My first post. I usually find all my answers by searching these forums but not this time. Hope you can help.

I've owned my '99 300m since new and have always maintained it myself to the highest degree. A steady coolant leak developed yesterday and it's coming out of the bottom directly between where the engine bolts to the transaxle - right through the bolt-on piece that the manual calls the case stiffener (it structurally helps tie the engine to the transaxle). It's as if a core plug let go behind the flexplate, but I don't think there is a core plug back there - or is there? I took everything off the top side (cowl cover, strut tower support, etc) to get a good look at all the heater and coolant tank hoses, as well as the rear core plugs in the heads - everything is perfectly dry up top and no sign of coolant running down the sides of the engine - only directly at the back of the engine.

The car has only 64,000 miles on it and I've replaced the coolant every year with Zerex G-05 & distilled water.
Are there any known issues Chrysler has had about something like this. If the engine needs to come out, that's a bigger job than I want to tackle. Is a project like this better left to the dealer or can a competent independant shop be expected to do it right?

Thanks for any suggestions
Don.

 

Oops, I got the case stiffener part wrong - it's called a structural coller and it bolts directly to the bottom rear of the oil pan and to the bell housing. The coolant is leaking directly through and around this piece.

 

I suggest u take it to a shop let them pressure test the system and see where the leak is really coming from because there is no coolant going into or around the trans

 

Agreed,

Just for giggles, Humor me...

Pull the transmission dipstick, and make sure the trans hasnt been filled with coolant. I recently saw a Radiator go defective, where the transcooler ruptured, and the coolant was pumped int the trans, overfilled, and spit out the vent.....Surprising enough, The stuff that hit the ground was PURE COOLANT and NOT the Milkshake Slush I would have expected to see.

 

I tracked it down to a water pump leak. Turns out the coolant leak follows the pan rails to the back of the motor and dribbles down from there. Also doing the timing belt, idlers, hoses and thermostat while I'm in there. What a pain to get at the thermostat - any hints to make it easier to get to? I got a few days before the parts get here from Rock Auto.

Don

 

Take off the power steering pump and lay it out of the way. You have a straight shot at it from the top. You'll need a wobble socket or a gear wrench...Sears has them.