Do Thermostat and water pump outlets/inlets have o-rings on them under hoses?

[rmz]

i've been having a fun time dealing with a coolant leak in 10 degree weather. i was convinced it was the thermostat housing's o-ring to water pump in my 98 740i, changed it but still leaking.

in this picture from a writeup on e38.org the thermostat housing looks like it has some o rings in the grooves, is this the case or was it just old hose gunk? mine had nothing, not on thermostat outlet and not on water pump inlet below it (from expansion tank to pump)

i changed the tank to wp hose because i thought it was dripping and changed the thermostat/housing with new o-ring, but it's still sizzling back there.

i took off the fan/cover and the air inlet assembly and ran the car till it got hot with a paper towel over the throttle body but nothing leaked after 30-40 mins of freezing my balls off... then, lo and behold it's leaking again. there is a small stream of coolant spraying out of somewhere and everything is soaked in that area, hard to tell what specifically while fan/cover are on. i'm just going to replace the water pump with all new gaskets/rings to make sure i take care of it unless my car didn't have the o-rings under the hoses (looks like there is a spot for them) and that's why it's spraying out.

also how tight are the water pump bolts supposed to be? while i had it all apart I tightened the ones that were accessible and they turned a full half turn before being slightly more than hand tight.

any ideas? anyone else had similar problems?

all these bimmers ive owned have always had cooling system problems... otherwise i love them. also broke my coolant level sensor in the bottom of the expansion tank after the 50th time removing it and putting it aside... great day...

[Edwin NL]

Tighten them hand tight and then a little nudge

[rmz]

thanks for the info. any idea on the o-rings in outlet/inlet grooves?

mine were empty, and like on most cars, i assumed that ridged/grooved portion is just to make a better fit when hose clamp is tightened, but pic above and one of the write ups i read talked about o-rings under the hose, if one was meant to be there this would make a lot of sense since it is leaking right in that area and now i know it's not the lower hose or thermostat gasket.

[Edwin NL]

there are no O rings for the hoses

[cazal740i]

there are no O rings for the hoses

there ar o-rings in the hoses but they are Built in...If they fall out when removing the hose...the hose is bad...ask me how I know

[Edwin NL]

Yes we do have then, his is a 98

[nm530]

I recently changed my water pump and thermostat on my '95 740i and it appears to be leaking from under the thermostat housing. I replaced the thermostat O-ring and the hose that connects to it. Is this a common problem? Could it be the hose that is leaking? I guess my next step is to remove the thermostat housing to check the O-ring.

[rmz]

Yes we do have then, his is a 98

wait what do you mean? it does have o-rings because it's a 98?

mine has hoses/hose clamps not quick disconnect

[Edwin NL]

No pre 10-98 cars have normal hoses and clamps, after that they have quick connect