Author Topic: Jazz 1339cc, IVTEC, 2010 - overheating  (Read 5235 times)

culzean

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #30 on: March 09, 2021, 04:58:39 PM »
Cars like VW have the pressure cap on top of the reservoir, and the reservoir is high up in the engine bay, so the expansion reservoir is pressurised. Honda have the pressure cap on the radiator and a pipe down to an Unpressurised expansion reservoir low down in engine bay- if you get a problem with Honda cooling system like a blown head gasket, the water in cooling system will be blown past pressure cap on radiator and into reservoir, where it will blow out of the system completely and will be visible under the car.
« Last Edit: March 09, 2021, 05:00:16 PM by culzean »
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sparky Paul

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #31 on: March 09, 2021, 05:12:54 PM »
What would you know about?

What is the significance of the reservoir bottle being open to the atmosphere?

Most european cars have a pressurised expansion tank, the PRV is in the bottle cap and vents any excess pressure or combustion gasses. Can often go unnoticed.

The Jazz PRV is the radiator cap. Under normal circumstances, any expansion in the system overcomes the PRV and flows to the reservoir bottle, the PRV maintains the correct pressure in the system. When it cools, the rad cap has a bypass allowing fluid to be sucked back from the reservoir and into the radiator. Normally, only small amounts of coolant go between the rad and the reservoir bottle.

If there are combustion gasses in the system, they usually blow out into the reservoir bottle, and/or blow the coolant out too.


edit: culzean beat me to it ↑↑↑
« Last Edit: March 09, 2021, 05:16:00 PM by sparky Paul »

guest4871

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #32 on: March 09, 2021, 07:34:58 PM »
@  sparky Paul

@ culzean

Simple concepts but very difficult to put into words.

Thank you both for such clear explanations.

embee

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #33 on: March 10, 2021, 12:33:18 AM »
The two systems are sometimes referred to as "hot bottle" and "cold bottle".

Personally i prefer the cold bottle system. The whole circuit runs full at all times (expansion and contraction pushes coolant into the bottle and then draws it back in to keep it full, as described by others above). They are easier to get right.

In the hot bottle system there is an expansion volume which is air. This volume relative to the coolant volume is important in regulating the temp/press characteristics, it's a more tricky arrangement. If coolant does get expelled it stays expelled. There is a trickle flow through a hot bottle to de-gass the system.

Systems are developed to cope with a certain amount of "gassing" (usually from head gasket and some is normal, especially in diesels). Manufacturers specs vary, but the system is designed to de-gass at the pressure cap, the gas should collect there and as the system heats from cold and pressurises it expels the gas into the cold bottle (and thus vents) or directly out to atmosphere in a hot bottle.

Jazzmeister

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #34 on: March 10, 2021, 08:59:40 AM »


If the fan is not switching on when it overheats then there's definitely an issue there.
As I said, my fan has never come on, so is this fan correct in not coming on because the temperature sender is saying it is overheating in error. I have never had an engine overheat (not Jazz) without obvious consequences like steam and engine sizzling.

Surely your cooling fan must have come on before when sitting in traffic?

If the ops engine was genuinely over heating you'd feel a very unusual blast of heat when you opened the engine bay.

I'm not sure how clued up the op is but he has been taking it to a garage so I'm assuming they have come to the conclusion it is in fact over heating or else why would they have changed all the parts they have so far?
Mk I 2007 Honda Jazz 1.5 CVT | Previous car - Mk II 2012 Honda Jazz 1.3 Cvt

Jazzmeister

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #35 on: March 10, 2021, 09:00:52 AM »
Has the Op tried an ODB reader to check the temps?

They are cheap and will give you some idea of if the temp sensor system is reading accurately.
« Last Edit: March 10, 2021, 09:10:23 AM by Jazzmeister »
Mk I 2007 Honda Jazz 1.5 CVT | Previous car - Mk II 2012 Honda Jazz 1.3 Cvt

sparky Paul

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #36 on: March 10, 2021, 09:41:49 AM »
I'm not sure how clued up the op is but he has been taking it to a garage so I'm assuming they have come to the conclusion it is in fact over heating or else why would they have changed all the parts they have so far?

You would have thought so, wouldn't you. It's a lot easier to diagnose when you actually have your hands on it, we're only guessing here really.

I think the OP is looking for help because the garage is just working their way through a list of most likely causes. It's always been the problem - you pay for work done, not results.

The OP says he has had an obd2 reader on it, the temp on obd is going well over 100°C. However, the garage hasn't changed the head sender, only the one in the rad AFAIK.

FWIW, I never notice the fans run much here in the UK, you have to be stuck in traffic on a moderately hot day.

Jocko

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #37 on: March 10, 2021, 09:54:04 AM »
I crawled the length of the Edinburgh City Bypass on a scorching summers day. The temperature rose to 93°C, but the fan never kicked in. I was beginning to think my fan doesn't work, and then I saw it mentioned in this thread that it comes on at 110°C.
« Last Edit: March 10, 2021, 09:56:04 AM by Jocko »

culzean

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #38 on: March 10, 2021, 09:59:03 AM »
@  sparky Paul

@ culzean

Simple concepts but very difficult to put into words.

