"What did you do to your E39 today V2.0."

[seagreen323i]

I have all the finesse of a blind gorilla when it comes to those things. That's how I killed a miata head a few years ago, scored the crap out of the tappet bore.

Sent from my SM-S901U using Tapatalk

[LuckyBill]

Update after the last cooling system bleed mentioned above:

After a 30 mile drive, car in the garage overnight. Checked expansion tank that was previously half full, it now looks mostly empty but I'm not getting a Low Coolant dash alert! I pulled the coolant level sensor from the expansion tank after some effort - it appeared heat damaged and has no manufacturer on it. I tested it with an ohmmeter and a spare expansion tank by sliding the red level float up & down and the sensor always makes contact. I then tested a new BMW coolant level sensor and it tested correct, open = low coolant, short = good. Installed the new sensor, tested it works. I added about 12oz 50/50 coolant/distilled mix.

I now have a cooling system with a new Stewart water pump and expansion tank is half full (allows coolant to expand and lowers pressure/temperature compared to totally filled).

On a test drive (70°F ambient) from cold the temperature goes quickly to 96°C regardless of how I drive. After a few minutes, with spirited driving the engine temp will drop to 87°C and go as low as 84°C. Sitting and idling, the engine will slowly increase to 96/97°C. The engine never went above 99°C.

[computiNATEor]

Update after the last cooling system bleed mentioned above:

After a 30 mile drive, car in the garage overnight. Checked expansion tank that was previously half full, it now looks mostly empty but I'm not getting a Low Coolant dash alert! I pulled the coolant level sensor from the expansion tank after some effort - it appeared heat damaged and has no manufacturer on it. I tested it with an ohmmeter and a spare expansion tank by sliding the red level float up & down and the sensor always makes contact. I then tested a new BMW coolant level sensor and it tested correct, open = low coolant, short = good. Installed the new sensor, tested it works. I added about 12oz 50/50 coolant/distilled mix.

I now have a cooling system with a new Stewart water pump and expansion tank is half full (allows coolant to expand and lowers pressure/temperature compared to totally filled).

On a test drive (70°F ambient) from cold the temperature goes quickly to 96°C regardless of how I drive. After a few minutes, with spirited driving the engine temp will drop to 87°C and go as low as 84°C. Sitting and idling, the engine will slowly increase to 96/97°C. The engine never went above 99°C.

That is normal behavior. If it's hot enough, and you drive it hard enough, it'll drop to 80ºC, but no lower than that.

[R Shaffner]

Okay so I got the coolant expansion tank kit from FCP Euro today. I started the procedure to replace the tank and on my 530i removed the expansion tank cap. But when I removed the expansion tank bleeder screw, I heard some gurgling from the expansion tank. After a few seconds the red level float bobbed up and it looks like I have a full expansion tank!

That's normal too.

The whole point of bleeding the air out of the top of the system is to fill the engine and radiator with coolant, all the way up to the top, while the level in the expansion tank is low, leaving air in the tank. The radiator stays full, even with the lower level in the tank, because (normally) there's no way for air to get back to the top of the radiator. When you open the bleed screw, you let air back into the radiator, which lets coolant in the full radiator flow into the less-full tank.

That's not a problem. And in that case the high float "bobber" doesn't mean the system is suddenly full. The amount of coolant hasn't changed, of course, it's just moved from the radiator to the tank. These cooling systems are somewhat self-bleeding. Just put the bleed screw and cap back on. When the engine gets back to operating temp, the expanding coolant will force that air from the top of the radiator back into the expansion tank. Then, after it's cooled down, you can remove the cap and see that the coolant level in the tank has dropped back to its previous level.

Here's more about these BMW systems, if that any of that sounds confusing:

https://www.bimmerforums.com/forum/s...ding-Explained

And... I've never seen a 2 bar cap release pressure. Though I've seen MANY plastic cooling systems fail because 2 bar is WAY too high. My bet is you have a leak from somewhere, which might be from a leaking/faulty cap or almost anywhere else.

Plus (there's more!)...a leak anywhere in the system that lets hot pressurized coolant out will let cold air back in. That air will float up to the top of the radiator, which might let the tank still look OK or full, when the system is actually losing coolant and taking on air. If that continues more and more coolant can be lost, while the level in the tank still looks ok!

So one should keep a close eye on leaks and fix them promptly.

