Radiator and heater system "while you're in theres"

After a surprise 5+ hour HPDE enduro and 3 road trips (all in 3 weeks), my original radiator has started leaking near the point where it connects to the expansion tank.

My ET has been replaced, but I'll replace it while I'm in there because it's the weakest point on the car and has about 46,000 on it.

The entirety of my cooling system on the front of the engine has been replaced, so I'm going to leave those alone for now. My current project will be:
- Radiator
- Expansion tank
- expansion tank mounting braket thingy (it's the plastic thing that clips/bolts to the radiator)

I have a few questions:
1.) Are there any radiators worth upgrading to over OE for a street vehicle that sees track time in desert areas. My research says no, but I just wanted to double check.
2.) If there are not reasonable radiator upgades, is a Behr radiator sufficent over the BMW branded one?
3.) Heater hoses and control valve... they're original. Are they known weak points? I can't follow them to the back of the engine bay/heat core area. The valve looks super easy to change, so I'm not too woried about that one, but:
3a) there's a heater hose that goes from the tank back to... the heater core or somewhere,
3b) the hose that goes from the core to the heater valve
3c) the hose from the heater valve back into the heating system
4.) Any other items in that area I should do?

I've looked on RealOEM and can't really get a diagram that matches what I'm seeing in the car's heater hoses.

Also, item 3a above, on my car shows part #11538377702, but when I search it on all of the parts sites, nothing shows up. Any ideas?

Attachment 35763

This is from the expansion tank back towards the heater hoses

How many miles are on your car?

Answers, below in brown.

- 1.) Are there any radiators worth upgrading to over OE for a street vehicle that sees track time in desert areas. My research says no, but I just wanted to double check.

Probably not. The OE manufacturer is Modine, I believe, and seems to be a stout unit. I wasn't able to source a Modine unit when I did my cooling system so I went with a Nissen. Fitment is about 99.5%, but that last 0.5% wasn't a big deal. The top of passenger side was a slightly tighter than the OE unit I replaced. No issues in the 3,500 miles so far. But of course, I'm in southern California with mild climate and the car is a DD so no HPDEs or track days or 110F temps like in Vegas or AZ.

- 2.) If there are not reasonable radiator upgades, is a Behr radiator sufficent over the BMW branded one?

I'm not sure the Behr is an upgrade. My only experience with a Behr unit was on my '01 330i. The fitment was not as good as the Nissen - main reason why I went with a Nissen instead of a Behr. Keep in mind I got the Behr unit about 4 years ago, so I'm not sure if any changes were made since then. No problems with it in the last 4 years, again, DD in mild climate. This car spent most of the time in Portland, OR with some time in southern CA. All without problems.

In my opinion, OE = Modine > Nissen (just barely), and if all you can get is a Behr then so be it.

- 3.) Heater hoses and control valve... they're original. Are they known weak points? I can't follow them to the back of the engine bay/heat core area. The valve looks super easy to change, so I'm not too woried about that one, but:

Doesn't seem like a weak point. I wouldn't change the heater control valve. If your heater control works and you're getting either hot or cold air as desired then the valve is working (opening/closing). It's also easy enough to access that you can do it later on if it fails (no heat, or always heat).

- 3a) there's a heater hose that goes from the tank back to... the heater core or somewhere,

This hose goes to the heater core. It should be fairly easy to route, the difficulty might be access to the screws/clamp at the firewall / heater core connection. The Rein hose, I believe, is the OE Mfg - the clamps on the Rein hose I bought had the BMW Roundel on it just like the OE unit).

- 3b) the hose that goes from the core to the heater valve

It's pretty easy to get to. Similar to 3a, above, the difficulty might be the screw clamp at the heater core / firewall. Rein is the OE mfg, again, just like 3a.


- 3c) the hose from the heater valve back into the heating system

Do you mean the valve to the hard pipe from the engine or the hard pipes that run along the engine?

The rubber line is pretty easy to get to. The hard pipe is a little more tricky due to the intake manifold and the PCV/CCV system (I always forget what it's called, but the bundle of snakes).

This one is really up to you, depending on how involved you want to get into it. For photos of these hoses and where they go, take a look at my project thread (http://www.zhpmafia.com/forums/showt...acement-first) ) I think page 2 shows the routing of the heater hoses.

If you replace the pipes (the ones that run along the block), the easiest way to gain access is removing the intake manifold. It's surprisingly easy (11 nuts and the CCV/PCV system connections. be sure to get new intake manifold gaskets for reassembly). So much access with the manifold off.

