Thermostat and Coolant Bleeding Issues

[iamcreepingdeath]

UPDATE PAGE 6

ok guys here goes:  

So i have been having cooling problems for a while now with my 318is, i replaced the mechanical fan with a volvo fan, and that helped, but up until now, i have been running without a thermostat.

So i put in the thermostat today, and after alot of revving the engine and putting coolant in, i got it to work, sort of.

My question is, with the 88 degree T-stat that i got from Pelican Parts, is the temp gauge supposed to be between the halfway and 3/4 mark?  that seems a bit high, since when i first bought the car, the gauge stayed a little below the halfway mark.

Also, i had major issues getting the coolant to flow again.  Was i doing it wrong?  i had the car on a slight incline, and i filled the reservoir, and as i revved, coolant came bubbling and overflowing and spurting out of the reservoir (cap off of course.) so i capped it, and then opened the bleed valve.  Nothing but steam came out for the longest time, and then i killed the engine, and removed the bleeder valve completely.  Steam came out for a long time until the pressure finally subsided.

Then the reservoir was empty, so i filled it, closed the cap, and ran it again.  Then as i started to unscrew the cap, i could see the water level shooting up as the cap relieved pressure.

So anyway sorry for the essay i can never seem to keep these things short, but was i doing it all wrong?  what is the step by step process to re-filling coolant once the T-stat has been replaced?

thanks a bunch guys!

[dvmotorsports]

No. Over half is too hot period.

You should have a bleeder screw on your expansion tank next to the filler cap.

***Warning***
These bleeder screws snap very easily. They strip easily too if your screw driver is too small.

Now, fill it to the KALT line, close the cap, let it get to operating temp and crack the bleeder. When it starts pushing fluid, hopefully that should be the end. Close it gently. Come back when you can open the cap. Check the level. If it is too low, repeat. Once completed, drive spiritedly and monitor the temp. You should be good to go.

[iamcreepingdeath]

No. Over half is too hot period.

You should have a bleeder screw on your expansion tank next to the filler cap.

***Warning***
These bleeder screws snap very easily. They strip easily too if your screw driver is too small.

Now, fill it to the KALT line, close the cap, let it get to operating temp and crack the bleeder. When it starts pushing fluid, hopefully that should be the end. Close it gently. Come back when you can open the cap. Check the level. If it is too low, repeat. Once completed, drive spiritedly and monitor the temp. You should be good to go.

but while i do this of course i have to have the car on an incline, right?

but why would my car run consistently at a little over half?  if my coolant wasn't bled, wouldn't it be shooting up to the red when the sensor hits an air pocket?

but i will go out and do this right now.

[iamcreepingdeath]

OK i need some help!!!  the same dang thing is now happening with my car that happened last time i tried to put in a new thermostat.

the reason i was running thermostatless in the first place was because the last time i put in a brand new T-stat the car overheated and the lower coolant pipe (from the T-stat housing to bottom of radiator) never warmed up, it was stone cold.  When i took the T-stat out then everything was fine, the car ran on the cold side obviously, but there was coolant flow as all coolant pipes were warm.

Now the same thing is happening AGAIN!  the car heats up to 3/4 the way to hot and the lower coolant hose is STONE COLD.  I do not understand this at all.  

OK obviously it can't be a bad radiator, because when there is no T-stat both hoses are warm, and with this new T-stat in, i can squeeze one pipe and feel the coolant pressure build up in the other pipe, so there is flow across the radiator.

So the only logical conclusion is that the T-stat is closed!!  how can this be???  its the second brand new T-stat i have installed!  I know i have it in correctly, because i consulted the RealOEM diagram.

The one thing i noticed is that there is no air escape hole in either of the new T-stats.  Is this normal?  if so, what else could it be?    help!!!

EDIT:  oh and the heat does work, and when i drive around with the heat blasting the temp gauge is at the 1/2 mark, and when i turn off the heat it goes to the 3/4 mark.

[Murdul]

Add a 50-50 mixture of coolant and water into the radiator until it reaches the cold like. Turn the key so the car is on, but the engine is not running. Put the heat on full hot. The valve should open the fluid will empty from the expansion tank. Add some more.

Take the bleed screw out. It is right next to the expansion radiator tank opening. With the car running, keep adding coolant until it starts to run out of the radiator bubble free.

This Method comes from ZOSO in the how-to section.  Try this, it worked best for me.

[iamcreepingdeath]

I think the radiator is full already, but i can try that.  i'll be right back.

