Thread: Coolant leak behind crankshaft?

My '04 Grand Prix (172,000km / 107,000 mi) has already been through two coolant leaks (first was a bad block heater three years ago, and more recently a coolant elbow). It's down to -15C (5F) up here in Ontario, and yesterday when going to the store I noticed a pool of coolant on my driveway, thanks to the help of a heavy snowfall. The leak seems to be predominantly on the right-hand side, and the middle. I took a quick look around the engine compartment with a flashlight (it was dark out) and didn't see any obvious signs of leaking/splatter at the coolant elbows, along the serpentine belt, at the upper/lower rad hoses, or at the hoses coming off the belt tensioner/coolant elbows. I parked the car pointing down the driveway instead of up, and I did see where some coolant is pooling (pic below, sorry it's not the best angle) - it's just past the crankshaft on what looks like some sort of pan / tray directly underneath the engine.

I topped up my coolant last night just to be safe, as I had some errands to run today. My driveway is at a pretty decent incline (I use my parking brake to park), and after adding more snow to my driveway, there's less visible leaking after driving around today. I'm wondering if my 'leaking' is old coolant that could've gotten down there when the elbow burst (i.e. snow/slush on the underside of my car assisted it to run off), but this is probably just wishful thinking on my part.

I searched through the forums and it sounds like this could be coming from the water pump, which may drip down and potentially pool under the engine. I'm thinking about getting a stop leak product (Rislone Pelletized Radiator Stop Leak) just to get me by for a few months until I can properly work on my car. I still need to check under the passenger seat to see if it's the heater core, but I'd be surprised if that was the problem. And when the elbows were leaking, I had absolutely no warning other than my engine started redlining in temperature. My engine has been running normally between the 1/4 and 1/2 markings on my temp gauge. I think my coolant ratio is closer to 70/30 coolant/water than 50/50, and I have seen the P0128 code thrown recently during this Winter, which someone noted was due to a less-than-ideal water mixture.

Are there any other areas to check? Has anyone else had a similar problem? I'm going to try to get over to a friends house where there's a flat driveway/garage to jack my car up in, but until then any comments are appreciated.

Sorry the comment was on another forum, "classic too stong of a mix. most antifreexe straight of of the bottle, pure is between 40 and 50 below. dexcool very rarely comes pre mix, at least in my experience. 2 qts out, 2qts of distilled water in. do you think he needs to get 'oe' distilled water? lol. in a very cold climate or very cold conditions, the proper mix is crucial for the coolant to ramp up to temperature quickly."

It's strange, if I let the car idle for 5 minutes after the P0128 comes on, I do see the temperatures rise, so I'm not sure if it's the thermostat acting up or not... I did 200km driving a few weeks back before getting stuck in stop/go traffic. During the long haul I was roughly 1/4 to 5/16 of the temp gauge, but once I hit stop and go I spiked to slightly over 1/2, which then came down. So strange.

I'm gonna pick up an inspection mirror, and remove my overflow tank to get a better look down the side of the engine tomorrow.

Even less coolant visible today on my snowy driveway. All the hoses look fine, and it's not the coolant elbows. I popped the overflow off so I could see the bottom elbow, both elbows and the surrounding area were bone dry. Didn't see any wet spots around the water pump but it was hard to see the underside/back, so I'm not gonna rule it out just yet.

Took off the belt today, the wp pulley didn't have any side to side play. I did see a small amount of coolant pooled under the upper coolant elbow, but everything below looked dry so I'm confident it's not leaking from here. There was a bit of coolant to the right of the lower elbow, which was l ocated pretty close to one of the water pump bolts.

I was just parked on level ground for the last 3 hours, and only saw a few drops underneath my car. Got home, parked in the driveway at an angle, now it's starting to dribble down. Looked around the engine compartment, still couldn't see anything at the elbows or hoses. Gonna try to make it over to a friends garage this week to jack the car up and take a look from the underside.

Whereabouts on the LIM was it leaking on you? A small pinhole leak doesn't sound like it would produce alot.

Coolant leak strikes again... this time as I was driving home from Easter. Luckily didn't overheat but the temperature was certainly creeping up. Unfortunately I don't have much time to look at it myself over the next few weeks before going on vacation so I am going to take it into a shop to have them at least do the diagnosis (never ended up finding a reasonably priced pressure test kit). The leak looked like it was coming from just to the right of the lower coolant elbow, but I didn't see anything odd around there.

Just heard back from the shop. It's pissing coolant out of one of the bolts and down the side, and they want to replace the intake gasket. Was quoted 5hrs labour (400) and parts (240), plus pressure test/tax.

Does the intake gasket make sense if it's leaking from a bolt? There's no oil into the engine so it's not leaking internally, oil looked good and no milkiness around the cap. Now that I think about it, there was a bolt just to the right of the lower coolant elbow that looked very wet...