My radiator cap is knackered - the rubber seal is shot to bits but not bad enough that it loses hardly any water at all - however when I stop the car I get a bubbling noise behind the dash board - My theory is that the system cant get pressurised enough due to the bad rad cap and is allowing the water to boil when the engine is turned off and the water sint flowing.. .I also reckon it may be allowing parts of the engine to run hot.

 

Anyone think this sounds about right - or any other offers of ideas?

 

Thanks.

I got a spare rad cap if you want? Dunno what they go for? :)

Cheers mate - sorted one out for tomorrow!

Did you know Nismo do one for £40 bloody hell!

Standard ones are £9 odd from Nissan - I tried one from Halfords for £4.54 and it was crap.

Getting an uprated one for a Skyline tomorrow from Middlehursts.

Also check the 'bayonette' mounting that the rad cap twists on to. My one had worn on one side, enough that when the car was hot and the pressure was up, it pushed one side of the cap up. It would release all the pressure (and all the water) and cause the car to over heat.

 

I ended up playing safe, and instead of just buying the plastic side tanks I replaced the whole radiator with an all metal one from the USA.

Got a GReddy Cap here if your interested :)

I got a Blitz one off Macca for a tenner, think i got his last one though!

 

Think the problem with the stock ones is when they are on the way out, they tend to let air in, not water out, thus causing your bubbling.

 

Cant remember what the PSI of the blitz one is though i think its about 50% higher than the stock one.

Just an update - got an uprated one from Middlehursts - its a HKS one and is rated to 1.3 psi - old one was 1.2 psi - seems to have done the trick - top hose is now nice and firm and no bubbling...Will wait and see if this was the cause of my detonation - it didnt do it on the way home though....