Author Topic: Thermostat and Coolant Bleeding Issues (Read 35687 times)

iamcreepingdeath · « **Reply #90 on:** October 03, 2009, 10:55:33 PM »

Quote from: johnwoo;79344

whats the pn for the 75 degree t stat. i would like to put that in cuz i have the 88

here: http://www.bmaparts.com/ShopByVehicle.epc?q=1991-BMW-318is--/--L4--1796cc--1.8l--Gas--Fi--m4---Cooling--Components&yearid=1991@@1991&makeid=BMW@@BMW@@X&engineid=1011373@@318IS++/+L4-1796cc+1.8L+GAS+FI++(M42)@@318IS&catid=Cooling+Components@@Cooling+Components&subcatid=Thermostat@@Thermostat&mode=PA

Quote from: qualicas;79346

How old is the rad? If it is the original one you might want to install a new one because it is just a matter of time before it goes. The problem with the cooling system on these cars is that it is a parallel circuit. The pump pumps through the engine and at the same time through the rad. If the rad is plugged all the flow goes through the engine and none through the rad. Other systems are just one flow path so the water would get forced through the rad until it is really plugged.

hmm.... well that is a good point. we will see what happens when i get the new t-stat in.

hbgoonie · « **Reply #91 on:** October 05, 2009, 02:55:38 AM »

iamcreepingdeath you are not alone. My car does the same thing and I am lost at whats causing it. Took it to the shop and they say everything is running normal. For some reason it runs at 12oclock when I take it to the shop (just to torture me). But now it doesn't seem to matter what temperature it is outside it will run hot. Ive had my system flushed, water pump, thermostat and radiator replaced. Still have the problem though. Was tempted to replace both sensors but since you had no success I won't try.

What I find weird, and I don't know if you have this, but sometimes (rarely) it will run perfectly fine. The needle will be stuck right before 12 o'clock and it will stay that way for a few days. Then eventually it goes back between 12 and 3/4. Ive been driving around for the last week or two with it running hot. I'm hoping today my car will actually run at 3/4 tomorrow when I bring it to the shop so they can maybe tell me whats going on.

iamcreepingdeath · « **Reply #92 on:** October 05, 2009, 02:32:31 PM »

Quote from: hbgoonie;79426

iamcreepingdeath you are not alone. My car does the same thing and I am lost at whats causing it. Took it to the shop and they say everything is running normal. For some reason it runs at 12oclock when I take it to the shop (just to torture me). But now it doesn't seem to matter what temperature it is outside it will run hot. Ive had my system flushed, water pump, thermostat and radiator replaced. Still have the problem though. Was tempted to replace both sensors but since you had no success I won't try.

What I find weird, and I don't know if you have this, but sometimes (rarely) it will run perfectly fine. The needle will be stuck right before 12 o'clock and it will stay that way for a few days. Then eventually it goes back between 12 and 3/4. Ive been driving around for the last week or two with it running hot. I'm hoping today my car will actually run at 3/4 tomorrow when I bring it to the shop so they can maybe tell me whats going on.

weird. My car doesn't have times when it runs at the right temp, it is pretty much overheating all the time. Well, at the moment, i have no t-stat, and i just got the radiator blasted out and it is running really cold, like between the completely cold and 1/4 mark. When i get my t-stat in the mail i will see what happens.

DesktopDave · « **Reply #93 on:** October 05, 2009, 02:53:14 PM »

Quote from: hbgoonie;79426

iamcreepingdeath you are not alone. My car does the same thing and I am lost at whats causing it. Took it to the shop and they say everything is running normal. For some reason it runs at 12oclock when I take it to the shop (just to torture me). But now it doesn't seem to matter what temperature it is outside it will run hot. Ive had my system flushed, water pump, thermostat and radiator replaced. Still have the problem though. Was tempted to replace both sensors but since you had no success I won't try.

What I find weird, and I don't know if you have this, but sometimes (rarely) it will run perfectly fine. The needle will be stuck right before 12 o'clock and it will stay that way for a few days. Then eventually it goes back between 12 and 3/4. Ive been driving around for the last week or two with it running hot. I'm hoping today my car will actually run at 3/4 tomorrow when I bring it to the shop so they can maybe tell me whats going on.

Did you check your aux fan & relay? Mine does that...runs fine sometimes, overheats at other times. No real pattern. I found that the resistor is defective. I fixed it temporarily by removing the resistor & wiring it straight. Now it works some of the time. So there's another problem to track down...maybe the low-speed relay, rad switch, dirty contacts, broken wire, etc.

DesktopDave · « **Reply #94 on:** October 05, 2009, 02:55:34 PM »

Quote from: iamcreepingdeath;79446

weird. My car doesn't have times when it runs at the right temp, it is pretty much overheating all the time. Well, at the moment, i have no t-stat, and i just got the radiator blasted out and it is running really cold, like between the completely cold and 1/4 mark. When i get my t-stat in the mail i will see what happens.

