[bigdogdazza]

Hi guys just thought I would ask done advice on my Jimny, it constantly pumps the water out of radiator when driving it over 100kph and results in overheating. I have no leaks, new radiator cap, just changed all fluids, oil fine, doesn't bubble or pressurize with cap off suggesting not blown head gasket? Thoughts please!

[jimny_timmy]

Maybe an airlock in the engine somewhere? Have you recently replaced the coolant etc?

[31zook]

That or are you sure it's out your rad? could be any of the hoses under the manifold.....

[alien]

airlock in the thermostat housing... you can unscrew the sensor on the top to act as a bleed valve. (can do this on my g13bb, i assume VVT is similar).

[bigdogdazza]

Definitely not a hose as I spent a day under the car fiddling around no leaks, could possibly be an airlock but I notice my overflow bottle runs full all the time.

[royce]

alien wrote:

airlock in the thermostat housing... you can unscrew the sensor on the top to act as a bleed valve. (can do this on my g13bb, i assume VVT is similar).

This makes no sense, any air under the thermostat bleeds through it, on a running engine coolant running through the bypass will still open the thermostat which will allow any left over air pocket to escape, any air above the thermostat is equalised in level with the radiator and simply means its not full

otherwise it would be impossible to ever change the coolant without removing the thermostat, filling everything and them somehow vacuum filling the remainder on a hot engine so the thermostat is open without actually overheating it

If you are pumping out coolant and then overheating due to coolant loss its going to be hard to not point the finger at the head or gasket, if you are overheating first then pumping out coolant look at a blocked rad, faulty thermostat, fan not working etc

[Turismo07]

Just wondering, does anyone here run a scan guage or similar on their Jimny's to read coolant temps? I have a bluetooth trasnmitter plugged into my OBD2 port and use the 'Torque' app on my Android phone to read the ECU.

What I have noticed is that drving around the city, my coolant temps are between 88-93degrees constantly. But as soon as I hit the open road and drive for longer than 10mins at 100-110kmph, my coolant temp varies between 90-108 degrees (constatly moves up and down within this range)... While it does this the stock temp guage in the dash does not move at all, always sits just below the half-way mark. I figure if it wasn't for my OBD2 reader I'd be none the wiser..

Is this normal or is something wrong? Everything seems to check out ok in the cooling system, it just confuses me that this only happens when traveling at high speed. the only thing I can think of is that I have a bull bar and lightforce 240's that may be blocking the airflow required to keep it cool with the load/stress that is put on the little 1.3L to drive at such speeds (especially up hills on the open road...).

Cheers

PS sorry if this is a thread hijack, just figured it was coolant related.

[zooky08]

My gauge sits just below half way all day long. As soon as I sit at 120 for a while on the highway my guage goes to H
I have ARB bar and 240 blitz and winch. If your guage is below half way then Thats normal. If it doesn't then you have other problems
I have more stuff in the road then you and I only have problems if I'm roaring the guts out of the engine up the highway for 10mins.

[royce]

Turismo07 wrote:

Just wondering, does anyone here run a scan guage or similar on their Jimny's to read coolant temps? I have a bluetooth trasnmitter plugged into my OBD2 port and use the 'Torque' app on my Android phone to read the ECU.

What I have noticed is that drving around the city, my coolant temps are between 88-93degrees constantly. But as soon as I hit the open road and drive for longer than 10mins at 100-110kmph, my coolant temp varies between 90-108 degrees (constatly moves up and down within this range)... While it does this the stock temp guage in the dash does not move at all, always sits just below the half-way mark. I figure if it wasn't for my OBD2 reader I'd be none the wiser..

Is this normal or is something wrong? Everything seems to check out ok in the cooling system, it just confuses me that this only happens when traveling at high speed. the only thing I can think of is that I have a bull bar and lightforce 240's that may be blocking the airflow required to keep it cool with the load/stress that is put on the little 1.3L to drive at such speeds (especially up hills on the open road...).

Cheers

PS sorry if this is a thread hijack, just figured it was coolant related.

And this is exactly why the gauge is made to be pretty broad in its middle range, because the middle range is pretty damn broad!
I wouldnt be concerned about those temps, boil temp is over 120, if I saw 110 for a period of time I would think about backing off so it runs cooler though

I have a head temp gauge, interestingly it reads highest when cruising at 2500rpm in any gear

[Turismo07]

zooky08 wrote:

My gauge sits just below half way all day long. As soon as I sit at 120 for a while on the highway my guage goes to H
I have ARB bar and 240 blitz and winch. If your guage is below half way then Thats normal. If it doesn't then you have other problems
I have more stuff in the road then you and I only have problems if I'm roaring the guts out of the engine up the highway for 10mins.

Cheers mate, I figure that when the guage is just below half it 'must' be normal, but you never know how vauge stock temp guages are and hence I was suprised with my findings when reading the OBD2 data.

[Turismo07]

royce wrote:

And this is exactly why the gauge is made to be pretty broad in its middle range, because the middle range is pretty damn broad!
I wouldnt be concerned about those temps, boil temp is over 120, if I saw 110 for a period of time I would think about backing off so it runs cooler though

I have a head temp gauge, interestingly it reads highest when cruising at 2500rpm in any gear

Cheers mate. Yeah biol temp is approx 125 degrees on a cooling system that is in 'perfect' condition (no leaks, fatiged hoses etc). I watch the temps carefully and have pulled over before when I saw them get as high as 112 (after roaring approx 3/4 of the way up a steep hill approx 1km long, now I just take it easy instead of roaring up it ).

That is weird that the temp reads higher at 2,500rpm...

[Docka83]

Hey I am having the same symptoms with my Jim. Pumping coolant out whilst driving over 80kms hr for extended period. Have M18 conversion. Have just done TStat, colant and rad flush and new coolant all bled, new vicous fan clutch, new rad cap. Still doing it. Have done compressi,on no problems, have done head gasket test (rad vapor) nothing detected hot or cold. No oil in water or water in oil.

I put a Chinese rad in about 18months ago after I popped my original. I'm starting to think my rad has a blockage? The water pump seems fine I.e. moves coolant faster with revs etc.

Anymore ideas or experiences appreciated!! Cheers

[alien]

i have just had my head gasket replaced - it was blowing bubbles into the overflow bottle - turns out the gasket had a leak between cylinders 2 & 3 - looks like it started at #2, went around the cylinder, half way over to #3, through to the other side of the gasket, over to #3, around the cylinder on #3 then out to one of the cooling channels!

it passed a TeeKay test too - but the overflow actually smelt like unburnt fuel which was a pretty good hint at where the bubbles were coming from.

When it started acting up though it wasn't blowing bubbles into the overflow - but there was an oily residue buildup occuring in the overflow over a long period of time. As it worsened it started bubbling more.

One of the symptoms of mine, was that over 100km/hr it would also start to really heat up... slow back to 80km/hr and it'd cool down again.

Since fixing the head gasket its not doing it anymore... but then i'm now also running a new radiator and vitara viscous fan rather than stock sierra so there's a few more factors that have changed other than just the head gasket.

So far as bleeding from the thermostat sensor goes - it works every time on my g13bb after a coolant change to get any air out of the system. With the g13bb and 1.6 bottom end, the thermostat sits higher than the rad cap - so air does tend to get stuck up there. The sensor doesn't need to come out completely, you just have to loosen the thread a little until you get a bit of coolant weeping out (usually you'll hear the air hiss out first). If you do take the sensor out completely on a pressurised system it will shoot hot coolant about 3m clear of the engine bay (i accidentally undid it all the way once due to being distracted and was lucky not to burn my face off).