2001 Malibu overheating problem

billyboy782 · #1 02-27-2006, 07:31 AM

A few weeks ago my '01 Malibu started overheating, and my wife drove it hot to get off the highway.

I have had the head gaskets replaced, heads checked, Coolant sensor replaced, thermostat replaced twice, radiator pulled, checked and flushed, new hoses and the water pump replaced, and $900 later it still overheats.

After I changed coolant sensor, the car ran perfect for about 300 miles, and then when right back to overheating. It will not overheat if I leave it at idle in the driveway, but as soon as I get it onto the road, the water will boil, and temp gauge goes to red.
I am using the correct coolant fluid and water ratio as far as I can tell.

I have read other threads on this site and have seen similar issues

Any ideas or has GM had any resolution?

dab64 · #2 02-27-2006, 02:03 PM

I have a 99 Malibu LS, 6 cyl with the same problem. I have replaced the thermostat, water pump, coolant sensor and currently have cleaner in radiator to clean and flush. Sitting in the drive is fine but get on the road and after a few minutes the temperature gauge shoots up and you pull over. No other known problems until it overheats. Could the overflow tank or pressurized cap contribute to the problem? The fans work when sitting in the drive but unsure when on the road. Is there a sensor I need to replace for these? I've seen the other comments posted but so far nothing has worked.

billyboy782 · #3 02-27-2006, 02:25 PM

Your symptoms sound exactly like mine. I have thought of the fans as well. But, like you, the fans are working at idle in the driveway. What I want to do now is drive it, and when it just starts to overheat, pull over and quickly check the fans at that point.

What is throwing me, is after I changed everything else, I changed the coolant sensor last, the car ran perfectly for about 300 miles, including highway and stop and go. Then it reverted to the same problem.

As for the cap, that definitely has something to do with it. In an attempt to add water early on, my wife broke that cap, and I had to get another one. The second cap broke as well, (defective maybe???) and I got a third one. I just tried putting that one on last night, and it doesn't fit the same for some reason. I was also thinking of replacing the whole tank, but haven't talked myself into it yet. Very frustrating.

wymi · #4 02-27-2006, 07:35 PM

Did you make sure you bled the cooling system with the bleeder screw? I would defintely check those fans while out on the road when the needle goes up. Do the fans kick on if you turn the AC on?

billyboy782 · #5 02-28-2006, 07:28 AM

yes, the system was bled at the mechanics shop, after I gave up on it. He actually took the whole radiator out and did a few tests of some sort. Changed all the hoses, ect.

As for the fans, I haven't been able to check them on the road yet. I do know they come on with AC on. I checked that in driveway.

BeatnikTermite · #6 03-01-2006, 07:16 AM

Quote:

Originally Posted by billyboy782

...As for the fans, I haven't been able to check them on the road yet. I do know they come on with AC on. I checked that in driveway.

I think that the fans come on for high temperature, and for AC, under two different control settings. The AC is hard wired into the fans so that the AC compressor clutch will not engage if the fans are not on. The temperature sets off a sensor for the fans. I think I remember this being discussed on the board at a previous time.

billyboy782 · #7 03-01-2006, 07:37 AM

thanks for that info on the fans. I am going to check it out after work today.

dab64 · #8 03-01-2006, 09:10 AM

I talked with a mechanic at the local vocational school and after explaining all I had replaced he said it sounds like an air flow problem. He had two thoughts: 1.) the fans are programmed not to come on after the car reaches 60 mph, therefore they may not be coming on while driving down the road, and 2.) if an air spoiler or damper has been removed from under the car, this could disrupt the air flow. I had removed the one from my car when I first worked on it and have not put it back yet. I will try that tonight. Any thought on his suggestions?
I put on a new overflow tank cap last night and it seems to have helped, but overheating still occurs. Also, I saw this note on a Consumer Guides site regarding the 99 MAlibu. Have you heard of this before?

Engine temperature: Overheating and coolant loss may be due to rough surface on radiator filler neck. Neck should be sanded smooth and cap replaced. (1999-2000)

billyboy782 · #9 03-01-2006, 09:28 AM

I've never heard that about the fans not coming on after 60mph - how do I even check that?

As for the spoiler/ air flow problem, don't think so, all the pieces are in place.

johnholl · #10 03-03-2006, 11:13 AM

"Engine temperature: Overheating and coolant loss may be due to rough surface on radiator filler neck. Neck should be sanded smooth and cap replaced. (1999-2000)"

That's a good one. Hahahaha. Did Mr. Goodwrench tell ya that!

John

bcopeland · #11 03-04-2006, 12:33 PM

I noticed a water leak on my 1999. After replacing the water pump, I looked under the car and noticed the leak was flowing down onto the transaxle pan. I found out it originated near the oil pump housing on top of the engine block. It looks like its leaking near where the heads connect to the block; i.e. - I think the intake manifold gasket or the head gasket is leaking - - - AGAIN !. I heard there was a new gasket type out now - I last changed this in May 2003 and I assumed I used the last type of gasket. Can anyone provide me details???

BeatnikTermite · #12 03-06-2006, 07:34 AM

Quote:

Originally Posted by bcopeland

I noticed a water leak on my 1999. After replacing the water pump, I looked under the car and noticed the leak was flowing down onto the transaxle pan. I found out it originated near the oil pump housing on top of the engine block. It looks like its leaking near where the heads connect to the block; i.e. - I think the intake manifold gasket or the head gasket is leaking - - - AGAIN !. I heard there was a new gasket type out now - I last changed this in May 2003 and I assumed I used the last type of gasket. Can anyone provide me details???

I posted this a while back, hope it helps.

http://www.automotiveforums.com/vbul...d.php?t=314398

bcopeland · #13 03-09-2006, 07:45 AM

Yeah beatnik - that was the one. Thanks! The new gasket design is much better. Cannot believe Mr. Goodwrench is still pushing that old cheap plastic design. The Fel-Pro looks real good.

GeoStormRS · #14 03-10-2006, 10:55 PM

hey billyboy,
did you ever find out what was wrong with the bu?

bcopeland · #15 03-11-2006, 08:26 PM

He never mentioned the intake manifold gaskets, but he diod mention the head gaskets. I thought from my posts and suggested areas, you all would pick up on the intake manifold gaskets - but I guess not.

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