Exhaust Man and Overheating

[jzmq]

Recently my HJ60 has started to run hot, not overheating but running at about the 3/4 mark. This started awhile back and only happened when at highway speeds and in 4th-5th gear. Lately it has begun to do it all the time, the temp climbs quickly to 3/4 and then stays there.

I have tried flushing the engine twice, though after doing more searches on this site, I have realized that I may not have properly burped the engine. I have also put in a new T-stat 82 degrees (there was none in before and no probs). The t-stat doesn't seem to want to open for awhile, but several posts seem to suggest that this may be common with a new t-stat, so I am not yet blaming that.

I recently noticed the engine is drinking quite a bit of oil as well and after giving the engine its first good cleaning in a long time noticed that it seems to be leaking at the rear most exhaust manifold port. I also noticed that the engine cools quite quickly once the engine has been turned off. Could this exhaust leak be the cause of the higher than normal temps? Also does anyone have any tips/ suggestions on replacing the exhaust manifold gasket? The manifold seems a bit warped so I thought I would take it to the machine shop to have it skimmed to size- any tips?

John

 

[crushers]

are you loosing coolant? have you done a coolant pressure test?

 

[Eric Winkworth]

I just kept the rad cap open and filled it from the very top of the system, on top of the manifold, in the line there. Running hot eh, is your toyota gauge telling you this, a mechnical gauge is nice, and will give you a more accturate reading. Other suggestions, clogged rad fins, obstruction maybe, could try some water wetter and maybe a thermostat.

Just some things to check

good luck
Eric

 

[roscoFJ73]

Hi John If the thermostats not opening there is no coollant flow and the coolant in the block is trapped and will overheat.
So the thermostat must fully open at the right temp. You can feel the warm water rush through the bottom radiator hose usually within 5-6 minutes on most vehicles in warm climes.

I would also take Eric suggestion and have the radiator unblocked if you havnt done it.
Having the exhaust manifold machined is a good idea.

Removing manifolds is simple in theory. What makes it a PITA is the broken studs that often occur.

Soak them for a few days in Penetrene/PB blaster without driving and you may get them all out unbroken.

The oil leakage could be from the valve cover
Download a FSM here,I think there is a 2H manual there http://www.birfield.com/

Another thing, higher running temps and and higher oil usuage are not good combinations.
It can be an indication of a worn out engine.
Prepare yourself for the worst and if its a lesser problem then great.

 

[jzmq]

Thanks for the suggestions. I want to take the Rad out and try flushing from the bottom up. Water seems to pass through quite easily when I open the draincock and it is all clear now. I've noticed there are two spots on the rad where the fins are bent in a fairly wide area. Is there any way of straightening them after I flush the rad? I think they may have been bent when I had the car pressure washed.

Also I see alot of comments about back flushing. What kind of pressure is recomended? I'm assuming we are not just talking about connecting a garden hose to the return piep.

 

[crushers]

what i do is remove the heater line from the firewall and LEAVING the other end open, i shoot high ressure water through the system, first one way then the other.
then i REMOVE RAD CAP and plug the one line with my finger and shoot the high pressure back thorugh the system again and then blocking the other line i pressure feed the first line again. the release is through the rad cap. this make sfor a very efficent cleaning...
cheers