Radiator Fan Dilemma

[MasterDon]

hi guys....i have a little problem

the radiator fan on my del sol seem to only work only when the teperature of the engine goes beyond the "boiling" point...normally the fan starts to work when the temparature guage reaches about half... but now it doesnt start untill the guage is reading extreme heat,and well beyond the boiling point....

for now i have managed to connect a direct wire from the fuse box to the fan so that it works all the time...and so far things seem to be normal

here are some of my concerns

1.what could be stopping the fan from working properly?.....is there a sensor type thingy that controls the fan?

2.is it ok if i come to colombo(from n'eliya) with the fan constantly working?....will it harm the engine?

3.some bloke said that the radiator cap might be the problem...is there any truth to this?

thanks for reading...and looking forward to your reply's

[GearHead]

1.probably something to do with the water temp sensor

2.it wont harm the engine, but your car would take a longer time to reach the normal operating temp(keep the revs down for a bit longer ).some say that this could reduce the life of the radiator fan, but IMO just one day wouldnt hurt

3.according to your description it seems like your water temp sensor fails to signal the radiator fan at the right time/temp...

hope this would help

Edited April 16, 2009 by GearHead

[MasterDon]

1.probably something to do with the water temp sensor

2.it wont harm the engine, but your car would take a longer time to reach the normal operating temp(keep the revs down for a bit longer ).some say that this could reduce the life of the radiator fan, but IMO just one day wouldnt hurt

3.according to your description it seems like your water temp sensor fails to signal the radiator fan at the right time/temp...

hope this would help

thanks gearhead.....i'm cutting my holiday short and coming down tommorow with the hot wired fan...keeping my fingers crossed,dont wanna get stuck in the middle of nowhere(especially somewhere between n'eliya and pussellawwa)

[Mani]

There should be two. Sending unit and a sensor. Most likely the sensor is the culprit [per Gearhead]. You should be able to test the resistance and compare it to what the factory recommended tolerance is to quickly identify if the sensor is the problem. Better than average that it is the problem.

[MasterDon]

There should be two. Sending unit and a sensor. Most likely the sensor is the culprit [per Gearhead]. You should be able to test the resistance and compare it to what the factory recommended tolerance is to quickly identify if the sensor is the problem. Better than average that it is the problem.

thanks mani,as always......

any idea of how to check the resistance on the sensor,cos i'd like to know exactly what's the problem before i go to garage,and avoid getting ripped off by installing unnessessary parts...you know how it is here

[Mani]

Also, have you confirmed that the water is actually boiling before the fan comes on, as in the actual temperature of the water? There is the other possibility that the temp gauge is faulty.

I would also make sure that your thermostat is functional. Fairly easy to do by placing it in boiling water to monitor operation.

Both the above are easier to do than the sensor so get them out of the way before tackling the sensor.

As far as I understand about your car, and please don't hold me to this and only use it as a general guide; cooling fan should begin to operate when coolant temperature reaches approximately 191-197°F. Fan should stop running when coolant temperature drops to approximately 182-188°F.

You'll need a tool like below. Someone who has it should know how to use it. Then, test the resistance across the sensor terminals to make sure that the sensor is functional.

Testing procedure

Drain cooling system and remove cooling fan temp switch from the thermostat housing.

Connect suitable ohmmeter [above] between sensor terminals.

Heat thermo sensor in water and not fire while observing ohmmeter.

Meter should indicate continuity when temperature reaches ~190 degrees F.

Allow sensor to cool while observing meter. Meter should indicate no continuity as temperature drops below approximately 182-188 degrees F.

If sensor fails to operate as outlined, sensor is defective.

Good luck

Edited April 17, 2009 by Mani

[Mani]

Oh one last thing. Some cars have a separate switch to activate the fan, as in 3rd sensor dedicated to the fan operation only. So please make sure of that as well.

[GearHead]

thanks gearhead.....i'm cutting my holiday short and coming down tommorow with the hot wired fan...keeping my fingers crossed,dont wanna get stuck in the middle of nowhere(especially somewhere between n'eliya and pussellawwa)

dont worry about the fan too much, and according to your description its quite clear that its the radiator fan thats causing the engine to overheat. Just give it a direct power supply and run the car till you get back. If i were you i wouldnt worry about it too much. Just keep an eye on the temp gauge..

[Iroshana]

If i were you i wouldnt worry about it too much. Just keep an eye on the temp gauge..

Its true for me too. Once I went from Colombo to Galle and came back without the radiator fan without any issue. I kept a good speed during the entire trip since it was in night. I think the AC fan is also doing some work for the radiator too. But this is only both are at same place.

[isam]

Its true for me too. Once I went from Colombo to Galle and came back without the radiator fan without any issue. I kept a good speed during the entire trip since it was in night. I think the AC fan is also doing some work for the radiator too. But this is only both are at same place.

With the intense heat these days I doubt the AC fan alone could help.

[GearHead]

Its true for me too. Once I went from Colombo to Galle and came back without the radiator fan without any issue. I kept a good speed during the entire trip since it was in night. I think the AC fan is also doing some work for the radiator too. But this is only both are at same place.

