2004 BMW 330i ZHP overheating ?
So the other day i was driving back home
with a buddy after work. We were out of
town and there wasnt much traffic so we
let it go a bit. Nothing to excessive, and
not for a sustained period of time either,
only a could good pulls up the straights.
but i noticed that i started to run hot so i
pulled over and got my friend to give me a
ride back home. Later on i managed to get
back to it, check coolant seemed level
seemed fine. I got it half way back home
before it got hot and i had to get a ride
again. Managed to get it back in the
morning without overheat. Immediately
went and bought a new water pump and
thermostat because i figured those would
be the culprits. Before i went to put the
water pump and thermostat in, i checked
coolant resevoir and it seemed full but
when i drained it all out, so little came
out... after putting everything in i went to
put in the coolant and the resevoir filled
really quick without being able to see any
filling up in the bleeder. I did some
searching and found out that you have to
keep pouring until its full and burp then
suck the raining out of the resevoir. So i
did that (on ramps in the front) ended up
putting in waaay more then i had in there
before, took it for a test run and then i was
overheating again, coolant spewing out of
the resevoir cap. So this time i went a
grabbed a clutch fan because mine
seemed rather weak and wasnt doing its
warmup run when i started my car, figured
that would be my next plan of attack. Got
that all put in, retopped up my coolant on
ramps and burped, bled like 4L of coolant
through the system and left the key on
position two with heat on full for like 20
minutes. Started the car while in neutral
and on ramps, let it idle for like 10
minutes. All seemed good. Took for a test
run around the block, i went around 3 and
a half times before i overheated again.
Once again coolant spewing out of the
resevoir cap..
Im getting stumped as to what it could be,
im looking for any opinions on what to do
next. I feel like my next options are
coolant temp sensor, maybe its not
reading the temp right. New resevoir cap (i
beleive its supposed to spew when over
pressured tho) maybe a coolant system
flush out to see if theres any clogs in
there. Or possibly a new radiator, maybe
even a heater core ? At idle it seems to
blow kind of cold air, not super cold but
should be hotter in +40 celcius, when
driving it was fine though. Maybe i just
need to keep burping and bleeding even. I
dont want to beleive its a head gasket
issue because its not the best, but theres
no milky oil, white exhaust smoke or
coolant smell either. Well coolant smell
but only when overheated and spewing.
Really need to get my car up and running
again and not sure which direction to take
next, anything helps !
Thank you
This is going to be a coolant circulation problem. Water pump, thermostat, clogged cooling system passages, etc. I'd suggest you flush the cooling system with a chemical cleaner and make sure you have all the air out of the cooling system when you refill it. Hope that helps! Jim
https://www.bimmerfest.com/forums/showthread.php? t=764267&highlight=overheating+coolant+refresh
So today i tried to empty out all the coolant ive put in and start fresh. Got it all out and only like 3L came out... i didnt think that much spewed out lastnight when i overheated. But regardless i started to refill. I had 10L of 60/40 coolant (canada is a bit colder and the bmw coolant bottle advises to do so) ready to go because thats what ive read is the amount it takes. I got about 3L in and the coolant stick was already maxed out, i got to 5L and then it was flowing out of the bleeder... how is that possible ? Im thinking there may be a block thats not allowing it to circulate all the way through. Currently have car on position 2 with heat on and all that trying to burp. It doesnt seem like ill be able to get more then 5L of coolant in tho, which is a problem
Unless you removed the drain plug from the block and drained the heater core separately there's going to be coolant left in the engine and heater core. Are you getting heat from the heater? If not there's still probably air trapped in the cooling system. Another thing to consider is you might have a blown head gasket. BMWs do not like to be overheated and it's not uncommon for them to blow a head gasket if they are! With the engine cold, pressurize the cooling system. It should hold the pressure for at least 15 minutes. If not, something is leaking! Start the engine and watch the needle on the pressure tester gauge. If it bounces with the engine running, the head gasket is blown. One other thing to look at is the lower radiator hose. Make sure it's not collapsing and shutting down the coolant flow from the radiator. Hope that helps! Jim
I undid the plug underneath the resevoir i beleive. Its right behind the front bumper on the drivers side. I drained as much as i could, also quite a bit hit the ground lastnight. Going to keep burping and hope its an airlock because it doesnt blow the hottest air when in position 2, but when i took for a test drive yesterday it started blowing heat real good. When it overheats the needle doesnt bounce though. It just steadily rises until i shut off, then usually the coolant is pouring from the cap, but i beleive the cap is designed to do that under pressure. I want to take it in to see if theres a blockage somewhere in the coolant system, but i dont want to pay all that money to find out i have an airlock somewhere yenno. Thank you for all the advice though, much appreciated. Ive been so indesicive on which route i should take. I dont want to keep guessing and end up spending money i dont need to, also overheating it in the test process. Last thing i want is blown head gasket.
The bouncing needle I'm referring to is on the cooling system pressure tester. It's a tool that you can buy or borrow from your local auto parts store to check the cooling system for leaks and a blown head gasket as I've described. Hope that helps! Jim
One other thing, if you do decide to take it somewhere, take it to a shop that specializes in imports! A gas station or chain type of repair shop won't be able to fix it and will have no idea of what they're looking at! My Nephew learned that lesson the hard way with his 98 528i. Jim
So i looked around and settled on a place called Euromart, found them on a website that lists places that do bmw work, has some good reviews. Called and talked with him a bit and he said it sounds like a radiator issue, he got me to take it out and bring it down to him just now. Hes going to take a look at it and give me advice on my next steps in this. I asked about a pressure test and he said it doesnt sound like a headgasket to him. Either way, Im hoping this fixes up my problem. After all this im getting a nice coolant system clean from bmw here and hopefully all will be well. Ill will continue to update until im 100% fixed. Thanks for all the help
You're welcome. Glad to help! Thank you for letting us know and I look forward to hearing the outcome! I hope it is just the radiator! When the engine overheats at higher speeds, like you first described, it's a coolant circulation problem. So it could very well be a blockage in the radiator! I'm also very happy you went with a shop that's familiar with BMWs! You won't be sorry!! Jim
