Help Solve this heating problem...

[msf23]

Bought a 92' vert at end of summer and as things got colder this winter I noticed the car would not warm up very quickly and there was little heat...(if engine temp got at all warm I would have some heat).
Did some research on this site and came up with i guess 3 things it could be...Thermostat, Heater Valve or Heater Core.
Just changed Thermostat yesterday (might as well start with the cheapest fix) and when I took it apart the old thermostat was cut apart leaving the large flange and oring (so a slightly restricted path).

I swapped out the parts and filled the coolant per forum instructions...car jacked up and heat on full blast...
Once I started the car the engine temp began to raise but I dont think the thermostat ever opened...I sat in the car when engine temp was about 1/2 and I didnt have any heat increase through the vents...I eventually shut down the car when the engine temp gauge got to about 3/4.

Any ideas.....maybe just an air bubble??? (wishful thinking)

Any help would be greatly appreciated!!!
Mike

[Adrian_Visser]

You need to bleed the system, there is a bleeder screw on the thermostat housing which you crack open to release trapped air from the system. You were on the right track the first time having the front end elevated. First make sure the bleeder screw isn't rusted in place and you can open it when you want to. Make the bleeder screw the highest point in the system, run the car for long enough to pressurize the system and warm up the coolant i.e. half way on the temp gauge. Then open the bleeder screw enough to relase the steam/air when al that comes out is a coolant with no bubbles you should be good to go.

[jlevie]

At idle the temp should stabilize just below the 12'oclock mark. You could have a bad thermostat, air in the system, a partially plugged radiator, or a bad fan clutch. Any of which could cause the idle overheat. Fixing that is the priority at this point. Seeing a gutted thermostat suggests that the car has had a problem with running hot in the past and a PO essentially removed the thermostat as a fix.

Test the fan clutch by dragging a rolled up newspaper against the blade tips with the engine idling. It should be easy to stop the fan when the engine and radiator are cold and difficult to stop the fan with the radiator hot. In really cold weather you may need to partially block air flow to the radiator to get it fully hot.

If the fan clutch is good, I'd pull the thermostat and test it. Heat the thermostat in a pan of water an measure the temperature that is needed to open it. You should be using an 80C thermostat and it should open when the water is 170-180F.

If the thermostat tests good, re-bleed the system (procedure below) and see if the idle temp runs hot. If it still runs hot the radiator becomes the prime suspect. Before I replaced the radiator, I'd do a cooling system flush (see below), then install a new radiator and replace all hoses.

Once the engine is reaching and holding normal temperature, you can re-visit the heater problem. If the radiator is partially plugged, it would be a safe bet to say that the heater core and valves are also. Once out of the car, you might be able to flush out the core and valve.

Bleed Procedure:

1) Using ramps or a jack get the front of the car 1' or more higher than
the rear. That will make the radiator and bleed screw the highest point
on the engine and facilitate removal of air.

2) With the bleed screw open, add coolant until no more air comes out of
the bleed.

3) Leave the filler cap off, or at least loose, and set the heat for max
temp and fan speed. Leaving the cap loose will prevent air that's still
in the system from causing a "coolant fountain" once the engine heats
up. Start the engine and allow it to warm up to operating temp. As it
warms up occasionally crack the bleed screw to release any air and top
up the coolant as necessary.

4) Once the engine is at temp bring it up to 2000-2500 for a few seconds
several times. Then crack the bleed until no more air is released. At
this point the heater should be throwing lots of hot air, which
indicates that the heater core is filled with coolant. You may have to
repeat this a few times to get all the air out.

5) Drive the car a bit, allow it to cool back down, and recheck the
bleed for air. Over the next few days you may get very small amounts (a
few bubbles) of air out of the bleed screw.

Cooling system flush:

1) Get the front of the car 1-2' in the air on jack-stands.

2) Drain the coolant (radiator & block) and remove the thermostat. Set the
heater controls for full hot.

3) Add flush compound and fill with plain water. Then run the engine at normal
temperature as specified by the flush manufacturer (usually about 15
minutes at operating temperature). In cooler weather it may be necessary to
block off some of the air into the radiator.

4) Allow the engine to cool until you can place your hand on the cylinder head
w/o discomfort. Drain the system and refill with plain water.

5) Run the engine for 10-15 minutes or until temp is close to normal.

6) Repeat (4) and (5) until the water drained from the system is clear and
free of debris.

7) Re-install the thermostat and fill with coolant.

Notes:

You need the thermostat out in order to have full flow through the radiator.
That will also make draining & filling faster and easier.

Always allow the engine to cool to the point that you can hold your hand on
the cylinder head without discomfort. That will prevent scalds from hot
coolant and prevent thermally shocking the head when you dump the coolant.

Filling the system with hot water makes the process go faster and keeps from
having to run the engine a lot in a cold condition (rich mixture).

[msf23]

Thanks guys I will give this a shot...hoping I just need to bleed it better.
Yeah the cut in half thermostat was not a fun find. This is my first e30 and not a fan the readiator filling tank....like the cap on the raditaor. Saw someone on the forum did a M42 radiator swap...if I have to replace radiator might check that out.

Again thanks and if anyone has other ideas fire them at me!

Mike