Do I need to use this?

Patrick · #1 4th April 2006, 20:41

I was putting the hose clips I ordered the other day on this evening and a thought struck me.

The header tank has a pressure over flow and also has a connection to the top of the old rad - persumable to get rid of air in the top of the rad. Now with my new rad I dont think I can connect it this way because the small connection seems to be a pressure release like on the header tank. So I guess I will have to use this:

MartinClan · #2 4th April 2006, 21:20

Hello Patrick

If you are using the BMW expansion tank then I guess you dont need the radiator filler/cap thing (technical term) in the middle of the top rad pipe. The expansion tank has a cap on it and an overflow pipe. The only worry I have is that the expansion tank needs to be the highest point on the cooling system otherwise it will be impossible to get all the air out - but I think mounted where it is it should b OK.

Using the BMW expansion tank means you are using the cooling system as BMW originally intended - must be the best way.

BTW - my rad looks different to yours - it doesn't have anything that looks like a filler cap and it has a small bleed hose at the top that connects to the expansion tank.

Take a look at the ETK and you will see what I mean.

Cheers

Robin

Patrick · #3 4th April 2006, 21:32

Its the bleed hose that my rad is missing which has lead me to thinking I will need to use the cap/pipe thingy in the top hose as its taking the place of the bleed pipe on the rad.

peterux · #4 4th April 2006, 21:51

Looks like another question for Mr Mathews?

It really is time Marlin put together an assembly manual or at least a list of Q&A's. There are too many unanswered questions leaving us all buying things that are wrong or not needed, adding to the cost and our time.

Don't get me wrong I enjoy the 'hunt the right solution' but there really are too many open ends.

Like for example: Marlin happily modify the BMW front suspension, so how come they don't offer to modify the rear springs at the same time?

How about a build manual with the correct Radiator part number, Servo part number, best heater type, whether to fit the rear brake compensator or not, the correct brake master cylinder part number, the ant-roll bar mountings, the high pressure fuel pump system, best position for the brake fluid reservoir, the cooling system, even, how to fit the radiator mounting brackets that fooled most of us! etc, etc

Or am i just having a bad day??

I still love the car and can't wait to get it finished, just wish I had more time!

Patrick · #5 4th April 2006, 22:01

Looks that way - my rad is the "BMW" rad from Marlin - that top hose thingy came with the kit which suggests it is is needed.

But you are right the lack of any form of proper build manual is infurating at times!

It is irritating that I've had to piece the cooling system together - I've wasted a lot of money on pipes and connectors I dont need now.

Also the amount of times something does fit. A superb example is the rear sping seats on mine and Robin's car being completely out.

peterux · #6 4th April 2006, 22:37

Ok back to your radiator question............

Did yours come with a radiator cap? Is it presurised or not as there is a little overflow pipe near the filler neck.

Also, looking at Staurt's pictures, i don't thnk you can get at this rad cap once the front cowling is fitted, perhaps that's why they provide a filler neck?

Go on, send an email question to Mark and Terry and post the reply for us all to enjoy!

Peter

Stuart · #7 5th April 2006, 06:19

I have a cap on the top of my radiator but its impossible to take it off due to the front cowling so I have fitted the Marlin supply top hose cap. But then I dont think it is nessecary as I have the BMW expansion tank fitted and can fill the system through this. So i guess I have paid for this hose /cap/filler which really is not nessecary.

Stuart

Patrick · #8 5th April 2006, 07:22

Quote:

Originally Posted by peterux

Ok back to your radiator question............

Did yours come with a radiator cap? Is it presurised or not as there is a little overflow pipe near the filler neck.

Also, looking at Staurt's pictures, i don't thnk you can get at this rad cap once the front cowling is fitted, perhaps that's why they provide a filler neck?

Go on, send an email question to Mark and Terry and post the reply for us all to enjoy!

Peter

The rad didnt come with the cap, I had to order that. There is an overflow pipe near the neck. I need to examine the layout of the donor rad as I recon that just a thin open pipe rather than an overflow. I'll have a look when I get home tonight.

Quote:

Originally Posted by Stuart

I have a cap on the top of my radiator but its impossible to take it off due to the front cowling so I have fitted the Marlin supply top hose cap. But then I dont think it is nessecary as I have the BMW expansion tank fitted and can fill the system through this. So i guess I have paid for this hose /cap/filler which really is not nessecary.

Stuart

Yeah, that will be pretty well covered, but you can fill it from the header/expansion tank so that less of an issue.

