View Full Version : Automotive question

Keith Wilson
02-03-2004, 01:21 PM
I have a diagnostic question I figured I'd toss out here, and see what the "village" says, particularly those who know more about cars than I do.

The vehicle in question is a 1992 Saturn with 178,000 miles, my wife's car of which she's quite fond, and was hoping to make it last until 200,000 miles. The major symptom is brown crud in the coolant - thick slimy brown crud, not soluble in hot or cold water. There's a fair layer of it in the tank (Saturns don't have a radiator cap, the tank is where one adds coolant). Now some history: a couple of months ago, the radiator was leaking a bit and in an attempt to postpone the inevitable, I added some stop-leak to the system. It didn't work (of course), and I replaced the radiator and coolant.

Now I'd suspect oil in the coolant due to a bad head gasket or some similar serious problem. However, the car is running as well as it ever has, and there's no trace of coolant in the oil (no whitish sludge in the oil). I think we're going to replace the car this week anyway, it's getting pretty ratty, and after 177K reliable miles I really can't complain. However, my 17-year-old daughter might want the car, and it would be a lot better than having her drive the new one. :eek:

So what's up? Do you think I have an oil leak into the coolant, or is there someting else that could cause the problem? Residue of the stop-leak, perhaps? How do you tell if it's really oil? If it is oil, is the source most likely a leak in the head gasket, or is there another place that oil could leak? If I replace the head gasket, how the %#&^$%! do you get the stuff out of the cooling system, or do you even need to? Thanks in advance.

[ 02-03-2004, 01:24 PM: Message edited by: Keith Wilson ]

Gresham CA
02-03-2004, 01:28 PM
What color is the coolant, red or green?

Keith Wilson
02-03-2004, 01:30 PM
Orange. Saturn says use the no-phosphate stuff.

Gresham CA
02-03-2004, 01:35 PM
It likely is Dexcool. I have read that it will sometimes "gell" and form a brown sludge. Have the radiator flushed WELL and keep driving. Read this! (http://www.fordbarn.com/earlyv8/forum03/messages/51232.htm) And this! (http://www.penray.com/bulletins/dexcool.htm)

[ 02-03-2004, 01:41 PM: Message edited by: Gresham CA ]

02-03-2004, 01:44 PM
The brown sludge is probably releated to the stop leak and a build up of sludge over the years. Recomendations is, like Charles said, have it flushed and keep driving.

Water in oil will make the water look milky or make the oil look milky. If you suspect the water in the radaitor, check the dipstick and see what the oil looks like. If the car is running fine, chances are its not a head gasket.


edited to add: When you have your radiator flushed have them do a pressure test on your cooling system and this will help identfy any other potential problems.

[ 02-03-2004, 01:45 PM: Message edited by: cs ]

Keith Wilson
02-03-2004, 01:45 PM
No, it isn't GM antifreeze; I don't remember exactly what brand it is, but it came from the auto parts store when I put the new radiator in. It's only around six months old. OTOH, after reading the articles, it's probably almost the same stuff under a different name.

[ 02-03-2004, 01:49 PM: Message edited by: Keith Wilson ]

Gresham CA
02-03-2004, 01:51 PM
Did you flush the system good when you put the new radiator in? I'm still leaning toward a problem with coolant. Did you read this one (http://www.fordbarn.com/earlyv8/forum03/messages/51256.htm) ?

[ 02-03-2004, 01:56 PM: Message edited by: Gresham CA ]

Keith Wilson
02-03-2004, 01:53 PM
Maybe not well enough. :( I opened all the drains and ran water from the hose through it for a while. And FWIW, the car doesn't run hot even a little (although it was -5 this morning, so even marginal cooling would work fine).

[ 02-03-2004, 01:57 PM: Message edited by: Keith Wilson ]

Gresham CA
02-03-2004, 01:58 PM
That won't flush a system. Read this (http://www.fordbarn.com/earlyv8/forum03/messages/51256.htm) .

edited to add: Take it and have it flushed at a garage you trust and let your daughter drive it. My brother-in-law got over 350,000 out of his Saturn.