I thought it'd always run cold without a themostat? Without the thermostat to keep heat in the engine, you're essentially giving it max cooling when you're moving. It should heat up when you're idling, does it? The gauge or sender might also be wrong.

iamcreepingdeath · « **Reply #95 on:** October 05, 2009, 06:21:31 PM »

Quote from: DesktopDave;79450

I thought it'd always run cold without a themostat? Without the thermostat to keep heat in the engine, you're essentially giving it max cooling when you're moving. It should heat up when you're idling, does it? The gauge or sender might also be wrong.

after getting the radiator blasted out, the temp gauge has not gone past the 1/2 mark yet, it runs below the 1/4 mark when driving on the interstate, and at a park it crept up to the 1/4 mark. So far, so good, i am just crossing my fingers to see what happens when i get this new t-stat installed when it gets here.

nhevynopal · « **Reply #96 on:** October 06, 2009, 01:12:51 AM »

Ok I ain't no pro but I had da same problem for like a month looking every were to find the solution for overheating did every thing like pump the t nothing I work in a little shop I took my car and I said just for the hell of it I am going to do a coolant flush with a machine we got and guess what wala I think u should take ur car to like a jiffylube or something were they can do a realy good flush I did mines myself I did a pretty good job make shure they put the outlet hose to the t stat. The machine puts so much pressure that it forces the air out the system also leave ur ignition on with the heat blasted. When I was done with my car I wanted to cry of joy try it it will work but make shure u go to some ho nows how to do a good flush and with a machine. Good luck

iamcreepingdeath · « **Reply #97 on:** October 06, 2009, 10:49:36 PM »

Quote from: nhevynopal;79483

Ok I ain't no pro but I had da same problem for like a month looking every were to find the solution for overheating did every thing like pump the t nothing I work in a little shop I took my car and I said just for the hell of it I am going to do a coolant flush with a machine we got and guess what wala I think u should take ur car to like a jiffylube or something were they can do a realy good flush I did mines myself I did a pretty good job make shure they put the outlet hose to the t stat. The machine puts so much pressure that it forces the air out the system also leave ur ignition on with the heat blasted. When I was done with my car I wanted to cry of joy try it it will work but make shure u go to some ho nows how to do a good flush and with a machine. Good luck

whoa buddy slow down and type more legibly so i can understand what you are saying.

So the coolant flush fixed your overheating problem?

monty23psk · « **Reply #98 on:** October 06, 2009, 10:51:59 PM »

Yeah, hard to understand but looks like a flush helped in his case. I would still recommend it and not expensive, just need to buy more coolant, which I recommend the blue bmw version. I can also get it cheaper than Pelican Parts in case you are interested. I alwasys offer parts that can save people money, might be a few dolloars but it adds eventually.

When do you get your tstat. I just shipped a 75 degree version to JohnWoo.

nigel · « **Reply #99 on:** October 06, 2009, 11:25:24 PM »

This isn't exactly what you guys are talking about, but just in case it helps anyone else:
I was having some (severe) overheating issues a while back, and bled the system 3 or 4 times without any improvement. Did everything anyone said... car on an incline, car level, rad cap off, rad cap on, etc. - sometimes the temp would stay down for a little while, but went back up before too long. Eventually figured out that for whatever reason the lower rad hose was never filling with coolant (no, rad wasn't clogged - brand new, actually). So I primed the hose by disconnecting from the pump and filling directly with coolant. Reattached it, bled the system again, and the problem was fixed.
I still can't figure out how that solved the problem... or why that bubble didn't bleed out.
I blame it on voodoo.

johnwoo · « **Reply #100 on:** October 07, 2009, 01:11:02 AM »

Quote from: nigel;79532

This isn't exactly what you guys are talking about, but just in case it helps anyone else:
I was having some (severe) overheating issues a while back, and bled the system 3 or 4 times without any improvement. Did everything anyone said... car on an incline, car level, rad cap off, rad cap on, etc. - sometimes the temp would stay down for a little while, but went back up before too long. Eventually figured out that for whatever reason the lower rad hose was never filling with coolant (no, rad wasn't clogged - brand new, actually). So I primed the hose by disconnecting from the pump and filling directly with coolant. Reattached it, bled the system again, and the problem was fixed.
I still can't figure out how that solved the problem... or why that bubble didn't bleed out.
I blame it on voodoo.

hmmm interesting....which hose you talking about willis? got a picture.
my lower hose the one that goes from the tstat housing to the lower part of the radiator on the passenger side always takes forever to warm up. and i have new radiator too. if that is the hose you are talking about and dumping coolant down there before filling up your cooling system works then im gona try that this weekend.

johnwoo · « **Reply #101 on:** October 07, 2009, 01:23:11 AM »

there is a pic to clarify. i circled it in red. is that the hose you are talking about. on mine that takes forever to warm up. i have to run my temp gauge to between 1/2 to 3/4 before that hose heats up. im thinking my sensor for the coolant or gauge is screwy. anyways if you could clarify, thanks.

monty23psk · « **Reply #102 on:** October 07, 2009, 08:50:10 AM »

That hose would take a while to heat up as only when the tstat opens would it allown the hot coolant to pass by. Of course, hot coolant has to be passing through it for a while so that when you touch the hose, it is piping hot. I will take a drive to my father's warehouse after work, about 10 min drive, and see if after it is hot or not. I need to replace the upper hose on the ether side as it is bulging a little and dont want it to burst. Never replaced it 4 years ago when I did the rebuild.

Your tstat is in the mail.

iamcreepingdeath · « **Reply #103 on:** October 07, 2009, 11:36:44 AM »

my t-stat should arrive today, but i am not sure if i can put it in today or tomorrow, because of stuff i have to do.

I will try the priming idea to that lower hose when i replace the t-stat, and maybe also i will take it to a lube place to have the engine coolant flushed with high pressure.

johnwoo · « **Reply #104 on:** October 07, 2009, 12:06:33 PM »

Quote from: monty23psk;79543

That hose would take a while to heat up as only when the tstat opens would it allown the hot coolant to pass by. Of course, hot coolant has to be passing through it for a while so that when you touch the hose, it is piping hot. I will take a drive to my father's warehouse after work, about 10 min drive, and see if after it is hot or not. I need to replace the upper hose on the ether side as it is bulging a little and dont want it to burst. Never replaced it 4 years ago when I did the rebuild.

Your tstat is in the mail.

cool cool. i was just seeing if op had the same issue and maybe that solved his overheating problem buy dumping coolant directly into the pipe to prime it.