Hey guys and gals, been searching around a bit but either not searching in the right place or I'm not wording my searches properly. I'm wanting to use the radiator cap that is on my Koyorad, not the one at the top of the water neck on the engine. Is there a block off plate or something to block off the radiator cap at the top of the water pump housing?

Yes, I know it's the highest point in the engine and is the better option when coming to bleeding the coolant system. But the one on the radiator will also work just fine, also the cap at the top of the water pump housing gets in the way of my strut tower bar, real annoying...

Is there anything out there?

 

Make one??

 

find a 2 bolt v band adapter thats the same size of where the filler neck bolts up, then find the proper v band block off and v band... dont forget to run to your local auto parts store to get gasket maker for when you bolt the adapters up. I reccomend the Autozone blue gasket roll because its maded for water pumps. be sure to check for leaks at the v band block off, you might need to add some sealant on it... I havent done this, it was just an idea that popped in my head, hell there there might not be an adapter the right size, but wouldnt hurt to research them cause there might be one out there, just need to find the right bolt spacing that matches up.

 

Maybe even an FB omp block off plate will work hell idk, bolt spacing needs to be right though, let alone beable to fit in the area.

 

I've been searching since I made this post all morning, I don't think there is one. So making one might be my only chance, but that was option number two. It shouldn't be too hard to make a block off.

 

I just realized The stuff I posted would remove the line going from your water pump to your radiator so forget everything I just posted

 

I wonder if this will work?

 

Those are 3-bolt flanges for a S5...the OP has a S4.

 

can you post pics of yours? Because there are acually a few differnt types of necks. Like my top filler, I can unbolt the plastic that my cap is on an put on a block off.

Here's how mine is.

 

Seems everybody might be over thinking this; I've considered doing the same thing on my FC. I believe this piece might help you accomplish what you desire.



I can verify that this S3 piece fits the S4 water pump housing when I get off work... as I have both at home. It will probably require a special upper rad hose.

 

^^^^^^^^^^^^^^^^
if the S3 neck fits and fixes the problem, that that would be the easiest way to go.

 

I'm just going to create a block off plate and use some sealant. My only concern with using a different water neck other than OE to the engine is my RB hoses won't fit properly.

 

Well if you ever change your mind, or if anybody else is in the same boat but wants to delete the FC filler neck completely, I have confirmed the fitment of the S3 upper rad hose outlet. This means the S4 filler neck will also fit the S3 W/P housing; if anybody were ever in such a situation. (I didn't take pics of this, but I did try it just for fun.)

 

Good to know!

 

They also make radiator caps that are just that, a cap. No pressure release valve built in . I have a s4 neck and s5 radiator which means I have 2 caps . But I do like these s3 necks cause it's cleaner

 

Like I said before, I have the RB silicone hoses for the s4. If I use the s3 neck, would it cause and issue with my hose kinking or anything like that?

 

It probably would kink because the S3 outlet points up, the S4 points out and forward.

 

I was poking around under the hood of my FC after I took those pictures and the conclusion I came to isn't an issue of the hose kinking, but more so an issue of it possibly not being long enough. It's worth a try I guess if you have already torn into your filler neck; but be prepared to lose a good amount of your coolant, a gasket, possibly a couple rusted bolts. (they some times break.) At the cost of it not working this seems hardly worth it. I'd have a universal radiator hose on hand, a new thermostat, and you'll need the right length bolts as well. The outlets are the same diameter, but look at the length difference side-by-side. You're definitely going to need a different upper rad hose, no doubt about it.



Believe me when I say I've considered this swap. The reason I haven't done it is because I like my cold start thermowax. It's the highest point on the engine with coolant on an N/A S4, and it's more difficult to my mind to get that air bubble out when it has to travel all the way to the radiator filler neck. I could drill and tap the thermowax housing for an air bleed, but why bother when my filler neck works/looks just fine. (Albeit with my RE-Amemiya strut tower ornament. I'm sure your set up is different, hence this thread.)

 

I don't have to worry about gaskets and coolant, I just finished building my engine last weekend and it's still on the engine stand while I decide what I'm going to do about a flywheel and clutch kit. Also, no thermowax in my system as I've ditched EFI and the S4 IM for an Atkins wrap around intake and Weber 48 DCOE.

What I plan on doing is taking the cap flange off, tracing it off onto a sheet of steel or aluminum and cutting out my own block off plate. Leaving the rubber o-ring in the neck and using RTV or some kind of sealant to make a water tight seal.

 

wouldn't deleting that cap leave a lot of room for air in the coolant system, since the radiator cap sits a lot lower than that cap?

 

I'm sure it will be a bit harder to get all the air out of the system, but why would Koyorad add a cap at the radiator if it was impossible?

 

S5 cars don't have the upper cap, but it does make it suck a little bit more when you are burping the system to get air out.

 

2 words.
Flat cap.

 

It's also worth noting on the s5 the cap is still not ontop of the rad but remote and angled upward higher