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-   -   Overheating 202 (http://www.318ti.org/forum/showthread.php?t=32759)

Romoser.MD 02-12-2011 03:50 PM

Overheating 202
 
Hey guys, I'm at a point where I'm really confused, and could use some advice.

Basically about a week ago that one part that everyone says is gonna break ( the plastic piece in the cooling system in the back of the engine ) - broke. I saw the thermostat rise a bit and instantly pulled over and turned off my engine, checked things out, saw a huge leak in coolant. Long story short, ordered the part and had it fixed.

So I've got her home now and it was about a 20 minute drive home from the shop with no troubles. But the next time I tried to drive her, I got about 5 minutes on the road and I see white smoke out the back of the car and she starts over heating about the same time.

I pulled over. Opened the hood, looked at the coolant, and it was full in the expansion tank. When I opened the top, it was boiling but the coolant wasn't even hot!

If I let the car sit for about 10 minutes the thermostat shows shes starting to overheat to the 3/4's + range.

Any ideas? There doesn't seem to be anymore leaks.

spidertri 02-12-2011 04:38 PM

White smoke out the exhaust? Was the car bled properly?

Romoser.MD 02-12-2011 04:48 PM

Quote:

Originally Posted by spidertri (Post 292428)
White smoke out the exhaust? Was the car bled properly?

I can't promise it was bled properly. The mechanic who changed the cracked plastic piece wrote on the receipt that the coolant system was "flushed", but more than that I don't know.

(-EDIT: Just called the shop that did the work, they said its standard procedure to bleed it a few times, and assured me that it was bleed properly. I still don't trust anyone, but for what its worth heres more info.)

Could improperly bleeding it lead to that white smoke? It never overheated even close to the red. Just 3/4 at most, never even past it.

Based on the strange "cold" boiling of my coolant , the only way that can happen is abnormal pressure , which could be a result of air pockets I think. And as I'm reading the forum and waiting for responses I'm getting the feeling atleast the system was bleed improperly. Probably, and I'm getting airlocking.

But I'm also wondering if its a blown hg cause of this whitesmoke, or something else? Maybe the thermostat is bad because after 10 - 15 min idling in 25degree F weather it'll start to overheat on the temperature gauge but the coolant is still cool.

Or could it all be tied into being improperly bleed.

Basically I just want some slightly more expert advice/opinions.

appreciated everyone.

Junk 02-12-2011 06:10 PM

Definately make sure it's bled properly. Sounds like it wasn't. Flush is different than bleed, but the mehanic surely SHOULD have bled it.

(lift front of car, heater on full, fill bleed screw) seems to be the trickier points.

Air in the coolant shouldn't create white smoke unless the headgasket blew..With air in the system, your temp guage may not be reading hot air pockets.

Romoser.MD 02-12-2011 06:36 PM

Anymore Opinions? Advice?

-also, anyone can tell me where the bleed screw is?

familytruckster 02-12-2011 06:53 PM

if it's smoking the HG is blown. The thermostat might have gotten stuck from the first overheat. Personally, I would have had the whole cooling system replaced-or at least the 3 plastic parts, the rear piece, the side piece, and the thermostat.

Oh, and the thermostat is a regulator valve on the motor, the temperature gauge is what you look at in the dash that shows the temperature.

Romoser.MD 02-12-2011 06:55 PM

Theres no white smoke out the exhaust when it idles, or even when I drive it, just when I'm driving it and it gets to the point where its beginning to overheat.

White smoke can only mean blown HG?

cooljess76 02-12-2011 07:21 PM

Are you sure the white smoke wasn't just fog from it being cold outside? Does it still smoke? You can look inside the radiator for signs of oil, as well as look at the oil dipstick and under the oil fill cap for signs of coolant(it'll look like chocolate milk), but it doesn't always mix when a headgasket blows, sometimes the gasket fails in a spot that allows the coolant to flow out of the engine without mixing with the oil. The only way to tell for sure is by doing a cylinder leakdown test. AutoZone sells a kit for about 30 bucks. This will tell you for sure if you have a blown hg. I suspect it wasn't bled properly or maybe the engine had been overheated in the past and this last issue with the coolant fitting was just enough to push it over the edge. At the very least, you should try bleeding it yourself. Maybe the gasket isn't blown and you might of gotten lucky and caught it in time.

Now here's a possible answer to your coolant level issues. When there's air in the system, it does all kinds of wacky stuff to the coolant level. The cold boiling you speak of may not have actually been boiling, just thousands of air bubbles under pressure. When you have airlock(radiator fills with air and prevents coolant from circulating), the coolant in the engine has nowhere to go. It evaporates into steam and builds up pressure. This can also damage your temp sensor, fan switch and thermostat due to extreme heat. So how does air get into the system? Well there's two ways. One way, is when you open the loop to change a component such as a thermostat, water pump, plastic coolant fitting, radiator hose or radiator. Coolant drains out and when you try to fill the radiator back up, the air void has nowhere to go until you bleed the system. Even then, it takes several tries to completely bleed all of the air out. Once is simply not enough. The other way air gets in the system is through a leak. A cracked radiator will not only allow coolant to leak out, when the coolant is gone, you have nothing but air left to fill the void of the lost coolant. I suppose air can also get in from wherever the leak is whether it be a blown hg, cracked radiator or leaking coolant fitting. Think about it this way, when you take a bottle of water and dump it out, what do you have? An empty bottle right? Wrong, you have a bottle full of air:wink:

