overheating problem..

[njbmw]

Hey everyone.. so i was doing some researching on this overheating problem that started today. On my way to work, I noticed the temp rising SLIGHTLY (not going past the 3/4 mark ofcourse). It was actually kind of in the middle of the half and 3/4 line. I read about different over heating issues but nothing like mine. I also noticed that the temp only starts rising if I'm speeding and going 60-70mph +...when I go below 50mph, the temp is fine... Any ideas? The fan clutch was replaced about 4 months ago and the water pump about 2...

[Albertan]

Has the rad ever been replaced. When you are driving fast, the engine creases a lot of heat that the rad has to remove. The airflow around the rad
is sufficient to remove the heat. However, if the rad is partly plugged, heat transfer will be poorer than needed and the engine will over heat.

[njbmw]

I just got back from trying to see if there was any leak in a hose or waterpump but nothing is leaking. Before that I went a little bit passed the cold line with coolant and then tried to see if any leaks. I had the car running for about 25-30min and the water evaporated... when I turned the car off I popped the coolant cap off really careful and noticed that there was about 1 litre of the coolant gone but no leaks...

[pussiwillow]

i just did a cooling overhaul finished last night. when you have it sitting there running, can you hear it boiling? did you recently change a part out that included a part with the cooling system? you may have an air bubble and when the air bubble gets released coolant takes its place, try bleeding the system, best way is to park on an incline or jack the front up, i prefer jacking the front up so you can check and be positive about leaks dripping on the ground, having the front up higher than back is good because the air will want to move upwards which is the radiator. have the radiator cap off, as air will escape through there and you can add coolant as needed while doing this. usually you can loosen the bleed screw but then you cannot watch the coolant. air bubbles will mess with you and can be a pain.

by the way, there is a head connector mounted to the backside of the head, its very tight back there, theres two hoses running off that, check and double check thats not leaking, thats where mine started

[njbmw]

checked those two hoses a few minutes ago and no leaks. I also checked air filter and it was VERY dirty. I changed it and I drove about 100 miles today with NO heating problems.. I just got back and let the engine get cold, checked coolant level and not a single drop missing... it is all there. I'm takin a small trip tomorrow so I will check to see but right now I think the air filter was the problem. Since the engine gets hot, air comes through the breather but the filter is dirty.. it does make sense but will see tomorrow. thanks for the replies guys.

[rtd328]

I definitely don't see how the air filter would hurt the cooling system, but I'm no technician either. I'd venture a guess that you had air in the system.

[pussiwillow]

im voting that when you took the cap off the radiator you helped bleed out an air bubble that was caught up somewhere causing coolant to have a hard time getting through correctly, the air filter has nothing to do with it and was a coincidence. thats why you saw coolant missing in the tank but not on the ground, it freed up an air bubble and replaced the air with coolant, therefore lost coolant that was never really lost. hope all is well with your car, cooling issues are horrible

[njbmw]

yea, air filter has nothing to do with it, it was just a coincidence.. a big one too. lol

[rtd328]

yea, air filter has nothing to do with it, it was just a coincidence.. a big one too. lol


In good news, that cooling system issue got you looking around, and you found something that need attention, your dirty air filter.