Same coolant leak after replacing water pump and thermostat

**fedisrico** · 02-06-2019, 12:18 PM

2 weeks ago my water pump seized on the highway and my belt snapped. When I pulled over there was a lot of coolant on the ground, got it towed home and bought a water pump, thermostat, belt, and new waterpump gasket.

There had always been a small coolant leak for the past couple of months with a check coolant level message, I thought it must have been a weeping waterpump since it finally seized. I replaced everything yesterday and made sure everything was tightened down.

I put coolant in and there is STILL the same leak coming from the front driver's (L) side. It's a small continuous leak, I put cardboard down last night and this morning it was completely wet. The whole engine area got sprayed with coolant and since it's cold here it doesn't dry, so it looks like everything is wet. I'm sure it's not the hoses as I checked them when I was changing everything and nothing leaks from there. Should I check the engine coolant drain plugs? My radiator must be aftermarket because it does not have a blue drain plug or screw, it just has a hose where those would be.

**jicaino** · 02-06-2019, 12:26 PM

Probably the transmission cooler. The thermostat cracks, the lines also leaks.

**mattmar1** · 02-06-2019, 01:04 PM

might get a pressure tester (loaner or cheap rental from a local parts house), pressurize the system and see where its coming from.

**cfo20** · 02-06-2019, 01:06 PM

Maybe radiator? I had a less than 2 year old Behr with less than 7k on it leak, drivers side, near bottom of radiator, on seam above drain plug. Local BMW indy shop in Woodstock, GA (awesome shop BTW) warrantied the part as they did the replacement nearly two years ago for the previous owner. The owner of the shop said he has seen this same leak happen on the Behr rads very frequently in the recent past. Not sure status of your radiator but might be worth checking out.

**crazy4trains** · 02-06-2019, 01:08 PM

What I have learned is that when you mess with one thing associated with the cooling system, you end up going back and replacing something else in the cooling system. This is why pre-emptive maintenance is recommended for the cooling system.

**DennisG01** · 02-06-2019, 01:16 PM

If it's leaking as bad as you say it is, it should actually make it pretty easy to find the source. Either try the pressure cooker or simply clean everything REAL well and then start the engine and observe. Trying to find the leak after the engine has stopped is hard if it's being leak all over the place and being kicked around by wind and possibly the fan.

**fedisrico** · 02-06-2019, 01:48 PM

Originally Posted by cfo20

Maybe radiator? I had a less than 2 year old Behr with less than 7k on it leak, drivers side, near bottom of radiator, on seam above drain plug. Local BMW indy shop in Woodstock, GA (awesome shop BTW) warrantied the part as they did the replacement nearly two years ago for the previous owner. The owner of the shop said he has seen this same leak happen on the Behr rads very frequently in the recent past. Not sure status of your radiator but might be worth checking out.

No, the radiator seems somewhat new and is fine

**fedisrico** · 02-06-2019, 01:53 PM

I'll try and get some pictures or videos later today of where the leak is. I should also mention that the areas directly under BOTH vanos solenoids are covered with coolant, but as far as I know there shouldn't be any coolant in there? The area on top of them is dry though

**fedisrico** · 02-06-2019, 02:12 PM

Originally Posted by jicaino

Probably the transmission cooler. The thermostat cracks, the lines also leaks.

This is exactly where the leak drips, the automatic transmission cooler on the drivers side, I assumed it was coming from above because it's also wet up there but what could I do to test this, any specific checks?

**jicaino** · 02-06-2019, 02:31 PM

Originally Posted by fedisrico

This is exactly where the leak drips, the automatic transmission cooler on the drivers side, I assumed it was coming from above because it's also wet up there but what could I do to test this, any specific checks?

If it has more than 50k miles without previous trustable records that says the whole exchanger/thermostat/lines have been replaced, I suggest you go ahead and buy the whole set of parts.