[ 02-03-2004, 02:02 PM: Message edited by: Gresham CA ]

02-03-2004, 02:13 PM
Had the same problem with my wife's Jimmy. Had the cooling system professionally flushed, and after that drained and replaced the coolant after 3000 miles. No problems since.

02-03-2004, 02:27 PM
My past experience with what you are describing is if it feels tacky between the fingers its related to the stop leak you put in. For an experiment take a shot glass of coolant add some motor oil to it. Shake it up let it sit and then feel it with your fingers (rub between index finger and thumb). If it don't feel like the crud in your coolant reservoir chances are its not oil.

Also if its your headgasket leaking oil into your coolant I'd expect to see some foaming in the coolant in the reservoir due to the pressure on the oil side.
I'd change my coolant, check the oil for coolant,and do a compression test. (Thats what I'd say I'd do in reality I'd just keep driving it)

Keith Wilson
02-03-2004, 03:05 PM
Thanks very much, folks. I think I just got myself a decent high-mileage used car instead of a terminal case, for a very reasonable price. :D

I really like Raycon's empirical approach. The sludge does feel sort of tacky, BTW. You'd think that after all these years I'd learn that quick fixes aren't, but nooo . . . :rolleyes: I'll check the compression when it warms up a little, but I suspect it will be fine.

02-03-2004, 06:19 PM
The critical mistake you made is that you didn't use distilled water to make your 50/50 solution of coolant and distilled water. You need to flush also with distilled water. Completely drain ,flush and add your 50/50 solution properly this time. Regards ---Bill

Jim H
02-03-2004, 07:28 PM
Originally posted by bukuboy:
The critical mistake you made is that you didn't use distilled water to make your 50/50 solution of coolant and distilled water. You need to flush also with distilled water. Completely drain ,flush and add your 50/50 solution properly this time. Regards ---BillThat's interesting, my mechanic has me using undilluted anti-freeze. It works equally well in summer & winter and I have no rust in the coolant.

ken mcclure
02-03-2004, 07:31 PM

The car started out with Dexcool, or a long-life equivalent.

If you or someone else put conventional coolant in with the long-life, it will have gelled and made a sludgy mess.

Add to that the fact that the system was probably not flushed every two years, and you have corrosion and all kinds of stuff in there that will have made it look like the Missouri river on a bad day.


Power-flush the entire system with a product designed to clean out the sludge that is there. This will take a pretty strong flush product, and if it's a good one it should be in the system no more than an hour.

Once the entire system has been cleaned out, you can replace the coolant with either a conventional or a long-life anti-freeze product. You can also consider an additive to boost the corrosion protection.

Don't be surprised if it gets messy looking again soon after flushing. It may take two or more flush cycles to get the problem resolved.

Heh. This is what I do for a living now. Can you tell?

Email me at kwmcclure@adelphia.net and I can give you some specific recommendations.

02-03-2004, 11:08 PM
Jim, You don't place undiluted coolant in a car radiator, damage will occur. For maximum protection you typically can go 70/30 ---70 being the coolant and 30 being distilled water. For minimum protection you use 50/50. Go find yourself another mechanic. Regards, ---Bill

Jack Heinlen
02-03-2004, 11:59 PM
Hmm. Not having read the entire thread in detail, I think you've got an oil leak, in the head gasket.

Now. I once knew a physician, a very bright fellow, top kidney specialist in Milwaukee, type A. Something he said to me one day will never be forgot, "The mothers who find problems with their children are ninety nine times out a hundred seeing their own ghosts. They pay so much attention they are sure to find something wrong."

I'll bet, if the car is otherwise sound, that your wife, or your daughter, will get at least a couple more years out of it. Could be wrong, it could blow that head gasket tomorrow.But at the moment it's not overheating. And I wouldn't schedule it for a trip across country. And I would change the coolant with a little more regularity. But unless it gets markedly worse, I'd just drive it. It's cheaper than a car payment.

Oyvind Snibsoer
02-04-2004, 04:26 AM
A cheap and easy way to do an emergency repair to a leaking radiator, is to put a few tablespoons of ground cinnamon into the coolant. This is a trick for emergency repairs that has been recommended by the Norw. Automobile Assn. (NAF) for years.

