[Mitch_N]

Hi guys,

My car does not seem to be too happy lately.

Problem:

Engine overheats. Up to 6 months ago the temperature was climbing to 180F (1/2 way) and would stay there. Lately the temperature gauge climbs up to 220 F (3/4) when stop and go, and not higher than 200 F when driving at a steady speed and constant RPM.

Observations:

1) The Coolant is at the right level, right concentration and clean.
2) Radiator and cooling system has been bleed.
3) Thermostat. Testing the thermostat was easy; around 180 the thermostat opened making the upper and lower hoses and radiator become hot.
4) Fuses- all fine.
5) No Flashing lights on dashboard or codes (tested at AutoZone).
6) Relays- I switched the relay positions between relays controlling fan 1 and 2. And also switched them between HVAC and relay mode. Nothing changed the situation but it is very unlikely that all relays have failed and they work for the A/C.
7) Cooling fans- kick in at 220F and run until temp reaches 180F then they stop until temp reaches again 220F. 1 fan works when A/C is on at all times but does not seem to help too much.

I hope you can help me here.
Thank you.

 

[Macleod52]

Sounds like you've got a case of the normals. Nothing is wrong with your car.

 

[WILL I AM F117]

Check the oil level on your car, if it is low, you can get a lot of friction on the engine and that could result in overheating.

 

[Mitch_N]

Thank you for your answers.

WILL I AM F117 - The oil level is ok and I still have about 500 mi on it.

Macleod52- That is what my mechanic is telling me. Being a student(limited funds) and having a 11 yr old car I pay attention to everything out of order.

Mitch

 

[Malibu Glow]

Overheating would be if the needle goes into the red on the gauge. What you've mentioned is normal operation of the cooling system. Are you sure you have a 180 thermostat in you car, these come with a 195 thermostat from the factory and the PCM/ECU is programmed for this.

 

[Mitch_N]

Hi Malibu Glow,

The thermostat that comes with the car is 195 F i have no idea if the thermostat was changed before I bought the car.
In the first 2 years the Temp Gauge was at 180F never above and now it goes up to 220. My question is what could cause the big change? Of course I understand now that the fans are supposed to kick in at 220 F. Were they coming on earlier?

Thank you for the post,

Mitch_N

 

[Macleod52]

The fans would only come on if it reaches 220, not before. Either you have never noticed it before, or you have never had a scenario that would cause the car to reach 220. Either way, the car seems to be doing what it was designed to do. If you fans didn't kick on, or your car reached started going above the 220 mark with no fan kicking in, then I'd worry.

 

[dennisk]

While you say the coolant looks clean, when was the last time the system was flushed? Just because it looks ok doesn't mean it actually is. I've come across this before where someone thought their coolant was ok, took it to the dealer, and the flushed the system and problem solved.

 

[Mitch_N]

Hi,

220 F being normal operating temperature makes me not to worry anymore.

Just as a precaution measure I`ll have the system flushed probably is time. It is cheaper than a new radiator.

Thanks Mates.

Mitch_N

 

[Mitch_N]

I found the source of the problem. The cap was not sealing the surge tank (mechanic was adding a pint every 3000 miles). It does not seam to make any sense. Liquids under pressure reach boiling point faster... Now with a new cap temperature stays at 180 solid and steady as it did before.

 

[Malibu Glow]

I found the source of the problem. The cap was not sealing the surge tank (mechanic was adding a pint every 3000 miles). It does not seam to make any sense. Liquids under pressure reach boiling point faster... Now with a new cap temperature stays at 180 solid and steady as it did before.

Liquids do not reach boiling point quicker under pressure, it allows the coolant to go above the normal boiling point of water. without pressurizing the cooling system the coolant would already boil before it ever reached 180 degrees.

 

[Red LTZ]

Liquids do not reach boiling point quicker under pressure, it allows the coolant to go above the normal boiling point of water. without pressurizing the cooling system the coolant would already boil before it ever reached 180 degrees.

So I wonder.... Since the system was not pressurized the coolant was actually boiling and then causing bubbles in the system that caused pour circulation, and thus the higher than normal operating temperature????????

