: need advice-- cooling

10-23-03, 06:33 PM
97 seville delegance. 90,000. got low coolant warning. expansion tank was low. had not been checked in a long while. car has not been overheated in 10,000 miles that i have owned it. added coolant. level seems to hold after 150 miles. But, noticed a slight oily (emulsfied) coating in the expansion tank. no water in oil system.
so, here are the questions?
1. sell it quick?
2. what kind of coolant can i get that is compatable, beside the overpriced gm type.
3 what are the pills that are added to the cooling and where can they be obtained.
4 how hard is it to flush the system?

love the northstar power and gas milage, but it's a little scarey to own such a high tech (expensive) engine
thanks guys

10-23-03, 10:19 PM
after reading alot of tech stuff on here---maybe---the slight oil on thesides of the expansion tank is from the mobil one being so good at finding a place to leak out of.,
and on the oil consumption issue, when i bought this car at 80,000 miles it was burning about a qt every 1200 miles. since running it hard to get the carbon out of the rings and changing to synthetic, it's now about 1 qt every 2000.
but i still need some help on the coolant situation

10-24-03, 07:54 AM
Your system uses Dex-Cool, correct? If not, disregard this entire post. If it does, the material you see in the expansion tank could be a harmless accumulation of the coolant supplement. It is obvious in there and collects because there is no active coolant "flow" through the expansion tank during engine operation. Not to worry.

Texaco Havoline Dex-Cool is available at Wal-Mart and I believe Prestone has also recently been licensed to produce Dex-Cool. I keep my supply jug of anti-freeze pre-mixed 50/50 with distilled water for top-offs on several Dex-Cool equiped vehicles.

My vehicles do not get flushed. As they approach 5 years / 100K miles, I drop a hose and drain as much as possible and refill with the 50/50 mix.

The pills (coolant supplement) you mentioned are available from GM of course. And BarsLeak GOLD SEAL powder in a tube is the same material. Also available at Wal-Mart (most of the time!). When you have the hose off to drain, put the powder or the (crushed) GM tablets in the hose, not in the expansion tank.

You use synthetic oil because of cold winter temps?

Jim / '98 STS

10-24-03, 12:18 PM

I was having the same coolant leak problems in my '97 DeVille. I thought about using BarsLeak or the Cadillac pills, but both the Caddy dealer and my personal mechanic told my that those additives, some of which contain particulate matter (aluminum or natural fibers) can clog some higher mileage cooling systems that already have some dirt in them (around 100k plus miles). With a high mileage car, it might be best to flush the system before using one of those products. Otherwise, I would suggest using a cellulose based cooling system sealer, which is less likely to clog older systems. I was too cheap to pay for a flush, so I use one of these, and it has been working great so far... I can't remember the brand of the product I used but I'll find out. It was $7 per can, which is enough for a V8.

Good luck,

10-24-03, 03:50 PM
"You use synthetic oil because of cold winter temps?

Jim / '98 STS[/QUOTE]"

I use synthetic just because i think it's a better lubricant. Now of course that is debatable in many circles, but from experience with Volvo turbos for 17 years, I have seen a difference in different ways. Now i do think it is even more beneficial in turbos, but i'm paying about the same on oil changes doing it myself with synthetic as letting some high school drop out do it at jiffy screw.
Also, i am a Marine engineer, (I make the propellor go round) and I have seen over the years some very penny pinching companies switch over to synthetic in various equipment.
Thanks for the info


10-24-03, 10:51 PM
Bill[/QUOTE] (edited)....I have seen over the years some very penny pinching companies switch over to synthetic in various equipment.
Thanks for the info

Just trying to further my education on synthetic oil and empirical (no matter the motivation) data cannot be beat.

Good luck with your Northstar cooling situation.


10-24-03, 11:45 PM
Was the emulsified oil "pinkish"? If so you MAY have a transmission cooler leak.

Typically you will get transmission fluid into the coolant, not good. Eventually it will start going the other way i.e., coolant into the transmission. Very bad!

If this is the case I would replace the radiator (which contains the transmission and engine oil cooler), thoroughly flush the engine with plain water until there is no evidence of contaminants, two capsules of Bars Leak Gold added to the lower radiator hose, then refill with correct type of 50/50 coolant mix.

I have replaced the radiator in each of my STS's and they cost about $189 online.

Good Luck