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Overheating - Bigger Radiator?


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#16 cptkirk

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Posted 28 June 2010 - 11:54 AM

Al

do you have your heater matrix pipes blocked or are you using a bypass pipe?

If your using a bypass pipe like I previously had then I would recommend removing it, this will improve the flow to the radiator.

If this still doesnt work then we might need to look at the routing of the coolant pipes as it sounds like there is either a blockage, lack of pressure to pump round, an air lock or the coolant piping is somehow wrong????

When you squeeze the top hose at the rad and the top hose at the block do they feel like they have water in them?

Where is your temp sensor mounted? Near the radiator or the engine? You ideally need to mount it as close to the output of the engine block as possible.

The only other thing that I can think of is that the dash and sensors arent calibrated correctly together giving high/false reading - I dont know if this is possible with your setup!!?!!

by the way I was out in mine yesterday in the hottest part of the day and was not suffering with overheating issues, so theres got to be something a miss somewhere.....

Edited by cptkirk, 28 June 2010 - 02:19 PM.


#17 Mini Type R

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Posted 28 June 2010 - 12:32 PM

I got my car back yesterday, been at Z-cars having the engine rebuilt for the past couple of months, and have the same problem. I found that it was running at about 105° when travelling at a steady 60mph but jumped up to 115° as soon as I stopped. It even got to 104° on the way into work at 7.30 this morning, 15 minute drive with no traffic. Before the engine died it used to sit at about 85° but that was back in April when it was cooler, at the MOT it rose to 102° after idling for about 10 minutes.

I'm going to try bleeding it tonight to see if that helps.

#18 cptkirk

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Posted 02 July 2010 - 08:57 AM

Al,

Me and a mate (a mate who builds concourse Rolls Royces of all ages for a living) were disussing your overheating problem last night. I think we can narrow it down to:

1) As I stated before about the flow round to the heater matrix bypass

or

2) Considering that you have bled out the system it can only leave that fact that there is some form of restriction, also assuming that all of the pipes OK and not crushed in any way (or go flat when hot) then you would have to assume that the thermostat cant be opening, or is partially opening.


Anyone else got any ideas??

#19 al_reidy

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Posted 06 July 2010 - 07:38 AM

Al,

Me and a mate (a mate who builds concourse Rolls Royces of all ages for a living) were disussing your overheating problem last night. I think we can narrow it down to:

1) As I stated before about the flow round to the heater matrix bypass

or

2) Considering that you have bled out the system it can only leave that fact that there is some form of restriction, also assuming that all of the pipes OK and not crushed in any way (or go flat when hot) then you would have to assume that the thermostat cant be opening, or is partially opening.


Anyone else got any ideas??


Thanks for all the messages and time about this one, over the weekend i replaced the thermostat with a spare i had from the orig engine (long story). i also found that the ECU mis reads the engine temp sensor 10 deg (it might be 10% as its not exact) over what the dash does.
Either way i am in the stages of removing the dash temp cable from the ecu output and mounting its own closer to the engine. (currently about 20 cm from the engine, new one about 10cm)
The other thermostat does seem to help, but it still had problems when i left it at idle. went up to 98degc on a warm day 21 deg outside temp.

I have also noticed that now i re-bled the system again it does still overheat but only occasionally, at odd times. which would suggest to me like there is crap blocking the pipes or rad, and that i have dislodged this or moved it by the removal of the thermostat drain.

cptkirk i thought the bypass hose was a good idea to let the engine get up to temp without killing it. looking at the front of the engine i can see the small black pipe that looks like the bypass you are talking about. Zcars plugged the other 2 pipes at the back of the engine which once went to the heater matrix, i would have thought it would have been safer to join them up to keep the flow going throughout the head?

i have tried this before but i though i better check, top of the engine output of the water to the top of the radiator? thats currently how i have it but have tried it the other way around.

The rad gets very hot and you can feel the water in the pipes.

hmmm again...

#20 cptkirk

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Posted 06 July 2010 - 11:23 AM

Thanks for all the messages and time about this one, over the weekend i replaced the thermostat with a spare i had from the orig engine (long story). i also found that the ECU mis reads the engine temp sensor 10 deg (it might be 10% as its not exact) over what the dash does.
Either way i am in the stages of removing the dash temp cable from the ecu output and mounting its own closer to the engine. (currently about 20 cm from the engine, new one about 10cm)
The other thermostat does seem to help, but it still had problems when i left it at idle. went up to 98degc on a warm day 21 deg outside temp.

