as of late ive been smelling the sweet smell(sarcasm) or burning coolant when i go to push the car hard, its been happening for about a month, and now that I installed my 15% SC pulley its slightly worse. i can see the white streaks coming down the expansion tank from the seam line in the middle. i also saw a little up by the cap but not as much. so im ordering a new tank and cap, but can anyone point me in the direction of how to check the whole system? obviously ill check all the hoses, water necks, outside of radiator, the spots around the water pump flange and thermostat housing, and any point there is a clamp for any obvious signs of leak or blockage. In January I replaced the water pump, flange, and thermostat, with all new seals, and i dont see any white/blue smoke coming from the tail pipe. there usually is a little bit of condensation sitting at the end of the tail pipe, but its not at an abnormal level, and is probably just to do temperature changes and water condensing there.

so can anyone tell me what else to inspect? and how to check them?could it be my coolant(Peak Long Life 50/50). i was considering changing the ration to only about 20% antifreeze, ive been told water is more efficient than antifreeze to remove heat

Thanks,
Ben

 

Leaky expansion tank fix: Get the Canton or RMW w/ a real cap. The thermostat is a known weak part on gen1s. Rubber degenerates over time so check your clamps & hoses. Inspect the waterpump for leaks&, o-rings might need replacing. Heat exchanger leaks are usually oil, but when they fail internally, water can mix w/ oil.
Change coolant every 2-3yrs to keep coolant from turning acidic. This is when it becomes harmful to the engine & radiator. Bleed system w/ 2 bleed screws. It's true that water dissipates heat better than coolant, but the latter is there for many purposes: anti-freeze/corrosion, raises water's boiling point & alkalinity. Depending on your climate conditions, BMW coolant has its recommended coolant ratios printed on their bottles. Make sure it's pure distilled water you mix with.

 

Stick with the recommended coolant mixes IMO....going to mostly water will result in less corrosion protection....OK on a track car that gets drained/filled...but disastrous on a street car that is allowed to have the coolant sit...
And first thing I would do is change the coolant tank....
The OEM tanks do start to split and leak at the seam....especially if overfilled...longterm solution is a metal tank, but cheap fix is the OEM for another 40,000 or so...new one comes with a new cap ..is a couple minute swap.

 

so it seems like im doing all i can, i will visually inspect everything, but i know the thermostat and pump should be fine, they're new with al new seals, ill check around them, and ill pull em out to look if the problem persists, but this problem didnt show up till much later than i installed them. i want to go with the RMW tank, but i dont have money fr it right now so I just ordered a new oem tank and cap for now. and ill check the heat exchanger.

Ive been hearing alot about the RMW tank that uses a "real" radiator cap. What do you guys mean by this? is it just that its the traditional style rather than the plastic one? or is the pressure mechanism different?

also where is the second bleed screw? i know of the one on the upper hose infront of the intercooler

 

Second one looks more like a screw...look at the thermostat housing...near the bypass valve/factory airbox/and cold side map sensor on the driver side front area over the general area of the tranny...just to the side of the motor....you will need a flashlight to see it...and a extention to reach it.

 

is it a hex, like 10mm? or a phillipshead/flat/torx screw?

 

This is the screw that Zippy is referring to. Thanks Pelican parts :-)

10mm I think

 

Canton Tank. You can chose 16-30psi cap: