s13 Rad Cap

[Maff_1991]

Hi guys, Just installed a Mishimoto alloy rad to my 13 and whilst trying to remove any airlocks i noticed:

Rad Cap pressure is 19ibs / 1.3 bar

personally i think its too high, especially when bugger all fluid seems to be passing through it

can anyone recommend a better cap?

cheers

[clive12155]

Hi mate I had the same issue with all the water hoses busting due to high pressure so I used 0.9 bar

[Maff_1991]

Cheers for the quick reply , much appreciated, thats sounds about right to me too, was just interested to see what other people are using on theirs, last thing i want is more work haha

[pointz]

I think the maximum "uprated" is 1.1bar but as above 0.9 would be best!

[croustibat]

Use the oem cap. Your water system was designed to work at that pressure.

[Maff_1991]

Use the oem cap. Your water system was designed to work at that pressure.

Would do if it had a standard rad in it in the first place (had a cheapo alloy one) with a 1.1 bar cap (i think) , which i sold a few weeks ago lol

Probably going to put a 1.1 cap on it again, cheers for the input guys

[Rochester]

I went up from an OEM 1.1 to a 1.3 and over the course of the next three months four different pipes burst / split / gave up.

Which pissed me off at the time and I thought oh dear naughty bad uprated rad cap and evil higher pressures.

However on second thoughts I realised that

(a) the fact that the pipes failed showed that they were worn out after 120K miles
(b) I'd rather know that they were defective and replace them sooner than later
(c) ditto than standing by the side of the road beside an overheated waterless dead engine fit only for the scrap yard
(d) if it weren't for the pipes failing the uprated cap does the job of preventing boiling in the head under high stress, an improvement in safety and heat tolerance
(e) right approach to change all old worn out pipes with new ones and forget the worries.

[steve109]

I had a 1.3bar one in for a few drives, as my 0.9 factory one was shagged, blew pipes, jubilee clips the works. Now back down to a 1.1bar one that came with my new rad, still recon its a bit too much so will be trying to source a 0.9bar one. Should have replaced all my pipes when i had the block out, live and learn.

[Maff_1991]

seems like everybody has had problems with 1.3 bar caps, i'd rather not risk blowing anything to be honest, especially in a 300hp car, would scare the shit out of me! lol

[croustibat]

I do believe stock is 1.1, not 0.9 .

I had a 1.3 too. Now i am back to 1.1, not worth it. The increase in pressure ups the boiling point of maybe a couple degree, and that is something a good coolant will give you too.

TBH, if your coolant temp reaches its boiling point, find what is causing the overheat and fix it. High coolant temp is the consequence of something done wrong, trying to hide the problem by raising coolant pressure if not the way to go. Get a better suited map, clean your radiator, duct it correctly, fit the undertray again, use a better fan, you name it. Just dont up the coolant pressure.

[Jonny Wilkinson]

I do believe stock is 1.1, not 0.9 .

I had a 1.3 too. Now i am back to 1.1, not worth it. The increase in pressure ups the boiling point of maybe a couple degree, and that is something a good coolant will give you too.

TBH, if your coolant temp reaches its boiling point, find what is causing the overheat and fix it. High coolant temp is the consequence of something done wrong, trying to hide the problem by raising coolant pressure if not the way to go. Get a better suited map, clean your radiator, duct it correctly, fit the undertray again, use a better fan, you name it. Just dont up the coolant pressure.

This. ^^^^^

[steve109]

Stock cap on my old rad was 0.9, 1.1 cap came with my alloy rad

[MerLiNz]

stock is 0.9. when i bought apex alloy rad this came with 1.1

[dbssgti]

I went up from an OEM 1.1 to a 1.3 and over the course of the next three months four different pipes burst / split / gave up.

Which pissed me off at the time and I thought oh dear naughty bad uprated rad cap and evil higher pressures.

However on second thoughts I realised that

(a) the fact that the pipes failed showed that they were worn out after 120K miles
(b) I'd rather know that they were defective and replace them sooner than later
(c) ditto than standing by the side of the road beside an overheated waterless dead engine fit only for the scrap yard
(d) if it weren't for the pipes failing the uprated cap does the job of preventing boiling in the head under high stress, an improvement in safety and heat tolerance
(e) right approach to change all old worn out pipes with new ones and forget the worries.

Do this wish I had!!! Cost me a top end rebuild.

[MerLiNz]

oem rad cap:

[BeerBringer]

Lifting. Does anyone know where I can get a 1.1 Bar cap for my Driftworks radiator? Stock one does not fit.