- 4.) Any other items in that area I should do?

If you don't change the hoses, I'd recommend replacing the o-rings at the hose ends. You can source your own (there are threads on e46fanatics which has the o-ring sizing (inner diameter and the oring thickness) you'll need). I sourced the o-rings from https://oringsusa.com/catalog/index....ath=26_122_101. Order a few extras while you're at it, it's cheap enough. For convenience, I believe a member on ZHPMafia and M3forum (same member) sells a kit he assembled.

And I'd recommend using a tiny bit of silicon lube (Home Depot sells small tubes of this in the plumbing department) to help lubricate the orings for installation, and should help in removal down the road.

Depending on the age of the components and your budget, you might want to consider changing:
- fan clutch,
- water pump pulley with an aluminum one. Although I've never experienced the plastic pulley shattering a few people I've know had theirs go. Not a good failure to have.
- coolant temp sensor on the lower radiator hose, or perhaps at least the o-ring.
- an electric fan to replace the mechanical fan and fan clutch.
- radiator cap. Lots of people went with a 1.2 bar cap. The original is a 2.0 bar, I believe. I went "Goldilocks" with a 1.4 bar cap (17-13-7-639-023)
- Coolant level sensor that goes in the expansion tank (17-13-7-553-919)

- If you have a automatic transmission, consider:
- a) the transmission thermostat that is installed in the expansion tank (17-11-1-437-362).
- b) transmission cooler-to-mounting plate o-rings. (14.5 x 2.5, you need two).

- I've looked on RealOEM and can't really get a diagram that matches what I'm seeing in the car's heater hoses.

Maybe:
11-53-1-436-410
64-21-8-376-153
64-21-8-363-198

Check out my project thread, it'll might help you visualize the hoses / pipes. Keep in mind, if you replace the hard lines (pipes), the neck of it might break off due to age. Just be sure to remove the broken neck before you install the new pipe. Silicon lube helped for re-install.

- Also, item 3a above, on my car shows part #11538377702, but when I search it on all of the parts sites, nothing shows up. Any ideas?

Maybe 64-21-8-376-153

Glad you caught the coolant leak before it lead to serious problems. Keep us posted.

I just did a complete overhaul on the cooling system which included the hard coolant pipes under the intake manifold. At this point every E46 should have this job done.

There are 2 hard coolant lines and a total of 4 coolant hoses. Plus the upper and lower radiator hoses. I suggest replacing them all.

I went with a genuine bmw radiator since I didn't want to deal with fitment issues. You can use rein brand rubber hoses but for the hard coolant pipes, go with genuine bmw.

Sent from my Pixel 2 XL using Tapatalk

Quote:

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Originally Posted by Will

How many miles are on your car?

Answers, below in brown.

- 1.) Are there any radiators worth upgrading to over OE for a street vehicle that sees track time in desert areas. My research says no, but I just wanted to double check.

Probably not. The OE manufacturer is Modine, I believe, and seems to be a stout unit. I wasn't able to source a Modine unit when I did my cooling system so I went with a Nissen. Fitment is about 99.5%, but that last 0.5% wasn't a big deal. The top of passenger side was a slightly tighter than the OE unit I replaced. No issues in the 3,500 miles so far. But of course, I'm in southern California with mild climate and the car is a DD so no HPDEs or track days or 110F temps like in Vegas or AZ.

- 2.) If there are not reasonable radiator upgades, is a Behr radiator sufficent over the BMW branded one?

I'm not sure the Behr is an upgrade. My only experience with a Behr unit was on my '01 330i. The fitment was not as good as the Nissen - main reason why I went with a Nissen instead of a Behr. Keep in mind I got the Behr unit about 4 years ago, so I'm not sure if any changes were made since then. No problems with it in the last 4 years, again, DD in mild climate. This car spent most of the time in Portland, OR with some time in southern CA. All without problems.

In my opinion, OE = Modine > Nissen (just barely), and if all you can get is a Behr then so be it.

- 3.) Heater hoses and control valve... they're original. Are they known weak points? I can't follow them to the back of the engine bay/heat core area. The valve looks super easy to change, so I'm not too woried about that one, but:

Doesn't seem like a weak point. I wouldn't change the heater control valve. If your heater control works and you're getting either hot or cold air as desired then the valve is working (opening/closing). It's also easy enough to access that you can do it later on if it fails (no heat, or always heat).