17217505823 Exchanger (there's an aftermarket source I got from eBay that works very well and doesn't cost an arm and a leg)
17211437772 it says Voltage Regulator but's actually a flow regulator or thermostat. Get an OE Genuine. It's a pain in the butt to replace later and it cracks if it's "el cheapo".

Off this diagram: http://www.realoem.com/bmw/enUS/show...diagId=11_2267
replace hoses #2 #4 #5 o-ring #7 loosen bolt #8 before bolting back up the exchanger or you'll crack the plastic thermostat aka regulator

**sienayr** · 02-06-2019, 02:55 PM

Originally Posted by mattmar1

might get a pressure tester (loaner or cheap rental from a local parts house), pressurize the system and see where its coming from.

'nuff said

**DennisG01** · 02-06-2019, 02:56 PM

Are you sure you don't also have an oil leak?

Either way, the first step is to clean it. That's gotta be done as pictures of sloppy splatter and wind-affected splatter won't help. Also, what a liquid finally drips OFF of, may not indicate where it started. Clean it real good.

**jicaino** · 02-06-2019, 03:06 PM

If your leak it's where I bet my family jewels it is, it might be worth considering doing the old style air/atf cooler. Your transmission would be way better cooled and happier and your engine cooling system would be a lot more reliable.

**jicaino** · 02-06-2019, 03:14 PM

https://www.bimmerforums.com/forum/s...perience/page2

**fedisrico** · 02-06-2019, 05:42 PM

Well, I finally jumped the car and got it started after sitting for two weeks. Instant white smoke from the exhaust, what's the most likely possibility, blown head gasket? I seem to meet the symptom of always having low coolant before the pump seized, and it was very noisy idling, although the needle was always perfect when idling. Also, there is liquid around the spark plug nuts, I'm guessing that would be coolant? I'm going to pull them out today or tomorrow, if they're white I'm guessing it is a blown head gasket? I just let it run for a minute rn and the smoke never stopped, the temperature gauge never moved, I'm guessing the leak will also then be coming from the exhaust manifold if it is blown, I'll check that also.

- - - Updated - - -

There also seemed to be a sporadic "slapping" from one of the cylinder heads, I'll try and check that too, I was going highway speeds when the belt snapped so who knows how much damage was done until I pulled over

**jicaino** · 02-06-2019, 05:44 PM

Long period with no start and you being in the winter it could also be constructed as condensation. A healthy engine will do it. blown gasket or coolant into the combustion chamber will smell like "sweet" to some extent. Also there's chemicals that you can add to the coolant and detect compression blowby. Check your oil, your coolant, and your plugs.

**fedisrico** · 02-06-2019, 05:56 PM

I checked the oil right after I turned the car off, it looked completely normal, no check engine light except for check coolant level as what I had put in had leaked out and was low. What do you guys think of using Blue Devil Head Gasket sealer? I'm hoping it would block any leaks that I have, and fix the head gasket if it is blown. Does it even work? I can't afford to repair or replace head gaskets and cracked heads, I'm trying to sell the car anyway, would this be an acceptable temporary maybe a couple thousand miles fix? Or would it permanently fix it, I don't think it would hurt to try at this point. And jicaino, the smoke was definetly thicker and whiter than normal condensation, and there was a lot of it.

**DennisG01** · 02-06-2019, 06:03 PM

2 weeks of sitting shouldn't require a jump - even in cold weather. Obviously this isn't the main problem here, but your battery may also be on it's last legs.

1 minute of idling may not be enough to cause the temp needle to start moving.

What does your oil look like? Oil level? Does your engine have a dipstick? If needed, an oil analysis is simple to have done and inepensive. You can send a sample in the mail, or look for a local CAT dealer.

It sounds like you're jumping all over the place. Slow down. I know I sound like a broken record, but it seems as if the suggestions of cleaning things up first are somehow invisible.....

What's a "spark plug nut"?