[computiNATEor]

And... I've never seen a 2 bar cap release pressure. Though I've seen MANY plastic cooling systems fail because 2 bar is WAY too high. My bet is you have a leak from somewhere, which might be from a leaking/faulty cap or almost anywhere else.

Plus (there's more!)...a leak anywhere in the system that lets hot pressurized coolant out will let cold air back in. That air will float up to the top of the radiator, which might let the tank still look OK or full, when the system is actually losing coolant and taking on air. If that continues more and more coolant can be lost, while the level in the tank still looks ok!

So one should keep a close eye on leaks and fix them promptly.

Pretty sure the 2bar cap is for the V8s. They can run at 113ºC, which does indeed pressurize the system, and if you shut the engine off when it's that hot, the sudden lack of air flow and stagnant coolant can push the temps even higher, until the cylinder head temps equalize. This can result in extreme coolant temperatures (think 140ºC+, for brief periods) that require a 2bar pressurized cap.

No I6 should ever run that hot, though. I installed a GAS 1.2bar coolant cap on my first 530iA. When I had a partially stuck thermostat, on a particularly warm day, and about 30 seconds after I shut the car off, the cap vented. It sent scalding hot coolant all over the engine bay, and my parents' driveway. They were less than pleased.

[LuckyBill]

That's normal too.

The whole point of bleeding the air out of the top of the system is to fill the engine and radiator with coolant, all the way up to the top, while the level in the expansion tank is low, leaving air in the tank. The radiator stays full, even with the lower level in the tank, because (normally) there's no way for air to get back to the top of the radiator. When you open the bleed screw, you let air back into the radiator, which lets coolant in the full radiator flow into the less-full tank.

That's not a problem. And in that case the high float "bobber" doesn't mean the system is suddenly full. The amount of coolant hasn't changed, of course, it's just moved from the radiator to the tank. These cooling systems are somewhat self-bleeding. Just put the bleed screw and cap back on. When the engine gets back to operating temp, the expanding coolant will force that air from the top of the radiator back into the expansion tank. Then, after it's cooled down, you can remove the cap and see that the coolant level in the tank has dropped back to its previous level.

Here's more about these BMW systems, if that any of that sounds confusing:

https://www.bimmerforums.com/forum/s...ding-Explained

And... I've never seen a 2 bar cap release pressure. Though I've seen MANY plastic cooling systems fail because 2 bar is WAY too high. My bet is you have a leak from somewhere, which might be from a leaking/faulty cap or almost anywhere else.

Plus (there's more!)...a leak anywhere in the system that lets hot pressurized coolant out will let cold air back in. That air will float up to the top of the radiator, which might let the tank still look OK or full, when the system is actually losing coolant and taking on air. If that continues more and more coolant can be lost, while the level in the tank still looks ok!

So one should keep a close eye on leaks and fix them promptly.

Thanks, that's a great explanation. Yeah, as I've learned this cooling system I figured out that when I removed the expansion tank bleed screw it was like taking my finger off a straw full of water, and the coolant in the fill tube emptied into the tank. I can see how this system would be self-bleeding if the expansion tank is left half-full.

I just bought a 1.4 bar coolant cap.

[LuckyBill]

In the middle of replacing the expansion tank. First bottom hose came off easy, but the bottom hose to the electric water pump did not want to come off, I had to chisel it off using a screwdriver & rubber mallet.

I'm installing the new expansion tank and that electric water pump hose refuses to press onto the tank. One hour into that hose. I removed the spring clamp, tried gently filing away the plastic on the hose, pushed it in, rubber mallet, nothing works. Looking for suggestions.

[rimpilot1]

I replaced the cam chain tensioner in my M62 as part of a bigger project. The new part (BMW 11317531813) was collapsed when I took it out of the packaging. I pulled it apart to see why. There was not a spring inside, unlike the original tensioner. I realize that oil pressure is the primary thrust generator, but was surprised. The parts guy at the dealership had no idea. Was this a design change? Should I transfer the spring from the original unit to the new one?

[Jason5driver]

In the middle of replacing the expansion tank. First bottom hose came off easy, but the bottom hose to the electric water pump did not want to come off, I had to chisel it off using a screwdriver & rubber mallet.

I'm installing the new expansion tank and that electric water pump hose refuses to press onto the tank. One hour into that hose. I removed the spring clamp, tried gently filing away the plastic on the hose, pushed it in, rubber mallet, nothing works. Looking for suggestions.

Use WD-40 and / or penetrating oil .
Pictures ?