I think you misunderstood what i said there machan.What i actually meant was, "i wouldnt worry too much about it since the radiator is now running constantly and cooling the engine/radiator"...

Edited April 17, 2009 by GearHead

[GearHead]

With the intense heat these days I doubt the AC fan alone could help.

specially with a honda it wouldnt..dont know much about the cooling system of the del sol, but in EG, EKs(correct me if i am wrong) AC fan wouldnt cool the radiator. pic of the engine bay would help....

[MasterDon]

ok...i made it...i'm back on home turf...and damn it's HOT!.....

nothing to report except i had to fill up the radiator with about half a coca-cola bottle(mega) of water after arriving

a special thanks goes out to my brothers from the states(mani) and down under(gearhead)...thanks guys

Also, have you confirmed that the water is actually boiling before the fan comes on, as in the actual temperature of the water? There is the other possibility that the temp gauge is faulty.

yes mani....the first time this happened the water was boiling so much the radiator was shaking so rapidly like it was havig a fit or something...so temp guage is not malfunctioning

You'll need a tool like below. Someone who has it should know how to use it. Then, test the resistance across the sensor terminals to make sure that the sensor is functional.

Testing procedure

Drain cooling system and remove cooling fan temp switch from the thermostat housing.

Connect suitable ohmmeter [above] between sensor terminals.

Heat thermo sensor in water and not fire while observing ohmmeter.

Meter should indicate continuity when temperature reaches ~190 degrees F.

Allow sensor to cool while observing meter. Meter should indicate no continuity as temperature drops below approximately 182-188 degrees F.

If sensor fails to operate as outlined, sensor is defective.

Good luck

thanks again for the detailed response dude.....i think one of my buds(a mechanic) has that gadget...will test the sensor out with it before going to a repair garage

Its true for me too. Once I went from Colombo to Galle and came back without the radiator fan without any issue. I kept a good speed during the entire trip since it was in night. I think the AC fan is also doing some work for the radiator too. But this is only both are at same place.

no machan my journey couldn't have been made without the fan working...even when coming downhill

Edited April 17, 2009 by HelRazor

[GearHead]

ok...i made it...i'm back on home turf...and damn it's HOT!.....

nothing to report except i had to fill up the radiator with about half a coca-cola bottle(mega) of water after arriving

does this mean that the engine temp went higher than the normal level even with the radiator fan running constantly..Was it full when you left there?

[MasterDon]

does this mean that the engine temp went higher than yep it was full...the normal level even with the radiator fan running constantly..Was it full when you left there?

the temp guage was showing just below half throughout the journey machan....but i'm, worried about the half bottle of water too....i have checked so many times but i cant find any leaks......i had it inspected by a pro race car tuner as well before leaving....the only thing we noticed was the fan not working properly.....but with fan working properly where did the water vanish???....it's a puzzler

Edited April 17, 2009 by HelRazor

[GearHead]

when the engine boiled for the first time, how much water did you have to add to that? and did you check the water level just before leaving? you are using coolant right? if you do a radiator pressure test you would be able identify leaks, if any, very easily...

[GearHead]

If I were you i would do the following,

1. Get the radiator fan issue sorted out first

2. Give the radiator a good flush and fill it with 'water'

3. Now that the fan is fixed, so i would drive the car around colombo and check if it still overheats

4. If its not overheating and if the water level remains stable i would just drain the 'water' off and fill it with a good coolant...

Edited April 17, 2009 by GearHead

[MasterDon]

when the engine boiled for the first time, how much water did you have to add to that? and did you check the water level just before leaving? you are using coolant right? if you do a radiator pressure test you would be able identify leaks, if any, very easily...

the first time it needed about three mega bottles of water.......

yes left with a full radiator and checked at regular intervals until i reached kandy....after that it was straight home

yeah machan i use coolant always.....i added another two after the first incident...so i think about 50% was coolant the other 50 water

i'm going to check the sensor first like mani said....then i'm going for a honda mechanic after finding what exactly the problem is for myself......cant afford to get ripped off from that so called honda expert again...

[GearHead]

cant afford to get ripped off from that so called honda expert again...

are you talking about the one in malabe? If yes, then you are not the only one..

Yea better get it tested your self before you take it to any garage. First try to get the sensor issue fixed, and then with that working properly, concentrate on the water level, etc..if you try to get all these fixed at once, then you'll be back on the 'I got ripped off path'...

[GearHead]

reply sent

[DJshehan]

reply sent

u must have put dat mega bottle water into the coolant reservoir! usually when engine heats up, water expands. the excess water goes out of the coolant reservoir (plastic tank). when the engine cools, the water in the coolant reservoir is sucked back into the engine. the little water left shud be in the normal factory marking of eithr MAX or MIN in the tank. there is so much more space in the tank for u 2 add more water. so no probs.. as long as the water is in the MAX position, dont worry. i hav experiencd those probs b4. even if u had airbubbles in the system, dis wud hapn. but returns to normal aftr u run the vehicl for arnd 2 days. Air bubbles or air space occurs aftr you hav completely drained the system, like a water change or coolant change or a flush.

for the heatin prob, jus change the temp plug.. cost nly arnd 300 odd or max 700. u plug maybe weak or its contaminated wit rust or sediment.

Best of luck!!