Did you unhook the upper hose near the oil filter? There is an o- ring to be replaced.

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No....just the hoses that connect to the pump and thermostat. I find coolant near the pump, and I believe it is making serpentine belt squeal. And it seems to be worse if I drive it hard. Thanks so much for helping! I am scared for my baby!

 

I still need help on running this problem down, as far as I can tell, there is no leak from the hose at the oil filter.

 

The upper hose (bypass) to the t-stat with the push on connector is sneaky, it may look fully on, but not be. I had to use a pry bar to push the hose on. I pushed on the bosses on the fitting. Just couldn't get my hand in there to apply enough force to the connector.

To bleed the system: Car cold, open bleeder. Key on but not running turn heater controls to max heat, fan on low. Press and hold accelerator pedal to floor for about 12 seconds. You'll hear the pump kick on. It will cycle on and off for about 12 minutes. When done, turn off the key and check your coolant level (don't overfill) and don't forget to close the bleeder.

 

Thanks for this! I am taking it to DIY Auto this weekend so that I can work on it with a lift. Those connectors were a pain in the ass, and I think that you're right, I probably did not get one on properly. Looks like you have an awesome setup with your car! Love it!

 

Make sure all of those connections are fully connected. Like push as hard as possible when connecting back together. Make sure your screw clamps are at the right angle and make sure they are not too far near the end or opposite (it needs to be right in middle of hose when clamping). Clean up all coolant you can see. Refill the system then see where a leak is present. Not bleeding the system has nothing to do with leak. If anything bleeding the system correctly will make it leak more, if there is a leak. Not bleeding the system will allow air to be trapped causing improper cooling. Instead of low coolant message you would get an high temperature message.

It's more than likely thermostat housing related.


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Make sure all of those connections are fully connected. Like push as hard as possible when connecting back together. Make sure your screw clamps are at the right angle and make sure they are not too far near the end or opposite (it needs to be right in middle of hose when clamping). Clean up all coolant you can see. Refill the system then see where a leak is present. Not bleeding the system has nothing to do with leak. If anything bleeding the system correctly will make it leek more, if there is a leak.

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Thanks! Do you know what sort of damage not bleeding properly could do?

 

Btw...try not to drive the car with a cooling wet belt...it might slip....get inside the crankshaft and well...game over.

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Thanks Everyone! You guys are AWESOME!

This has been Great! Hopefully, I will be able to help someone out someday! The only mystery that seems to be unsolved is the inconsistancy. Sometimes, it leaks very little, at other times, quite a lot. Any ideas?

 

...Sometimes, it leaks very little, at other times, quite a lot. Any ideas?

Vapor Pressure increases with coolant temperature in a closed system:
https://en.wikipedia.org/wiki/Vapor_pressure

George

 

i have also have what must be a very small coolant leak after replacing the waterpump/thermostat in August on a 2006 12 year old car. This thread got me thinking that perhaps all that manipulation of the hoses...taking them off and putting them on in tight quarters...maybe the other end was disrupted in some way or a small tear along the length of the hose. Come warmer weather I will take off the lower engine cover and search for the leak. Maybe with a now 13 year old car its coming from another spot.

 

After cleaning, 'Puff' some baby powder in the suspected area. You'll be able to follow the trail to the source of the leak.

 

Replaced waterpump/thermostat in 2011 335, and now have an inconsistant loss of coolant... The leak appears to be coming from the general vicinity of the water pump/thermostat. As far as the inconsistancy goes, there are times when it does not leak much at all, maybe a few teaspoons a day, and at other times, it seems to lose pints a day. my typical commute is 45 mins to an hour, one way.

got that, but the loss varies on same drive, same temperature outside, everything similar. wonder if the co;nnectors might jiggle from looser to tighter. and so on. Another thought I have, is variance in presence of air in system, as I am having to add coolant every other day. Anyway, I do appreciate your input! Thank you!

