red247wings

Ok, first off, thanks to those who responded to my last (Dec '14) thread about a short and blown fuses. I got it fixed and failed to send a thanks.

Now, about 3 weeks or so ago, truck was running fine. started to have coolant lead from the front of the engine, not hoses or radiator. After slowly losing coolant and replacing it, driving mostly highway speeds (65-70 mp); It ran Very hot (edging past the upper white limit). Stopping twice on the way home to let it cool, Stupidly, I took the easy route and put "stop leak" in the radiator. It seemed to stop, or at least seriously slow the leak, but then it would constantly run very hot. Hind sight being 20-20, I'll never do that again. I finally replaced the water pump (which was probably still good but leaking most likely from an old gasket), thermostat and flushed the radiator. While the water pump, thermostat and radiator were off, I used a garden hose and tried to "flush" the system through the water pump hole, thermostat hole and where the lower radiator hose connects. Water went good through both the lower hose tube and thermostat hole and both came out the water pump hole. When trying to flush through the water pump hole, it would come back out (aggressively). Fearing that I "mucked up" the heater core and possibly inside the case, I bypassed the heater core all together, connecting the hose that leads to the heater valve directly to the return. After putting it all back together it still runs very hot. After draining the radiator, I put some "radiator flush" in and topped it off with the garden hose while the engine was running. No more leaks anywhere but it's still running very hot. I haven't drained or flushed the radiator yet, as the instructions were to leave it in for 3 to 6 hours of run time or a couple of days at normal driving. It's only been in since yesterday. I'm planning to flush it out tomorrow when I'm off.

Also, it doesn't run "very hot" until after about 20 miles of hwy speed and doesn't rise quickly. It stays about 1/4" short of the upper white limit by the time I get to work which with medium traffic is about 30 mins or 27 miles. The first 10 miles or so would be considered city driving or no more than 50 mph. It stays pretty consistently at mid level of the temp range at about 55-60 mph then rises gradually till I reach work and smells hot. Before the initial leak, the temp stayed at about 1/4" to 1/2" above the lower limit since I've had the truck (about 4 years now.) It has 214000 miles on it but unk how many of those are original miles.

Any ideas, recommendations as to the BEST way to flush the system (i.e. store bought flushing kit, regular drain and run it, etc.)? Also, is the possibility of an "air lock" that plausible at this point or did I seriously f up the truck? Thanks in advance.

osv

the "air lock" thing is internet fud, i wouldn't worry about it, you have much bigger issues to deal with... fwiw, this could be a good time to flush out the heater core, in both directions, water pressure from a hose shouldn't hurt it.

i think that there is a block plug that can be unscrewed, to help flush out the stop leak garbage?

what have you replaced so far? thermostat and fan clutch is a good idea, assuming that the radiator itself is in decent shape... there should also be a fan shroud on the engine.

Flash319

The air lock that happends with these trucks is in the heater core. Wont affect the engine temp just weather you get heat or not. I would look to thermostat first, and if your rad is any good. The fan never comes on under normal conditions so that is prob not your problem. If thermostat and rad are good your head gasket may be screwed from the overheat.

red247wings

I have replaced the thermostat and water pump. radiator seems to be in good shape. pushed water through it with the hose and no garbage came out and seemed to flow good. Checked the fan clutch and seems to be in good shape as well. Get's "looser" after having been driven home. I'm assuming that is what it is supposed to be like. It has a fan shroud and praying it isn't a head gasket. I haven't been losing fluid and level seemed good even though it was running hot. I bypassed the heater core, so that shouldn't be an issue at this point. https://www.yotatech.com/forums/imag...head.gif:bang:

red247wings

Anybody know what torque for the block plug after flushing it?

grumpin

I had the same type issue. Had to replace the radiator.

red247wings

should I just take the thermostat out and try to run it that way to see if that makes a difference? Does it matter that the engine takes time to run very hot and doesn't just shoot up there?

osv

the delta of temp change is helpful for troubleshooting... as flash319 indicated earlier, the fan clutch shouldn't be an issue for most driving conditions, i.e., where the vehicle is moving and has airflow thru the radiator... where you see fan clutch failures is with extended idling, rock crawling, etc., in hot conditions, because there is no airflow.

i'm running an $89 radiator from rockauto.com, it's been fine for over a year.

did you put a toyota thermostat in? don't ever leave it out, they are designed to slow the water flow enough to soak up heat, so the engine actually runs cooler with it... the efi needs accurate engine temps to operate properly.

do not overtorque that block plug.

red247wings

Thermostat was from O'Reilly's auto parts and was rated at 195 degrees, I believe. not sure but looked like a two stage, but I don't know enough about them to tell for sure. Still don't know the torque for the block plug. I did notice that driving in "traffic" and lower speeds that it kept the heat from spiking. Actually driving at freeway speeds made it run "hotter". smelling heat from the engine area afterward but can't locate the source and no steam or smoke. No leaks either.