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I now officially have a heating issue.

My main issue is that when I am driving hard the overflow is spraying out all the coolant and when I'm at idle the car overheats and the needle goes close to red (maybe cause coolant is low at that point)!!!

This never happened before my recent tune which put the power to 155bhp, which was fine, no over heating even after a hard run, but still got overflow spray. Maybe at that power level it didn't generate too much heat that the radiator couldn't handle and didn't overheat at speed or at idle/standstill/traffic.

The car now is tuned to 180bhp and I'm am supposed to go to the tuning garage again this Tuesday to bump it up from 6psi to 9psi to hit my target 200bhp goal as he didn't have time to do this last time.

1. Could it now be that the car is putting out more power + more heat, than what the STOCK radiator cant handle?
2. Also could it be that the coolant flow when running so hard/fast is spraying out before it couldn't go down the channels fast enough in the radiator due to the flow, hence the coolant spraying out the overflow reservoir?

I read about a bad head-gasket could force gases into the coolant jacket or something and this displaces the pressure and causes the overflow to spray out, however do you guys think my initial analysis on question 2. has value and weight to it?

I drove it had to test it just now, however it is always a brief journey to work approx 20mins. While driving it was fine, its just when I pulled up it gradually stated to heat up in about 5mins it went close to red. What do you guys think is actually going on?

I checked, and I don't have any milkshake stuff in the oil or on the oil cap
I checked, the radiator cap and there is no gunk or blockage
I checked, the exhaust although the gasses coming out is clear (no smoke or visual steam) I put my hand to it and feel steam/moisture (is that coolant?, sometimes I feel I can smell a hit of it also)
I checked, and I do have little bubbles in the radiator (not loads or any big bubbles, just a few small ones here and there) but I also feel that this is happening now because I have been topping it up with coolant/anti freeze mix and not fully bled the system and may have caught some air along with the topping up and circulation? Also as I have been topping it up from the bottle of coolant whenever i see its low, I didn't add water as it wasn't to hand,can this make a difference?
I checked, the radiator fan and it was on and blowing air when I parked up and even had the bonnet up. Its at this point my car overheated during idle, my tuner said this also happened during traffic after the tuning (that day was also very hot) today was normal (not a hot day).

Could a new thick core, dual channel, aluminum radiator and 12" fan solve this issue?

I really need to sort this out, if anyone can suggest ideas or know about what could be causing this or confirm if my thoughts are on the right track please do let me know.

I am afraid you got gasket issues as well...

but on the power heat thing: if your turbo pressure did not increase I would think the engine might even run a little colder than when it had 155 bhp. The better tune also made it run a bit more efficient, turning fuel more in power than heat. So unless you really upped the pressure of the turbo I would not really think it would be the increase in power causing too much trouble for the cooling system.

On the other hand it's a turbo.... which can increase inlet pressure by itself when exhaust pressure is higher... ehr.

Anyway normally I would say your cooling system should be able to handle it.

One last question, what is your maximum pressure in the inlet and what is max torque produced now? (Do you have dyno graph btw?)

I don't have the dyno graph at hand unfortunately. I should hope to get a printout when the final tune is done.

What you said about the the power/heat issue makes a lot of sense as the tuner did say he tuned it so that it would run cooler with added fuel (rich) just enough that I don't suffer any risks high up in the rev and power (this turner is really good and do trust him with my car so I don't doubt the tune or his skills)

I did a bit more reading and lots and lots of people throw up the bad head gasket, but as you mentioned and I also read a good post by one individual from Australia on Honda-tech, who stated the inlet pressure could be what caused the leak at the inlet gasket. As there is a coolant opening there and at high pressure this may have caused a leak and forced air which increased the coolant pressure and hence the spraying out the overflow.

I have a strong suspicion this may actually be the culprit, however i need to check the inlet gasket and see whats going on.

I guess the only reason why the car over heated after a hard run was because the coolant was sprayed out to the point the radiator was almost emptied, and if i had enough coolant it would never over heat as it did.

When the car was 155bhp the vtec was not activated and the timing was also stock, I read about head lift? Could this be something relevant as vtec is now activated and was retarded 4 degrees?

Is the thermostat in good condition?
Maybe the thermostat is blocked and when the engine works hard the overheated coolant does not have to go anywhere from the engine-radiator. It is supposed to be returned the cooled coolant from the radiator throw the thermostat housing.
As a result of the heating is to maximize the coolant pressure and that helps to be sprayed out.
I suggest to take of the thermostat and run the car without it for some days in order to see the behaviour of the coolant on the hard working engine.
Also it is wise to but fresh coolant (but not the red one) and flash the system.

Another item that is critical is the radiator cap that keeps under pressure the cooling system as the degree that it has stamped on it but when the coolant passes this degree if the cap is worn it can' t open to help the coolant to pass to the expanding bottle.
Maybe it will be good idea to changed the cap with new one (genuine preferred).

I think this video will help a lot to solve the overheating problem
http://www.youtube.com/watch?v=hUzOTnsW ... r_embedded#!

Betek that is some sound advice, and I cant believe I didn't checkout this video by Eric the car guy first, thank you so much for linking me up to this video, as always he is very, very informative.

I will start simple and replace the cap with a good one, check/replace thermostat and bleed the system and see where that leads me.

more power will not always mean more heat. higher compression will. I've seen several high compression engines here with sub optimal tuning [excessively advanced ignition timing] overheat and overwhelm the stock cooling system. a friend of mine is running a B16 swap and using the D series radiator and fans without any problems. when you are doing low speeds or standing still, there is little or no headwind to assist the fans and the engine overheats.

I would suggest you thoroughly bleed the cooling system first. make sure you turn the heater on so that the air in the heater core also gets out. then post a video with the radiator cap off and engine running.

jangz wrote: I checked, and I do have little bubbles in the radiator (not loads or any big bubbles, just a few small ones here and there) but I also feel that this is happening now because I have been topping it up with coolant/anti freeze mix and not fully bled the system and may have caught some air along with the topping up and circulation? Also as I have been topping it up from the bottle of coolant whenever i see its low, I didn't add water as it wasn't to hand,can this make a difference?

I do not want to disappoint you but this sounds to me like head gasket failure

I had the same issue as you (overheating when driving hard) and little bubbles during normal driving
It started to get worse after some time
My head gasket had failed between the coolant channel and the cylinder sleeve, most likely caused because I did not skimmed the head and frozen coolant during winter night

Skimmed the head and put on a new head gasket and it has been perfect ever since

I see you are running a turbo, the problem might be headlift... Dodo do you think that is possible with the amount of boost jangz is running ?

I am not entirely convinced yet its the head gasket, as i can still drive hard and the car is fine but when at a stand still it heats up due to the coolant being sprayed out and emptied via the overflow and with no coolant inside it heated up.

As long as i have coolant in my system I'm fine, hence topping up and not bleeding it properly (hence little bubbles). I did drive it today and done a little blasts and i was fine as not much was sprayed out cuz i took it easier than normal and sat in the car and let it idle and i was fine as coolant was still present as i filled a lot this time.

I have no oil mixed with coolant or coolant in the oil, no white smoke and when the car was tuned it was tested for compression and it was fine and then strapped it to the dyno and tuned as it was safe to do so.

I think i will check the basics, cap, thermostat, bleed, need new radiator any way and new fan a long with it. I'm suspicious about the intake gasket also and wonder if this is linked to the pressure build it.

My vtec cam was retarded by 4 degrees. I also wonder about this head lift issue people also speak about.

do you have an a/c? Maybe a larger radiator from an integra? Or simply a fatter one? They don't go that expensive.