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Mysterious Coolant Leak

67mgb

New member
I have a 2000 GTP with 175K miles and this is my second posting.
My first posting was for “Engine is OFF-CENTER” and you guys very quickly found the correct answer Bad Motor Mount.
Anyway, I now have a new problem.


First, some background:

I had a Low Coolant Level Light.

Because I did not want to deal with the Coolant, I had the Firestone Dealer (the car was in for tires) Flush the Cooling System & replace the Coolant Level Sensor. While they were doing this they said it needed a new Lower Radiator Hose, so I had them replace that too (Boy did I bend over & grab my ankles on that one.).

Ok, great. Shortly after getting the car back my wife mentions that the Coolant Temperature Gauge is running higher that before. When I check the car, I notice that the Gauge is fluctuating Up & Down. After searching the Forum, I decided that the Cooling System needs to be Purged.

Ok, great again, that cures the Gauge fluctuating Up & Down.
Then the Transmission Fluid leak starts. It is coming from the Upper Connection to the Transmission Cooler on the Radiator. Apparently, Firestone disconnected the line to replace the Coolant Level Sensor and did not reconnect it properly. I reconnect the line and return the car to my wife.

When she returns from a trip. The car is dripping Transmission Fluid from the same area. Inspection shows the leak to be in the same area, but it is not the line. So, I remove the line to check the fitting that screws into the radiator, only to find that the fitting is not even finger tight. I do not know why, Firestone would have loosened this fitting. Anyway, I tightened the fitting and reinstalled the line. No more leak.

My wife uses the car all day, no leaks.

The next morning she calls and there is a puddle under the car. When I check the car, the puddle is in the same location. However, the area around the Transmission Cooling Line is clean and dry. I check the puddle and it is not ATF, it is Coolant. I cannot find a leak. I clean up the puddle and send her on her way.
After she returns, I check and I cannot find a leak.
I check 2-hours later, no leak & no puddle.

The next morning, a puddle of coolant in the same location (passenger side, front @ the Radiator).

Any ideas where the Coolant is leaking from?
Or, why it is not leaking while the Cooling System is under Pressure?
Or, why it is leaking hours later?
 


Are the elbows still plastic? If so replace them. Leak fixed.
Mine was doing the exact same thing, it was running down the front of the motor and dripping off only under WOT and after it sat awhile. I assumed it was the radiator so I replaced it, ended up fixing the elbows anyway. Got a spare radiator out of the deal though! Lol

Sent from my SGH-I747 using Tapatalk 2
 
Like to know it that worked. I'm leaking a little but mostly the smell and that's it. No lights or anything.
 
My car leaks coolant when it wants. I had a good sized puddle one day, could not find it at all, ignored it and never saw another drip until a month later, I saw a tiny puddle. I cleaned it up and no leaks still. They just leak when they want I guess. The only place I didn't check is the water pump, I couldn't get my hand down far enough at the time. I bet it was that since the pulley ends up in different places when it's shut off, and a certain position may cause it to leak.
 
sounds like the low coolant sensor wasn't put on correctly? had to change one on a venture van (same setup) and wasn't to hard to put it on. also too unplug the dam sensor lol
 
grab the water pump pulley with both hands, leave the belt on, car off (obviously) push one side, pull the other, if the pulley moves, the pump is bad. once the bearing starts going bad water pumps can leak when they feel like it, off and on for months, till they hold no more.
 


grab the water pump pulley with both hands, leave the belt on, car off (obviously) push one side, pull the other, if the pulley moves, the pump is bad. once the bearing starts going bad water pumps can leak when they feel like it, off and on for months, till they hold no more.

Scotty: I'm giving her all she's got, Captain!
 
grab the water pump pulley with both hands, leave the belt on, car off (obviously) push one side, pull the other, if the pulley moves, the pump is bad. once the bearing starts going bad water pumps can leak when they feel like it, off and on for months, till they hold no more.

Sure, why not the Water Pump.
This year I
have already replaced the Alternator, the Power Steering Pump, the Harmonic Balancer, one of the Serpentine Belt Idlers
and the Supercharger Drive Coupling.
The Water Pump and the AC Compressor are the only belt driven items left to replace.

It still appears that the leak is @ the Radiator, the Elbows and the Water Pump are to far back.
I just do not understand why it does not leek under pressure.
Maybe this weekend, I can watch it closer and actually see the leak.
 
Last edited:
Water pump tends to leak a bit further back.

I believe your answer is in your first post. They swapped your lower hose, and it's right there on that side. The lower radiator connection point is right there at the bottom. You being a reasonable guy who tightened his own trans line (it's because they didn't have the right tool for the line and undid the fitting instead BTW :cool:) leak, therefore had the level sensor been leaking, I think you'd have said so. Likely there was a little corrosion on the outlet of the pump where the hose connects or at the radiator. Both will end up wetting the same area. Although the upper one might also drip straight down as well as running down the hose.

The fix.. Loosen the clamp and move the hose a little and or swap out the factory engineered clamp for a worm drive one. Aka..you add the worm drive next to the factory..cause you aren't pulling the clamps off.
 
Problem Solved!!

It was not the Elbows, the Water Pump or even a Hose Clamp.
The Radiator finally Exploded in a cloud of Steam.

I still do not understand why it only leaked when it was cool and not when it was hot.
 


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