Disappearing coolant leak?

[Rob175]

Thanks again. I just took the car out for a drive again, got about two blocks away and the “low coolant” light on the dash began blinking so I drove right back and added 2/3’s of a cup of 50/50 to the tank in the trunk to raise the level for the sensor. Drove out again, made a few errands and returned. I placed a large cardboard sheet under the car ....... after 5 hours of sitting..... not one drip!
I would think that it would start losing coolant since it obviously did that yesterday (thus the low coolant level light today on the first ride).

My thinking is that IF it’s going to leak it would be leaking all the time especially when it’s pressurized and hot.

[Rob175]

Enough is enough....Monday it goes to my Porsche indi guy for diagnosis and repair.....hopefully my 98' w/86,000 miles won't cost me an arm and a leg!....maybe just "an arm".......
I can confirm that the dripping is coming from the engine area as opposed to the front or middle, so it's NOT the heater core or radiators or the lines running to the rear. So, my "uneducated guess" is a hose or connection. To my knowlege, the hoses are either original (20 yrs old) or at least 16 yrs old, because that's how long I've owned it. I don't know the symptoms of a failing water pump other than possbly overheating, which I'm not experiencing, so my hope is that it's jsut a hose, clamp or other connection.

[Beelzy]

It's the water pump. The reason you don't see a leak when it's hot is because the coolant is evaporating due to the heat. When it cools off it doesn't evaporate and you see the puddle. My water pump leaked for a while before it went out but I never saw a leak, but there was evidence in the engine compartment that it had in fact leaked.
Good Luck!

[Rob175]

Well.....for everyone that said it was the water pump that was the cause of the leak YOU WIN! (and I lose). My shop is installing a new water pump, thermostate and belt and I should have it back tomorrow. The cost quoted is $1350 out the door. I'm not sure if that's high, low or average for the Chicago area but it seems OK to me. My 20 year old 98' with 86,000 miles is my "fun summer car" and since it hasn't ever been maintenace "hog" I'll fix her up and drive on........

[blue62]

a water pump kit is around $350.00 I believe it includes a new belt and t-stat.
So your paying around $1000.00 for labor. If your fine with that more power.to you!
But that $1000.00 is why I always do my own work

[Starter986]

3 hour job, tops, for a mechanic who knows what he's doing.

I'm not a mechanic. I replaced my water pump. Once. I could do it again in less than 3 hours.

I'd be finding another mechanic. One who doesn't take advantage of the unsuspecting.

If you were in SoCal I'd do it for you for free.

Best wishes.

[Rob175]

OK.....water pump has been replaced so the obvious leaks in front of the rear wheel on the passenger side are no longer........BUT......

I now have some very small coolant drops (at engine cool-down) appearing behind the rear passenger wheel with a few drops where the bumper cover screw is located (the one closest to the passenger rear tire). I pulled the truck lining up and the lining along with the truck floor is bone dry BUT THEN I realized that there is what looks like a "black masonite material" that creates a sub-floor which is raised up from the steel body. After removing the section of "sub-flooring closest to the coolant holding tank there is a very small amount of the newest bright yellow coolant that I soaked up with paper towels. I've NEVER had a leak under that portion of the car and there really wasn't very much....AND it was the yellow colored coolant my mechanic used to refill the system after he drained (the old coolant was more greenish)....so I know it's the new stuff used for the new water pump2 weeks ago.

I wiped the tank and the connecting hoses with paper towel and the towel was dry.....only the metal trunk floor had a little bit of coolant, which as I said, I dried up with paper towel.....

So here's my question, since I've never before had any sort of drops coming from the rear bumper cover area and know its the NEW yellow coolant added 2 weeks ago during the water pump install job (complete coolant flush and fill), and all sides of the tank and hoses are dry, could it just be a coincidence or could it somehow be related to the water pump install? (overfill, sloshing around in the tank, etc)......where does the tank overflow to?

Any thoughts?

Obviously, I plan on driving the car in the next day or two and then once again checking for any additional coolant in the trunk again.

[Starter986]

I'm guessing it burped... maybe some air in the system, or too much coolant.

We're you running it hot and hard before you shut it off/down? I believe the recommendation is to, after running the engine hard, is to let it idle for a couple of minutes in the driveway... then shut 'er down.

Wiser minds?

[Rob175]

I suppose....but IF it "burped" or it was overfilled I would assume it would flow out of the overflow tube (IF there is such a tube) and not deposit a little bit in the trunk.
As I wrote it just seems too coincidental to the water pump replacement 10 days earlier.

I guess I'll remove the trunk carpet and sub-floor after I drive it next and inspect it again.

[blue62]

Originally Posted by Rob175

I suppose....but IF it "burped" or it was overfilled I would assume it would flow out of the overflow tube (IF there is such a tube) and not deposit a little bit in the trunk.
As I wrote it just seems too coincidental to the water pump replacement 10 days earlier.

I guess I'll remove the trunk carpet and sub-floor after I drive it next and inspect it again.

If it was me I would leave the carpet and sub floor out for a number of drives and check it each time I drove it. Then I would know for sure. Also there is a wire loop on top the coolant tank it is a bleeder valve there is a gasket under it which can go bad and cause some coolant weeping. Or the service tech could have just spilled a little around the top of the tank and it found its way to the ground.

[alynch]

Originally Posted by Rob175

OK.....water pump has been replaced so the obvious leaks in front of the rear wheel on the passenger side are no longer........BUT......

I now have some very small coolant drops (at engine cool-down) appearing behind the rear passenger wheel with a few drops where the bumper cover screw is located (the one closest to the passenger rear tire). I pulled the truck lining up and the lining along with the truck floor is bone dry BUT THEN I realized that there is what looks like a "black masonite material" that creates a sub-floor which is raised up from the steel body. After removing the section of "sub-flooring closest to the coolant holding tank there is a very small amount of the newest bright yellow coolant that I soaked up with paper towels. I've NEVER had a leak under that portion of the car and there really wasn't very much....AND it was the yellow colored coolant my mechanic used to refill the system after he drained (the old coolant was more greenish)....so I know it's the new stuff used for the new water pump2 weeks ago.

I wiped the tank and the connecting hoses with paper towel and the towel was dry.....only the metal trunk floor had a little bit of coolant, which as I said, I dried up with paper towel.....

So here's my question, since I've never before had any sort of drops coming from the rear bumper cover area and know its the NEW yellow coolant added 2 weeks ago during the water pump install job (complete coolant flush and fill), and all sides of the tank and hoses are dry, could it just be a coincidence or could it somehow be related to the water pump install? (overfill, sloshing around in the tank, etc)......where does the tank overflow to?

Any thoughts?

Obviously, I plan on driving the car in the next day or two and then once again checking for any additional coolant in the trunk again.

Check the dimple in the middle of the underside of the coolant tank. That was where mine had a crack and the coolant was seeping out into the trunk. The coolant was then leaking around the rubber plug in the trunk floor eventually ending up in the same location you described above.