Coolant System Issue???

[jggonzalez]

I did a search, but I'm still confused. I went on a 2 hour drive yesterday and when I got out of the car I smelled coolant. I popped my hood and I was getting steam out of a screw on top of the radiator and there were signs of a small leak (see pics). The temp gauge was right in the middle where it should be.

I let the car cool overnight and the water level is at the proper mark. I've replaced the plastic cooling connectors and water pump at 180K (currently at 186K miles). The thermostat housing was replaced at 140K by the previous owner. I think it still has the original radiator. I'm going to check for leaks, but if I can't find anything obvious, does anyone have any suggestions?

[cooljess76]

Did you remove the bleed screw or radiator cap while the engine was still hot? Don't ever do that it's extremely dangerous. Otherwise if you didn't remove the bleed screw, the pic shows that it's not screwed down all the way and that would explain the coolant on your airbox and expansion tank. When you replaced those parts, did you follow it by properly bleeding the air out of the system? If so, how many times did you bleed it. I ask because it usually takes several attempts to completely bleed all of the air out. This requires allowing the engine to reach operating temp and completely cool between each bleeding cycle. My advice would be to wipe everything down really good, maybe give it a good bleed exactly as outlined the bleed procedure posted in the knowledge base. Then allow the engine to run while the hood is open so you can inspect and watch for coolant leaks. It may help to have someone lightly rev the engine a couple times as this will speed up the water pump which will likely expose the source of the leak.

[wolferj-RIP]

Joe;

I agree with Jesse, it looks like your bleed screw is a little loose, which would account for the spray pattern of coolant.

Words from the wise Jesse again regarding getting it all bled properly and checking for leaks.

Good Luck!

[jggonzalez]

Originally Posted by cooljess76

Did you remove the bleed screw or radiator cap while the engine was still hot? Don't ever do that it's extremely dangerous. Otherwise if you didn't remove the bleed screw, the pic shows that it's not screwed down all the way and that would explain the coolant on your airbox and expansion tank. When you replaced those parts, did you follow it by properly bleeding the air out of the system? If so, how many times did you bleed it. I ask because it usually takes several attempts to completely bleed all of the air out. This requires allowing the engine to reach operating temp and completely cool between each bleeding cycle. My advice would be to wipe everything down really good, maybe give it a good bleed exactly as outlined the bleed procedure posted in the knowledge base. Then allow the engine to run while the hood is open so you can inspect and watch for coolant leaks. It may help to have someone lightly rev the engine a couple times as this will speed up the water pump which will likely expose the source of the leak.

I had the parts replaced by my mechanic, so I'm sure he bled the system. I haven't touched the screw, so if it looks loose in the pic then that might be the problem. I thought I had a leaking expansion tank. I'll try tightening it and bleeding the system. Keep your fingers crossed!

[spidertri]

If that bleed screw is tightened too much the head will break off, I learned that one the hard way. Luckily the philips slots go down into the screw more than just at the head. Just snugging it down should be enough to keep the coolant in.

A few sites sell a brass replacement, it's pretty nice.

[cooljess76]

I used to use a coin to tighten mine down.

[jggonzalez]

Nope, it wasn't the screw. Looks like the plastic area connecting the cooling tank to the radiator is cracked. I'm going to have to get a new radiator. Oh well, after 16 years and 186K miles I guess I can't complain about the durability of BMW OEM parts.

O'Reilley's has a Murray radiator for $170. Does anyone have any experience with that brand? I need to find one nearby because I can't wait to have one shipped to me. I'm going to try calling around tomorrow to locate a Behr, but I may need to go with the Murray if I can't find one.

[jggonzalez]

How many hoses do I need to replace? I've done the plastic cooling connectors and water pump already. If I do the radiator and three main connecting hoses, am I good to go?

[cooljess76]

Originally Posted by jggonzalez

How many hoses do I need to replace? I've done the plastic cooling connectors and water pump already. If I do the radiator and three main connecting hoses, am I good to go?

Yep, should be good to go. Should probably pick up a couple gallons of coolant while you're at it. Might be able to salvage a gallon from your old radiator and catch bucket if it's clean. Don't forget to bleed it a few times afterwards. And FWIW, it took less than 24hrs for my Behr to arrive when I ordered it from these guys a few years ago:

http://stores.ebay.com/Radiator-and-...=p4634.c0.m322

Idk if they still sell Behr radiators, you might want to contact them. IIRC, they're out of SoCal, Burbank or Northridge.

[ryszardsh]

Not surprising that the plastic cracked. The bleed screw takes very little torque to get it sealed - there is a rubber o ring on it which seals quite nicely with very little torque. Too much torque and crack goes the plastic - don't ask how I know.

Jess's suggestion to use a coin is darn good - probably cannot overtighten with a coin. I have always feared the brass screw for just this reason - too easy to use a honking big screw driver and crack....new radiator time.

RAS

[jggonzalez]

Well, I got the radiator installed by a mechanic. He's a friend of my Dad's and only charged us $300 P&L. He used a Behr radiator and BMW coolant. He said he bled it properly and I've driven it for about 30 mins at 80 mph and the temperature needle never wavered. Looks like we're good to go. I love this car so much I'm thinking of getting a license plate that reads "0RGA5M".

[mreroc]

Noticed the small crack in photo when I went to install a temp sensor. Nothing leaking...yet. Anything that will seal this or stop the crack, or am I looking at a new radiator?

[BlackBMWs]

Hey Joe! Remember when I was supposed to meet up with you guys in Vallejo and my cooling system failed, it turns out, while I was stuck in the traffic by Davis on that hot day, my coolant leaked out from the bleed screw on my rad. It was snug, thought it was sealed, but leaked. After a quick tow home, I replaced the rad and no issue since. I had seen some coolant leak out of the screw, but thought it was just loose. Turns out it was somewhat stripped and the stop and go on the freeway on a very warm day was just enough to cause it to fail.

BTW, I hope you are doing very well...

[jggonzalez]

Yes, I remember that. We need to plan another get-together like that.

I had a mechanic install a new radiator, but I don't think he bled the system completely. The next day I drove from Fremont to SJ to Foster City and back to Fremont. The water temp indicator stayed in the middle, but I smelled coolant and the engine seemed hotter to the touch than usual. Plus, the heater was only blowing somewhat-hot air. The next day I bled it according to Cooljess76's instructions and everything seems fine. I think my mechanic bled it like he said, but these cooling systems often need to be bled a few times, so its no big deal. She seems fine now.

[wolferj-RIP]

Yes, Rich & Joe, we need to plan another GTG!

Joe, glad that you got everything sorted out, and sucks that you had to do the work that the mechanic should have done completely (that you paid him for!).