[solved] Need help, car heats up on VTEC! But only on very hard runs!

Car: ek4
Engine: B16a

Basically when ever I go for a nice long drive say through the national park, the car will eventually overheat to the point where the temp needle will be only a few bars from H!!

But this only happens if I spend alot of time above 5600rpm (on VTEC!)

And heres the thing, when it heats up I just back off the gas and if I stay off VTEC as in shift before 5500rpm the needle won't budge from it's usual position and this is with 20mins of hard driving just below 5500rpm.

This doesn't happen when I hit VTEC during daily driving eg: VTEC in 1st 2nd and 3rd, then drive normal ans the repeat, needle doesn't move! But as soon as I got for a long drive hard drive and start hitting VTEC too much OMG the needle starts creeping up!

Have recently replaced thermostat with genuine Honda one.

Also replaced radiator with dual core aluminum radiator and flushed the coolant.

Car has aftermarket cams and cam gears and VTEC does come on pretty aggressively, what I'm suspecting is that the change in power output from off to on VTEC is so big that engine gets really hot really fast and stock Honda thermostat can't keep up?

Will getting after market low temp thermostat help? Coz it kinda sounds like an over heating issue which others would only normally face on a track day..

Or is my problem elsewhere?

Note: car does not suffer from any other over heating symptoms eg it can sit idle for 10 years as still be fine, problem is of I spend too much time above 5600rpm!!

Solution: Replaced Headgasket, installed ARP studs

problem is honda dont have accurate temp gauge that gives on the fly reading.
lags like mofo. and you probably only have single core half size radiator.

edit: you have dual core alu rad.

Quote:

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Originally Posted by EG52NV

Car: ek4
Engine: B16a

Basically when ever I go for a nice long drive say through the national park, the car will eventually overheat to the point where the temp needle will be only a few bars from H!!

But this only happens if I spend alot of time above 5600rpm (on VTEC!)

And heres the thing, when it heats up I just back off the gas and if I stay off VTEC as in shift before 5500rpm the needle won't budge from it's usual position and this is with 20mins of hard driving just below 5500rpm.

This doesn't happen when I hit VTEC during daily driving eg: VTEC in 1st 2nd and 3rd, then drive normal ans the repeat, needle doesn't move! But as soon as I got for a long drive hard drive and start hitting VTEC too much OMG the needle starts creeping up!

Have recently replaced thermostat with genuine Honda one.

Also replaced radiator with dual core aluminum radiator and flushed the coolant.

Car has aftermarket cams and cam gears and VTEC does come on pretty aggressively, what I'm suspecting is that the change in power output from off to on VTEC is so big that engine gets really hot really fast and stock Honda thermostat can't keep up?

Will getting after market low temp thermostat help? Coz it kinda sounds like an over heating issue which others would only normally face on a track day..

Or is my problem elsewhere?

Note: car does not suffer from any other over heating symptoms eg it can sit idle for 10 years as still be fine, problem is of I spend too much time above 5600rpm!!

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sounds normal, push your car, it heats up.

Are you losing coolant?

what radiator? did you get a new one, second hand, brand, bought from where....

the biggest test is if your car can sit forever idling........

if it can idle forever, then its fine....

Engines that run lean, run hot! Could that be your issue?

Coolant is getting so hot it bubbling out of overflow bottle!

Quote:

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Originally Posted by Touge Tom

Engines that run lean, run hot! Could that be your issue?

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Car runs overly rich IMO but can't say for sure Coz don't have air fuel gauge

Looks like car is juat getting hot coz its being pushed, and my last option is investing in a low temp thermostat to move the hot coolant out of the block sooner!

But aren't these bad for daily driven cars?

Quote:

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Originally Posted by EG52NV

Looks like car is juat getting hot coz its being pushed, and my last option is investing in a low temp thermostat to move the hot coolant out of the block sooner!

But aren't these bad for daily driven cars?

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its bad for cars without a programmable ecu.

Just run no thermostat!

Quote:

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Originally Posted by tiksie

Just run no thermostat!

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Lol car actually had no thermostat when I first bought it and man was it a bitch to get it warmed up!!! Even after a 15 min local commute I'd still have no VTEC Coz needle wouldn't even rise from cold position! With no VTEC I might as well buy a Hyundai lol

Any feedback from those out there running a low temp thermostat in their daily cars!

I agry, no thermo is shite