Don't believe me? Then try this: Punch a small hole on the side of an empty can. Pour in some water and watch it leak. Now, stir in some ground cinnamon and watch it stop!

02-04-2004, 12:22 PM
Hey Bukkaboy,

I don't think that distilled water is good for cars. Especially those with aluminum heads etc. Not good for the cooling system.


John Meachen
02-04-2004, 03:51 PM
Distilled or de-ionised water should not hurt the engine as they are less likely to react with engine components.
John Meachen

02-04-2004, 04:40 PM
Oyvind, we used to use ground white pepper in the same way. The pantry cupboard is a handy place for the amateur mechanic. smile.gif

Peter Malcolm Jardine
02-04-2004, 05:24 PM
Generally, antifreeze should be changed every 30k miles. On modern cars, the radiator is aluminum and is subject to attack from the propylene glycol. Metallic inhibitors are mixed with the coolant to prevent this from happening, but their life is limited. A good flush is something to start with, but if the coolant is really old, it might have shortened the life of the rad. The new high quality coolants are good for a little longer life.. about 40 to 45k miles.

Jim H
02-04-2004, 05:54 PM
That's really strange, my first radiator lasted 150,000 miles or so, it sprang a leak in a plastic seam. The core is metal and the ends (tanks?) are plastic. Let me say this, I always had thought it was a 50/50 mix but so far it's worked well for the last 75,000 miles. The truck has been running on straight antifreeze for 125,000 of it's 176,000 miles.

Keith Wilson
02-05-2004, 10:15 AM
Thanks, everyone for the advice and counsel. A quick update: The problem was as far as I can tell NOT oil in the coolant. I replaced the thermostat yesterday (Rubber seal disintegrated, wouldn't close. An unrelated problem, but damnably uncomfortable when it's 15 below.) and drained most of the coolant while it was still fairly warm. There was no evidence of oil. There was no sludge in the thermostat, the hoses, or the radiator. I also did a small experiment, and couldn't get motor oil and coolant to form anything like the tacky sludge I found in the tank.

So here's what I think happened: The design of the Saturn cooling system is kind of unusual; the expansion tank is pressurized, but out of the normal flow path of the coolant. I added stop-leak to the tank, but unlike in other cars where one adds it directly to the radiator, it doesn't get circulated very well. Hence, brown stop-leak goop accumulated in the tank, exacerbated by low temperatures, and both the Saturn tech and I feared it was oil. I'll get the cooling system flushed as soon as it's convenient, however.

Anyway, the car's now working fine, and since I fixed the thermostat the passengers aren't freezing. Maybe we will get it to 200,000 miles. smile.gif smile.gif

One point for Peter - most antifreeze, in the US anyway, both the ordinary and the long-life type, is ethylene glycol based. There is a type that uses propylene glycol, but mainly because it's less toxic, not for superior cooling or corrosion protection. And Jim, I suspect straight antifreeze wouldn't work around here; if I recall correctly it freezes at a considerably higher temperature than a normal ethylene glycol-water mix. I think the lowest freezing point is at a 70-30 ratio.

[ 02-05-2004, 10:19 AM: Message edited by: Keith Wilson ]

Nicholas Carey
02-05-2004, 07:16 PM
Originally posted by Keith Wilson:
I replaced the thermostat yesterday (Rubber seal disintegrated, wouldn't close. An unrelated problem, but damnably uncomfortable when it's 15 below.)Not to mention a little hard on the car.

The engine doesn't get warm. Gasoline vapor in the cylinder condenses on the cylinder walls and washes the down, stripping the cylinder walls of the oil needed for lubrication. It drains into the crankcase and dilutes the crankcase oil.

How's your oil level? Higher than it was when you last changed it? You might want to change the oil.

A friend of mine blew up his engine by drift-busting his way across Indiana in a blizzard. The radiator and engine compartment were repeatedly packed with snow and never let the engine get warm. Eventually the engine threw a rod and that was that.

An expensive way to travel.