I have a small pile of bits coming together now that will be putting on eBay

MartinClan · #9 5th April 2006, 07:30

Perhaps we should write a build manual ourselves, or at least an FAQ, - sharing our experiences of what to do and what not to do, what bits to use and what bits not to use. I am a technical author (sometimes) it would be quite intersting to put something together....

I have a question now about the brake master cylinder - but I think I will start another thread.

Patrick · #10 5th April 2006, 07:35

Quote:

Originally Posted by MartinClan

Perhaps we should write a build manual ourselves, or at least an FAQ, - sharing our experiences of what to do and what not to do, what bits to use and what bits not to use. I am a technical author (sometimes) it would be quite intersting to put something together....

I have a question now about the brake master cylinder - but I think I will start another thread.

That sounds like an idea. Part of the reason I take so many photos is because the "build manual" CD is not very comprehensive. So alteast other and potential builder have a nice selection of photos to look at (with some description)

The only thing that is a problem is that I don't know when I am doing something wrong so it takes some else to point it out (wrong fuel pump for example)

Patrick · #11 5th April 2006, 07:58

I think the simple answer to my questions is - yes I do need to use it as the connection on the donor rad isn't an overflow but a open connection - at least thats what it looks like to me

:

http://www.realoem.com/bmw/showparts...06&hg=17&fg=05

Would seem sensible to me when filling the coolant system to open the cap on the rad to let air out there.

Patrick · #12 5th April 2006, 21:18

I have a good look at the donor rad today - it is an open small connection at the top. So the system will need some for of connection from the rad top hose to the header/expansion tank.

I want to find a better way than the extra cap - its a bit silly once you have 3 caps in a coolant system!!

peterux · #13 5th April 2006, 21:52

Patrick,
I had not found this website before, it is just awesome, thanks.

What do you all think about connecting the small outlet on the radiator neck directly to the coolant expansion tank? I can't see why this would be diffrent to connecting to the pipe adaptor thingy.
Don't forget there is also an air bleed screw on top of the thermostat housing too.

I am using a Ford made expansion tank, that I bought from Westfield, just to complicate matters further!

I decided last night to buy the same rad as you and Stuart have, since this is the one Marlin supply, so their funny brackets should fit OK?

(I've also got a pile of stuff to sell on ebay!)

cheers

Peter

Patrick · #14 5th April 2006, 22:03

Quote:

Originally Posted by peterux

I can't see why this would be diffrent to connecting to the pipe adaptor thingy.

The small pipe connection on the marlin supplied rad is a pressure overflow - its outside of the normal coolant flow - water only gets to this if it breaches the rubber seal in the cap.

On the stock 325i system the small pipe connection is part of the normal water flow in the system.

Thats why you need the additional connection in the header.

realoem is great when you dont have access to an ETK

Yeah funny brackets will fit that one - i ended up making my own though!

peterux · #15 5th April 2006, 22:13

Ok, back to the 'drawing board'.............

Peter

Patrick · #16 6th April 2006, 22:08

I've spent a little more time looking at radiators. Seems the one that Robin has is the best choice. It fits and had the connection for the header/expansion tank. The system then only have one single filler cap as well.

I'm considering selling the rad I have now and getting the preface lift E30 325i one like Robin's. The plumbing looks different though for the main bigger pipes!

I wish I had know about this before buying the Marlin BMW rad! Not enough research done by me!

EDIT: Might see it its possible to modify the rad I have or make a cleaner take off pipe from the top hose.

Patrick · #17 7th April 2006, 07:13

Right plan X, Y no Z err never mind

Anyway new plan involves either modifing the ali joiner in the top hose to add a take off pipe for the header tank, or gettings CBS make one. That gets rid of one cap out the system and looks a bit prettier!

peterux · #18 7th April 2006, 20:54

Patrick,
how about one of these with a suitable adaptor for the hose connection.

http://www.nfauto.co.uk/temp_sender_housing.htm

just need to find a right angle hose connector to M10 screw, any ideas if these exist?

Peter

Patrick · #19 7th April 2006, 21:22

Yeah that would work! Trying to remember if I saw M10 pipe connectors some where.

I might have a go brazing a connection on to one of the hose joiner I have in my spare bits box first

Alfie · #20 9th April 2006, 09:55

I think my cooling system is different again,as I have an extra port off of water pump leading to expansion tank. The only cap is on the expansion tank though, together with an overflow. There is just a thin pipe leading from top of rad to expansion tank.

Alfie