Hitachi zx 25 overheating...

[Alan caddy]

I have also seen impeller doing that, at least if no flow you know straight away, there is a tap beside thermostat housing that switches of flow to heater make sure that's open to increase water circulation to see if it makes any difference

 

[GazCro]

Is it using water? If your going to the hassle of taking water pump off to check impellor which may seem ok when cold anyway I'd price a new water pump first. If not silly expensive might be worth changing anyway while you've gone to the hassle of removing it.

 

[Hg2702]

Edit, I see your only at Bovey Tracey..... Buy the Combustion test kit. PM me your phone number and I will pop up and look next Friday night if you want..... No charge to look see but a donation to my beer fund is appreciated if the problem is solved.

Another local

 

[JD450A]

Is it using water? If your going to the hassle of taking water pump off to check impellor which may seem ok when cold anyway I'd price a new water pump first. If not silly expensive might be worth changing anyway while you've gone to the hassle of removing it.

There is some witchcraft to check it before removal Gaz, will only get certainty by removing it throwing in a bucket of boiling water and checking it though.

 

[GazCro]

There is some witchcraft to check it before removal Gaz, will only get certainty by removing it throwing in a bucket of boiling water and checking it though.

I wouldn't go for taking it off before being more sure that it's the issue.

 

[JD450A]

I wouldn't go for taking it off before being more sure that it's the issue.

Thats the trouble with all "mechanics" these days is the penchant to fit new bits until it works.

Issue is as soon as you start ripping something to bits you can't diagnose it....Temperature issues have 4 general causes - Airflow, Water Flow, Constrictions and Outside Heat.

My guess personally is it's a outside heat issue, either via the hydraulic oil cooler or Head gasket. Water pump seems unlikely as 10 minutes should not heat the coolant up that quickly, the Merc 1317 that had that issue would do a 30 minute trip before it started boiling.

 

[GazCro]

Thats the trouble with all "mechanics" these days is the penchant to fit new bits until it works.

Issue is as soon as you start ripping something to bits you can't diagnose it....Temperature issues have 4 general causes - Airflow, Water Flow, Constrictions and Outside Heat.

My guess personally is it's a outside heat issue, either via the hydraulic oil cooler or Head gasket. Water pump seems unlikely as 10 minutes should not heat the coolant up that quickly, the Merc 1317 that had that issue would do a 30 minute trip before it started boiling.

There are very few mechanics about now tbh that's a fact.

 

[doobin]

Thats the trouble with all "mechanics" these days is the penchant to fit new bits until it works.

Parts bingo!

 

[JD450A]

Parts bingo!

52, New injectors for you, 38 theres a hole in the plate, 21 strip it down for fun, 60 Show me the dough.

 

[craig]

Edit, I see your only at Bovey Tracey..... Buy the Combustion test kit. PM me your phone number and I will pop up and look next Friday night if you want..... No charge to look see but a donation to my beer fund is appreciated if the problem is solved.

This is a very good offer, well done Rory.

 

[Left hooker]

A guy I know who repairs machines / tractors did a Hitachi 22u the other day for over heating he flushed it out several times that seems to have cured it

 

[V8Druid]

A guy I know who repairs machines / tractors did a Hitachi 22u the other day for over heating he flushed it out several times that seems to have cured it

yeh could well be sludged up if it's stood about much and the recent weather'll been no help in the temperature stakes ... only neds one gallery to be constricted to upset the whole flow and cause a hot spot, which'll spread fast

 

[Left hooker]

yeh could well be sludged up if it's stood about much and the recent weather'll been no help in the temperature stakes ... only neds one gallery to be constricted to upset the whole flow and cause a hot spot, which'll spread fast

The guy I know said he used rad flush acid and power washer in top of rad several times as the cores are so small it don't take much to clog

 

[Mick-the-fitter]

Looking at it, it seems to be Yanmar 3tna engine, when running does it black smoke when you use any lever?

 

[V8Druid]

Looking at it, it seems to be Yanmar 3tna engine, when running does it black smoke when you use any lever?

running lean? blocked filters?

 

[Mick-the-fitter]

Had plenty of tan’s running with head gasket gone between the cylinders, run fine, til under load, the one hard working cylinder, runs black smoke and gets very hot trying to drive everything, and push the lazy two up and down, (compression test)

 

[Canal Navvy]

I see that Rory thought head gasket failure was likely for that model.

That one working cylinder would be burning excess fuel on the piston crown so would get very hot quickly (as discovered by over enthusiastic re-mappers )

Sounds a good shout, looking foward to hearing how it goes.

 

[Will zaxis 25]

Edit, I see your only at Bovey Tracey..... Buy the Combustion test kit. PM me your phone number and I will pop up and look next Friday night if you want..... No charge to look see but a donation to my beer fund is appreciated if the problem is solved.

Sorry I've only just seen this.... If the offer is still there I would definitely appreciate that. I have the combustion test kit, there didn't seem to be any air coming out of the rad (which I guess is good!) however feeling the oil cooler rad when the engine is hot, I can touch it easily and the inlet/outlet pipes seem the same temp(just very warm, not "boiling" hot.

 

[Will zaxis 25]

I have also seen impeller doing that, at least if no flow you know straight away, there is a tap beside thermostat housing that switches of flow to heater make sure that's open to increase water circulation to see if it makes any difference

The heater is blowing hot air

 

[Jakeyzx25]

Hello all, any wizards out there? I'm trying stop my zx25 overheating. The manual for it doesn't mention the cooling system. View attachment 25787I've put a new thermostat in, the rads are clear, I've flushed the system. Nothing has stopped it from overheating after about 10mins of work. I'm wondering if there is air in the system. I've attached a photo with an arrow pointing to a possible bleed point. Does anybody know what this is? It has ptfe tape in the threads. The big pipe next to it seems to go to the radiator but doesn't seem to get water in it. Any help much appreciated.
Will

Hi Will, I’m a bit late to the party but I have a similar issue with mine at the moment. I suspect the water pump as it’s very squeaky and can’t feed water getting down to the heater matrix. Did you get to tge bottom of your issue? Any help appreciated, thanks Jake