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Discussion Starter · #1 ·
ANYONE have a link to a site with a Flow Diagram for N52 Engine Coolant?
Has anyone reliably traced the hoses to determine such a Flow Diagram, at least as far as external components & hoses are concerned and willing to share your findings?
ALSO: what is the expected life (years of service) of the coolant hoses on our E9x models? On Jags, I had developed a maintenance schedule of replacing ALL coolant hoses every 7 to 8 years, but you could get all 15 hoses for the V-12 in a kit for ~ $70, and the quality was almost certainly inferior to OEM BMW hoses.
Is there any similar "Hose Kit" available for the N52 engine, either from BMW or any Vendor?
FINALLY: WHAT is up with BMW hose clamps? I haven't had to remove/replace any, but what is the drill when you do? Recommended method for removing old & what to get to replace & how install?
Discussion of block heaters got me realizing I have NOT come across any diagram showing coolant flow in the N52 engine. Old-style engines I am familiar with have the thermostat between the head and the top radiator hose. Of course these engines have the thermostat by the LOWER Radiator outlet and an electric pump, with a much more complicated (and Less Visible) set of coolant hoses.
Thanks,
George
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You can get all the hoses on eBay for cheap.
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Some are removed and installed using a simple Phillips head or 6/7 mm socket and some are removed and installed using crimp/clamp pliers.
I don't recall any hoses that require a crimped clamp to be removed for replacement.
Most BMW coolant hoses have plastic couplings to their mating components. The end fittings are attached by a band clamp that is not meant to be removed. Replacement hoses should be supplied with the fittings already attached. AFAIK, BMW always uses a screw-type clamp on hoses that do not use fittings.
I have seen a few BMW cooling systems butchered by inexperienced mechanics attempting to install replacement hoses that were sourced without proper fittings. The end result is invariably frustration and/or leakage, because the re-clamped hose fittings (being plastic) usually fail in short order.
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I don't know if I would touch the hoses unless pump fails, or one swells visibly.
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The coolant hose that runs from expansion tank to radiator top hose is pinch clamp. It's commonly snapped when trying to remove the radiator fan. It can only be replaced by clipping the clip off and crimping a new one down.
And yes MOST are the plastic connectors but the one like I explained above you will be stuck once you come across it.(not any more)
Two of the hose ends to thermostat is screw clamp
One screw clamp on water pump.
The "band clamp" you are referring to indeed can be removed and reinstalled, but instead it's easier to just pry up leaving it halfway installed, removing connection, pushing back down on "band clamp" and it will automatically lock when reinstalling.
It's definitely 100% ok to remove and replace every single coolant hose. You can leave the one steel one that comes from the engine to water pump since it's the hardest to get out.
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Discussion Starter · #7 ·
N52 Coolant Flow Diagram
Attached is an example of a Coolant Flow Diagram. This is a screenprint from BMW Training Manual ST501 Engine Technology, Part 04 Engine Mechanical, page 33. It is for the N54 engine. What I am asking for is ANY cite or link to a similar Flow Diagram for the N52 engine. I can probably trace all my hoses and identify any differences cf N54 (such as turbos ;-) but it would be nice to have a flow diagram for the N52 to make sure I have NOT missed or misinterpreted something.
ANYONE???
I had already assumed from simply looking at the hoses and location of the pump & thermostat, that the thermostat worked "backwards" from old mechanical thermostats located where the OFH is located on our cars. On the N52 & N54 engines, the heated coolant coming from the head would go into the top radiator hose and be cooled in the radiator IF the thermostat at the lower radiator outlet were open and allowed flow. But flow during warmup is blocked at the radiator outlet rather than the inlet, hence the bypass hose (smaller diameter hose) that goes across the front of the engine from the OFH to the thermostat.
I had NOT fully appreciated the potential problems of a leaking OFHG until carefully examining the coolant flow: Top Radiator Hose & Radiator Bypass Hose both coming from the OFH. There's a LOT more than OIL going on in there. 
Thanks to Zeichen & others who have responded re hoses. My 2007 N52KP has NO old-style screw clamps that I can see. ALL coolant hoses on top & in front (I haven't gone underneath yet & taken photos of everything under there after removing undertray) have plastic fittings which I presume have o-rings or other provisions for seal to fitting, such as the top radiator hose to OFH, or to top radiator fitting?
I understand from Zeichen that replacement hoses come with new plastic end fittings (and any necessary o-rings or other seals) and you do NOT remove the hose from the plastic end fittings by cutting the fixing bands, etc.?
Also do you just pry the spring clip outward to "unclamp" the plastic end fitting?
