Author Topic: hissing from thermostat housing?!  (Read 3829 times)

jdirty

  • Full Member
  • ***
  • Thank You
  • -Receive: 0
  • Posts: 116
    • View Profile
hissing from thermostat housing?!
« on: July 08, 2011, 09:45:08 AM »
i recently replaced my head gasket, timing profile gasket and upper timing case gasket.
thought i fucked something up at first start up, diesel sounding engine, mad ticking noise.. then it went away. realized those were the lifters. (read it on a write up in r3v.. "zen and art of e30 maintenance" where the guy experienced the same exact thing)

but yeah when i went out to test drive the car, i was like 5 minutes away from my destination when i noticed my temp gauge up at 3/4's. went i finally arrived, i saw the lower rad hose on the passenger side fizzing out with coolant, realized i was a dumbass and forgot to tighten the clamp. tightened it. let the engine cool down and refilled and 'bled' the system. since where i was at the place was, the parking was uphill anyway so i thought cool this should be easy. put fluid in up the kalt/ cold line. maybe 1" +/- above. heater on full blast. warmed the car up to halfway. opened bleeder down below. no bubbles in coolant. turned car off. checked level. repeat. car was good! till i got to the gas station. 3/4's again. spent around 2 hours bleeding via different methods. one of them was relieving pressure via bleeder beside rad cap. revvin the engine until air/ coolant is not exiting.. hold the rev and close the valve and rad cap. idek if that did anything because after trying several methods, i thought it had been dealt with coz it was idling at half already. but as soon as i fuckin left the gas station, maybe 5 minutes (or less.) i got to 3/4's again and a couple seconds after, bam, redline!!! popped the hood and there was steam coming out of the thermostat housing like a train. waited there for an hour. couldnt get the car towed so i ended up doing a stop and go travel. hitt halfway, shut off car. mostly though i was rolling with the engine off. being that the trip was 70% downhill. primitive, i know.

the morning after i checked again. idled the car till engine temp, crept a little bit over the halfway, right before i turned it off i notice that heater on full heat at fan level 4 wasn't blowing as hot. it was even hotter outside. (112 vegas weather) i tried the bleeding the car while elevated up front. released fluid from bleeder below rad til no bubbles came out. i didn't even notice any to be honest. then halfway mark, still not as much heat from heater. the engine temp eventually went up to 3/4. shut te car off right away. same hissing noise from thermostat housing but no visible steam.

does this sound like a stuck thermostat..?
all three hoses from the rad are hot.
no coolant leaks except i did i notice that my right shoe was a bit wet.
looked at the heater pipes under the dash and there was a drip coming from it. the heater core was bypassed by the PO. i put a new one in though and plugged it up when finishing the HG replacement. and before i installed the new core i ran water through it via garden hose and it 'wasn't clogged' from what it looked like.

ideas..?

bmwman91

  • Administrator
  • Legendary
  • *****
  • Thank You
  • -Receive: 33
  • Posts: 2798
    • View Profile
    • http://www.e30tuner.com/
hissing from thermostat housing?!
« Reply #1 on: July 08, 2011, 12:55:15 PM »
It almost sounds like a stuck thermostat. Sometimes people put it back in backwards. If all 3 rad hoses are equally hot, then coolant probably isn't flowing. The one on the passenger side (return) should feel noticeably cooler than the one on the driver's side (hot feed) if coolant is flowing through properly. Although, the heater should be blowing really hot air. I am not sure why it isn't when the motor is overheating.

Usually high temp readings like that are the result of an air bubble, but it sort of sounds like you have bled it sufficiently.
« Last Edit: July 08, 2011, 12:57:38 PM by bmwman91 »

06/05/2011 - 212,354 miles
Visit HERE for a plethora of 318iS stuff and some other randomness.  Would you say I have a, plethora, of pinatas?

DesktopDave

  • Administrator
  • Legendary
  • *****
  • Thank You
  • -Receive: 60
  • Posts: 5076
  • Lives in the 80s
    • View Profile
    • The Iconic BMW
hissing from thermostat housing?!
« Reply #2 on: July 08, 2011, 07:24:29 PM »
I'd say the coolant overheated & burst the weakest point in the system.  Usually it's not the thermo housing though.  My upper expansion tank o-ring tends to bleed off pressure when mine overheats.