- 3a) there's a heater hose that goes from the tank back to... the heater core or somewhere,

This hose goes to the heater core. It should be fairly easy to route, the difficulty might be access to the screws/clamp at the firewall / heater core connection. The Rein hose, I believe, is the OE Mfg - the clamps on the Rein hose I bought had the BMW Roundel on it just like the OE unit).

- 3b) the hose that goes from the core to the heater valve

It's pretty easy to get to. Similar to 3a, above, the difficulty might be the screw clamp at the heater core / firewall. Rein is the OE mfg, again, just like 3a.


- 3c) the hose from the heater valve back into the heating system

Do you mean the valve to the hard pipe from the engine or the hard pipes that run along the engine?

The rubber line is pretty easy to get to. The hard pipe is a little more tricky due to the intake manifold and the PCV/CCV system (I always forget what it's called, but the bundle of snakes).

This one is really up to you, depending on how involved you want to get into it. For photos of these hoses and where they go, take a look at my project thread (http://www.zhpmafia.com/forums/showt...acement-first) ) I think page 2 shows the routing of the heater hoses.

If you replace the pipes (the ones that run along the block), the easiest way to gain access is removing the intake manifold. It's surprisingly easy (11 nuts and the CCV/PCV system connections. be sure to get new intake manifold gaskets for reassembly). So much access with the manifold off.

- 4.) Any other items in that area I should do?

If you don't change the hoses, I'd recommend replacing the o-rings at the hose ends. You can source your own (there are threads on e46fanatics which has the o-ring sizing (inner diameter and the oring thickness) you'll need). I sourced the o-rings from https://oringsusa.com/catalog/index....ath=26_122_101. Order a few extras while you're at it, it's cheap enough. For convenience, I believe a member on ZHPMafia and M3forum (same member) sells a kit he assembled.

And I'd recommend using a tiny bit of silicon lube (Home Depot sells small tubes of this in the plumbing department) to help lubricate the orings for installation, and should help in removal down the road.

Depending on the age of the components and your budget, you might want to consider changing:
- fan clutch,
- water pump pulley with an aluminum one. Although I've never experienced the plastic pulley shattering a few people I've know had theirs go. Not a good failure to have.
- coolant temp sensor on the lower radiator hose, or perhaps at least the o-ring.
- an electric fan to replace the mechanical fan and fan clutch.
- radiator cap. Lots of people went with a 1.2 bar cap. The original is a 2.0 bar, I believe. I went "Goldilocks" with a 1.4 bar cap (17-13-7-639-023)
- Coolant level sensor that goes in the expansion tank (17-13-7-553-919)

- If you have a automatic transmission, consider:
- a) the transmission thermostat that is installed in the expansion tank (17-11-1-437-362).
- b) transmission cooler-to-mounting plate o-rings. (14.5 x 2.5, you need two).

- I've looked on RealOEM and can't really get a diagram that matches what I'm seeing in the car's heater hoses.

Maybe:
11-53-1-436-410
64-21-8-376-153
64-21-8-363-198

Check out my project thread, it'll might help you visualize the hoses / pipes. Keep in mind, if you replace the hard lines (pipes), the neck of it might break off due to age. Just be sure to remove the broken neck before you install the new pipe. Silicon lube helped for re-install.

- Also, item 3a above, on my car shows part #11538377702, but when I search it on all of the parts sites, nothing shows up. Any ideas?

Maybe 64-21-8-376-153

Glad you caught the coolant leak before it lead to serious problems. Keep us posted.

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If I look at your post on tapatalk, none of The stuff is there that I see on the web browser version.

Attachment 35780

Quote:

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Originally Posted by Will

This one is really up to you, depending on how involved you want to get into it. For photos of these hoses and where they go, take a look at my project thread (http://www.zhpmafia.com/forums/showt...acement-first) ) I think page 2 shows the routing of the heater hoses.

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None of the photos show up in your thread.

Quote:

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Originally Posted by stephenkirsh

None of the photos show up in your thread.

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Thanks for pointing that out. I'll take a look and see if I can get the photos back up.

This was the specific photo I mentioned for those heater hoses:
https://lh3.googleusercontent.com/tS...6=w919-h689-no

The long one from the firewall (closer to centerline of car) runs to the expansion tank.

Ah great, thank you.

Also: shit, that’s where the ABS module is?

The ABS module is behind a black covering that is not shown in the photo. You don't need to remove the black cover to change the heater hoses. I removed them to do some cleaning.

Radiator time. Hoping to get to it Sunday.

Kittens make terrible assistants when unpacking things.

I skipped on the heater hoses this time. I’ll get them when I do the hard lines under the intake manifold.

Attachment 35803