Hi all - I'm still relatively new to the cruiser world, but my JDM HJ61 has recently started overheating - well really, running on the warm side, which is a new occurrence -- and one that I'd like to stop. I've done my damndest to figure out what's going on (using the search function on MUD) but I'd like to run some ideas past those far more experienced and knowledgeable than I. It is also my DD and only vehicle, so she can't be out of commission for more than a weekend if at all possible.
some quick facts:
For the first month of ownership, I never saw the water temp gauge go past juuust above the lower end of the center marks (green line in the image below). About a month in (and interestingly enough, right after I changed the oil - so not sure if there's any correlation there) I noticed that under load, temps would slowly increase under heavier load. Not towing or anything, just highway speeds going up big steep hills in CO.
The more time has passed, the easier/quicker this seems to happen. I know the factory temp gauge is notoriously unreliable, and I don't currently have the $$$ to put in anything more accurate. Long term plan is to fit an EGT gauge and digital readout water temp gauge, but I'm broke as a joke at the moment due to some unexpected expenses, and having to move due to some really s***ty roommates and a dishonest landlord.
When I first noticed the issue happening, I did a full (like 6-stage flush) with distilled water, and then refilled with OEM Toyota Red Coolant diluted to 50% w/ distilled water. There doesn't seem to be any bubbling or leaking or air bubbles in the system -- I burped it pretty well. The coolant that came out was pretty nasty, definitely some rust and dirt in there for the first couple passes, but no larger chunks or anything, just your standard particles. Didn't seem like an absurd amount for a 30yo vehicle either, although I admit I have no real experience with what it should look like. Hoses seem to be in good shape, I doubt there's a blockage there, and definitely no leaks.
At the moment, the highest i've seen the factory gauge get is the top of the needle meeting the bottom of the middle marks on the temp gauge.
It runs 90% of the time dead in the middle of the two (still higher than it was when I got the truck - it basically always stayed exactly at the 'old high temp' mark in green.
I drove the cruiser most of the way up Guanella pass outside of Georgetown, CO last weekend, and temps didn't seem to get better/worse with altitude. I live at ~6000 ft, and probably drove as high as 9000-10000 ft.
Power does seem to decrease as the temp increases, but it may be a chicken-and-the-egg problem where temp increases cause the engine is working harder. Some days the hills seem easier, and some they seem harder. Temp increase is basically the same between 4th & 5th gear.
Not sure if it's relevant, but the oil pressure stays in between the two yellow marks in the image. It's higher when just started, and stays mostly at the lower when driving, although it increases back to near the top mark when the temp spikes.
I'm planning on putting a new thermostat in, wondering if a water pump is a good idea as well?
Are there any other things I should check before I start spending money on new parts? When the pedal is to the floor, there is noticeably black smoke from the tailpipe - although it passed CO emissions no problem, and doesn't seem to be getting any worse. Fuel screw still has factory safety wire attached, so it is unlikely it's been messed with (I think?)
If water pump is a necessity, is it necessary to get the pump and housing, or is it better to just replace the actual pump? the FSM gives a rather intimidating procedure for seating the pump - It'd be worth a few extra $ to not have to worry about doing that wrong.
or just
?
is there anything else I'd need or should replace at the same time if I do the water pump? Any additional tests I should perform?
Thanks in advance, and apologies for the long read - I'm trying to get all possible info in front of you to not waste any more of your time than necessary!
some quick facts:
- 180k km on the engine with no reason to believe that's incorrect or misrepresented.
- full radiator flush performed with Toyota factory coolant (after overheating issue began)
- no loss of coolant
- no oil consumption
- radiator seems to be in good condition
For the first month of ownership, I never saw the water temp gauge go past juuust above the lower end of the center marks (green line in the image below). About a month in (and interestingly enough, right after I changed the oil - so not sure if there's any correlation there) I noticed that under load, temps would slowly increase under heavier load. Not towing or anything, just highway speeds going up big steep hills in CO.
The more time has passed, the easier/quicker this seems to happen. I know the factory temp gauge is notoriously unreliable, and I don't currently have the $$$ to put in anything more accurate. Long term plan is to fit an EGT gauge and digital readout water temp gauge, but I'm broke as a joke at the moment due to some unexpected expenses, and having to move due to some really s***ty roommates and a dishonest landlord.
When I first noticed the issue happening, I did a full (like 6-stage flush) with distilled water, and then refilled with OEM Toyota Red Coolant diluted to 50% w/ distilled water. There doesn't seem to be any bubbling or leaking or air bubbles in the system -- I burped it pretty well. The coolant that came out was pretty nasty, definitely some rust and dirt in there for the first couple passes, but no larger chunks or anything, just your standard particles. Didn't seem like an absurd amount for a 30yo vehicle either, although I admit I have no real experience with what it should look like. Hoses seem to be in good shape, I doubt there's a blockage there, and definitely no leaks.
At the moment, the highest i've seen the factory gauge get is the top of the needle meeting the bottom of the middle marks on the temp gauge.
It runs 90% of the time dead in the middle of the two (still higher than it was when I got the truck - it basically always stayed exactly at the 'old high temp' mark in green.
I drove the cruiser most of the way up Guanella pass outside of Georgetown, CO last weekend, and temps didn't seem to get better/worse with altitude. I live at ~6000 ft, and probably drove as high as 9000-10000 ft.
Power does seem to decrease as the temp increases, but it may be a chicken-and-the-egg problem where temp increases cause the engine is working harder. Some days the hills seem easier, and some they seem harder. Temp increase is basically the same between 4th & 5th gear.
Not sure if it's relevant, but the oil pressure stays in between the two yellow marks in the image. It's higher when just started, and stays mostly at the lower when driving, although it increases back to near the top mark when the temp spikes.
I'm planning on putting a new thermostat in, wondering if a water pump is a good idea as well?
Are there any other things I should check before I start spending money on new parts? When the pedal is to the floor, there is noticeably black smoke from the tailpipe - although it passed CO emissions no problem, and doesn't seem to be getting any worse. Fuel screw still has factory safety wire attached, so it is unlikely it's been messed with (I think?)
If water pump is a necessity, is it necessary to get the pump and housing, or is it better to just replace the actual pump? the FSM gives a rather intimidating procedure for seating the pump - It'd be worth a few extra $ to not have to worry about doing that wrong.
is there anything else I'd need or should replace at the same time if I do the water pump? Any additional tests I should perform?
Thanks in advance, and apologies for the long read - I'm trying to get all possible info in front of you to not waste any more of your time than necessary!