So, how could you tell if you have a coolant leak? You can't always see where coolant is leaking from. Sometimes the leak is so small, the coolant evaporates as soon as it comes out. Or sometimes the leak is in a spot that is hidden and not visible. I had a hairline crack in my radiator right between the radiator and expansion tank. I couldn't see it because the expansion tank was covering it and the leak was so small the coolant was evaporating before it could drip down the side of the radiator and onto the ground. One way to find a leak is to park the car in a quiet location such as a garage or in an alley between adjacent buildings. Then you're gonna want to wait for the engine to cool, never remove the radiator cap when the engine is warm. Then you'll need to pressurize the system. I rigged up a cap that threaded onto my radiator to a bicycle pump. Pump it up to about 5psi, no need to go over 7 or 8 psi. Once the system is pressurized, stick your head in there and listen for hissing.

All that being said, I remember a few members having problems with the plastic coolant fitting that your mechanic replaced. I believe the brand sold by pelican parts(maybe other vendors as well), were not a perfect fit and they leaked. You definitely want to make sure you get Genuine BMW Parts.

It sure sounds like you still have air in the system. You may have a blown headgasket, but don't just take your mechanics word for it. In fact, don't even let him mes with it anymore. They might just try to "make" your headgasket fail so they can get more work/money out of you. Do the leakdown test yourself, it's pretty simple. If it checks out good, follow up by doing a PROPER BLEED:

1) Park the car on an incline so the front is raised

2) Allow the engine to cool

3) Start the engine

4) Turn the heater to full hot(red)

5) Turn the blower on full blast

6) Remove the bleed screw on top of the radiator next to the radiator cap

7) Remove the radiator cap

8) SLOWLY pour coolant into the radiator expansion tank through the FILLER HOLE(not the bleeder hole)

9) Continue filling the radiator to the top until you see a steady stream of coolant coming out of the bleed hole. As you're filling the radiator, tap and massage the radiator and hoses to encourage any trapped bubbles to make their way out of the bleed hole

10) Once you see a steady stream of coolant WITH NO AIR BUBBLES, replace the bleed screw and radiator cap

11) Drive the car around the block, allow the engine to reach operating temp(12 o'clock on the temp gauge)

12) Park the car on the same incline

13) Allow the engine to completely cool

14) Repeat the same process several times until you feel HOT air coming from your dash vents

Follow these steps PRECISELY and in this EXACT ORDER. I can't stress enough how important it is to bleed the system properly. No matter how many times I post the instructions, people always seem to screw it up. I wish BMW would've made a big yellow sticker and attached it on the radiator cover. It would've saved thousands of people from replacing motors due to headgasket failures. I hope that helps man. Best of luck and lets keep our fingers crossed that your hg didn't blow.

cooljess76 02-12-2011 07:29 PM

Quote:

Originally Posted by Junk (Post 292433)
Definately make sure it's bled properly. Sounds like it wasn't. Flush is different than bleed, but the mehanic surely SHOULD have bled it.

(lift front of car, heater on full, fill bleed screw) seems to be the trickier points.

Air in the coolant shouldn't create white smoke unless the headgasket blew..With air in the system, your temp guage may not be reading hot air pockets.

Just to clarify, fill the radiator expansion tank via the filler hole NOT the bleed hole. The bleed hole is for air to escape, although you will see coolant flowing out of it once the expansion tank is full. Continue filling until a steady stream of coolant is coming from the BLEED HOLE with no air bubbles.

chudzikb 02-12-2011 07:50 PM

What does the white smoke smell like? And I second looking at the oil and under the oil fill cap, and or inside the filter housing.

cooljess76 02-12-2011 08:04 PM

If it only smokes when the engine starts to overheat, don't wait for it to overheat to smell the smoke:wink: In fact, just don't let the needle go past 12 o'clock period.

Romoser.MD 02-12-2011 08:18 PM

Updates will be coming. Thank you guys.

Romoser.MD 02-12-2011 10:58 PM

Quote:

Originally Posted by cooljess76 (Post 292448)
If it only smokes when the engine starts to overheat, don't wait for it to overheat to smell the smoke:wink: In fact, just don't let the needle go past 12 o'clock period.

Well right now I'm just trying to figure out how to prevent it from overheating.

When I first noticed this problem, the second time I drove her after I got her back from the mechanic ( this was about 3 days ago ). Atleast once a day I'd start her up just to see if I could find a leak or something, and I'd check the dip stick and oil cap, and if oil was in the expansion tank and there was nothing. But just now I checked the dipstick - nothing , expansion tank - clear, oil cap and I found a little bit of white slime looking gunk on most of the oil.

When I started her up she was rough with a little tweet, twirp thing from the engine. That was also the first time I heard that.

So now I'm very depressed and without a car.

pdxmotorhead 02-13-2011 02:43 AM

LEAK DOWN NOW!!!!!!!!!!
Its the ONLY way to check for the blown head gasket.

There is a dye you can put in the antifreeze that glows with UV.

Put redline watter wetter in , it will help bleed the air out. I've done it ever since I've owned my Ti and I never have a problem bleeding the system.

There are several good writeups about swapping all the correct parts of the cooling system. Its a maintenance item on these cars.

Dave

Romoser.MD 02-13-2011 08:03 PM

So now the radiator is leaking as well.

Leakdown test coming monday.


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