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Yeah, it's working just fine. I have tons of oil leaking from somewhere, but my temp issues are no longer a problem. The brief upward temperature spike is nowhere near what it used to be (pre- two-stage T-stat install) as it just goes a little above the midway mark (not even close to redline.) I guess it wouldn't hurt to check it out sometime, but it's the least of my worries.
Sorry for the thread-jack sortof
Either way, it just seems strange that more people with these motors haven't ever experienced this issue.
babyfood1217: Before the engine was worked on it worked perfectly fine. The temp would slowly rise to 1/3 and stay there no matter if I had the heater running on not. It does seem weird that I have only had these problems since then. I wish I could see what thermostat the Toyota dealer pulled out of my truck.
Funny story: I went to the local Napa auto parts store and asked the sales rep. if they had any dual-temp thermostats and he told me they did not exist.
Last edited by RayMackenzie; 10-30-2010 at 02:55 AM.
babyfood1217: Before the engine was worked on it worked perfectly fine. The temp would slowly rise to 1/3 and stay there no matter if I had the heater running on not. It does seem weird that I have only had these problems since then. I wish I could see what thermostat the Toyota dealer pulled out of my truck.
Funny story: I went to the local Napa auto parts store and asked the sales rep. if they had any dual-temp thermostats and he told me they did not exist.
the only place your gonna find the dual stage thermostat is the dealership.
Mine didn't have the overshoot either till i rebuilt the motor as well.
I just drilled the small hole as 4crawler suggests.
I had the same problem with my 88 pickup and the problem was solved when i went and asked the guy at advanced auto if there were any other options for thermostats that open at different temps and there was i bought the 196 degree thermo and i should have bought the 180 so after installing the 180 havent had that problem for 6 months and it did the same thing as yours ran up to almost red then dropped to normal. now i just installed a new radiator because mine was leaking and it was an aftermarket for A/T or M/t and didnt look the same as original and sat higher to where i could barely close the hood, since then my temp has risen to 3/4 or so before it drops to normal.
Last edited by ToyMachine88; 10-30-2010 at 06:09 AM.
I had the same exact pbm as Ray and I did everthing at once. Rad flush,dual t stat, hoses and water pump even though it appeared to be fine. I also put a digital gauge for precise temp monitoring. Seems like a bit over the top but still less than 150.00 to do the whole job.
The dealership was who I talked to first and they told me they don't stock them and when I asked where else i might find them they said call the main toyota warehouse.
The two most common oil leaks are the front crank seal & the valve covers. One that seems to trick folks the most, however, are the cam seals.
And you don't want to run a 180 degree thermostat, as the engine doesn't run properly except in the 195 degree range. You'll run into issues with emissions and sensors, and your fuel economy will suffer.
And you don't want to run a 180 degree thermostat, as the engine doesn't run properly except in the 195 degree range. You'll run into issues with emissions and sensors, and your fuel economy will suffer.
I have heard this also, that these engines need to run hot in order for the fuel to burn properly.
I drilled a hole in my thermostat, and this got rid of the temperature spike. However, the engine runs quite a bit cooler now, even after it has warmed up. The temp gauge sits about 1/4 of the way over (or less) compared to 1/3 of the way over before I drilled the hole.
Now I'm concerned that my fuel economy might suffer if the engine is not running hot enough, even though the thermostat is one that the dealership installed when they replaced my cylinder head a few years back, so I assume it's the correct 195 degree model.
So by drilling the hole, have I effectively bypassed my thermostat or essentially converted it into a 180 degree model?
I had the same problem, spiked on start up and dropped to normal and hold. right before it would drop I would smell a slight antifreeze smell and when i would first start the truck my heater core would make noise.I spent weeks trying to burp the system or looking for other problems, because everyone else said that a heater core would not cause it to overheat like that.sometimes you gotta think outside the box. try turning you temp select to cold and drive it or by-pass the heater core all together by connecting the the two heater hoses together. if it runs normal you know that's the problem. easy check for possible headache solved.
Yeah, "burping" the cooling system is very important on these trucks.
Easiest way to do it is to park the truck on an incline, or hill, such that the radiator cap is the highest point in the cooling system. Ramps work well also.
Once you "filled" the system, put the radiator cap on about 1/2 way tight. Just to the first stage of tightening it. Start the truck and run it for 20-30 mn. Make sure the heater is set all the way HOT, to allow any air in the heater core to come out.
Water will go into the recovery tank like normal, but also, any air in the system will bubble out into the recovery tank, and then overboard. Having the cap on only to the first stage will allow water and air to flow back and forth to/from the recovery tank easily. Or the water, anyway. The air will go overboard.
Once it's run for the 20-30 min, shut it down, and let it cool down. Once it's cooled off, check the radiator is filled with coolant/water properly (all the way up). Place the cap on all the way tight. Make sure the recovery tank is filled to "cool" line.
Now park the truck where you normally do, and run it as you would normally. Drive it around normally. Check the recovery tank every couple of trips to make sure it's properly filled. After 2-4 trips, you shouldn't loose any more water from the recovery tank. You may during those first few trips as a little more air bubbles out, but eventually, that should stop. If you're a little OCD, like I am, you can watch to see that eventually, you will use about 8 qts of water/coolant to completely fill the cooling system/recovery tank.
I used a Prestone flush kit and installed the tee-fitting at the highest point for engine flushing and it works for burping as well. The kit has several sizes of Tee-fittings. One did fit the heater hose line. Used a good ole tie warp around the heater valve frame to hold it secure. I have since added a rubber strip under the tee-fitting to prevent any potential abrasion in the metal framework, thus leaks.
Use
That's a problem the older Toyotas have. It's due to the routing of the return line for the heater. The routed it such that the "cool" water returning from the heater core is fed back into the main cooling system just before the thermostat. The cool water holds the thermostat closed longer than it should be, causing the water temp at the gauge temperature pickup to climb as the the truck warms up. Eventually, the thermostat will pop, allowing the normal flow of water, bringing the temp down.
This is the reason Toyota came up with their two-stage thermostat. The first stage will open at the temp of the "cool" water from the heater core, allowing enough flow that the truck doesn't overheat, until the second stage, the regular sized portion, opens and allows the normal system ops.
Alternatively, just keep the heater temperature control set all the way to "Cool" while the truck warms up. It'll pop the thermostat normally, and once it's settled at the normal operating temperature, set the heater temperature control where desired.
Burping the system IS critical, no question. But it's not the total solution to the situation. Installing a two-stage thermostat will be a big step towards the solution. You don't have to drain the system completely to change the thermostat. About a third of the way, give or take, will do the job. You still need to burp it properly when you get done.
10-29-2010, 10:26 AM