EDIT: Looks like we were typing at the same time. Another thing... this isn't always a "tell all" test, but with the engine running, open the coolant reservoir... any bubbling?

**DennisG01** · 02-06-2019, 06:23 PM

As far as the stop leak stuff goes, it's all a gamble. Chances are better that it won't work, though. Can't really hurt anything by trying it, though. But if you're selling it, you'd want to disclose what you did to be fair to the buyer, anyways.

**mattmar1** · 02-06-2019, 06:31 PM

Originally Posted by fedisrico

What do you guys think of using Blue Devil Head Gasket sealer? I'm hoping it would block any leaks that I have, and fix the head gasket if it is blown. Does it even work? I can't afford to repair or replace head gaskets and cracked heads, I'm trying to sell the car anyway, would this be an acceptable temporary maybe a couple thousand miles fix? Or would it permanently fix it, I don't think it would hurt to try at this point.

nooooooooooo...head gasket repair in a can is not a good thing to try. as stated above, jicaino stated in post 16, one can obtain a test kit from most parts stores that can prove or disprove if theres blow by gases in the coolant, a definitive test for a HG leak.
youve had some funky weather in CHi town as of late, i wouldnt jump to a conclusion on the problem without doing a coolant dip test. the scuba tanks of the exhaust system of a 540 can hold a surprising amount of water.

**fedisrico** · 02-06-2019, 06:38 PM

Sorry Dennis, pretty dumb of me, the 4 nuts below the spark plugs on each side have liquid/ i'm pretty sure coolant around them, what are these 4 nuts anyways? Should I unscrew them and see what's underneath? That being said I have not checked the plugs it turns out but I will tonight or tomorrow and see how they look. As for the bubbles in the coolant, I'm going to have to get more coolant tomorrow and see, I poured 1.5 gallons in yesterday at 6pm and the reservoir tank is now completely empty, even though there was still some coolant this morning

**jicaino** · 02-06-2019, 06:50 PM

1.5 gallon gone in less than a minute idling, it would smell like Willy Wonka's factory. Relax and start & complete the tests without abandoning halfaway and opening another battle front. Think. Ponder. Do. Tinker. Touch, feel, smell, reason. You can save it! or not. But if not, it's beyond your reach by now. As mattmar says with the weather you've been having your scubas could be holding a few gallons of water. If all that coolant would have gone into a combustion chamber your engine will be hydrolocked by now. And yes, I had an hydrolocked engine. There's no way in which all that coolant have gone into the exhaust. Something's leaking on more than just one spot. Have you checked your footwells? You could have a broken heater core and your interior all soaked up. Or if your engine bay looks like a mess upwards, you could have a blown seals heater valve and that's at the lower row of valve cover bolts that you're reporting all wet and soaked.

- - - Updated - - -

at the lower row of bolts LEVEL.

**fedisrico** · 02-06-2019, 06:56 PM

Thanks jicaino, now I know what they are, as for my original issue with the leak, https://www.bimmerforums.com/forum/s...er-seen-the-VR this thread seems helpful, I'll try and diagnose the voltage regulator, since my leaks seems identical to his, and mine has been leaking there for months.

**fedisrico** · 02-06-2019, 07:31 PM

https://www.bimmerforums.com/forum/s...cement-(540iT)

This seems like a good write up on what I'm going to do, hopefully this stops the leak. Then I'll tackle the smoke and possible blown gasket

**jicaino** · 02-06-2019, 07:57 PM

That's one of the things I said earlier, the exchanger has 2 parts: the atf metal thing and the "voltage regulator" which is the plastic thingy with 3 legs that connects to the radiator, the alternator and the expansion tank line.
Also the back of the engine has a coolant manifold below those heater lines. All good sources for the major leak you appear to have. This starts as a minor leak that since it opens pressure escaping path, causes the coolant to boil and overstress the sealing, starting to break weak or neglected spots.
This is also a fine oportunity to replace the too hot 105°C thermostat with an 88°C one.