HJ60 Running cool

[sandcruiser]

1988 HJ60 runs cool.
I replaced the Tstat a week or two ago, that seemed to help a little bit, but in general the temp read around 150. If I idle for a while it can climb up to 175.

After driving, if I shut down, when I return it is usually at around 180, but when I start it up, it falls back down towards 150.

I'm puzzled.

When I replaced the Tstat (with an 82*) I also flushed the engine and rad, a fairly large amount of rust-looking stuff came out.

Currently running a very lean mix of antifreeze-- about 15% AF to 85% water. I figured I'd run it that way while I trouble shoot to avoid having to dump antifreeze when I next mess with it.

Also: after running for about 2 weeks (but not only 200Km or so about 160miles), the rad was around 1liter low.

Any thoughts?

 

[Stone]

Have you verified the dashboard gauge reading with a thermometer? Would be the first step that I would take anyway. Also, does your heater blow hot?

Could it be bypassing? Verified that the gasket and t-stat were installed correctly?

Also, it wouldn't be unusual to have a defective thermostat right out of the box.

 

[crushers]

as for the coolant being low, there could have been a trapped air bubble...

 

[Stone]

as for the coolant being low, there could have been a trapped air bubble...

Maybe in the heater core? I guess it's warm enough down there that you probably don't use the heater and didn't purge it when you flush and filled your system? Just a guess.

 

[crushers]

whne i am adding the coolant i open one of the lines that is level with or above the rad cap height near the back fo the block since this allows trapped air to escape without having to go back through the system, i have good results with this.
cheers

 

[sandcruiser]

I didn't think about the trapped air idea
I did run the heater while flushing/filling - there is something perverse about sitting in the truck sweating your tail off with 90* temps outside, and the heater blasting away inside....
I'm topping off the rad now and we'll see what happens. It is certainly possible that the tstat housing gasket is no good: I fabbed it myself from some cardboard and RTV (hey, it was better than waiting a week for the part....) but it doesn't appear to be leaking. Will keep an eye on it.

The temp guage is an aftermarket mechanical, no I haven't checked w/ a thermometer. Should probably get one and try it out.

My newest problem is that I installed an old mechanical oil pressure guage to double the check the reading on the stock guage, as it was reading low.... now I've got on guage that reads 60psi at idle and spikes up to infinity when I rev the motor.... and another (stock) guage that reads low and low and low. grrrrrrrr.....