Any tricks to prevent damage to other plastic pieces like radiator fittings?
Thanks,
George
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My 2007 N52KP has NO old-style screw clamps that I can see.
You might be able to lay eyes on a couple from underneath. As Chuckkkthomas stated, some thermostat connections use them.
I understand from Zeichen that replacement hoses come with new plastic end fittings (and any necessary o-rings or other seals) and you do NOT remove the hose from the plastic end fittings by cutting the fixing bands, etc.?
Also do you just pry the spring clip outward to "unclamp" the plastic end fitting?
Correct on both counts. Most of those wire locks use captive bails--you pull it outward until it stops, then go to work on separating the fitting. Invariably, you bump the extended bail, which snaps back home, re-locking the connection, and then you start over.
Any tricks to prevent damage to other plastic pieces like radiator fittings?
Patience. Lots of patience. And a good feel for when you are applying too much force.
The longer the hose has been in service, the more difficult it's likely to be to separate the coupling. On my old 325xi, I once had to resort to a hacksaw, making several axial cuts in the female fitting until I could literally crack it apart to separate it from the male half on the radiator. That was not a relaxing day in the garage.
Sorry I can't help you on the flow diagram, George, but good luck in your quest.
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The coolant hose that runs from expansion tank to radiator top hose is pinch clamp.
Interesting that they went with a different design for that hose on the N52. On the N55, that hose has couplings.
The "band clamp" you are referring to indeed can be removed and reinstalled, but instead it's easier to just pry up leaving it halfway installed, removing connection, pushing back down on "band clamp" and it will automatically lock when reinstalling.
I believe you are describing a crimp clamp, which is a different animal. Yes, those can be removed & reinstalled without special tools in many cases. The ones I meant are near-seamless bands that lack any sort of fastening feature. Not quite sure what the official name might be, but they are not removable, let alone reusable. Basically, it's a metal strap that permanently clamps the hose to the fitting--it's not coming off without destroying it.
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Nothing in the Bentley about coolant direction of flow, if you find one post it.
If you want to practice, use the hose coming out of the expansion tank. Just pry the clip up with a flat head. Don't remove it completely. When you pry it up, it may be a little hard to remove but just keep wiggling. You can also use a flathead at this point to wedge off each side. The rest of the fittings are pretty much the same just bigger.
Most fittings don't have o rings. They just tightly seat against one another and the clip locks it in. The only one that does have a o ring is the one that runs from oil filter housing to thermostat.
You do have clamps one on top is the hose that runs from expansion tank to radiator top. If you somehow break this hose, you will need a new crimp clamp a long with the correct pliers to crimp them. Just because you haven't discovered it doesn't mean it isnt there. And it's not really a "hose" it's more of a "line" but it is indeed a part of the system.
This is the part that the crimp clamp goes on to. It's a nipple coming off the radiator hose 17127531579
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Interesting that they went with a different design for that hose on the N52. On the N55, that hose has couplings.
I believe you are describing a crimp clamp, which is a different animal. Yes, those can be removed & reinstalled without special tools in many cases. The ones I meant are near-seamless bands that lack any sort of fastening feature. Not quite sure what the official name might be, but they are not removable, let alone reusable. Basically, it's a metal strap that permanently clamps the hose to the fitting--it's not coming off without destroying it.
This is what I'm referring to when I say "crimp clamp" p/n 32411712735
The only way this part can be removed is by destroying it. The only way it can be installed is with a clamping plier tool (new clamp).
The "band clamp" I was referring to can be pryed up and reinstalled. These are the half circles that are a part of the hoses that automatically lock them
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This is what I'm referring to when I say "crimp clamp" p/n 32411712735
The only way this part can be removed is by destroying it. The only way it can be installed is with a clamping plier tool (new clamp).
The "band clamp" I was referring to can be pryed up and reinstalled. These are the half circles that are a part of the hoses that automatically lock them
Gotcha - thanks. Yeah, those are an actual clamp, unlike the strap (for lack of a better term :dunno that attaches couplers to hoses.
The "band clamp" isn't a clamp at all. It's just a wire locking bail that fits in a groove inside the coupling. But, at least now we each know what the other is referring to!
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Gotcha - thanks. Yeah, those are an actual clamp, unlike the strap (for lack of a better term :dunno
The "band clamp" isn't a clamp at all. It's just a wire locking bail that fits in a groove inside the coupling. But, at least now we each know what the other is referring to!
Ok now I see why you were confused lol, I was using band clamp for those "wire" locking mechanisms. I think a previous poster referred to them as band clamps I never knew what they were called (still don't). The actual band clamps go over the air filter hoses and intake hoses
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