fan switch and thermostat

[icecrm]

noob question, is there any point in changing fan switch and thermostat???

[CRXer]

no, not on a stock to mild vehicle,they work quite effectively from the factory,honda aint stupid

[icecrm]

cool thanks
wat exactly are they for??

[CRXer]

quite simply to lower the working heat range of the motor.

honda have already setup the working range of the motor,to where it is most efficient at the factory.

its not until u start heavily modifying your motor or doing extensive high rpm track work,that u will need to address this issue.

[dsp26]

no, not on a stock to mild vehicle,they work quite effectively from the factory,honda aint stupid

i agree... as i have them both and it got the car running a little cooler and as others have said in other threads, it may actually be forcing the ecu into cold idle mixtures and running rich.

if anything though a low temp fan switch maybe an ok idea on its own to keep cooler temps in the radiator ready on tap, at the end of the day its the oem thermostat thats going to regulate the water temp in the engine.


quite simply to lower the working heat range of the motor.

honda have already setup the working range of the motor,to where it is most efficient at the factory.

its not until u start heavily modifying your motor or doing extensive high rpm track work,that u will need to address this issue.

are these mods together at least justifiable if say the CR was at ~12:1?

[CRXer]

im seeing figures of 20% fuel at 76degC high load,open loop in my calibration,dont know how that compares to stock,but i'd imagine pretty close

[CRXer]

are these mods together at least justifiable if say the CR was at ~12:1?

im n00b ron,ud have to ask someone that works on modified engines what they have been experiencing for that one.

[bennjamin]

are these mods together at least justifiable if say the CR was at ~12:1?


compression ratio of the engine alone is not a determining factor to use a "lower temp" thermo + fan switch.

But combined with lots of other mods , and on the track for many laps at a time perhaps there is a benefit. otherwise , as said no stick with OEM parts.

[CRXer]

i'd imagine u'd experience some overtemp conditions from the higher combustion pressures,but how much & whether the stock system is capable of controlling it,i wouldnt have a clue

[bennjamin]

no one here would..but from my browsing honda-tech for years i have never ever heard of a OEM honda cooling system fail or let down a worked engine.

[fatboyz39]

no one here would..but from my browsing honda-tech for years i have never ever heard of a OEM honda cooling system fail or let down a worked engine.

As above. As long as the radiator, thermostat, fan switch all working then overheating shouldn't be a problem.

[CRXer]

as an addition,im also seeing figures of around 70-75degC on these cold nights,when cruising down the motorway at 80km/h for just a few minutes.

thats a stock engine with D16 cooling components,running a B18C(also stock cooling components) in a rather cramped engine compartment,there is an oil cooler but i really dont know how effective that is.

so i'd hate to go lowering my temps even further.

[dsp26]

gee.. i've given each one of you a +rep recently so no rep for j00 lol

[CRXer]

just out of interest are u running a temp gauge?

if so what are u seeing with those in place?

[dsp26]

just out of interest are u running a temp gauge?

if so what are u seeing with those in place?

nope but cluster temp gauge, when car was perfectly fine temp sat stable between 1/4 and halfway.. when it was stock it sat closer to halfway.

BUT if it matters my fuel consumption observations in sequence of mods degraded as follows (per 42l when light comes on):
stock = ~450-480km
fan switch + thermo = ~400-420km (which i consistently get now)
spoon chip (lol) = ~280-300km

[CRXer]

nope but cluster temp gauge, when car was perfectly fine temp sat stable between 1/4 and halfway.. when it was stock it sat closer to halfway.

BUT if it matters my fuel consumption observations in sequence of mods degraded as follows (per 42l when light comes on):
stock = ~450-480km
fan switch + thermo = ~400-420km (which i consistently get now)
spoon chip (lol) = ~280-300km

yeah,i'd prob look at taking them out again,ud prob be hitting that 20% fuel marker quite regularly in these colder months,if your regularly running around giving it a bit.Even 76degC lowload open loop its still at about 8% fuel,not that these conditions occur very frequently.

