Car running hot WTF? LOOOOOONG

[delatlanta1281]

So I searched and came up with same old crap.
Here is my deal, wanted to see if anyone else has run into this.
My temp gauge is usually at halfway. Now it is in between half and three quarter, it climbs to 3/4 and then the needle flicks down to halfway and it cycles up slowly again. This is all while I am at a long light.
When I accellorate the needle drops back down.
I know it isn't: The thermostat, it is new and opens at the right temp.
Coolant leak, The hoses are new and the clamps are tight. it isn't loosing coolant at a noticable rate.
Radiator, the thing is six months old.
Aux fan, jumped to run on high, doesn't really help.
Gauge, seems fine when started only time it acts weird is the three quarter mark.
Water pump, changed it 5 months ago when I had the timing done.
I haven't checked:
Cap, seems unlikely though I will replace asap.
Cat, Maybe, I have been noticing a lack of power vs revs lately, like it is revving faster than normal. Can't be the clutch slipping it is a week old.


I live in Sacramento now and it is @ 104 most days, so am I being a puss and paranoid or could it be my cat???? Is there a way to check the cat besides gauging the amt of air coming out the tailpipe?

[E30_pilot]

Sound kind of like my car.
When I'm in heavy traffic,or long light the temp goes between 1/2 and 3/4.
But when I'm rolling the temp goes down.And than at a long stop again,it goes up.But in your case you say "it climbs to 3/4 and then the needle flicks down to halfway and it cycles up slowly again. This is all while I am at a long light.When I accellorate the needle drops back down, " that shows the Aux Fan is working,so you can scratch that off the list.

Problem could be Fan clutch.
So here are some possible solutions,if it is the fan clutch:

-replace it.
or
-delete fan clutch,leave stock electric fan that's in front of the radiatior, and swapped in the fan switch from an E36.

As for the revv vs power problem thing, I have no idea.

Hope that helps.

[325iCabrio]

I just got done working with this same problem. I ended up replacing my thermostat, fan clutch, and flushing the system.

It sounds like your thermostat is working since it heats up and then cools down, so I'd try the fan clutch first. It's a cheap part, but make sure you go BMW OEM--this is the best part/deal for a fan clutch: 11 52 1 466 000.

If that doesn't work, I'd suggest bleeding your system, and if that doesn't work, because it's so hot, get a thermostat that opens at a lower temperature. That's what I did, and it's been 105 F+ here in SLC and the car doesn't get hotter than 11:00 on the gauge.

Good luck. Cooling problems suck ass.

[luvin my 325es]

I ran a toggle switch to the temp switch on the radiator. The aux. fan has 2 speeds. Mine always ran at low speed, now when I sit in traffic I flip the switch and turns the fan on high. Also helps the a/c keep cool when sitting in traffic. Check bimmerdiy.com I found it there under a/c toggle switch, I think.

[delatlanta1281]

Weird though would a fan clutch go in a year????? Some of the blades on my fan are damadged too. but not bad. But not the cat huh?

[bmdub5]

i wouldnt say its the cat since that doesnt hav much to do with the cooling of your car. since you have already changed most of the parts which would normally be your problems, i would say that you may have some sort of air bubble in your system. i would bleed everything and see how that goes. also im with the others on maybe a bad fan clutch. hope you fix it soon. i hate cooling problems because once you test the normal things and those dont work, i get real nervous of head/block problems. GL with everything though

[delatlanta1281]

yeah i know, I can't imagine it is the head though. The car runs so strong.
How long do you think it takes to bleed the system?

[etxxz]

DUUUD this just started happening to me yesterday...but the car wasnt hot or anything.

i just replaced the intake manifold gasket...well sort of if you read my thread...and the car started up beautifly yesterday BUT the temp gauge is above 1/2 and it got to the red zone twice yesterday...BUT this was shortly after i turned on the engine and i touched the IM and it was cold...touched the coolant and it was COLD!

so idk. maybe the temp sensor is bad? where's that? where the upper rad hose connects to the part next to the IM?

[dirty30]

I'm having the same problem as well, I just replaced my broken electric fan and thermostat. Its gotten better but I am going to try a waterpump as well as a temperature switch/ coolant flush. I'll post up here with the results.

-R

[Adrian_Visser]

if the cat disintegrated it would cause higher back pressure in the exhaust. this would inturn cause higher engine temps, it is possible to measure back pressure,
as far as i understand if you have a pressure gauge and an insert to fit into the boss for the O2 sensor that is threaded right.

but as for what those readings are supposed to be... bentley?

i havent checked

also i think youd problaly notice some power loss so maybe thats out

[redhatpat]

In a lot of cases where the cat falls apart inside, the engine will still idle normally, but it won't be able to rev up well past 3000 rpm (give or take some depending on the extent of the cat's damage) because of the back pressure. It won't normally cause the engine to overheat unless you insist on running the engine at that higher rpm.

I'm not saying this isn't the problem, but its one of the less likely causes for overheating.

[delatlanta1281]

Pretty sure it is the fan clutch. I have added purple ice by Royal Purple, that seems to have droopped the temp drastically.

[etxxz]

i fixed it!! i drained the coolant...which was DARK green and poured some new prestone in threre...meaning my sensor was working right and the car was indeed overheating! also did my P/S fluid. whhuuuAt! a difference