dirt in coolant reservoir, where is it coming from?

Cutehumor · Jun 13, 2003

ok..I'm checking my oil it's full and clean light brown. Since it's summer, and getting really hot. I inspect my coolant reservoir and it's empty. My car has been sitting for three days so I thought there should be some in there up to the cold mark. After opening the coolant reservoir, there is some kind of blackish dirt at the bottom of it. Pretty extensive actually. I was concerned about it but I was on my way to apply for some jobs so I went ahead and filled the reservoir up to the cold mark so there would be no overheating. It only took about 200 ml to bring up to full cold. 1st question: should I be concerned about a leak since the coolant reservoir was empty? 2nd question: what about this blackish dirt at the bottom of the reservoir? Any ideas where it is coming from? is it doing any damage? I did have an oil analysis done posted on this board and no antifreeze was found in the oil 500 miles ago. oh, I did check the antifreeze in the radiator, it was full but was not a solid green color, it was a faded watery color. I don't know what to think, any suggestions?

I forgot to add, this is a 92 Mitsubishi Mirage 1.5 Liter engine. 111700 miles apprx. I had antifreeze flushed out and changed at 104k miles, but it was a year and a half ago.

[ June 13, 2003, 05:12 PM: Message edited by: Cutehumor ]

timzak · Jun 13, 2003

The resevoir can capture some outside dirt, as it isn't sealed (it should have an overflow hose to drain out excess coolant). Also, part of that could be gunk cleaned out of the coolant system (radiator and engine block). Frequent coolant flushes will help keep the system clean. Personally, I shoot for one flush per year, or 15,000 miles.

Bogatyr · Jun 13, 2003

Cutehumor,
I'll agree with timzak that the best preventative maintenance is coolant changes. I'm wary of chemical flushes as I've always seemed to spout problems after using them. IMO the best thing to do is every 30k or two years drain the system. Fill with distilled water. Run for a few minutes with the heater on hot. Drain that. Then fill with fresh coolant.
While the system is draining, remove the overflow tank and clean that, with a toothbrush if necessary, to remove all of that gunk. My old Civic had the same strange stuff in there. I assumed it was just grunge from the engine and possibly mineral deposits from non distilled water.
Do you have a leak? Only time will tell. Just keep an eye on the coolant level. One other thing, with the age of your car, I'd check all of the coolant hoses now before it get's too hot and replace them as needed. You don't want to pop one of those puppies on the highway. When changing the fluid out, that's the best time to renew the hoses.
Bogatyr

JohnBrowning · Jun 13, 2003

I agree with the above posts but will add that a leaking head gasket can dump alot of combustion byproducts into the system. So check things out!

Cutehumor · Jun 19, 2003

quote:

Originally posted by JohnBrowning:
I agree with the above posts but will add that a leaking head gasket can dump alot of combustion byproducts into the system. So check things out!

actually, the head gasket was replaced at 51k miles at a mitsubishi dealership by the previous owner six years ago. I'm going to take out the coolant reservoir scrape all the dirt at the bottom, flush the coolant out of the radiator, and replace the hoses. hope this does the trick. I've been having alot of bad luck lately!

widman · Jun 21, 2003

Traditional coolants have a life of about 18 months, used or not used, before the silicates (if that's the right english for silicatos) drop out and form deposits or gels. (This is what often causes pump failure) As mentioned, minerals from tap water may also be dropping out. It may also be corrosion from the end of life of the coolant. The additives drop out leaving exposure of the surfaces, and cavitation starts on the side of the cylinder against the power stroke.
If you can flush it clear without chemicals, better. Once it gets to a certain point, the chemical cleaners can be good as long as they are flushed out later.
If you use a product with carboxylates (dex-cool) you will avoid much of this problem.
I know Dex-Cool has a lot of non supporters on this site, but after studying the tests and bulletins over the last few weeks I'll never go back.

moribundman · Jun 22, 2003

Regardless of the manufacturer's claims, even it's a "lifetime" coolant (VW/Audi) or whatever, when the coolant changes its color it's high time to replace it. I'd drain the coolant (radiator, block, waterpump) every 30k miles and refill it with fresh coolant. That's cheap insurance.

ekrampitzjr · Jun 22, 2003

Any chance it was oily "dirt"? I found oily residue in my coolant overflow tank some time back with none in the radiator itself. The tank had not been flushed in a while so I did so. That stayed clean, but I then found droplets of what looked like engine oil in the radiator neck. Needless to say, I feared a head gasket leak, but the oil on the dipstick looked fine. When I poked a finger around in the filler neck, it ended up with a bunch of what looked and felt like heavy grease on it. This was only in the neck and no further down as far as I could tell.

My hunch is that some friendly mechanic, knowing how I maintain my car, put grease in the radiator filler neck figuring that I'd panic after seeing "oil" in the coolant and then would come to him for a head gasket job. Maybe someone messed with yours?

Matt89 · Jun 24, 2003

quote:

Regardless of the manufacturer's claims, even it's a "lifetime" coolant (VW/Audi) or whatever, when the coolant changes its color it's high time to replace it. I'd drain the coolant (radiator, block, waterpump) every 30k miles and refill it with fresh coolant. That's cheap insurance.

I agree with the moribundman's post, but also add that with the aluminum systems these days, you can definitely have problems and see no color change. Electroplating of the aluminum can be going on in the radiator and you'd never know until something failed!