[dsp26]

yeah,i'd prob look at taking them out again,ud prob be hitting that 20% fuel marker quite regularly in these colder months,if your regularly running around giving it a bit.Even 76degC lowload open loop its still at about 8% fuel,not that these conditions occur very frequently.

yeah will do!! i should've asked you about those readings earlier when you mentioned the duty cycle stuff. thanks:thumbsup:

[Snoop_gee]

keeping in theme with fan switches

exactly where do u install a fan switch on the radiator is it the outlet neck or end tank the bottom one itself ?!?!

[e240]

In our engine, we run Stock Fan Switch and Stock Thermostat, we do have an oil cooler and a full length radiator. We do not have overheating issues even after 5 hard continuous laps. At the last ozhonda track day, most of the time, the car was out for the entire 15 minute sessions cover at least 10 laps. We also drive to and from the track. Very reliable.

[dsp26]

keeping in theme with fan switches

exactly where do u install a fan switch on the radiator is it the outlet neck or end tank the bottom one itself ?!?!
none of em... it's on the thermostat housing.. on the b series anyway...

[CRXer]

agree with e240

i beat the living crap outta my engine for 12 straight laps the other day & temp issues were non existent,admittedly it is a stock engine though.

[bennjamin]

agree with e240

i beat the living crap outta my engine for 12 straight laps the other day & temp issues were non existent,admittedly it is a stock engine though.

did the same at the same time with a actual stock engine with stock thermostat , fan switch and coolant etc , and temp still wasnt ever an issue.
OEM parts and fluids when properly maintained are fine.

The only way to overheat a untouched engine is to drive in reverse for a few minutes and watch the temp gauge soar.

[Snoop_gee]

none of em... it's on the thermostat housing.. on the b series anyway...
sorry i should of said its for the K series

[dsp26]

agree with e240

i beat the living crap outta my engine for 12 straight laps the other day & temp issues were non existent,admittedly it is a stock engine though.

ok maybe you gents can shed some light...

i've since replaced the low temp with a 90*C item... now my coolant is always boiling and overflows the overflow... i have tried:

- water only
- 25% coolant premix
- ~40% coolant mix

all boil. thermostat is not seized because both hoses are the same temp plus i also have a 1.3bar rad cap

it's not the head gasket coz its new and theres no traces of water in oil and vice versa.


on another note though my car feels like it struggles and i rev it past 6krpm despite feeling stronger than stock.. i've always had the suspicion that the dc2r muffler i have on the car is causing a massive restriction or it's just shot because of the horrible sound it makes.... i know a backpressured system also heats up the engine a lot more.. could this be the issue?

[bennjamin]

on another note though my car feels like it struggles and i rev it past 6krpm despite feeling stronger than stock.. i've always had the suspicion that the dc2r muffler i have on the car is causing a massive restriction or it's just shot because of the horrible sound it makes.... i know a backpressured system also heats up the engine a lot more.. could this be the issue?

nothing to do with it. I ran a stock vti muffler , twin loop copy and now a EP3R muffler...all run the same mph and similar ET down the 1/4.
FYI my ep3r muffler , on back off makes a terrible noise too...more than likely loose matting inside or rusty bits flying around etc

[dsp26]

nothing to do with it. I ran a stock vti muffler , twin loop copy and now a EP3R muffler...all run the same mph and similar ET down the 1/4.
FYI my ep3r muffler , on back off makes a terrible noise too...more than likely loose matting inside or rusty bits flying around etc

fair enough...

does anyone know the exact oem temp?

coz its too cold on 77*C open.. and its boiling at 90*C open.... 85-87*C perhaps?

[fatboyz39]

boiling? does the fan kick in? Bleed the coolant system properly?

[CRXer]

boiling at 90C???,cmon ron,even straight water at atmospheric dont boil that low.

with a decent coolant mix & 1.3bar,shouldnt boil till up over the 130's.

oem fan switch is about 92C,well mine is anyway,& turns off again around the 87C mark.

how are u measuring all these temps?

if its overflowing at 90C,replace the cap.

