hey guys im swapping a s5 t2 in my s4, my question is since the s5 didnt come with a raditot cap on the filler neck, and the radiator i bought didnt come with a place for a cap will that be ok or will i actually need a new radiator with a cap to pressurize the system?

 

More importantly, if there is no cap anywhere in the system, how will you fill up the system?

Please think a little bit more about your question.

 

Well, you could always pop off the upper radiator hose from the thermostat neck, and fill from there...

Running with no cap in the system is a terrible idea. The cap is there bleed off hot coolant to relieve excess pressure that would build up since the coolant expands as it gets hot. If you don't have a place for this expanding coolant to go, it could possibly:
- Just push one of the coolant lines to the radiator, heater core, throttle body etc off its nipple, dumping all your coolant
- Cause one of those lines to burst, again dumping the coolant
- Burst your radiator (especially if you have plastic end caps or poor welds)
- Burst your in-cabin heater (now you have a mess in the car too)
- Push coolant past the seals on the water pump, front cover, past the housing-to-iron cooling seals into the engine

And im sure plenty of other bad stuff. OEM's include everything on the car for a reason (what, they like paying for equipment that doesn't serve a purpose?), make sure you understand that reason & are willing to live with the side effects before removing, bypassing, or otherwise modifying things.

 

what you are proposing is impossible. when i look to see what can be done on a car i look to BMW, as any sketchy or outright dangerous thing you can think of, they have done on a production car.

however while BMW might have 7 radiator hoses and 2 thermostats, they always run a radiator cap

 

ok i do see the flaw in the design of that previous purchase, so ill chunk it and charge it to not bein thorough

 

You could buy a radiator hose splice adaptor with a pressure cap on it.

 

never thought about that, will it also have an attachment for the overflow?

 

and do you have a particular one youd recommend?

 

JEGS Performance Products 53098 JEGS Inline Radiator Hose Filler Neck - Free Shipping on All Orders @ JEGS

Remote Radiator Filler Cap

http://www.summitracing.com/parts/csi-973

Remote Radiator Filler Cap

Some ideas to work with. ;-)

I am designing my cooling system to be very custom, and I still have a cap to vent pressure. I feel it is a necessity. Having some sort of pressure release is definitely important.

 

What he said.

 

and would either one of these need to be ran closer to or further away from the radiator?

 

Monkman might be running an air separator tank, hence the small diameter unit...the 1 1/2" would fit the upper rad hose and no, it wouldn't matter where you put it in that hose.

 

ok, id prolly just do it close to the radiator, and clokker do you know where i can find the mdflaps for the fc?

 

j9fd3s, do you work for BMW? because your 100% about BMW . BMW does engineer amazing stuff though. they just over engineer at times... well most the time .

 

You don't really have much choice where it goes.
The fitting will want "x" inches of straight length in the hose and there's only one straight part to the molding.
The upper hose is not the most ideal spot for the cap when considered from a filling/burping aspect, so a few inches closer/further from the rad will make little difference.

Mudflaps show up in the classifieds but you must be quick or Landon will ****** them up.
Infinity G35 rear caps seem to fit quite well and I have seen front flaps from a few different cars that look promising.
My factory ones came with the car.

 

which cars if you dont mind me asking

 

I don't mind you asking if you don't mind me saying I don't know offhand.
Seems to me I've a few recent threads or pics about flaps but they are not a current concern of mine, so they just blur by.
The G35 rears I think you can see in the last few pages of the wheel fitment (ugh, I hate that word...) thread. They are kinda swoopy compared to OEM but seem popular with bodykitted guys.

 

lol, no, i have worked on and raced a few, there are so many around here its basically impossible to avoid em. i do like comparing Mazda and BMW engineering wise though, they are complete opposites, sometimes this is really funny.

examples, we think the FC cooling system is complex, because its got 3 little hoses, or something, but an E30 has the same 3 little hoses, but its then got 7 radiator hoses, and 2 thermostats, all of which have to come of every 60k miles to change the timing belt.

 

I know what you mean brotha.... I'm a BMW tech for a dealer so I pretty much see everything when it comes to BMW. But for some reason seeing bmw cars all day doesn't excite me enough to own one. But the rx7 with a little German design background does! Love both BMW and Mazda engineering.

 

had a beamer as well, great handling, responsive car, but electrical and emissions nightmare then again that could have came from p.o. negligance

 

I owned three e39s at one time.. My mom has an e46 and my brother an e46 zhp. They are great cars just keep up with the maintenance.

 

no FC radiator ever came completely sealed, even the ones without a pressure cap on the radiator had a surge line that went to an external cap located by the RF headlight and then to the overflow tank.

in this case you'd have to plug that port and then you would remove the low coolant buzzer sensor..

 

yeah this is an ebay aluminum radiator lol at the time i was just trying to collect parts, but now i may get the inline adapter clokker was talkin bout or a new radiator

 

The bmw system is diferent, they run an expansion tank!

Even then, many of the expansion tanks even have a little tube that dumps if all else fails

 

the ones with the remote cap have a sensor and angled hose combined into 1. I don't think youc an buy them anymore and they seem somewhat hard to come by these days.

that would probably be the guys best bet? and find one of those remote pressure cap assemblys at a junkyard

heres a picture of the sensor