I have also noticed that now i re-bled the system again it does still overheat but only occasionally, at odd times. which would suggest to me like there is crap blocking the pipes or rad, and that i have dislodged this or moved it by the removal of the thermostat drain.

cptkirk i thought the bypass hose was a good idea to let the engine get up to temp without killing it. looking at the front of the engine i can see the small black pipe that looks like the bypass you are talking about. Zcars plugged the other 2 pipes at the back of the engine which once went to the heater matrix, i would have thought it would have been safer to join them up to keep the flow going throughout the head?

i have tried this before but i though i better check, top of the engine output of the water to the top of the radiator? thats currently how i have it but have tried it the other way around.

The rad gets very hot and you can feel the water in the pipes.

hmmm again...



Re the bypass hose, The one I was going on about is on the rear of the engine and it appears that yours outlets are blocked off already. I thought it a good idea to use a bypass hose but actually all it does is create an unrestricted bypass which the flow of water will prefer to take before getting pushed round to the radiator.

Yes top engine outlet to top radiator inlet is correct. as they do in the Civic.

So your engine water temp sensor is going to be 10cm away from the top engine outlet, is this correct? That should be close enough to the block to get the warmth before the thermostat opens and then close enough to the action to be getting a good reading when it does open.

What is triggering your fans, is it the rad switch or the ECU?

Once the fans are spinning away does this cool the engine or does the engine temp continue to rise?

Do you have the coolant piping going to the throttle body or are they blanked off?

We should be able to get to the bottom of this - eventually.......

#21 al_reidy

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Posted 06 July 2010 - 02:02 PM

Thanks for all the messages and time about this one, over the weekend i replaced the thermostat with a spare i had from the orig engine (long story). i also found that the ECU mis reads the engine temp sensor 10 deg (it might be 10% as its not exact) over what the dash does.
Either way i am in the stages of removing the dash temp cable from the ecu output and mounting its own closer to the engine. (currently about 20 cm from the engine, new one about 10cm)
The other thermostat does seem to help, but it still had problems when i left it at idle. went up to 98degc on a warm day 21 deg outside temp.

I have also noticed that now i re-bled the system again it does still overheat but only occasionally, at odd times. which would suggest to me like there is crap blocking the pipes or rad, and that i have dislodged this or moved it by the removal of the thermostat drain.

cptkirk i thought the bypass hose was a good idea to let the engine get up to temp without killing it. looking at the front of the engine i can see the small black pipe that looks like the bypass you are talking about. Zcars plugged the other 2 pipes at the back of the engine which once went to the heater matrix, i would have thought it would have been safer to join them up to keep the flow going throughout the head?

i have tried this before but i though i better check, top of the engine output of the water to the top of the radiator? thats currently how i have it but have tried it the other way around.

The rad gets very hot and you can feel the water in the pipes.

hmmm again...



Re the bypass hose, The one I was going on about is on the rear of the engine and it appears that yours outlets are blocked off already. I thought it a good idea to use a bypass hose but actually all it does is create an unrestricted bypass which the flow of water will prefer to take before getting pushed round to the radiator.

Yes top engine outlet to top radiator inlet is correct. as they do in the Civic.

So your engine water temp sensor is going to be 10cm away from the top engine outlet, is this correct? That should be close enough to the block to get the warmth before the thermostat opens and then close enough to the action to be getting a good reading when it does open.

What is triggering your fans, is it the rad switch or the ECU?

Once the fans are spinning away does this cool the engine or does the engine temp continue to rise?

Do you have the coolant piping going to the throttle body or are they blanked off?

We should be able to get to the bottom of this - eventually.......



At the moment its ECU controlled fan from the temp sensor 10 cm from the engine outlet, which i was told was better as the rad switch is to far away. (unless i mount it closer to the engine?)
once the fans are spinning it does slow the rise of the temp, but it still crawls up. i lifted the bonnet and it seems to be trapping all the heat under it, maybe there is something i can do about that?
i have not looked at the throttle body in a while, i will check if they are blanked.

#22 AllanMcD

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Posted 06 July 2010 - 04:06 PM

Are you sure its to hot my many engines run close to 100° is the is the water circulating ?
What temprature is the water in the radiator when its hot ?
As you warm it up and the thermostat opens how quickly does the whole radiator get hot ?
Does the whole radiator get hot ?
Allan

#23 al_reidy

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Posted 06 July 2010 - 06:03 PM

Are you sure its to hot my many engines run close to 100° is the is the water circulating ?
What temprature is the water in the radiator when its hot ?
As you warm it up and the thermostat opens how quickly does the whole radiator get hot ?
Does the whole radiator get hot ?
Allan


yeah the rad gets very hot, i understand that the engines do run hot and can happily run at 100 all day long. but it shouldn't cause the oil to run so thin that it drops its pressure and the car alerts me that im killing it.

it is slightly cooler on the bottom of the rad near the exit, but that is to be expected as it shows the rad is actually doing what it should.

im going to the coast friday night so thats 1 and a half hour drive so will run with this and record its actions. it just doesn't feel right.

