Tech Tip: Slow Coolant Loss Finally Solved (?)
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From: Sammamish, WA
Tech Tip: Slow Coolant Loss Finally Solved (?)
My 1990 944 S2 has been experiencing a slow, mysterious loss of coolant. Top up the reservoir and it's fine for awhile, but it gradually goes down without much notice except for an occasional very small (quarter size or so) "puddle" on the garage floor.
So... yesterday I replaced the old yellow, ugly coolant reservoir with a shiny new one, and voila, the loss has apparently stopped. I say apparently because I've only driven the car for a day... but there's been no water loss that I can detect and the coolant temp has remained rock steady... something it didn't do before.
I guess the only plausible explanation for the fix is the old reservoir wasn't holding pressure for some reason, and that the coolant would occasionally boil upon shutdown and some of it would get dumped out the overflow.
Whatever... I'm happy
So... yesterday I replaced the old yellow, ugly coolant reservoir with a shiny new one, and voila, the loss has apparently stopped. I say apparently because I've only driven the car for a day... but there's been no water loss that I can detect and the coolant temp has remained rock steady... something it didn't do before.
I guess the only plausible explanation for the fix is the old reservoir wasn't holding pressure for some reason, and that the coolant would occasionally boil upon shutdown and some of it would get dumped out the overflow.
Whatever... I'm happy
Nordschleife Master
Joined: Sep 2005
Posts: 5,107
Likes: 4
From: San Francisco
I had a similar problem. The cause was the upper radiator hose was rubbing against the air box mount. It developed a small hole that would only leak when the car heated up. I took me a few weeks and a couple gallons of H2O to figure it out. Luckily they moved everything around when they designed the S2 so the hose wasn't near the mount.
I like your website btw. I've been looking for a nice S2 for myself.
I like your website btw. I've been looking for a nice S2 for myself.
Cast Iron Man
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Joined: Sep 2004
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From: Iowa
I had the same problem but it turned out to be the hose that goes from the waterpump back to the hardline for the heater core. It has two different diameters and a 90 degree bend. Looked like someone made a DIY hose that never quite fixed it. About 4 bucks later I had the right hose and no leaks! All the plastic and rubber on our cars seems to be ready for replacement.
