Help! My car WON'T STOP overheating!! - United Bimmer Community

**ecks** · 09-21-2007, 03:05 PM

Okay,

I ran into a problem a few weeks ago. The car overheated, the thermostat was bad as well as the water pump. Got both replaced, brand new. Sealed up the thermostat gasket properly so no air would enter or leave and STILL, it over heats after 10 minutes or so of idle or driving it. Now, there was a bit of white smoke coming out of the tail pipe but that's now gone, stopped. After the initial start, the engine shakes and whines a bit but after a minute of giving it gas, the engine settles down and idles just fine. Now, here is the biggest hint for anyone that knows what's up... when the car overheats, the hose on the left (when you're facing the car) isn't as hot (is warm-hot) but the hose on the right (again, when you're facing the car) is really heating up, I mean HOT and it seems harder when you squeeze it as if there is more water/coolant in there than in the left hose. Any ideas?

Thank you! Please email me at hairsolutionszack@yahoo.com with any info or just post here.

**Misfire** · 09-21-2007, 03:49 PM

maybe the radiator is plugged up?

**mzbmw325i** · 09-21-2007, 06:18 PM

Do a proper flush (and run a hose through radiator) and use the bmw ORIGINAL coolant mixture and mix 50/50 with distilled water. dont forget to do a proper breathing too (bubbles out) also may want to change all your hoses, if you have not, it's a good idea.

did you install the thermostat correctly, also is it the appropiate one, i mean temperature wise. it could be faulty.

it would be nice if you can post pics of your engine bay and point to which hoses you r referring to.

Looking left/right from the front and trying to picture it on a friday afternoon after lunch is torture, my brain is just asleep

just my 2 cents dont shoot me now.

**Dudesky** · 09-21-2007, 06:25 PM

Quote:

Originally Posted by Misfire

maybe the radiator is plugged up?

Hmmm . . could be, wabbit. The t-stat is working fine if there is heat/pressure on the right hose. This then travels into the radiator, then out the left hose. If there is no pressure, heat, or evidence of anything flowing through that left hose, then your radiator is probably blocked. I would replace the radiator anyways.

craig · 09-21-2007, 08:13 PM

yeah get the radiator cleaned out. my truck was overheating real bad on the highway, replaced teh thermostat, nothing. took the radiator to a shop and had them clean it out, works fine now.

**gabe_beamer** · 09-27-2007, 03:09 PM

u cracked the head gasket...be ready to spend about 1500 dollars on some head work..or buy a new motor..

**mullethunter3** · 09-27-2007, 05:44 PM

^^^ You sure about that?

**Kistoni** · 09-28-2007, 12:05 AM

It could be a pressure issue causing the coolant to boil. There is a connector on the back of the engine that feeds into the heating and some other things. Mine had a slight crack and eventually broke the same way the inlet neck on the radiator did. You could try some leak stop and do a pressure test. Are you loosing any coolant? Also the cap can perish if there is no obvious leak shown in the pressure test.

Another issue it could be is the electric fan which should kick in as the coolant warms in the radiator. The Bentley manual has quite a good diagnostic for fault finding in this area. I ended up hard wiring mine so that it is always on full speed: no more over heating. I now have all the parts to replace the radiator, t-stat, rear connector and back end hoses (x5) but I am reluctant to do the work as the car seems to be running fine... Its probally being held together by a thread.

Good luck sorting it out.

**stevo** · 09-28-2007, 12:52 AM

It might be worthwhile getting the entire system flushed through, if your radiator is blocked it's very probable that your heater matrix will also be sludged up and partially blocked.

**Carmine-i** · 09-28-2007, 06:59 PM

I am new with BMW's but experianced on many other types. Before you run the car any more, you may want to drain the oil to check for antifreeze...here is a great link to read about some cooling issues..http://www.pelicanparts.com/BMW/tech...lant-Flush.htm

From my experiance, when you have a bad t-stat the upper radiator hose will become very hard due to the increase in pressure. Also, it might not be as hot as the lower hose, the longer the vehical runs will obviously make a differance as too how hot it will be.

Ofcourse it would suck to pull the t-stat again, but a good way to check to see if it works is to boil it in water and measure the temp when it starts to open, if it opens. Don't forget to bleed the system the above link tells how.

Good luck with it, and let us know what happens.

**StiffCookie** · 10-18-2007, 04:57 PM

Hey are you still having trouble with the overheating? I only jus saw this thread so I thought I'd try and help too.

As your looking at the engine from the front bumper the left hose should be warm-hot (water coming from rad) and the right hose should be very hot, assuming its been running for a while (from the engine). So this is normal.

To me, this could only be that you need to bleed the system like Carmine said. A little bit of air in there can easily cause overheating. If you try this and it overheats again. Let the engine cool down and begin bleeding again. When my bimmer overheated I bled the system for about half an hour just to make totally sure - worked a treat.

The engine should always be at running temp after it's warmed up (centre of the gauge), so when it hits the 3/4 mark MAX...turn the engine off, don't wait for it to go into the red!

If you try our suggestions and they don't work...tell us so we can help think of more possibilities!

Hope this helps,
Stiff

**94bmw325i** · 10-20-2007, 06:51 PM

a radiator not bled correctly, and/or your fan switch not working can definetely cause overheating.