[iamcreepingdeath]

OK here is the scoop:

Did what Murdul said, went for a drive, and here is the situation:  the bleeder valve only bleeds coolant, the reservoir stays at a constant level, i can see coolant squirting into it as i rev it up, and after a drive, when the temp gauge reached the 3/4 mark, i noticed the lower coolant hose got hot, so apparently the T-stat opened.

It looks like the T-stat i have keeps the engine between 1/2 and 3/4 mark, usually closer the the 3/4 mark.  BUT this was the 88 degree T-stat from Pelican!!  shouldn't that be the cooler T-stat that keeps the temp below 1/2 mark??

it was the cheapest T-stat available, is it possible that this and the other one is a bad T-stat??

[Ramblin MAn]

When there is an air pocket where the coolant gage sending unit is the temp will drop because there is no coolant getting to to heat it up.

The spring side of the T-stat should go to the hot side. So coolant will just circulate around the engine and heater until it gets hot enough to make the spring open the tstat then coolant will be drawn into the waterpump from the radiator.

[iamcreepingdeath]

When there is an air pocket where the coolant gage sending unit is the temp will drop because there is no coolant getting to to heat it up.

actually, when there is an air pocket the temp gauge shoots up, not down.  Air in the coolant system has a much higher temperature than the water, but has a lower specific heat.

The spring side of the T-stat should go to the hot side. So coolant will just circulate around the engine and heater until it gets hot enough to make the spring open the tstat then coolant will be drawn into the waterpump from the radiator.

these things i know.  The T-stat is installed correctly in the car (as far as i know).  But the point is, the T-stat won't open until the temp gauge is nearly at the 3/4 position, which is way too hot.  The T-stat is supposed to open when the temp reached the 1/2 position.

[Ramblin MAn]

Your coolant temp sender for your guage is not meant to be an accurate measuring device. It's not like the coolant temp sensor that IS meant to be accurate. Your's may be way off. It's just a resistor that lowers in resistance as the coolant gets hotter. Less resistance lets more current flow so the guage needle goes further up the scale.

You may just need to replace your temp sender.

[iamcreepingdeath]

Your coolant temp sender for your guage is not meant to be an accurate measuring device. It's not like the coolant temp sensor that IS meant to be accurate. Your's may be way off. It's just a resistor that lowers in resistance as the coolant gets hotter. Less resistance lets more current flow so the guage needle goes further up the scale.

You may just need to replace your temp sender.

that could be true, but it seems to work all right, as it showed 1/4 temp when there was no T-stat, and before it started overheating like a few months ago that caused this mess, it used to read consistently a little below half.  What part number is the temp sender?

[dvmotorsports]

If one hose is hot and the other is cold, you have bled the system, i am going with faulty T-Stat

[iamcreepingdeath]

If one hose is hot and the other is cold, you have bled the system, i am going with faulty T-Stat

right, but continue reading, it turns out the lower hose gets hot when the engine temp hits the 3/4 mark, hence the T-stat must be opening at that point, and the final question at this point is: why does the T-stat open so late?  shouldn't it open when the temp gauge is at 1/2?

[dvmotorsports]

right, but continue reading, it turns out the lower hose gets hot when the engine temp hits the 3/4 mark, hence the T-stat must be opening at that point, and the final question at this point is: why does the T-stat open so late?  shouldn't it open when the temp gauge is at 1/2?

Sorry, jumped the gun.

Now the T-Stat could still be faulty, or your temp gauge is faulty. The best two attempts to remedy this IMO would be to borrow an infrared temp gun to test it, or hook up an aux gauge and see what reading you get.

Or you could do what I hate (electrical) get the values for the temp sensor and check the resistance periodically as the temp changes to see if it falls within the parameters allowed.

[iamcreepingdeath]

Sorry, jumped the gun.

Now the T-Stat could still be faulty, or your temp gauge is faulty. The best two attempts to remedy this IMO would be to borrow an infrared temp gun to test it, or hook up an aux gauge and see what reading you get.

Or you could do what I hate (electrical) get the values for the temp sensor and check the resistance periodically as the temp changes to see if it falls within the parameters allowed.

hmmm...  that sounds pretty complex.  I do have another brand new T-stat, i stuck it in a pot of water and heated it up, and it opened at around 90 degrees or so, so i know that one works, i am going to drill a small air bleed hole in it and swap it out with the T-stat that is in the car and see if anything changes.