My low coolant light has come and gone a couple of times and I had to add a small amount to the reservoir, about a quart max. So the coolant light has now come on permanently and after letting the car sit for about 4 hours after driving, I went out to add to the reservoir, and upon opening the cap I felt a sucking motion and it seemed as if the coolant got sucked out of the reservoir. So i added more fluid, drove home (20 minute trip), and noticed that fun coolant hot hot smell. Parked it and noticed fluid dripping out onto the drive right about where the reservoir is located.

Would this be caused from a sticking/ dead t-stat? What else should I investigate? Thanks for any and all input.

 

Could be a cracked reservoir, bad radiator cap etc,



Dave

 

The 4.0 has a history of the thermostat sticking closed, resulting in overheating and fluid being forced out. The temp. gauge does not indicate overheating until about 230 deg. F, which is approaching disaster. So that's one possibility.

Another is that the pressure cap is malfunctioning, another common problem.

If you have a OBD reader that can measure the temp, plug that in and let the engine idle. If the temp. climbs above 215 deg. it's probably the thermostat.

If you do replace the thermostat it would be wise to replace the housing at the same time with an aluminum one, as the plastic ones tend to become brittle. The crossover pipe and hoses should also be replaced.

 

I forgot to ask, do the cooling fans come on and keep running after you shut the engine off?

 

If engine is hot enough, yes. The fans will run until the temp drops to a certain level or for 5 minutes, whichever comes first. I forget what the temp needs to get to for the fans to stop.

If you have a puddle, then you are ahead of most. It should make it easier to find that leak. Lots of places that love to leak by that reservoir, including the tank itself.

 

And better than finding a poodle under the car...

 

I just read the first post again. I thought the puddle was under the overflow reservoir, not the pressure reservoir. If under the pressure reservoir it's more likely a leak in the reservoir itself, as Dave mentioned, or a hose or fitting.

The best way to locate the leak is with a pressure test kit. We don't know what country you are in, but in the US some auto parts stores will loan you the kit, which allows you to pump up the system with the engine cold.

 

Whip off the off reservoir top and bottom. See if leak if from cap, hose going into the bottom of reservoir, seam around the res tank, etc. See if your have any fluid on that side of motor/trans, there is a black plastic T there that tends to go also. Could be a heater hose as they are in that general area also, could have sprung a leak.

 

...And do not drive the car until this is resolved. If you do not do it yourself, have it towed to the shop. Towing is a bargain compared to fixing the damage easily done by overheating !

 

No, not driving the car and yes I do my own work. Used to working on VWs and old MGs so I'm learning my way around the engine bay. Fired up the engine and jacked up the front to see where if I could find the leak from underneath. Leak is coming down drivers side (USA) right by the what I think is the catalytic converter. Couldn't see a damn thing. Tried getting a mirror under the reservoir but still couldn't see. Probably coming from one of the hoses to the heater. Seeing how I believe that the heater pump is not operational I have to get into that mess anyways.

 

In my case, this was two leaks, in the Norma connectors on either side of the throttle body. The passenger side drips in the exhaust, the other side makes a puddle under the reservoir.

See my $5 fix for both in a recent post here.

 

I had a similar leak in location, I'd smell burnt water/coolant, but never found a leak. I'd pressure tested but nothing showed. While under car the drivers side Cat had streaks of what was probably burnt fluid, I knew it was coming from somewhere but it was a very small leak. Finally replaced coolant reservoir and no more problems. If you're getting a puddle I'd expect a pressure test to show this.. cheap and easy to do.

 

I had to pressure test to find my leak at the reservoir fitting.