BMW E46 Fanatics Forum banner

1 - 20 of 74 Posts

·
Registered
03 325xi Wagon 5AT
Joined
·
38 Posts
Discussion Starter #1 (Edited)
Hi everyone! I'm new to this forum and just acquired my first E46 (03 325xi wagon automatic) which I'm pretty stoked on..

Bought it a few weeks ago with ~192k miles on the odo. Car is quite clean, engine bay really clean with no leaks, hoses and plastics look new. Was apparently mechanic owned for a bit and alot of the cooling system has been replaced. I see records for new expansion tank, cap, fan clutch, and coolant level sensor at ~160k in March 2016. Radiator, thermostat, and auxiliary fan switch replaced at 170k in December 2016. I haven't been able to confirm whether water pump has been replaced recently.

Anyway, a week ago I took the car on a 3 hour road trip to Yosemite area from Bay Area where I live. I had to drive through some 100F degree weather and the car was fine through most of it until the last bit of the trip going through some twisty uphill.. I noticed the the water temp red light on! I can't recall how deep in the red the needle was or how long the red light was on for before I shut the engine off and pulled over immediately (probably within ~5sec, 10 sec MAX). I imagine the light couldn't have been on that long since I frequently look at my dash. I don't recall if the low coolant light came on. I opened the hood to find that it appeared to have puked out all it's coolant from the expansion tank cap.

So I wait maybe 10-15min for it to cool down and opened the cap which seemed to be not that tight.. added some distilled water; probably almost 1 gallon? Started the engine up with the cap open and it felt normal but the temp started to rise shortly after and it overflowed out the tank a lot so I turned it off. I remembered I have to bleed it so I looked up some youtube videos and added the rest of the distilled water and a bunch of coolant with the bleed screw open, left the heater on to get coolant through the heater core for a few minutes. It started right up again, felt normal.. let air bubbles bleed out the screw for a bit, tightened up the screw, capped off the reservoir, let it run a few more minutes.. temp gauge held steady the whole time. Drove another 10 miles to our campsite with the heater blasting and everything seemed alright. Made it back home the next day next day through the same 100F degree weather, 3 hour trip, no problems. Temp gauge held steady, engine sounded and felt normal. No visible steam coming out the pipes, no visible leaks in the engine bay..

It's been about a week since then and I've checked my coolant levels cold a few times and it's been well below minimum according to the coolant level indicator stick each time. Only had to add a couple splashes to get it between min/max though. I don't know how accurate that thing is.. and I still see no leaks. I'm bringing it into the shop to get it checked out in a couple days. I'm thinking cooling system pressure test, compression test, and leak down test. Are there any other things I should be aware of? Water pump damage from being run dry, etc?

This post ended up a bit more long winded than anticipated but I want to give some good background info. Hopefully it was just a case of someone not quite tightening the reservoir cap enough and a reminder to check the basics first. Your help is greatly appreciated, thank you!

Also, I've attached some pics of my cold coolant levels from this past week and how much I fill it to get it between min/max on the indicator. I've been driving the car regularly between checking.
908758
908759
908760
908761
 

·
Registered
04 325XIT 05 325IT
Joined
·
516 Posts
Too much coolant ,at the pics angle ,you shouldn't be ab le to see coolant that high.i would suggest rebleed ,and tap bobber so your sure it's free, once you know for sure it's floating, fill only to level of Et rim or mouth.
Don't drive it that full drain and rebleed, if temp stays stable , you may not even need a compression test , leakdown and all those wonderful tests.
 

·
Registered
2004 325i automagic
Joined
·
2,364 Posts
You dont need to fill it up so much that it reaches the rim almost ... that is waaay overfilled. The bobber should be floating freely and the bottom ballfloating at the rim level for a max fill, or with the top ball of the bobber floating at the rim level for a min fill. The coolant level will be lower down in the ET
 

·
Registered
03 325xi Wagon 5AT
Joined
·
38 Posts
Discussion Starter #5
Too much coolant ,at the pics angle ,you shouldn't be ab le to see coolant that high.i would suggest rebleed ,and tap bobber so your sure it's free, once you know for sure it's floating, fill only to level of Et rim or mouth.
Don't drive it that full drain and rebleed, if temp stays stable , you may not even need a compression test , leakdown and all those wonderful tests.
Yeah, your bobber is stuck. Coolant should be 5.5" below the ET filler neck top (without the cap).
Well.. sh*t! Yeah, I've tapped the bobber each time and that's how it settles.. stuck it is then.