 

[BillD64]

Antifreeze and pressure raise the boiling point of the coolant. Most 195 degree thermostats start to open around 86 degrees Celsius or 186 degrees Farenheit. The ones I have purchased recently have all been marked 86 C. Straight water boils at 212 at sea level and a 50% antifreeze mixture boils around 265 degrees. Add a working pressure cap and the coolant shouldn't boil until the temp reaches much higher. When the cap goes bad what usually causes the boiling are the hot spots inside the engine where the temp exceeds 265 degrees.

Bill

 

[Mitch_N]

I know that the damage was done oil started leaking around the seals this summer after the car started to heat up. I was wondering if the mechanic is responsible for this. I told him to check the belt and belt tensioner. Belt is shiny like a marble and the belt tensioner is at it`s wear limit. He told me that everything is ok- can`t trust that person. Need a new mechanic.

 

[Malibu Glow]

I know that the damage was done oil started leaking around the seals this summer after the car started to heat up. I was wondering if the mechanic is responsible for this. I told him to check the belt and belt tensioner. Belt is shiny like a marble and the belt tensioner is at it`s wear limit. He told me that everything is ok- can`t trust that person. Need a new mechanic.

Uh, where is it that the belt or tensioner are to blame for an oil leak? Just because the belt is shiny doesn't mean it's bad, the proper way to tell if it is bad is by checking the V grooves on the underside for cracks and when there's a good bit of cracking on the underside it'stime o replace before it breaks. The tensioner is not gonna be a problem from a wear aspect though, unless the tensioner is bouncing and not holding tension.

 

[Mitch_N]

Well the tensioner in bouncing like a guitar string. The only connection between engine overheating, belt tensioner and oil leak is my mechanic that assures me that everything is fine. For the overheating he ran all possible tests and turned out ok but did not think about a seal on the cap. When I got the car the engine was clean and stayed like that for a year. When oil started seeping around the gaskets I asked to fix it and he replied that in older cars (1998) is normal to have leaks. Lights would go dim when breaking with a cold engine- alternator output and battery voltage are ok. AC would stop working for a few minutes. All driven by the serpentine belt that is shiny and squeaks when cold, tensioned by a tensioner that is at the wear limit and bounces.

I think the guy wants me to go to him when the car would need bigger repairs or he is not the right one for my expectations. Any how I am done with that shop and have to find a new Mechanic.

 

[Malibu Glow]

Well over time you wil get oil seepage, not an actual leak cause you don't really loose much. Lights going dim are common on N-body, I should kno case it occurs on mine with no actual problem, just an annoyance. AC, does it shut off randomly? If this is the case then that is also a common issue related to the HVAC controls and NOT the serpentine belt. Why is it that I can give these circumstances? Because they have been discussed on United Malibu's website for the past three years with many of those members who've come across havng these issues as I have too.
The oil residue would be nothing to worry about. Unless you are losing oil by the quart. The dimming can't really be figured out, or it hasn't been yet, it's never caused me an issue and my car starts every day since I've owned it. The AC issue does have a fix, but it requires taking apart the HVAC controls to remove corroson on the contacts for the switch, or you could replace the whole HVAC control unit.

 

[green03malibu]

Being a student(limited funds) and having a 11 yr old car

Haha, I'm in college, anyways, this seems like a normal thing for our generation Malibu. About 95% of the time, I'm half way, where it should be and the other 5% of the time its at 200 F. And I'm glad to see you found your problem, I need to replace my cap too. By the way, how much did your new cap cost?

Lights going dim are common on N-body

I didn't know that was a common issue with the N-body, I figured it was my rebuilt alt that I thought was a dud. Thanks, that helps me out.

 

[Mitch_N]

Hi,
Geen03Malibu - The surge tank cap was 4.99 at autozone Part Number:
7039 . I am sure that other stores carry this same item at either better quality or price. I have no idea how much would it cost from the dealer.

Malibu Glow - A/C does shut down randomly and in the summer the mechanic run the engine for about 1 hour with gauges hooked up to the system, changing rpms - waiting for the AC to turn off so that he can observe what is wrong. Guess what in that hour everything worked, haha.

I think that my frustration is generated also by the fact that I don`t have experience with cars and I can`t tell the difference between a vital problem and a minor problem. Over all what matters the most is that the car is taking me every day from point A to B and back.

 

[green03malibu]

The surge tank cap was 4.99 at autozone Part Number:
7039 . I am sure that other stores carry this same item at either better quality or price. I have no idea how much would it cost from the dealer.

Is it a OEM (Original Equipment Manufacturer) part, as in it looks exactly like the original one?