[dsp26]

i swear fellas... i just bled the system again last night.. fan kicks in too.. plus i still have the buddy club fan switch installed which turns the fans on at around 80*C which should technically mean i have more cool water in the radiator as requried when thermostat opens.

Jase: not measuring the temps, just stating the tolerances of my cooling devices. I don't actually know the temps but the water definitely boils. the 77*C was the opening of the gates racing low temp thermo and the 90*C is the opening of the Tridon thermos i boguht at supercheap auto.


I put my oem 1.1bar cap on last night too while bleeding my system and the spring system broke and ended up in the radiator (luckilly got stuck in the ribs) will post pics tonight... but i've put the 1.3bar back on in the meantime.



On another note, before i had my rebuild i had a massive water pump leak where i had to keep topping the radiator up with water every 30mins of driving... because this also boiled a lot, i've got a lot of gunk in the radiator now (possible rust?) which i should've flushed but haven't... is this a contributing factor?

[dsp26]

i also can't see any signs of leakage around the engine.. have even lie under the car while idling it to check.. no drips.... yet neithe rad hose feels pressurized either... tis really weird.

i'm confident i got all the air pockets out while bleeding as i made sure there was a constant stream before closing the bleeder.

in case i did it wrong, whats the exact method for bleeding?

[CRXer]

id prob lose the fan switch first & get back to basics.

thermo starts opening at 78C,fully open about 90C.

ideal engine op temp between 80-90C.

fan switch should kick at about 92C.

your fans must be running most of the time,not good for your fans.

is it really boiling,ie steam overflowing or just coolant?

like i said,i ran my car at prob 95% above 6000rpm for 15-20mins straight with stock system,temps remained constant at 87C(datalog of ECT),admittedly it was about 12C air temp.

if both hoses are the same temp,then debris blockage is not really a prob at this point,unless a higher pressure from the blockage is blowing off the rad cap,remember higher pressure=higher boiling point.

also,oem coolant ftw.

[CRXer]

i also can't see any signs of leakage around the engine.. have even lie under the car while idling it to check.. no drips.... yet neithe rad hose feels pressurized either... tis really weird.

i'm confident i got all the air pockets out while bleeding as i made sure there was a constant stream before closing the bleeder.

in case i did it wrong, whats the exact method for bleeding?

to bleed,rad cap half closed, engine up to operating temp(which u prob cant achieve with that fan switch,lol) & operate the bleed screw as u are doing whilst topping up at rad cap.also dont forget car level & heater control on hot.

[dsp26]

to bleed,rad cap half closed, engine up to operating temp(which u prob cant achieve with that fan switch,lol) & operate the bleed screw as u are doing whilst topping up at rad cap.also dont forget car level & heater control on hot.



hhmmm okay seems i did it right-ish except that bit... why's that?

should i attempt the above anyway and just disconnect the fan switch just for this process?

[CRXer]

if u lock the rad cap off,u will pressurize the system & not be able to top up the radiator with out risk of burning yourself or getting hit in the head by a flying rad cap.

u need to achieve higher than 80C for your thermostat to open(assuming oem) so u can circulate all the air out of the system.

[connorling]

i got both, but i havent installed the thermostat, but the fan switch is good if u do some street run, my car now stays at below 90oC, which is good when my car used to exceed 95'c.

[dsp26]

to bleed,rad cap half closed, engine up to operating temp(which u prob cant achieve with that fan switch,lol) & operate the bleed screw as u are doing whilst topping up at rad cap.also dont forget car level & heater control on hot.

did this all again.. doesn't boil anymore.

i also put cleaner in and ran for ~400kms, got a lot of gunk out... did your method and all was sweet.. probably had some blockages as i was using the same water container and i managed to get more of it in this time....

was probably boiling/overheating before due to massive air pockets in the system