The car will keep on overheating if it can't hold pressure.  Drain the system and use a cap tester to see if it'll hold 15psi.

Here's a little trick I use to bleed the car...open the bleeder and fill the expansion tank all the way.  It'll bubble as it fills the upper radiator and the upper hose.  When it stops gurgling just put the cap back on.  It'll suck in the rest as it cools off.
'08 Karmesinrot 128i 6MT
'86 Zinnoberrot 635CSi (M30B32/G265/3.46 torsen LSD)

Sold: '97 Montrealblau 318iS, '91 Brilliantrot 318i, '91 Brilliantrot 318iS

monty23psk

  • Legendary
  • ******
  • Thank You
  • -Receive: 17
  • Posts: 1291
    • View Profile
hissing from thermostat housing?!
« Reply #3 on: July 08, 2011, 09:20:53 PM »
Our cars use 30 psi (2.0 bars). I bought a Stant tester with the BMW adapter to make sure it holds pressue. If you have a leak, it will show no matter water psi.
Alex  88 m5 | 91 318is | 19 Subaru Ascent
BMW Tool Rentals & Fender Roller

DesktopDave

  • Administrator
  • Legendary
  • *****
  • Thank You
  • -Receive: 60
  • Posts: 5076
  • Lives in the 80s
    • View Profile
    • The Iconic BMW
hissing from thermostat housing?!
« Reply #4 on: July 08, 2011, 09:58:11 PM »
30psi?  Seriously?  No wonder M42's die so quickly when they overheat...and I'll bet that contributes to cooling system components having such a short lifespan.  Good info to know!
'08 Karmesinrot 128i 6MT
'86 Zinnoberrot 635CSi (M30B32/G265/3.46 torsen LSD)

Sold: '97 Montrealblau 318iS, '91 Brilliantrot 318i, '91 Brilliantrot 318iS

jdirty

  • Full Member
  • ***
  • Thank You
  • -Receive: 0
  • Posts: 116
    • View Profile
hissing from thermostat housing?!
« Reply #5 on: July 08, 2011, 10:07:09 PM »
wow thanks for the replies guys. i gave in and put in a new thermostat but haven't been able to bleed thoroughly today due to rain suddenly pouring out of nowhere.. but i was able to run it abit. didn't heat up as fast but the heater was noticeably hot at fan 4 and warm at fan 1. during the whole hg replacement i didn't bother replacing the thermostat since it was replaced around 6 months ago and the system was vacuum bled or some fancy type stuff by my dad's bmw mechanic (has a shop and 98% of cars he works on are BMWs from 2002s to e9Xs and in between.. fwiw). but yeah.

before replacing my thermostat, i did find out that one of my thermo housing screws were missing. found a spare. torqued it down in a cross pattern. and filled the cooling system with via upper rad hose. idk why. i probably read it somewhere. i plan on test driving the car around the block in a bit as soon as it's not raining anymore.

edit: i just got a call from my employer saying that our job contract was forcefully ended. i guess my e30 is gonna sit for awhile. :s
« Last Edit: July 08, 2011, 10:17:38 PM by jdirty »

monty23psk

  • Legendary
  • ******
  • Thank You
  • -Receive: 17
  • Posts: 1291
    • View Profile
hissing from thermostat housing?!
« Reply #6 on: July 09, 2011, 09:06:09 AM »
Quote from: DesktopDave;105179
30psi?  Seriously?  No wonder M42's die so quickly when they overheat...and I'll bet that contributes to cooling system components having such a short lifespan.  Good info to know!


Yeah, the cap you say 2.0 on it. I had one that said 1.4 and would always hiss. Also realoem, confirmed it. 2.0 comes out to about 29.8 PSI. It is high and makes sense why the m42 has cooling issues plus it only has 1.7 gallons of coolan while the m20 has double that.
Alex  88 m5 | 91 318is | 19 Subaru Ascent
BMW Tool Rentals & Fender Roller