Strange Coolant loss Topic is solved

Ghassan S · Post by **Ghassan S** » 06 Jan 2006, 10:30

Hi,

I have a 1998 S70 T5 with 260,000km. One day I topped up the coolant reservoir tank to 'max'. The next day I noticed that the level had dropped to roughly halfway btw max and min. So I topped it up again. Then after one day I checked again and the same thing happened. It has been 3 weeks now and it is still halfway btw min and max. What is wrong?

Thanks.
Ghassan.

White850Turbo · Post by **White850Turbo** » 06 Jan 2006, 10:43

Is there any oil mixed with it? If so, the most likely problem is a broken barrier in the radiator that seperates the coolant from the oil. If not, maybe a leaky line somewhere or a very leaky heater core.

Guest · Post by **Guest** » 06 Jan 2006, 12:21

Same thing (coolant loss) would drive me crazy too and then I noticed a hairline crack in either the screw-on lid to the overflow/fill resevoir or the top of the resevoir itself. (It was a while ago and I'm not leaning over the car right now, thank God). I just stopped topping off and everything seems to be running fine. (of course there was a water pump replacement in betweeen all this but this is over 7 years, 4 before, 3 after). I just keep an eye on that temp guage, of course.

Ghassan S · Post by **Ghassan S** » 06 Jan 2006, 12:40

There is no evidence of oil/coolant mix in the reservoir tank and neither on the oil level dipstick. There is no coolant fluid on the parking spot either. The car runs absolutely probelm free.

What kind of hints should I look for?

White850Turbo · Post by **White850Turbo** » 06 Jan 2006, 13:10

Ghassan S wrote:There is no evidence of oil/coolant mix in the reservoir tank and neither on the oil level dipstick. There is no coolant fluid on the parking spot either. The car runs absolutely probelm free.

What kind of hints should I look for?

When coolant dries, it leaves a powdery white residue, so look for that. Can't believe I didn't mention this before especially considering the mileage on the car, but has the water pump ever been changed? It's pretty easy to get a look at the pump by removing the single (12mm I believe) bolt that holds the timing belt cover on. And as the previous poster mentioned, it could be a cracked overflow tank. The best time to look for leaks is just after you've driven the car as the system will be under pressure and leaks will be more evident.

Ghassan S · Post by **Ghassan S** » 06 Jan 2006, 13:24

Hi,

The water pump has never been replaced. The expansion (= reservoir tank) has been replaced since it developed a crack at one of the hose attachments.

Is there a quick and dirty way I can check if the water pump is leaking? For example revving a stationary car on the garage floor? Or looking for splash signs on the serpentine belt?

Thanks.

Post by **MadeInJapan** » 06 Jan 2006, 21:51

Ghassan,
Put a paper towel under and around your expansion tank. Sometimes these leak just enough not to be noticed. If your paper towel ends up being wet, this is the cause. I would doubt the water pump, but it could be. The one screw off of the TB cover will reveal the leak. Use a strong flash light and check below. Other possibilities is the main hose to the radiator. If it even gets out of position a little bit, you could create a small leak that's not revealed readily.

This whole thread reminds me of a coupule of posts I read a while back. A lady posted over on the brickboard who had a husband who was a fanatic about keeping fluid levels exact, all the time. She thought the expansion tank was suppose to be all the way filled up and so one day she noticed it was low and filled it up and didn't tell her husband. A few days later it was low (at the correct level) so she filled it again. This happened over and over but she never told her husband because he was involved with a bunch of stuff that caused him stress at work and she didn't want to worry him. The husband, during this whole time was involved on another board and was posting that every few days he would check his wife's car and the coolant level was at the top of the tank so he would drain some coolant off to get it to the right level. After a few days, the level had increased again. He was stumped and posted about the "mysterious increasing coolant." Someone finally figured out what was going on, matching up the couple from the 2 boards and informed the husand. All of us had a great laugh!

On a serious note though, I hope you figure out why you're losing coolant.

Ghassan · Post by **Ghassan** » 07 Jan 2006, 12:09

I will reply back with results.