2001 Malibu / Temp Reaches Max Then Rattles/Shuts Off

I’ve got a 2001 Malibu with 157k Miles that I’ve been having to feed water too, was trying to limp it til I got my VA check but it didn’t make it.

Tonight on the way to the store, in stop/go traffic it started rattling from the engine bay as the temp neared the red line. It’s never reached the red line before. Once the rattling began the first red light I came to the car stalled. I pushed it off the road and it started, with a fight, 20-30 minutes later after it cooled down a bit.

I need help on ideas of what’s wrong. I have some tools. Recent Oil Change done by myself ~200 Miles ago, checked that, still perfect color oil and levels. Coolant Tank is filled.

Any other information needed that might help let me know!

A mechanical failure such as a thermostat sticking closed will block the flow of coolant into the radiator which will also cause an overheating problem. Additional mechanical failures can include a cooling fan not coming on and a blown head gasket. If an engine is run while overheating it causes the pistons to expand and seize in the cylinder bore while cracking the engine block and cylinder heads.Take your car to an independant mechanic ASAP


You can also have a defective radiator cap, so there isn’t enough pressure in the cooling system to boost the boiling point, and you end up with not enough coolant and overheating. My favorite kind of repair, cheap and easy.

This car has the 3.1 liter V6 . . . an engine that’s known to have issues with the lower intake manifold gaskets

When they let go, coolant and engine oil will mix, and bad things will happen

The car’s old enough, that the gaskets might have literally disintegrated by now

I agree with the other guy’s advice, but I’m a cynic and a big believer in pattern failures

I suggest placing a large tub under the engine oil pan. Drain the engine oil into it and take a real good look. If it looks like milkshake or moccha frappuccino, it’s a good guess what happened

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I’m leaning towards a warped head or blown gasket. Can hear some hissing between the firewall and rear of the engine after it stalls. Once it cools enough the hissing goes away. I wouldn’t be surprised if it was both, as the coolant has been going somewhere and now I think the rear head finally warped from the heat. Just my guess. Not very knowledgeable by any means.

Have you actually checked the level of coolant in the radiator?
Even if the overflow tank is full, the level of coolant in the radiator could be low.
Just be sure to check it when the engine is stone-cold.

I REALLY hope that you haven’t been using “straight” water in the cooling system instead of a 50/50 mix of the approved coolant and water.

The 2001 Malibu is a complete sealed system so without draining the radiator I don’t have a cap to take off and check. The surge tank I checked and is filled to appropriate levels.

I’ve had to add a gallon of yes, I know bad, straight water once and “used” green coolant about twice a week with heavy driving.

Engine damage may have occurred during the over-heating incident. But you could be lucky, so the best course my guess is to fix what’s leaking the coolant, refill with fresh, replace the thermostat and hopefully you’ll be good to go. If not post back. When you’ve got a known leak, besides losing coolant, the cooling system can’t hold pressure to as may psi as it is supposed to, and that itself will cause coolant boiling & overheating. As posted above, straight water shouldn’t be used for any length of time, as that can corrode the metal parts inside the engine, especially those containing aluminum as is the case w/ many cylinder heads…

@George_San_Jose1 I just went outside and started the car. It didn’t start as easy as it used too but it started. Only ran for maybe 2 minutes and shut it off.

What would be the best method to finding the coolant leak? I’m hoping it didn’t damage the engine but if it did, it was an auction vehicle that wouldn’t be a loss and I could use it to learn more about repairs etc.

It’s the same as finding where a house’s roof is leaking. Start looking. It usually involves a lot of awkward contortions with a flashlight, crawling under the car, etc. Sometimes I’ve had to jack the front end up to find it, other times I had to jack the rear end up instead, in order to get it to leak while I’m looking. Sometimes it leaks with the engine off, sometimes with it running, sometimes w/cold coolant, sometimes w/hot coolant, so I try each case. I usually start at the hose connectors in the area that’s leaking, as those often split w/age and are not easy to tell by visual inspection until the hose & connector is removed from the fitting. The water pump, where the water pump attaches, and all the things that attach to the water pump seem to be common culprits. The dye method mentioned above is a good one too. Some auto parts stores will lend you the special uv flashlight you need to spot the dye, if you purchase the dye kit there.

One note, it seems like every time I used to look for a leak, I’d eventually get coolant dripping into my eyes , nose, or mouth, so now I use a full face shield whenever I’m looking upwards for a coolant leak.

the method George described isn’t necessarily going to work if the coolant is getting into the crankcase

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True, coolant can leak into the crankcase or into the combustion chambers too. A bunch of white smoke during heavy acceleration out the tailpipe indicates a combustion chamber leak. If coolant is getting into the crankcase, that’s usually pretty evident by looking at what the drained oil looks like. Also check for oil getting into the coolant, the oil will float to the top of the radiator. But these things are not nearly as common places for leaks to occur as things that cause external leaks, like hoses etc. And I think OP mentioned there’s an external leak, right?

I believe external. Used to get steam near the brake booster (heater hoses are in that area). Never had any white smoke on startup or acceleration. Oil looks fresh still. Can’t see the inside of the radiator as it’s sealed, doesn;t appear to be any oil floating in the surge tank either. I was planning on replacing the heater hoses on the 3rd (My VA check comes in the 3rd) along with the surge tank itself and the recommended dex-kill fluid, flush the heater core and everything else with distilled water. Also the water pump and serpentine belt, as the belt was showing cracks.

Now with the way she’s acting I’m wondering if I warped a head. Still not smoking from the tail pipe so I’m guessing gasket isn’t blown. I have novice experience and have only done routine items on vehicles. Brakes, oil changes, battery, water pumps, thermostats etc

I’ve encountered plenty of cases where coolant was getting into the crankcase, yet there were no clouds of white smoke from the tail pipe

No offense to George

Drain that oil into a tub, as I mentioned earlier

Update: Oil looked clean, no odors of anything weird.

I found 2 spots leaking and a possible Water Pump failure, when attempting to bleed air from the system I never got a stream or water coming from the bleeder valve attached at the Water Pump.

Upper Heater Hose seems to be dripping slowly. The other leak is near the rear of the engine, kind of around the Alternator. I’m unsure of what hose is back there, maybe someone could help me figure that one out, but I noticed at the engine got hot the firewall was being sprayed with coolant, not a lot but enough for me to see it and get my attention.