Coolant leak

[Dave1027]

This really pissed me off. I was working under the car and I barely bumped the tranny cooler that attaches to the bottom radiator. Yes, I have a steptronic tranny. It now leaks coolant right next to the cooler on the plastic bracket.

Does anybody have any insight into this?

[echo46]

You may have cracked a piece of the plastic. How much of a leak?

[danewilson77]

It was most likely brittle and you bumped it just right. Better to swap now, vice find out on the road.

[echo46]

All cooling system parts are the a Achilles heal of this exceptional ride. Plastic sucks. At least not as much plastic on the e46 as the e36.

[Dave1027]

It's drips one drop every two seconds. If I push on the tranny cooler I can change the rate of drip.

Dane, do I have to swap the entire radiator for this?

I think it's the mounting plate that is leaking.

[Dave1027]

See below. Maybe I am missing a screw. This unit has always had a slow leak but I made it worst by bumping it.

http://home.comcast.net/~dl1027/files/coolantleak.jpg

[Avetiso]

I think there is supposed to be a screw/clip there. I remember putting one in there when I was putting my front end back together.

[Avetiso]

You could JB weld the crack as a delay if you need a little time.

[Hermes]

You could JB weld the crack as a delay if you need a little time.

no... just buy the train station, they're not very expensive

[Dave1027]

I think there is supposed to be a screw/clip there. I remember putting one in there when I was putting my front end back together.

I have looked at posted pictures and see many without a screw but then I saw this diagram posted:

http://home.comcast.net/~dl1027/files/Cooling.jpg

Part number seven looks like a bolt should be there. Am I reading this correctly?

[Dave1027]

But then I see a diagram like this and there is no bolt.

http://www.e46fanatics.com/forum/attachment.php?attachmentid=325403&d=1248899179

[danewilson77]

Here ya go brutha.

http://www.zhpmafia.com/forums/showthread.php?5738-BMW-E46-330i-ZHP-Expansion-Tank-Removal-Made-Easy&highlight=expansion

Near the top of the "Frame"
http://i1015.photobucket.com/albums/af278/nicee46/IMAG1056.jpg

Below drain plug
http://i1015.photobucket.com/albums/af278/nicee46/IMAG1055.jpg

[Dave1027]

Thanks Dane. Now I only need to get a hold of that bolt that goes there or the proper dimensions of it to source one locally.

Also, I'd like to get all new o-rings for the mounting plate and the expansion tank as it seems all mine are weeping. Anybody know of a company that sells an o-ring kit? I'm going to contact G.A.S.

[danewilson77]

Thanks Dane. Now I only need to get a hold of that bolt that goes there or the proper dimensions of it to source one locally.

Also, I'd like to get all new o-rings for the mounting plate and the expansion tank as it seems all mine are weeping. Anybody know of a company that sells an o-ring kit? I'm going to contact G.A.S.

Something like this outta work.

http://www.summitracing.com/parts/wmr-w5202/media/images

http://i1015.photobucket.com/albums/af278/nicee46/Maintenance%20and%20Misc/wmr-w5202_w.jpg

[aurelius]

To shed some light on the diagram discrepancies, the part numbers for both the radiator and for the ET mounting plate are different for cars with manual vs automatic transmissions.

And in another exclusive story for automatics, verify the presence of the transmission cooling thermostat, which is part #4 in the diagram in post #11.

[Dave1027]

I checked last night and my car does have the upper screw attaching the mounting plate. It should be a simple task to remove that screw and match it up. It's called a "Self tapping screw D6x20mm". Right now I have zip ties holding the coolant back.

[aurelius]

Any of you ever test that thermostat for the auto tranny cooler? Pot of hot water? Is it known to fail? Asking because I'm doing the cooling system on an automatic 46 soon...

[LivesNearCostco]

I have a small coolant leak, or at least I did. Haven't seen the coolant on the plastic undertray for a week now. Maybe my local indie tightened up the drain plug when he was doing the tie rods? I did ask him to look at it but he didn't mention anything.