If the coolant had expanded and needed to vent somewhere, would it theoretically have overflowed out the cap first? (assuming there isn't a weaker spot elsewhere in my cooling system?) Now that I actually think about it, seems like there's no way having it that full would give it any room to expand.. it'd have to overflow somewhere right? Haven't noticed any leaks though..

Just to be absolutely sure, I should have the coolant level 5.5" below the indicated surface below? Appreciate all the help.

908781
 

·
Registered
Joined
·
274 Posts
I don't think yours is stuck, it's correctly going down with lower levels of coolant. And if you tap it down and it bobs up then it's not stuck. The 5.5" is a guide, the "right" height is on that little tab next to the ET. LeverThis was trying to explain this pic. See how it's showing where the ball should be relative to the top of the cap and the threads of the ET?

You said you had to add some to get it back to between min/max. How often, and how much, you're adding will likely tell the story here. If you have no external leaks, then the most likely consumption point after an overheat is the head gasket.
 

Attachments

·
Registered
E30M3 Race F10 535 R1150Rt M Coupe
Joined
·
1,947 Posts
All in all since it's no longer overheating, I think you're fine.
Search (I'm without power currently) this forum for instrument cluster unlocking, get access to test #7 for true coolant temps.
Also look up my bleeding procedure.
Should never be done with the car running.

Might want to think about a new pump, expansion tank and cap.
 

·
Registered
Joined
·
1,028 Posts
Overheats are never good.. you may have avoided a head gasket pblm, and your explosive expansion tank could be due to too much coolant and a loose cap.

However, disappearing coolant with no obvious leaks is a concern. I would suggest you go through with having a mechanic check it out.. I would also strongly recommend having him swab the cylinders in the morning after running the engine to temp the night before.

I recently had something similar. I was losing a little coolant, but had good compression. I did have a puff of white smoke on start-up... I swabbed each cylinder one morning, and sure enough, coolant in cylinder 6...the last one I tested. The head gasket took me 2 weeks.
 

·
Registered
03 325xi Wagon 5AT
Joined
·
38 Posts
Discussion Starter #9
I don't think yours is stuck, it's correctly going down with lower levels of coolant. And if you tap it down and it bobs up then it's not stuck. The 5.5" is a guide, the "right" height is on that little tab next to the ET. LeverThis was trying to explain this pic. See how it's showing where the ball should be relative to the top of the cap and the threads of the ET?

You said you had to add some to get it back to between min/max. How often, and how much, you're adding will likely tell the story here. If you have no external leaks, then the most likely consumption point after an overheat is the head gasket.
Yeah it's definitely not stuck in one spot but it appears to be far from accurate (maybe it got messed up from the overheat?) The pic I attached of it being way over filled is showing the stick indicating that it is about halfway between min and max level, which I now understand is way off. This is after tapping it. If I pull up on it then I can force it to stay higher.

So far I've checked and refilled the coolant (incorrectly i.e. overfilled) on 7/31, then 8/3, 8/4, and today (8/5).. except today I refilled I took some coolant out so that it sits 5.5" from top of the fill neck. I'll attach pics of what coolant levels looked like when checked cold.. I'd say I've driven anywhere from 5-20 miles each day?

On 7/31 (maybe ~2 inches below top of filler neck?)
908823


On 8/3 (~2.5 to 3 inches below top of filler neck perhaps?)
908824


On 8/4 (about same as day before)
908825


Today (8/5) I'd say ~2 inches below top of filler neck
908826


Then I took out some coolant to get it 5.5" below top of filler neck and it looked like this
908827


Each time (except today) after checking these cold levels I ignorantly overfilled it to about .5" from the top. I would think that the system got over pressurized each time and must have pushed coolant out somewhere. I noticed a tiny little drop of coolant from the under engine plastics today around the left tie rod area. Don't know where it came from but took off my airbox to get a better view..

Who knows how much if this came from the initial overheat puking and if any of this is coming from this current leak..
0805201331.jpg
 

·
Registered
03 325xi Wagon 5AT
Joined
·
38 Posts
Discussion Starter #10
All in all since it's no longer overheating, I think you're fine.
Search (I'm without power currently) this forum for instrument cluster unlocking, get access to test #7 for true coolant temps.
Also look up my bleeding procedure.
Should never be done with the car running.

