where does the coolant go?

[cheffy30]

guys... the m20 is drinking coolant. I wish it was kool-aid. back story... some of you know of the car...1990 325i sedan.. daily for 21 years all engine services performed on time all the time. I have changed the head gasket. twice now. because it had an external coolant leak back at no. 6 near the firewall. first time. THEN... about 4 months later she sprang an internal coolant leak.. i suspect a bad gasket... coolant was in the oil.... we put on an erling with new bolt set etc. head was on a straight edge and is within factory specs of ~.002" while in there...the head shows NO signs of steam cleaned anything. all plugs are clean. wear in the head is normal for 302k on the ticker. all hoses are relatively new in the last 5 years. all clamps tight. I performed a pressure test with a warm engine. ZERO leaks anywhere. after putting it back together and filling with coolant.... I ran it for for 20 miles at 60-80 mph. upon return tank was empty. I re-filled it thinking it was an oddball air bubble. probably was... filled it to a known and recorded level... midway in the expansion tank. like usual. checked oil. clean and fresh. next day... ran it for another test on the loop drive... she lost a few millimeters. drove it again on a "spirited" loop later that day for 20 or so miles, did a couple errands. opened it when she was cooled and the tank was empty. wtaf? I have checked the oil dipper several times during this and the oil is clean. it would show clearly by now if even 2 cups of coolant was leaking in to the oil. it is not. it's 40 degrees in seattle... there is no obvious signs of steamy exhaust either. overall the engine is in great shape. she's a daily and still pulls strong. 0-60 in 10 sec flat. not bad for an old slug. anyone had similar woes? any ideas out there? I am lost. what I remember is coolant should be consumed like this... I'm baffled. any ideas ? cheffy30 sent from hell using Tapatalk

[amcp]

Check the spark plugs. If one or more are much cleaner than the others coolants getting into combustion chamber.

[cheffy30]

Check the spark plugs. If one or more are much cleaner than the others coolants getting into combustion chamber.

all plugs are clean and equal. no green build up at all. combustion chambers and related pieces showed no signs of being "steam-cleaned" by any boiled off or burned coolant... sent from hell using Tapatalk

[amcp]

Crack in the head. Had it checked for cracks when it was off?
If its not in the oil and not on the ground, theres a leak in the heater core and theres antifreeze in the passenager compartment??
Stabs in the dark here.....

[djjerme]

My thought was in the heating lines. Look around/underneath for signs of fluid. I know it’s hard to do with all the rain, but try to see if it’s sneaking out. Sent from my iPhone using Tapatalk

[roguetoaster]

Radiator end tanks, or you need to stop drinking the coolant yourself and blaming the car.

[cheffy30]

Crack in the head. Had it checked for cracks when it was off? If its not in the oil and not on the ground, theres a leak in the heater core and theres antifreeze in the passenager compartment?? Stabs in the dark here.....

again no visual signs, upon inspection of the head, that would necessitate a pressure test on the head. no signs of "steam cleaned" areas as a result of burn/boil off. heater core, no leaks. cabin dry. sent from hell using Tapatalk

[e30austin]

i'd be inclined to guess heater core. it's happened before. you'd smell it and eventually, your windows would fog up (especially in our current climate). sounds like you've checked everything else. i would also pressure test everything when warm, as well as dead cold and see if you can pin point any leaks at the heater hoses.

[cheffy30]

i'd be inclined to guess heater core. it's happened before. you'd smell it and eventually, your windows would fog up (especially in our current climate). sounds like you've checked everything else. i would also pressure test everything when warm, as well as dead cold and see if you can pin point any leaks at the heater hoses.

performed a serious pressure test while warm with patrick at midnight motorsport. zero leaks anywhere. filled it drove it 20 miles at 60-80. let it sit overnight. water level same. next day same scenario but drank all the water in the tank. we are both perplexed. sent from hell using Tapatalk

[cheffy30]

Radiator end tanks, or you need to stop drinking the coolant yourself and blaming the car.

no leaks. I don't deserve this. I'll remove the siphon that I installed to the cabin. makes a sweet mixer with vodka. like red bull but really blurred. sent from hell using Tapatalk

[e30austin]

okay, so i had a similar situation years ago, except in this case, it was forcing it out the expansion tank. the car rarely ran warm and would occasionally have excess pressure. turned out, from the former owner of the car running only tap water (GRRRR), sediment and corrosion had filled the overflow hose, going from the expansion tank to the radiator, completely clogging it and not allowing anything to pass.

long story short, make sure that hose has a good flow going through it, both at the radiator and at the expansion tank - make sure the port isn't clogged with sediment, either.

[roguetoaster]

no leaks. I don't deserve this. I'll remove the siphon that I installed to the cabin. makes a sweet mixer with vodka. like red bull but really blurred. sent from hell using Tapatalk

Be like a Russian tanker from the 80s and make booze from your brake fluid, then add the coolant as a floater.

[cheffy30]

okay, so i had a similar situation years ago, except in this case, it was forcing it out the expansion tank. the car rarely ran warm and would occasionally have excess pressure. turned out, from the former owner of the car running only tap water (GRRRR), sediment and corrosion had filled the overflow hose, going from the expansion tank to the radiator, completely clogging it and not allowing anything to pass. long story short, make sure that hose has a good flow going through it, both at the radiator and at the expansion tank - make sure the port isn't clogged with sediment, either.

I will check those details next. albeit I did pull the overflow hose that exits out over the wheel well and it was dry. sent from hell using Tapatalk

[cheffy30]

Be like a Russian tanker from the 80s and make booze from your brake fluid, then add the coolant as a floater.

sounds like a scene from "the lighthouse" lmfao sent from hell using Tapatalk

[roguetoaster]

sounds like a scene from "the lighthouse" lmfao sent from hell using Tapatalk

I don't know about that, but you can reference "The Beast" for the recipe.