I took photos last night. Doesn't look like leak is from drain plug but from bottom of ET. ET is about 18 months old and doesn't appear to have any cracks. Should I post here or start my own thread?

[aurelius]

The last ET I replaced had a broken off float and was leaking from below. I think the 2 things were related. The broken semi-circular black plastic piece (formerly fully circular) in the photo came flying out when I removed the tank and shook it to see if the float would come out.

Doubtful your situation is the same on a fairly new tank but maybe check the mouthing plate for cracks where it attaches to the tank?

Original BMW ET @ 10 yrs / 70k miles:

http://i1125.photobucket.com/albums/l584/aurelius3/Random%20BMW%20Pics/F463C7FF-DD1C-46EC-8415-995242CD8DF8-4470-00000299C1548F3D_zpsc747c9b6.jpg

[LivesNearCostco]

While my ET looks good, it is on the original mounting plate. Does anyone know if the seals are on the ET or on the mounting plate? It does not appear to be leaking from the ET cap nor from the upper radiator hoses attached to the ET. The radiator drain plug does not have any coolant residue on it. The ET drain plug has residue, but can't tell if it came from the plug or the mounting plate.

Here are 4 pics of my ET and mounting plate area.

Right (passenger) side of coolant tank
7676

Left (driver) side of expansion tank and drain plug. Doesn't seem to be leaking on this side.
7677

Bottom of ET with mounting plate.
7678

Back/rear side of ET.
7679

[aurelius]

Did you fully remove the ET drain plug at some point? That may be the issue. Only supposed to loosen it for draining but I don't know what it is that gets messed up when it's fully removed.

The seals between tank and plate are o-rings inside the 2 larger bottom holes of the tank.

I wouldn't get a new mounting plate unless you find cracks where the tank attaches. But if you do need a new one, be aware that although the tanks are universal, the plates differ based on tranny type.

But if it's no longer leaking I wouldn't mess with it at all.

[LivesNearCostco]

Don't remember if I fully removed the ET drain plug. It's still leaking on and off. Not much, but leaking. Might be the ET cap leaking under pressure or the drain plug, but I doubt it--looks like coming from where tank sits on the plate. Anyone know what diameter those O-rings are, or if they're a standard size? Just bought a gallon of distilled water and a box full of metric O-rings from HF (link (http://www.harborfreight.com/397-piece-metric-o-ring-assortment-67580.html)).

A few days ago looking at the bottom of the ET with a caliper, I estimated the larger O-ring should be around 1.75" ID, or about the size of the largest O-ring in the box. Local Ace hardware probably has bigger ones available. Debating if I should drain and remove coolant tank and try replacing O-rings this evening.

[aurelius]

Well at the very least doing so will let you examine the mounting plate for cracks. If the o-rings weren't lubed prior to tank installation, maybe one of em ripped?

[LivesNearCostco]

certainly possible I ripped an O-ring, or the tank moved around and an o-ring moved out of place or got torn. But what do I do if the mounting plate is cracked, just JB weld it until I can get a new plate?

[aurelius]

I've never used JB on plastic but as long as it's temporary and applied to the outer part of the fitting where it won't screw up the ET o-ring, I would think you'd be ok.

You may want to inspect after driving around when it's hot. Maybe up on ramps, remove splash shield, then run the motor and look for where it's seeping. But from your pics it does look like mounting plate fitting.

[LivesNearCostco]

Today it seemed to be leaking faster so left work early, visited Stevens Creek BMW and bought a new ET for $139 minus 10% CCA discount. Then found my old BMW ET in a box in the garage, the one a PO installed in 2007 and I removed in 2011. Used that to determine none of the HF metric gaskets are exactly the right size. A few are close, and one is the right ID but thinner. Another is the same thickness but a little too small. Same for small O-ring: one of the HF ones is the right ID but not as thick.

