in this terrible story, i feel i didnt do the right thing and fix the problem right away, but i didnt know the problem exactly. here it is


we went camping, i was fourwheelin real slow, the truck started to over heat. i stopped, and the hose going to the thermostat housein was all inflated like a balloon and the overflow was full. so i let it cool down and hurry and hit camp. on the way to camp was a road that went 30 mph. once i hit that my engine cooled down way fast, so that was a relief for the ride home. when got home i noticed she was low and replaced the fluid cause i used that heatercore seal cause, well the heatercore leacked. so after that i was happy and the truck was happy.

well, wednesday we decided to go riding at 5 mile pass. i had 4 people, a trailer and 4 dirtbikes. a full load. it was around 5 so the traffic was bad. stop and go traffic. when i stopped the truck would get hot so i would turn on my heater. it wasnt blowing hot air untill the truck startedt o cool down and it would only cool down if i was going over 20 (weird) then i would get hot. so to clear that up, when i was stopped and the truck got hot, the heater wouldnt blow hot air.
ok so now, after about 6 times of getting hot (almost redline) it was cool and i was just about to ceder fort going up that hill. i had the rpms \about 4 and half and the temp was normal. right after i looked in my side few mirror i saw smoke coming out the exhaust (white smoke) i immedietely pulled over and shut her off. at that time she got hot. so, after about 30 min of looking under the hood i decided to have her towed back. i started her up again to move her (she ran normal) more off the street. then smoke was coming out from under the hood on the passenger side. so im thinking oh great, broken head gasket or head, or at worst broken block. i knew i was screwed after the smoke but i was really worried after i saw the smoke under the hood.

k so i towed her home, started her up again to pull her under the car port. she started normal with a little white smoke in back.

now, i smelled the exhaust it was really wet smoke and didnt smell like antifreeze or burnt oil. im hoping its a gasket but what do you guys think?

and why do you think it got hot in the first place?

kevan

If it only got hot during low speed or stopped then cooled off to normal at speed I would suspect the fan clutch is bad. The fan is only needed below 30 mph or so, above that there is enough air being forced through the radiator.

The smoke is most likely coolant. Could be from a head gasket but I'm guessing the head warped from getting hot.

Overheating - probably the fan clutch. If it didn't fix it, the radiator. My landcruiser is doing the same thing. New radiator fix it.

Smoke - head or gasket.

im pretty sure it isnt the fan clutch, when they go out, they lock up. i was thinking it was the thermostat, i know some of them when they break the stay open but heard not all are like that. Plus, the hose was all blew up like a balloon right before the thermostat housing

Sounds like the hose is old and needs to be replaced for one. If the hose was in good shape, it wouldn't balloon up. And the fan clutch can go bad and never lock up, thus the lack of cooling at low speeds. So, instead of pulling air through the radiator, it just sits there and freewheels.

Richard <img src="/forums/images/graemlins/patriot.gif" alt="" />

If the thermostat was frozen shut, that would explain the ballooning hose and the lack of cabin heat. Not sure though, it should've overheated at any speed with the t-stat shut. Maybe the higher rpms were able to force some coolant through the t-stat at speed.

I guess I would replace the t-stat and hose and see if you are still getting exhaust smoke...if so you may have popped a head gasket.

Wrong. When the fan clutch goes out, the fan spins freely. There is a silicon based oil in the clutch that uses the viscosity of the oil and a bi-metalic spring to change the amount of oil in the fan clutch. Over time these leak / dry up, and now the fan spins freely and doesn't lock up and turn at the correct speed. The simple way to check this is when the motor is good and warm, shut down the motor and watch and see if the fan keeps turning after the motor has stopped. After it has stopped, grab the end of a blade and feel for any resistance...

On my Mercedes, when its fan clutch went out I was able to buy some Toyota fan clutch oil and carefully refill it. Its worked for 2 years since then with no problems.

The thermostat is an easy / cheap replacement and wouldn't do any harm, but they seldom fail, and when they do, they tend to fail open, not closed, taking longer for the motor to heat up.

I'd suspect that the radiator is fouled.

As far as the head or head gasket: Well, either way you have to take the head off. Once you get the head off you check it out. If it is a warped / cracked head, it really depends on where / how it is warped or cracked. Some good machine shops can repair the head.

There is one other possibility: If you don't find anything wrong with the head or head gasket, you could have a hairline crack in the block between a cylinder and a water passageway. This is a fairly rare occurance though, and typically if this happens, then what can often happen when the car is not running is that coolant will leak in through the crack into the cylinder in a large enough volume to cause the motor to hydrolock the next time you try and start it, causing REAL damage like bent con rods. This scenario usually doesn't happen with head cracks / head gasket leaks because their isn't enough water in the top of the head to drain down like this.

Other things to look for are oil in your coolant and vice versa. If you had oil leaking into the coolant while running, this can foul the radiator and cause overheating too. Oil in the coolant makes chocolate milk looking gunk. Also, typically, while running oil gets in the coolant more often, as the oil system is pressurized higher than the coolant system is.

If it was me, I would buy the factory service manual, identify any special tools I may need, read the procedures in the manual a couple of times to familiarize myself, have a clean workbench with plenty of plastic baggies and a sharpie felt pen, latex gloves and a digital camera at hand. I take lots of digital pictures as I go so I have a record of how it goes back together. Get the head torn off and then assess the damage. Also, since this is a V-6, if you are going to do one head, do both. Now is also a perfect time to do other maintenance items like the timing belt, tensioner pulley and water pump, have a radiator shop evaluate your radiator, possibly tank dip it to clean out any corrosion or fouling. (But chances are it would be just about as cheap to simply buy a new radiator). Raplace all belts and hoses and any other consumables like that.

good luck

with the fan clutch the bad ones can many times be identified by streaks of the leaked oil spun out from the ceter of the inside of the fan.

good luck with the head/headgasket.

ok, nice reply, thanx for all the info

the fan clutch does work and does have resistance to it.
i think it is the thermostat but now that you mention radiator im gonna check that for sure.

it never smoked, once i seen it start smoking i shut it down. so i dont see any coolant in the radiator. the antifreeze looks brown because of the heatercore leak fix. it did fix my heater core. but that also could of messed up my radiator. the truck was sitting for over a year before i bought it so im assuming that has a lot to do with a lot on my truck (ball joints for sure)

im checking the compression friday, i dont have time today ill be working till dark. i have it already to set up, the battery was dead last night so i had to charge it. but its all in the plug hole and fuel pump fuse pulled and ready to get cranked over. I did take about 7 pics with my camera phone but i guess thats not enough. ive already sprayed as many bolts as i can find with the pb blaster, especially the exhaust bolts. ive got the manuel.

thanx for all the info for sure, im more confident about what i need to do now. ill replace everything while im in there as well, water pump, etc...

kevan

Running with no coolant in the radiator? Bad sign. Brown coolant is a pretty sure sign of oil leaking into the coolant system, especially if it is kind of chocolate milky like. In any case, once you get it all back together, you are going to want to flush the coolant system very well....

Oh, I get it, you put a stop leak in the coolant system to try and fix your heater core...bad deal...I normally avoid that crap because it can cause blockage in the system where you don't want it.