The center two looked okay though.
I also flushed out the coolant reservoir because it had a bunch of sludgey material in it. Odd though that the coolant that came out of the block was really clean.

I did manage to break something, the cable for the cruise control module uses a ball and socket on the end and well I broke the socket portion. Try finding one of those on a Sunday! So since the car would run with or without it, I pulled the whole cable out and will replace it later in the week.

The only other issue I'm having is that the temp gauge isn't reading quite as low as I'd like. Back before the problems started, the needle read at least two needle widths below half way. Now after the repair, it hovers right around the middle mark. The good thing is that before the repair, it would've over heated if left to sit, or in heavy traffic, but not now.

Thanks BNaylor for all your help.

[Cre8tive]

I have a 2000 3.4L and I am having the same problem. I tore the engine down to the heads and replaced all the gaskets last winter. Ever since then the engine wants to run hot when I am stopped. I can turn the AC on though and it will go down to the normal temp. Over the past month or so I have replaced the thermostat, the ECT sensor, the water pump and checked the fan relays. Can't figure out what it is. It seems like the fans are kicking on but are not running on high or something. I did read somewhere today that the coolant system needs to be bled when it is completely drained and then filled. I guess it can make the fans and the thermostat not work properly if there is air in the system. I'm going to try bleeding the coolant system tonight and see if that works. I'll let you know what happens.