Anyway, drained ET, pulled old one off and couldn't find anything wrong. It still had both gaskets in place, neither was torn, though maybe one had a little sand or crust on it. No obvious cracks. Didn't see any cracks in base plate and the round tubes that fit into the ET seemed okay. Debated... use Myele tank with new HF gaskets (which aren't quite the right size), or use old BMW tank with 75000 miles on it with its old gaskets, so I can return new ET. Or use new ET. I popped on new ET, filled, bled, and drove 180 miles. Just checked with a flashlight and so far doesn't look like it's leaking.

Assuming the new tank stays dry on the bottom, have to figure out why the Myele (which was less than 2 years old) was leaking. Maybe some sand or grit got lodged around the O-ring. Maybe I jogged it loose when I was playing with it and had the locking clip undone. Maybe one O-ring got twisted, but it popped back into place when I removed the ET. Who knows? :dunno

BTW the dealer had one base plate in stock for $81 but I didn't buy it. So far, it doesn't look like a base plate crack.

[aurelius]

As a follow-up, I'm helping a friend sell a ZSP (Sport Pkg 330i) and in going thru the service records, I saw there was an issue with a leaky o-ring on a newly-installed ET.

[LivesNearCostco]

Lo, maybe it can be the O-rings! Yesterday I found more coolant leaking, but at least in that case it appears the ET cap just wasn't tight enough so when coolant got hot enough, it was spurting out. Or my Myele ET cap is also defective! I topped off with distilled water, tightened the cap down, and am watching it like a hawk (with old ET cap in the trunk just in case).

[aurelius]

Speaking of ET caps, I got a couple of the 1.2 bar aluminum caps from G.A.S. Nice product but I've since learned a less expensive option for E46 is the cap from later E30 models. It's rated at 1.4 bar.

For those like me with an earlier E30, although those use a 1.2 bar cap, the GAS version doesn't fit.

[johnrando]

Good info. When you say later E30 models, do you know what years specifically?

[Dave1027]

Speaking of ET caps, I got a couple of the 1.2 bar aluminum caps from G.A.S. Nice product but I've since learned a less expensive option for E46 is the cap from later E30 models. It's rated at 1.4 bar. Awesome! Check this for nine bucks http://www.fcpeuro.com/products/bmw-expansion-tank-cap-14-bar-oem-17111742232?gclid=CPLuzY_VxbYCFSNyQgodW2wA8Q

[johnrando]

Nice! The GAS one is prettier though. :)

[aurelius]

Good info. When you say later E30 models, do you know what years specifically?

Model year 88+. The part number for the later cap is 17111742232 (per realoem). For those of you who have yet to do the DISA rebuild, consider the GAS combo pkg price for the rebuild kit + aluminum cap.


Nice! The GAS one is prettier though. :)

Yes, with a red cap, brass bleeder screw and silver water pump pulley, it's quite festive under my hood.

[LivesNearCostco]

Can you post the link to the combo on the GAS site? I see it listed there but cannot add it to my cart as a combo.

[aurelius]

I bought the DISA kit before they had the caps for sale, therefore I did not get the combo price. I would email them thru the site. My guess is they will credit you the difference after the order is placed. If shipping seems unusually steep once the 2nd item is added to the order, you'll get a credit for that too. Or at least I did on my cap purchase.

[LivesNearCostco]

GAS got back to me, said the black anodized ET caps are out of stock. They, with the combo, should be available again in about a week.

[Dave1027]

I ordered the nine buck E36 1.4 bar cap. Let you know how it does.

It's been working just fine. No issues.

[LivesNearCostco]

My GAS cap arrived, looking beautiful in red anodized aluminum. <Correction> But it is a tight fit with the aFe stage 1 intake. The widest parts of the G.A.S. cap hit the aFe CAI enclosure when turning it, but I was able to install it by holding the CAI housing a few mm towards the rear during installation of the ET cap. So not planning to put this up for sale.

Picture of it installed
http://www.zhpmafia.com/forums/attachment.php?attachmentid=8160&d=1367275929