#24 AllanMcD

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Posted 06 July 2010 - 06:30 PM

Are you sure its to hot my many engines run close to 100° is the is the water circulating ?
What temprature is the water in the radiator when its hot ?
As you warm it up and the thermostat opens how quickly does the whole radiator get hot ?
Does the whole radiator get hot ?
Allan


yeah the rad gets very hot, i understand that the engines do run hot and can happily run at 100 all day long. but it shouldn't cause the oil to run so thin that it drops its pressure and the car alerts me that im killing it.

it is slightly cooler on the bottom of the rad near the exit, but that is to be expected as it shows the rad is actually doing what it should.

im going to the coast friday night so thats 1 and a half hour drive so will run with this and record its actions. it just doesn't feel right.


If its cooler at the bottom it sounds like its fine but it would be very good to know what temp the rad runs at when under power then you would know if all is well.
What is wrong with your oil ? temp ? pressure ?
Are you sure the information you have is accurate ?
Allan
Ps this is constructive questioning I am just trying to help

#25 Sisu

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Posted 06 July 2010 - 08:26 PM

I would borrow an infrared temp sensor, the type you point the little red dot at something and then it tells you the temperature. Although it seems you have given your car a colonic and everything seems to be getting hot around the system.
Could you video this and punt it online so we can see the sequence of events. This engine shouldn't cook at idle.
You could have something miscalibrated or installed incorrectly.

Out of interest you said it has been rebuilt. Were these problems there before?

#26 e11evns

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Posted 06 July 2010 - 09:04 PM

al, i have the same problem the car gets hot then all of a sudden oil pressure goes low and throws up an alarm on the dash, it all sound very familiar but i have an ally race rad which has a thick core i think its an air issue but why is oil pressure dropping unless my digidash is giving false readings? but my car is at zcars now having a newly built race engine fitting so ive got them checking it all out, i'll let you know if they find something.

#27 AllanMcD

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Posted 06 July 2010 - 09:20 PM

al, i have the same problem the car gets hot then all of a sudden oil pressure goes low and throws up an alarm on the dash, it all sound very familiar but i have an ally race rad which has a thick core i think its an air issue but why is oil pressure dropping unless my digidash is giving false readings? but my car is at zcars now having a newly built race engine fitting so ive got them checking it all out, i'll let you know if they find something.


What is the oil pressure dropping to ? and at what revs ?
Allan

#28 al_reidy

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Posted 06 July 2010 - 10:07 PM

-- What is the oil pressure dropping to ? and at what revs ?

the alarm is for anything below 15psi i think. i was on the motorway so about 4000rpm revving it up briefly turned off the alarm maybe 30psi.

oil temp was 115 when it went funny for me.

i never had problems needing a rebuilt so everything is still factory on mine. i had some heat issues when going with the IVA test and on teh rolling road. i was advised to fit a 72deg c thermostat which i now have put back to standard.

i have still crazy issues with the tune at idle. the readings for gasses are fine, confirmed by many lambda widebands and the tuners probe. so its not leaning off. its lumpy and splutters like a misfire. im so sick of trying to get the IDLE right, the zcars loom and Hydra ecu are poor quality with many dodgy connectors. i feel this is my next course of action to the tune. either way the cars coolant should be able to cope.

i have a mate who is a science teacher, he has a spot temp sensor so i will pinch it for a testing.

once again cheers for your help guys.

#29 Mini Type R

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Posted 07 July 2010 - 07:59 PM

I tried bleeding mine last week and found that Z-Cars hadn't filled the system back up, I hads to put about 2 litres in. Having bled it it's better but the temperature still rises upto 100 degrees when sat idling with the bonnet off and the fan running, so very similar to your problem.

My fuel tank is only about 3" behind the radiator so the air flow through the radiator isn't great, I'm gonig to try moving the tank back a bit to see if that helps.

#30 e11evns

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Posted 07 July 2010 - 10:02 PM

ive had water temps in excess of 110 and oil pressure drops in the teens then it will go back up to 60-70 but it only drops when the water temp rises to be honest i think the vtecs are a pain in the ass, the hyabusa is a 100 times better! its so frustating when it spends more time off the road than on and ive never completed a track session it ALWAYS breaksdown some how and this time its a new engine and believe or not the supercharger blew up at the same time!!!! aaahhhhhhhhhhhhhhhh




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