Joe '87 S4

I'm slowly losing or burning coolant but I can't find any leaks. It's not much but yesterday I filled it to the line with the engine cold. Then I had about a 230 mile trip, used the AC the whole time with outside temps in the mid-80's. When I checked it this morning with the engine cold, it was down about 5/8-3/4 from the line. In the past 6 months I've had the low coolant light go on two times and each time I refilled it to the line. No light yesterday so it wasn't down enough to trigger the light but still it was down. Also, what are you all using for coolant?

dr bob

I had a leak that did the same thing. Turned out to be a hose that wasn't clamped correctly, top hose at the engine end. Took a while to find it. Hose was piched ever-so-slightly under the clamp, and there was a tiny bit of seepage. Not enough to make it to the ground, but enough to leave a telltale stain on the water manifold. It was also running forward on the bottom of the hose, and stained the back of the radiator end tank. It was my fault, since I replaced the hoses when the TB was replaced.

----

Before you do a lot more than casual investigation, replace the coolant bottle cap. These are inexpensive from 928 Int'l and others for the genuine Behr cap, less than $10 last time I looked. The rubber washer that does the sealing in the filler neck there does deteriorate over time. A small imperfection will allow coolant to go out the overflow hose to the ground, or more likely to "dissipate" on the belly pan. The most likely time for this leak is during a hot soak, when the engine is shut off after running on a hot day. IMO, the cap is a maintenance item that deserves regular replacement, like every 5 years or so when you do the TB and replace all the coolant hoses. You do have recent coolant hoses if you follow that plan.

Mrmerlin

check the top of the radiator on the passenger side, (this part gets the hottest coolant) does it look like there are deposits or white chalky stuff along any of the end tanks edges? If you see this, it is a sure bet that your end tank may be cracked or the internal seal has sprung a leak, the tank usually cracks along one of the bends near the metal tabs. If this is good I would still replace the coolant cap and also remove the aircleaner and inspect the hoses at the rear of the engine, you have the short hose to the heater valve(always replace along with), the heater valve , the block off plate to the rear of the DS head, the heater hoses

Joe '87 S4

Thanks for the tips on where to look. I'll check it out tomorrow morning.

heinrich

The loss of coolant is a terrible thing.
.... if your coolant died peacefully at the age of 16--a ripe old age for most coolant --the shock and grief you feel may be less than if it died of an unexpected illness at age 2. If your coolant is hit by a car or your coolant chokes on a bone, however, you will probably feel more guilt than you would if either coolant had died of old age. You may feel the absence of a beloved coolant more keenly and painfully if it was your only coolant than if you shared your love with several engine fluids. You may mourn the death of a particular coolant more strongly than you mourned coolant in the past, due to some special qualities of that coolant or of that particular relationship.

The length of time grief lasts also varies from person to person, and may be affected by the level of attachment one feels to an individual fluid. "My personal experience was an intense grieving process that left me emotionally devastated for several weeks," wrote Roanne H. of New Jersey. "I am still surprised by the ongoing feelings of love for the departed coolant that I am experiencing. The length of time it takes to begin accepting the loss of your coolant will vary."

I feel for ya bud

cdbtx

Let's take a beer away from Heinrich instead of passing him one...

Coolant leaks can be a PITA to find -

Chuck

83 Kiln Red 928S

heinrich

Joe, common leaks:
rad cap ... see the little hose
heater valve
radiator passenfer side top as Stan mentioned
water bridge at the thermostat housing (elephantine steel elbow attached to front of engine)
big rad hoses
sall rad hoses
under cowl at firewall, where heater hoses enter into cabin (look for drainage from rubber flap down against firewall, down from coolant reservoir)
into engine via head gasket
seldom, via heater valve steel elbow on rear top passenger head. I see you have a 1987. That elbow can be two-piece soldered together, and it will separate as mine did to where I was ableto pull it out ... by HAND

Chuck, pass the Hefeweizen

perrys4

3/4 of an inch?? If mine gets down a 1/4 inch the light comes on.

Normy

Oh no...why would you want to do that? Heinrich is cool as hell and funny too. We need to buy him more beer, not less!

-I second all of what dr bob said. Losing coolant? Tighten up all your clamps and replace your radiator cap. I change mine out every other year along with the coolant.

Mike Simard

Joe, a bloody blibe from England had a coolant loss issue discussed here recently. His was a leaky hose at the heater core, the coolant would run along the cowl area and come out the drain hole in the firewall behind the resevoir.
If your leak were in the same place but a slow one, the coolant could possibly evaporate before it gets to the drain hole and not make itself known, there's a long distance it would have to trickle and there's probably a bunch of dirt and leaves to help disapate it. I hope that's your problem!

cdbtx

Heinrich - If you make it out on the 4th I'll make sure I have the Hefeweizen.

On the coolant lose - Heinrich pretty much summed it up. I went through a series of coolant leaks on my 83. First the side tank, then the coolant tank cap, then the coolant tank, then a variety of hoses. Then it became a race car and everything was replaced. The most frustrating part of finding a leak is when it's in an area that cause the water to evaporate - touch to find.


Chuck


83 Kiln Red 928s

JP Rodkey

Also look just below the belt tensioner for a trail (or drops) of coolant. If your hoses/clamps are leaking at the connections on the crossover, that's where it oftens shows up. Look in the casting pockets on either side of the top of the block under the crossover. By all means, a coolant system tester is your friend when trying to find small leaks. Most car part chains have them for loan.

Joe '87 S4

I think I found the leak. The inside small hose from the tank is pulled away slightly at the fitting. The small hose next to it was replaced at some point but the one that looks to be leaking appears to be original since the screw for the clamp is screwed on from the top down and I can't see doing that with any screw driver. It looks to me anyway that that hose was put on when the tank was installed. Hard to work in there. Why is everything so cramped in tight? Thanks for the replies...I'll be checking all the other suggestions also.