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2003 R53, 170k. Car had been overheating and replaced T-stat and radiator fan. Coolant had been low and refilled it a could of times. Then saw a small puddle following the last refill. Pulled the skid plate off and coolant was puddling, jacked up the car and saw the leak.
Odd location for a leak, between the bolt in the engine housing? Where is it coming from?
Maybe the Radiator or a line blowing back under the engine? Wipe it can then let it heat up again and see where it collects that might be residue from the front or rear of the engine leaking down: possible waterpump leaking down.
You'll need to pressure test the system, it could be the thermostat, waterpump, oil cooler lines, or even coolant expanding out of the reservoir and making its way to there.
Which ever of the possibilities it ends up being we have all of those parts on hand and would be glad to help out with any questions or diagnostic concerns.
Maybe the Radiator or a line blowing back under the engine? Wipe it can then let it heat up again and see where it collects that might be residue from the front or rear of the engine leaking down: possible waterpump leaking down.
Didn't know there was an Engine Block Cover Plate, could that be why there is all that black crud in front of the engine?
The black crud you speak of is more likely to be the result of a worn crankshaft sensor o-ring which has been slowly seeping oil.
Replace that, and you'll have resolved the crud issue.
As to the source of the leaking coolant, try and get a good look at each of the items nkfry advised you to check into. It may help to remove the airbox assembly in order to get a flashlight in there to get good look at the driver's side of the engine, where a few of those items reside. If you can get the car into front-end service mode, you can get a good look at the front of the engine block and be able to see if the leak is waterpump related, as well as remedy the seeping crankshaft sensor o-ring.
It could also be any of the plastic hose fittings that sit directly behind the thermostat in that maze of hoses. They can get brittle with age, and since you recently replaced the thermostat, you may have broken one of the plastic 4-way fittings or the 'T' fitting while fiddling around in there. This dilemma has been documented many times on this forum.
For sure would do a pressure test. Also would check the water pump, pump flange, and the short hose that comes off the pump while your under it. Hard to see but common to leak down on that bolt.
Thx for the pointers. Putting into front-end service mode in the morning, and hope to find the origin of the leak. Will report back. Got a bunch of stuff to replace (pulley, belt, belt tensioner and harmonic balancer) anyways.
Originally Posted by AoxoMoxoA
The black crud you speak of is more likely to be the result of a worn crankshaft sensor o-ring which has been slowly seeping oil.
Replace that, and you'll have resolved the crud issue.
As to the source of the leaking coolant, try and get a good look at each of the items nkfry advised you to check into. It may help to remove the airbox assembly in order to get a flashlight in there to get good look at the driver's side of the engine, where a few of those items reside. If you can get the car into front-end service mode, you can get a good look at the front of the engine block and be able to see if the leak is waterpump related, as well as remedy the seeping crankshaft sensor o-ring.
It could also be any of the plastic hose fittings that sit directly behind the thermostat in that maze of hoses. They can get brittle with age, and since you recently replaced the thermostat, you may have broken one of the plastic 4-way fittings or the 'T' fitting while fiddling around in there. This dilemma has been documented many times on this forum.