Might want to think about a new pump, expansion tank and cap.
I'm taking it into the shop tomorrow so I'll put out my best expectations :) Thanks, I'll definitely check out your procedure.

I actually have been monitoring coolant temps via test #7 and I don't think I've seen it go above 96 or maybe 97 celsius.. even had some pretty hot days in there. I've seen it drop to 88-89 sometimes on the highway.

Are you mainly suggesting replacing pump, tank and cap because of potential stress from the overheat?
 

·
Registered
Joined
·
129 Posts
Your float is most definitely stuck. It should be able to freely move without any friction. You should be able to push it down and have it float to the coolant level. Considering this, has your expansion tank ever been replaced? Might be time for some refresh.

Am dumb had to reread the original post. Your records show that he replaced the tank. However, you have a sizable amount of coolant stains outside of the tank. Now that you’ve corrected the level, consider washing your engine bay. Careful with the electronics but it’ll be good to be able to know what stains are new versus old. Should help locate the culprit.
 

·
Registered
2004 325i automagic
Joined
·
2,364 Posts
I'm taking it into the shop tomorrow so I'll put out my best expectations :) Thanks, I'll definitely check out your procedure.

I actually have been monitoring coolant temps via test #7 and I don't think I've seen it go above 96 or maybe 97 celsius.. even had some pretty hot days in there. I've seen it drop to 88-89 sometimes on the highway.
88-89 while cruising on the highway might indicate a soft failing thermostat that is running the engine too cold. It should be closer to 92-93 at speed on highway with no real load.

Are you mainly suggesting replacing pump, tank and cap because of potential stress from the overheat?
The expansion tank is made of plastic, is under full cooling system pressure and thus is a main weakpoint of the cooling system. They are known to split and leak out coolant even without an overheat, especially if original or old. The cooling system in general is a weak point of the e46, so its good to stay ahead of the curve in terms of replacing things.
 

·
Registered
03 325xi Wagon 5AT
Joined
·
38 Posts
Discussion Starter #13
88-89 while cruising on the highway might indicate a soft failing thermostat that is running the engine too cold. It should be closer to 92-93 at speed on highway with no real load.
Hmm.. good to know. Well I'll pay closer attention to it. 88-89 may have occurred downhill, no foot on the gas, weather cooling down after sunset.. Don't know how much of a difference that might make.
 

·
Registered
Joined
·
675 Posts
Hmm.. good to know. Well I'll pay closer attention to it. 88-89 may have occurred downhill, no foot on the gas, weather cooling down after sunset.. Don't know how much of a difference that might make.
Lots of cooks (sous chefs) in the kitchen already! MrMCar’s advice is short and sweet.

You put your new e46 through quite a stress test of the cooling system! ...so all in all, I also would think that the problem was fill/ bleed issues and not something major TODAY. That said, you could surely do with a refresh of the parts MrMcar suggested if u plan to keep it. I got mine at 160-something k-mi in Bay Area and 40,000 mi later it’s been though 2 tstats, a sensor, a water pump, and hose refresh (tank is on the todo). It took a little while for me to figure out the coolant fill level as a newbie. Remember the level moves especially if it is cold in the mornings and hot later on !
 

·
Registered
Joined
·
3,103 Posts
The first 3 pic look all wrong -- overfilled and the red rod not working right. The coolant level should be below the floater top limiter (it cannot be pulled higher than the limiter), around 5.5" below the tank top as someone suggested. Use the top limiter as a check point if the red rod is not working.

Did you check the coolant level before the trip, and it was overfilled as the 3 pic shown? Going up hill with A/C on until overheated red light?

Do this to know if head gasket bad or not: cold morning check and fill the level to the top limiter. close cap drive 20 miles. Check next cold morning if level dropped. If yes, remove spark plugs and look carefully for any sign of wetness on the tips.
 

·
Registered
Joined
·
79 Posts
If you added a gallon of distilled water I would suggest testing the coolant mixture to make sure it’s not too much water and d not enough coolant. It only holds A little over 2 gallons so if you added a gallon of water your mix is probably way off.
I’d be trying to find out why it overheated to begin with.


