David_ek4

so, its a 96 ek4 with b18c4 block (rebuild brand new all oem parts) and b16a2 head and a p28 ecu tuned for the setup.
it's 81,5 with nipponracing headgasket

car runs very well
no white smoke
no loss of power
no oil on cooling system
normal oil color
no oil consuption
there is a little leak on the fitv hose
new and working thermostat
cooling hoses (top and bottom) are aftermarket
no overheating
fan works perfectly

i changed the radiator because the oem was cracked.
intalled a aftermarket radiator.

now the problem. i'm getting a lot of pressure in the top cooling hose and in the radiator.
i ride the car for about one hour then stop it for 5 or 6 hours and then i take the radiator cap and the coolant jumps out whit a lot of pressure.
the top hose is also really hard when the car reaches working temperature

what could it be? normal? headgasket? radiator cap? too much coolant?

Former User

Did you bleed the cooling system?

David_ek4

i did.
after reinstall the new radiator, i had the engine running till the fan starts to work. all this without the radiator cap.
after that, i put the radiator cap and i think it should be done like this.

tony_2018

Word of advice, never open the radiator cap right after just driving it. Did this car overheat?

David_ek4

i never did that. i dit once but the car was stoped for about 5 or 6 hours. it was cold.

the car never overheated.
always working on normal temperatures.

David_ek4

bump.... i need some help!

Former User

Does the B18c4 have a bleeder bolt for the cooling system?

Like this?

https://honda-tech.com/honda-civic-d.../#post38664177

David_ek4

no sir...it doesn´t

Jimi Hondrix

Possible that your water pump is weak but not leaking. Start car from cold start and leave cap off radiator..once the thermostat opens carefully check to see if the water inside the radiator is flowing well and if it is not then chances are your water pump is weak and not forcing the water/coolant to move through the cooling system properly.
Did you replace the thermostat recently?

David_ek4

uumm,ok thanks!
the engine is brand new...erverything from rod bearings, crank bearings, seals, gaskets, timing belt, tensioner, water pump and thermostat also, are new oem parts.
car runs fine. no oil comsumption. no coolant/oil mixing....its just that pressure problem.

could it be the aftermarket radiator? or radiator cap?

Former User

Replace the radiator cap and thermostat, and then bleed like this:

https://honda-tech.com/honda-civic-d.../#post39830585

Jimi Hondrix

Being that it's a new part then it's unlikely the water pump.. but could be possible ..check water flow as I describe
A radiator cap would be a cheap place to start.. did the aftermarket radiator come with a new cap?
A thermostat that is stuck closed will cause the coolant system to overheat quickly.
You coolant mixture should be 50% water and 50% coolant/anti-freeze.

David_ek4

that is what i did...just like that

i've got a 1000km trip next week and i do not have another car to do that! i really need to understand if this is normal or, at least, know if this is not ''dangerous'' for the engine

tony_2018

Note: do not mix water with coolant that is already 50/50 mix. If you're going to mix water with coolant to get that 50/50 mix than buy coolant without the mix.

tony_2018

So you're saying you replaced it with a brand new OEM, from Honda, radiator cap? Even the the thermostat, from Honda?

Former User

Why would over-pressurized coolant hoses be normal? Use a block tester kit to test for exhaust gas in the cooling system.

Also pressure test the the cooling system for leaks, and compression test the cylinders.

David_ek4

i just didn't change the radiator cap. everything else is oem honda brand new...

David_ek4

i really need to do that! i hope that the H/G is in good shape...it has less than 2000km...i dont think its normal a headgasket blown whit just that...

Former User

Here's what you wrote:

...suggesting that you had replaced it. Start replying to comments point by point so your answers are clear to everyone.

Replace the radiator cap.

Former User

Then do it.

What?

David_ek4

i'm sorry! i'm not a english speaker! i was trying to say that, i dont think my headgasket is broken with just 1500km on it!

David_ek4

im really sorry for that! my mystake!!
so, you think that the problem is the radiator cap is that right?

Former User

That's a nice opinion, but I easily can envision a new head gasket blowing for a variety of reasons.

Former User

I'm saying it's a possibility. Given that the cap is an inexpensive part, just replace it and see what happens.

David_ek4

yes it's not impossible but, the way i drive the car and the job that was done, i think it's really hard to blown a HG.

both block and head were resurfaced and the engine never overeathed.
i do a lot of highway (rmp between 3500 and 5000) and i just opened vtec 3 or 4 times.

i dont know...its possible yes. but i think its doesn't happen so easily..