Thank you both for such clear explanations.


The expansion of plain water between 0 degC and 100degC is about 4% - don't know what difference the 50% ethylene glycol / water mix makes.  The hoses in the cooling system will take up some of the expansion,  but some of the hot coolant will need to 'go outside' the system ( and come back in as it cools ). Every motorbike I have had has used the 'cold bottle' unpressurised system,  with the reservoir tucked away behind the engine somewhere in the frame.

The glycol in the mix + the pressurised system raises the boiling point of the coolant ( like a pressure cooker ) - I can never remember the fan coming on on any Honda I have owned ( except when aircon is on ).

I was quite common on older cars in traffic in hot weather to have to open the windows and turn the heater ( if you were lucky enough to have one :) ) on full blast to keep the temperature gauge needle out of the red....  such fun.
« Last Edit: March 10, 2021, 10:35:40 AM by culzean »
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

Jocko

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #39 on: March 10, 2021, 10:03:07 AM »
Every motorbike I have had has used the 'cold bottle' unpressurised system,  with the reservoir tucked away behind the engine somewhere in the frame.
High tech. Everyone I ever owned used cool, free, fresh air!

Jazzmeister

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #40 on: March 10, 2021, 10:21:27 AM »


I crawled the length of the Edinburgh City Bypass on a scorching summers day. The temperature rose to 93°C, but the fan never kicked in. I was beginning to think my fan doesn't work, and then I saw it mentioned in this thread that it comes on at 110°C.

The fan definitely comes on way before 110, that's near boiling the engine. I did an idle relearn the other day and I was monitoring the temp and the fan comes on around 95 if I recall correctly.
Mk I 2007 Honda Jazz 1.5 CVT | Previous car - Mk II 2012 Honda Jazz 1.3 Cvt

culzean

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #41 on: March 10, 2021, 10:34:09 AM »
Every motorbike I have had has used the 'cold bottle' unpressurised system,  with the reservoir tucked away behind the engine somewhere in the frame.
High tech. Everyone I ever owned used cool, free, fresh air!

Unfortunately in the quest for lower emissions air cooling is out.  Last couple of bikes have been Euro 4, fuel injected with twin spark plugs per cylinder and a CAT in the exhaust ( CAT is usually is tucked under the bike and no longer any room for a centre stand ).  Water cooling also allows tighter engine tolerances and better performance.  I remember the complaints from America in 60's and 70's ( the hotter areas ) the the air cooled British bikes like Bonneville, BSA, Triumph etc. used to 'destroy' the engine oils of the time ( before synthetics ) because they ran so hot.  The reason the American bikes didn't was because of their lazy low performance engines,  where sunflower oil would have been OK as a lube.
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

MartinJG

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #42 on: March 10, 2021, 11:06:11 AM »
@  sparky Paul

@ culzean

Simple concepts but very difficult to put into words.

Thank you both for such clear explanations.


The expansion of plain water between 0 degC and 100degC is about 4% - don't know what difference the 50% ethylene glycol / water mix makes.  The hoses in the cooling system will take up some of the expansion,  but some of the hot coolant will need to 'go outside' the system ( and come back in as it cools ). Every motorbike I have had has used the 'cold bottle' unpressurised system,  with the reservoir tucked away behind the engine somewhere in the frame.

The glycol in the mix + the pressurised system raises the boiling point of the coolant ( like a pressure cooker ) - I can never remember the fan coming on on any Honda I have owned ( except when aircon is on ).

I was quite common on older cars in traffic in hot weather to have to open the windows and turn the heater ( if you were lucky enough to have one :) ) on full blast to keep the temperature gauge needle out of the red....  such fun.

Indeed. I remember that one on my old mini. In fact, I remember a few 'work arounds' on that little mini before the time came...:)

MartinJG

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #43 on: March 10, 2021, 11:14:57 AM »

Based on the OP's initial observation before the remedial work (job creation scheme) was carried out by the stealer, it seems logical to perhaps consider that either short cycling (real world scenario) or the sensor/electrics (virtual world scenario) are out to lunch. The virtual world is incredibly trendy these days so it might be worth a gander in that direction :).

sparky Paul

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Re: Jazz 1339cc, IVTEC, 2010 - overheating
« Reply #44 on: March 10, 2021, 03:48:35 PM »
The fan definitely comes on way before 110, that's near boiling the engine. I did an idle relearn the other day and I was monitoring the temp and the fan comes on around 95 if I recall correctly.

That's about right.


Spec for testing the mk1 fan switch (on the head outlet) is on at 91-95°C and off 3-8°C below that.

http://www.hondafitjazz.com/manual/a00/html/00/saa2e00a14426149451feat00.html


Mk2 uses 2 thermistor senders to determine system temperature, one in the head and one in the rad - fans should run when system temp is above 93°C and should stop below 90°C. Workshop manual does not say if it uses rad sensor for this, or both.

http://www.hondafitjazz.com/manual3/en/html_en/000000000000040.html
« Last Edit: March 10, 2021, 03:50:18 PM by sparky Paul »

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