2H Thermostat problem...photos inside (1 Viewer)

[dousty]

G'day. A few months ago in winter I replaced my radiator, water pump and thermostat. The thermostat is the only genuine part, the rest aftermarket. The vehicle is a HJ60, fresh 2H with an aftermarket turbo kit fitted.

Now that summer is here I have been having overheat issues (even on mild days). I can get 220-230f on freeway climbs while maintaining 100kmh with a pyro of 450c. So I have replaced the fan hub with a Davies Craig unit and I have even removed the A/C core incase it was restricting air flow but have found no improvement.

It will not overheat at a stand still but will return to thermostat openning temperature (184f)

So I wound the fuel back but am still getting up to 210f with a 400c pyro, and it only stops there because I ask for less from the engine. Today I removed my thermostat to replace the bypass hose and decided to check it's travel while I was at it.

The first photo is in a closed state after running cold water through it. The second photo is after pooring boiling water off the stove into and through it (the fog ruined the focus a bit).

As can been seen the valve has not traveled a minimum 10mm as stated for a 84c thermostat.


So, after all that, my question is:

Should the valve cut off bypass flow completely or does it still allow some coolant to flow back to the water pump inlet at all times(maybe to prevent cavitation?)?



Hopefully a few of you could shed some light for me. /pray



Thanks

 

[BEE-JAY42]

The thermostat should extend far enough to close to bypass valve but they take a bit off time to move so you will have to boil it on the stove to tell for sure. Judging by your photos your cooling system looks pretty gross, go to your local cummins dealer and by a product called restore, it's a cooling systme flush. It is strong as all hell and is about the only thing that actually works (just a warning it isn't cheap).

 

[dousty]

Thanks. I have used alot of Restore over the years! The block is clean (acid dipped) it's just the old thermostat housing thats still a bit ugly.

I found the old aftermarket thermostat that I replaced in winter. So this morning I'll put it in the housing and give it the same treatment for comparison and post my results.

 

[Tapage]

In my case even without t-stat I found my 2H-TI got hot ( not really overheating ) when I push it hard .. uch more on HW .. I can wun it without problems at 2500 rpm and less than 10 PSI .. but in the moment that I start pushing more diesel ( pre turbo and reaise my EGT to 1000ºF ) it start getting hot ..

new rad .. clean, now I´m testing new BMW cooland forumula and seems to run a bit more fresh ..

 

[dousty]

Well aftermarket one reacted much the same but will probably close the bypass a little sooner.Only problem with it is the valve OD is too small to seat against the housing. Instead it will go through the bypass hole.

So I've put the Toyota one back in for now.

Thanks

 

[CharlieOGrady]

Hey guy’s,
having the same problem in my HJ60 with a N/A 2H. Did anyone get to the bottom of this issue?

 

[sodafeld1]

I would not be comfortable with my 'coolant' (if indeed the liquid illustrated is?). looking that dirty, should look like clean cordial.

Open the cab heater too, you want it squeeky clean as the first aim, then look at the other stuff, thermostat (cheap), thermo clutch, water pump.
I like the engine guard watch dog, good peace of mind.