Sent from my iPhone using E46Fanatics
 

·
Registered
Joined
·
3,103 Posts
The purpose of having a correct level is to have enough air volume in the tank for the hot coolant to expand; the first 3 pics -- regardless of red rod level -- show there was not enough air space in there.
 

·
Registered
03 325xi Wagon 5AT
Joined
·
38 Posts
Discussion Starter #18
The first 3 pic look all wrong -- overfilled and the red rod not working right. The coolant level should be below the floater top limiter (it cannot be pulled higher than the limiter), around 5.5" below the tank top as someone suggested. Use the top limiter as a check point if the red rod is not working.

Did you check the coolant level before the trip, and it was overfilled as the 3 pic shown? Going up hill with A/C on until overheated red light?

Do this to know if head gasket bad or not: cold morning check and fill the level to the top limiter. close cap drive 20 miles. Check next cold morning if level dropped. If yes, remove spark plugs and look carefully for any sign of wetness on the tips.
Yeah, it's been all wrong haha. It now sits 5.5" below top of filler neck. Are you saying if the floater doesn't work then keep it pressed down and fill to the max level indicator (which is the physically lower ball) on the red rod?

Yeah, slow uphill with A/C on until red light in near 100 degree weather. Turned off the motor and pulled over real fast though. I don't know how long it took me to notice the light but I can't imagine long as I'm generally pretty aware of my dash. I actually never checked the coolant level before the trip.. I had been driving around Bay Area for a couple weeks with no issues so I never thought to check.

If you added a gallon of distilled water I would suggest testing the coolant mixture to make sure it’s not too much water and d not enough coolant. It only holds A little over 2 gallons so if you added a gallon of water your mix is probably way off.
I’d be trying to find out why it overheated to begin with.
Yeah it's probably off at this point but it's at the shop now getting cooling system pressure test, compression, and leak down test. Once I get confirmation that everything looks alright then I'll have them flush and re-bleed it properly. I suspect the main reason it overheated was because of the cap not being tight enough as it seemed a bit too easy to open after the overheat.

I really appreciate everyone's help!
 

·
Registered
Joined
·
79 Posts
The purpose of having a correct level is to have enough air volume in the tank for the hot coolant to expand; the first 3 pics -- regardless of red rod level -- show there was not enough air space in there.
I re-read the OP and there wasn’t mention of if it blew the coolant out as a result of high temp or if the high temp resulted in a loss of the coolant. Usually when the coolant cap pops to vent the coolant hits the engine and it’s obvious by the steam and water going everywhere... with these cars perhaps the coolant would be so explosive as the cap is rather hidden and tucked behind the air box and such.

Personally, I would guess the over fill from previous owner was because of a leak, maybe when some of the parts were replaced.
I would do a cooling system overhaul, the kits from FCP are pretty inexpensive, especially since history is unknown, yes he replaced parts BUT they could be the lowest priced cheap parts possible, especially if he was a mechanic he probably bought them they the shop he worked at from the local auto parts store and a very low cost. I’d get the FCP kit as it uses only genuine OE parts.

When we did ours I found the water pump had a chunk of belt wrapped behind the pulley hub, a t-stat bolt was loose and the expansion tank was failing - the inside was cracked and the plunger was not in the guide and sticking. So it wouldn’t have been long until one or more of those failed.
The kits are 250-450 - a small price for peace of mind. Plus you can get that nasty green coolant out of there lol


Sent from my iPhone using E46Fanatics mobile app
 

·
Registered
Joined
·
6 Posts
So, yes. The cap is the "weak link" and is how the car releases too much pressure, it should burp vapor, and should not have fluid in its operation.
Yes the ball at the top of the red "stick" in the ET should be almost level or just below the bottom of the threads for the cap.
In regards to your "running hot" the weep holes in the M54 water pump is very small, and often evaporates on hot engines as it leaks, however, it does hiss as it does this, making a noise as I'd the expansion cap is leaking. (ask me how I know). This case here, I would seriously take a peak (at the bottom of the water pump), or pressure test the cooling system. These cars hate overheating like women hate cheap dates. I've over heated mine a few times and have been really lucky.. but pushing you luck is costly.. drilling the block, adding thread restorers, new gasket...blah blah blah..
Good. Luck and cheers!
 
1 - 20 of 74 Posts
Top