Hard to believe they used to just use water!

metroplex · Jun 24, 2003

what would happen w/ the radiator and heater cores grounded (tied to negative ground)?

unDummy · Jun 24, 2003

Overflow/recovery bottles are also passive filtration--settling tank. It is their job to allow coolant impurities that can settle, to settle.
This also gives you an idea of what is settling in the block and radiator. Every heat cycle allows the radiator to puke a pint-quart of hot antifreeze that has impurities that settle out, and siphon clean antifreeze back in when cooling.

I am a stickler for yearly antifreeze changes with distilled water. Wallyworld has distilled water for
Check bottle level regularly. Water evaporates!
If you have an automatic, make sure that the radiator ATF cooler isn't sharing cooling space or leaking with antifreeze. This can easily be mistaken for oil when it is actually ATF.

Greaser · Jun 24, 2003

quote:

Originally posted by ekrampitzjr:
Any chance it was oily "dirt"? I found oily residue in my coolant overflow tank some time back with none in the radiator itself. The tank had not been flushed in a while so I did so. That stayed clean, but I then found droplets of what looked like engine oil in the radiator neck. Needless to say, I feared a head gasket leak, but the oil on the dipstick looked fine. When I poked a finger around in the filler neck, it ended up with a bunch of what looked and felt like heavy grease on it. This was only in the neck and no further down as far as I could tell.

My hunch is that some friendly mechanic, knowing how I maintain my car, put grease in the radiator filler neck figuring that I'd panic after seeing "oil" in the coolant and then would come to him for a head gasket job. Maybe someone messed with yours?

Had a customer come in with the exact
'oily slime" in his 93 Honda Civic coolant bottle...turned out to be a blown head gasket.

Cutehumor · Jun 25, 2003

quote:

Originally posted by unDummy:

If you have an automatic, make sure that the radiator ATF cooler isn't sharing cooling space or leaking with antifreeze. This can easily be mistaken for oil when it is actually ATF.

I added a large transmission cooler in connection with the radiator ATF cooler to cool down the automatic tranny about the same time I changed out the antifreeze a year ago.

lght1 · Jun 28, 2003

Hi

Any deposits from dexcool, is usually corrosion going on inside the system.

Corrosion with dex is caused whenever there is air in the system. That can happen when the overflow bottle is allowed to empty due to a leak (internal , external)or simple evaporation.

The corrosion usually is from the impellor vanes of the pump and is deposited inside the bottle or radiator if there is insufficient coolant for the bottle.

On GM cars, the radiator cap should be replaced from the weighted OEM type to the sping loaded stant.

My LSS had an upper intake leak just before I purchased it. It was repaired and dex swapped out for prestone green-yellow as well as the rad cap to a stant.

Whenever swapping from OAT coolant to green, make sure to flush thoroughly with water before adding the green.

labman · Jun 29, 2003

quote:

Originally posted by Cutehumor:
ok..I'm checking my oil it's full and clean light brown. .... I did have an oil analysis done posted on this board and no antifreeze was found in the oil 500 miles ago.
I forgot to add, this is a 92 Mitsubishi Mirage 1.5 Liter engine. 111700 miles apprx. I had antifreeze flushed out and changed at 104k miles, but it was a year and a half ago.

I am not sure what you mean as a clean light brown. Was it the
same clear color as new oil? If it is cloudy and anything but black,
likely it has water suspended in it. Were you losing coolant back at
the time of the oil analysis?

Cloudy oil, and losing coolant sounds like it developed a head
gasket leak. 200 ml? That doesn't sound like much to completely
empty the coolant tank. Another indication of a head gasket leak, is
the failure of the radiator to draw coolant back in as it cools.

" I'm going to take out the coolant reservoir scrape all the dirt at the
bottom, flush the coolant out of the radiator, and replace the hoses.
hope this does the trick. I've been having a lot of bad luck lately!"

If after that, you keep a close eye on it, and are still losing coolant, it
sounds like more bad luck. I hope the bad luck didn't carry over to
the job interview.

RussellA · Jun 29, 2003

quote:

Cloudy oil, and losing coolant sounds like it developed a head
gasket leak. 200 ml? That doesn't sound like much to completely
empty the coolant tank. Another indication of a head gasket leak, is
the failure of the radiator to draw coolant back in as it cools.

My local Napa auto had a block leak tester for about $50. It uses a blue indicator fluid that turns yellow when exhaust gas is present. Might want to give this a try.

oilyriser · Jul 4, 2003

I used a carbon monoxide detector, a plastic
food storage bag, and a turkey baster to check
for exhaust gases in my radiator overflow tank.

Some CO detectors have a digital display. Put
one of these in a plastic bag, and use the turkey
baster to transfer some gas from the overflow
bottle into the bag, and wait for the CO detector
to respond.

It took two months for the Subaru dealership to
get the new head gaskets in, due to a parts
shortage.

labman · Jul 5, 2003

quote:

Originally posted by oilyriser:
I used a carbon monoxide detector, a plastic
food storage bag, and a turkey baster to check
for exhaust gases in my radiator overflow tank.

Some CO detectors have a digital display. Put
one of these in a plastic bag, and use the turkey
baster to transfer some gas from the overflow
bottle into the bag, and wait for the CO detector
to respond.

It took two months for the Subaru dealership to
get the new head gaskets in, due to a parts
shortage.

Great idea, thanks for sharing it with us. That eliminates the hazards
of driving a car with a doubtful head gasket somewhere to be tested.

Did the dealer get his start servicing English cars?

dirt in coolant reservoir, where is it coming from?

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