Author Topic: overheating issue (Read 3907 times)

91_e30_m42 · « **on:** June 01, 2009, 10:05:31 PM »

my 318 seems to overheat, i checked the radiator and the radiator was cold, i also checked the hoses, and the top hose was hotter than the bottom one, a friend told me it could be the thermostat, or the waterpump, or even the radiator is cloged, i just wanted to see what some of you guys thought

DesktopDave · « **Reply #1 on:** June 01, 2009, 10:32:17 PM »

Mine's overheating too...leaking coolant somewhere. I'll let you know if I get to the bottom of it. Temperature isn't stable, might be my thermostat or a leak off the plastic coolant manifold.

Radiator should be pretty hot especially if it's been idling. Could be all three...the thermostat is pretty easy to test though - boil it on the stove to check it. I use an old pan and an older meat thermometer to prevent marital strife. I suspect we could test the coolant sensor the same way.

Did you test the clutch on the main fan? Easy to spin when cool, shreds newspaper when hot?
What about the secondary fan (front of radiator)...does it spin with A/C on?

beemer1 · « **Reply #2 on:** June 01, 2009, 10:32:29 PM »

Quote from: 91_e30_m42;72778

my 318 seems to overheat, i checked the radiator and the radiator was cold, i also checked the hoses, and the top hose was hotter than the bottom one, a friend told me it could be the thermostat, or the waterpump, or even the radiator is cloged, i just wanted to see what some of you guys thought

When was the last time you changes the thermostat? In my experience when the thermostat goes it will read cooler, some may experience different results. Either way if the thermostat hasn't been replace in awhile I would lean towards that.

Next thing I would suspect is the fan clutch. With the engine cold, manually spin the fan and see if it spins freely. It should come to a stop pretty quickly. If it contnues to spin more than 1 revolution i would say to replace the fan clutch.

Then I would check the radiator and attempt to flush it.

When I had the dreaded timing case gasket fail I replaced the water pump.

You may want to start by bleeding the rad system first and then continue with everything else.

ps. my temp needle reads slightly above the halfway mark and personally believe one on the temp sensors (especially under the intake connecting to the head) has gone awry:mad:

Hope this helps,

Steve

91_e30_m42 · « **Reply #3 on:** June 02, 2009, 09:04:40 AM »

i imagine if the radiator stays cool the coolant isnt circulating, correct me if im wrong. i dont think its the fan clutch, it wouldnt cause the radiator to stay cool even while its really hot, again correct me if im wrong. i may have to replace all coolant components

xwill112x · « **Reply #4 on:** June 02, 2009, 09:42:17 AM »

your system is either not sealed properly, which doesn't allow the coolant to currculate properly, or you have a air-lock in your cooling system somewhere.

check for any spots/hoses bubbleing and bleed your system with the bleed screw on the radiator.

nigel · « **Reply #5 on:** June 07, 2009, 01:23:40 PM »

I've got overheating problems, too. I just replaced the water pump and thermostat - no improvement. the last time I warmed it up (to bleed it), a hose connection under the intake manifold stated to leak steam and fluid...

nigel · « **Reply #6 on:** June 07, 2009, 05:04:14 PM »

Fixed the problem!
I was squeezing the radiator hoses and there was just no fluid in them at all (and therefore no water for the pump to pump), even though I had filled the radiator and had the engine running. At first I thought that this was due to some other, much worse problem that I had yet to figure out, but it turned out to have an easy fix: I disconnected the top rad hose and poured water in so that the pump had something to move around. I did this a few times, reconnecting the hose and running the engine in between. Does the pump usually need to be primed? Maybe I was just being stupid, but I didn't think that was one of the steps in a coolant flush...

DesktopDave · « **Reply #7 on:** June 07, 2009, 07:05:38 PM »

I'll have to try that out...I'll be doing a hose delete later this year. I don't think the pump requires priming, but it definitely speeds things up if you displace as much air as possible.

Both hoses were empty? Wow. Amazing it didn't blow a gasket.

You used distilled water, right? Please tell me yes.

AcSchnitzer318is · « **Reply #8 on:** June 07, 2009, 07:07:33 PM »

^Not typically, glad it worked for you though.

I usually just fill the coolant reservoir until full. Loosen the bleed screw. Turn heater to full blast. Start car. Wait for it to run up to temperature so the thermostat opens. Check the hoses for temperature... though once it comes up to temp it will usually suck down the coolant in the reservoir. Then I continue to add fluid until I see a steady stream of fluid only coming out of the bleed screw. Finally tighten up screw and wipe up excess coolant. Then check level again after the car has been driven. Fill to the cold fill line. Done.

Thurber · « **Reply #9 on:** June 17, 2009, 09:54:07 PM »

Yeah sounds good. And to those double check that your aux fan is working correctly. turned out to be the temp sender. I'm really happy that I don't have to worry about it this problem anymore!