Probably getting "analysis paralysis" here. Now I tend to err on the side of over-analysis myself, so I'm NOT throwing stones. SOME analysis is needed to know what to focus your examination & testing on so you have a "plan."

However, in this instance, "vapor pressure" may be all you need to know (you can use that to pressurize the cooling system, rather than using a pump). Simply running the engine to get the coolant to normal operating temp will pressurize the system, and you will get some liquid coolant dropping on the cardboard on the floor/driveway (presuming you have taken off the undertray/splash shield. Running the engine also has the plus of having the thermostat valve move through it's range of motion, and runs the coolant pump at different speeds

It would be MOST unusual for a loose connector/fitting to "tighten itself." Thermal expansion could have an effect, and parts NOT properly retained/secured could "flop around" varying the size of the leak opening. I have never dissected either the coolant pump or the thermostat, so have no idea if thermostat position or pump speed might affect leak rate. Also "heat soak" can cause the leak to occur, or be worse, AFTER shutdown following 20 to 30 minutes of operation.

What YOU and I both know is that you say you have a leak, and it appears to be in the right-front of the engine compartment near the pump, thermostat, and lower radiator outlet. So why not just try to find the leak?

My Plan:
1) Get the front wheels on ramps;
2) Remove the Undershield (look for coolant in the shield -- leak, or at least bottom of leak path, is above ;-);
3) Examine ALL hoses, fittings & components in that area carefully with bright light for any sign of coolant; note suspected leak point per that examination if applicable;
4) Take photos;
5) Clean/Dry all hoses, fittings -- don't forget the reservoir above;
6) Place cardboard, newspaper, etc. below pump area;
7) Fill Coolant Reservoir, inspect cap seal, tighten properly;
8) DISCONNECT RADIATOR FAN CONNECTOR but remember that you don't want to run engine for more than ~ 5 to 10 minutes;
9) Set "Hidden Menu" to 7.00, Engine Coolant Temp (to read it on instrument cluster) or read that parameter with scan tool/ laptop connected to OBDII port -- monitor coolant temp every two minutes during engine operation;
10) Start engine and let idle, checking cardboard for dropping liquid;
11) If no leak, or only a drop or two after ~ 10 minutes and engine coolant temp reaching ~ 190, turn off engine and see if any leak THEN appears;
12) Get under vehicle with bright light & trace leak to source -- gently manipulate hose/fitting in that area to see if leak increases (wear goggles at least for that phase, to prevent injury if something breaks open and sprays hot coolant).
13) OBVIOUSLY: let system cool and release pressure before removing any hose fitting.

That "PLAN" is NOT meant to be taken as expert authority, just my best guess to date on how to approach, so any other thoughts/ critique are welcome -- purpose being to give Robie some ideas, just in case he's NOT already ahead of ALL of us.

George

 

It's also good for tracking mice.
heh, heh, heh......
good one.

Remember too that these coolant hoses, at least the larger ones, have o rings inside the end fittings. these o rings deteriorate or swell or get nicked and sometimes leak. It is smart to buy new hoses, but I have also found o ring kits that suffice nicely until the service interval for the hoses comes knocking.

I would bet on an unrelated leak, like perhaps the expansion tank is beginning to crack, or the vent plug is loose, or a crossover tube is leaking......

I had an issue, though self inflicted it turns out, where my air box was not secured properly, (my fault) and put pressure on the intake piping, which in turn rested against the upper hose, which in turn was just barely touching the spinning alternator pulley just below...got coolant low warnings every 50 miles. took a while to find it too....until I heard it whistle when I squeezed it.

so, squeeze all your hoses! and have a bright light shining right where you are working so you can clearly see any leaks.

OH, to get to the water pump another way, remove the passenger tire and inner fender shield...you can see a most of those hoses from a different angle that way. I rescued a nice 1/4" drive extension that a mechanic must have lost during a prior service on the car!

Jp