'99 Malibu - low coolant

My daughter's engine overheated briefly recently, just as she was arriving at her destination. After letting it cool off, she added water (only thing available where she was at the time) and headed home. It didn't overheat again, even though she drove it a few days before my husband could check it out.

At 122,258 miles, he did the following:

Oil & Filter Change
Replaced PVC tube
Replaced plastic coolant overflow tank (was cracked)
Replaced upper and lower radiator hoses
Flushed and filled coolant system (Peak 50/50 Long Life Coolant was used instead of DexCool)

Prior to doing this work, the engine was making a tapping sound. That went away by the next day. She doesn't ever seem to "hear" anything, and we haven't had access to the car since then, so we don't know if this "noise" has returned or not.

Now, 10 days later, her "low coolant" light is coming on and she can barely see coolant at the bottom of the overflow tank. As long as she can see coolant at the bottom of the tank, is she OK driving (not overheating) until she can get some more coolant to add this evening?

I'm still reading about possible causes for the low coolant, and it looks like the LIM gasket is the primary suspect. (It was replaced about 5 years ago, along with the upper.) What other things do I need to nag someone into checking? :biggrin:

Try tapping on the coolant tank with a rubber mallet and have someone watch if the light goes out

Hi There.

What happens is that the low coolant sensor "does not work right"
after you use the wrong coolant.
In my case I used water during the summer then dextrol during winter.
The good thing is that that light will burn out after a while.

Or you could get a new sensor and install the correct coolant.
But the other stuff is just as liable to mess up your other 2 sensors.

Cheers
Stripe

Hi There.

What happens is that the low coolant sensor "does not work right"
after you use the wrong coolant.

The overflow tank was just replaced after her car first overheated and was low on coolant. She never got a low coolant warning with the old tank in place because the sensor was broken. She has not added plain water to the new tank.

Maybe I've misunderstood what my husband told me, but the new overflow tank has a new sensor in it, doesn't it?

Are you saying that the Peak coolant is not acceptable and would damage the sensor in less than two weeks?

The sensor doesn't care what coolant is in it. Disregard stripes comments! If the light came on and the coolant was low (as you described) than it is working as intended. These do get finicky and sometimes will stay on after you fill the reservoir. A light tapping of the reservoir with a rubber mallet will usually take care of it. I doubt if you will experience this problem since it is new.

As far as driving with the reservoir low. Its leaking somewhere, how fast we don't know. Keeping the reservoir full until it is repaired would be your best option. If you don't keep it full you will eventually not know how low the coolant actually is and run the risk of overheating again. Two things that are really bad for an engine are overheating and lack of lubrication.

If it is the LIM gasket leaking again (it would not surprise me in the least) taking care of it as soon as possible would be a good idea. These can get bad enough that they will start leaking coolant into the oil. Once this happens there is a fairly good chance that the main bearings will get washed out and cause some severe damage. We don't bother giving estimates for these anymore if there is coolant in the oil. We give estimates on reman or used engines at that point!

Typically you can look down under the throttle body and see signs that it is leaking so it may not be a bad idea to at least give it a look-see.

Good luck and keep the reservoir full!!

Thank you ... I will have her keep a close eye on everything on a daily basis.

[quote=Airjer_]The sensor doesn't care what coolant is in it. Disregard [stripes] comments!

You are absolutly wrong in that statement.

The wrong coolant (water mostly) can screw up all three sensors.
First to go will be the low coolant sensor.
I have proof in my driveway.(wrong coolant used/low coolant light burned out)

Check Mitchel on demand and see what they say.

I only post from experience or I add it is a guess.

Cheers
Stripe

Stripe I am not going to argue with your one vehicle that had something go wrong through nothing more than coincidence. Theres no way the "wrong" coolant will burn out a bulb!!

I have 13 years of experiences and service at least 10 cars a day = 50 cars a week = 200 cars a month = 2400 cars a year = 72,000 cars at least over the 13 years. I am personally responsible for replacing the Factory coolant in thousands of GM vehicles and have found no ill effects from this practice. If this where an issue there would be some sort of "buzz" about it in the professional automotive community and there is not!

If you want to continue to compare your 1 car experience against my experience thats up to you, but please stop spreading unfounded misinformation on topics you have no real experience with!

Sell it

...
....If it is the LIM gasket leaking again (it would not surprise me in the least) taking care of it as soon as possible would be a good idea. These can get bad enough that they will start leaking coolant into the oil. ....

Good luck and keep the reservoir full!!

Well .. unfortunately it does appear to be the gasket. Can we get the most recently new and improved gasket through O'Reilly (where we get most of our auto parts) ... or somewhere else?

Most engines have a 60 degree slant, the malibu's...(even the new ones) have a 90 degree slant and for some reason it's not working out for them....p o c....

Will a new radiator cap (which has new O rings: one inner small one and one outter larger one) with cleaned coolant container surface help seal the coolant system to help prevent the coolant leakage?

Someone found this solution and had tried this method successfully and spent $10 only! Anyone has the same experience? Please comment.

Will a new radiator cap (which has new O rings: one inner small one and one outter larger one) with cleaned coolant container surface help seal the coolant system to help prevent the coolant leakage?

Someone found this solution and had tried this method successfully and spent $10 only! Anyone has the same experience? Please comment.

I have no idea what that has to do with a leaking intake manifold?

I have no idea what that has to do with a leaking intake manifold?

I have no idea either. My guess is it is probably a different kind of coolant leakage.

Not sure if you already replaced the LIM gasket on your `99 Malibu (vin M) yet, as this thread appears inactive for the last couple of weeks now, but I've got the same car and had read and heard good things about the "updated" FEL-PRO metal gasket and just had my `99 Malibu's replaced a couple days ago for $250 (labor @ $45/hour) + the FEL-PRO Part # MS98004T and 1 gallon of coolant.

RockAuto has this updated gasket set for ~$68, but nearly all auto parts stores (including O'Reilly) carry this gasket set (or can quickly get it) and I found mine for ~$74 locally after calling around a few favorite places. It's about $25-30 more than FEL-PRO's standard gasket set, but obviously the labor is the big cost so I'm hoping this one will out-last the car!

A couple years ago, I bought the LIM gasket for my `96 Monte Carlo at the dealer for ~$50 and although they said it was an "updated" version, it was black plastic/nylon and doubt it will last as long even though I've flushed out the DEXCOOL. Have sold the car since so don't know it's status, but I did recently hear a mechanic say that GM has a Tech Bulletin out now that says the LIM gasket on 3.1/3.4L engines is now a "routine maintenance" item to be replaced every 60K miles.

Don't quote me on that exact mileage, but I believe that 60K was what he said. I never researched it after hearing this, but I imagine it's true cuz this guy has proved to be credible with past remarks. I think it's incredible of GM to expect people to do this every 60K miles, but that's apparently how GM rolls on this issue!

Hopefully this new gasket will last!

Not sure if you already replaced the LIM gasket on your `99 Malibu (vin M) yet, as this thread appears inactive for the last couple of weeks now, but I've got the same car and had read and heard good things about the "updated" FEL-PRO metal gasket and just had my `99 Malibu's replaced a couple days ago for $250 (labor @ $45/hour) + the FEL-PRO Part # MS98004T and 1 gallon of coolant.


He did use MS98004T and thought he had it fixed, but unfortunately it is still leaking coolant somewhere. This is becoming a never-ending battle. :banghead:

And ... I would be thrilled if we could have work done with labor @ $45/hour. It would make it easier for my husband to tell the kids to find another mechanic.