unsolved over heating (Impossible to solve)

[BlueBoxFJ60]

Sorry abnout the length but this problem has been going on a month long now

Ill start off with the original problem. I was driving from Houston to Huntsville Tx. My water pump went out halfway there in The Woodlands TX. I had no tools with, no time and no where to work on it. I got it towed to the the mechanic that ive been using since i was 15(20 now) and the mechanic that all other land cruisers in houston use. He got the water pump replaced and while it was in i had him replace the thermo.

20miles down the road i over heat again. Figured it was left over air in the system. I made it back to huntsville after several "cool down" stops. The problem countinued. I got the radiator taken out boiled and rodded out. Still overheated. then removed thermo and tested it, still over heated. Put a OEM radiator in with only 1000miles on it in still over heated.

Fast forward to today the cruiser has been in the shop for 3 weeks and still over heating.

Work done so far:
2 water pumps
2 thermos
2 radiators
all hoses replaced
severl flushes and "burpings?
Fan clutch
timing check
Head gasket
Head machined
New sending unit
Dash gauge checked

If you let it idle it takes a while for it to over heat but on the highway it overheats really fast, with or with out heaters on full blast. Before the water pump went out i never had any heating/cooling problems

This is my 3 or 4th post on this problem, ive had tons of suggestions but nothing that has worked so far.

We are out of ideas, has any one had any kind of similar problem.

Kyle
KJW002@SHSU.EDU

 

[IH8Wood]

I'd start with a cooling system presure test. If it fails, you have leak. Otherwise it's a cooling system component.

 

[NocalFJ60]

You just going by the factory gauge? Did you hook up an aftermarket gauge to measure the temp or use an IR gun to actually measure the temp? You can pull the thermostat and check them in a pot of water on the stove to make sure it opens at the right point.

Does it idle smooth?

 

[60wag]

Have you done a hydrocarbon test on the coolant to see if combustion gas is getting into the water jacket?

 

[Tinker]

Did you check the head surface for true? How about the block?

 

[juzzydykes75]

have you been near any mud lately ?
i had a chronic overheating problem and one of my mates told me to check the core of the radiator to make sure it wasn't full of mud between the fins .
it was . i removed it , washed it out and the cruiser now runs cool and smooth.

 

[UpsideDown]

Do a pressure test that follows the pressure as the temperture goes up to running temperature. You may find that there is not enough system pressure.

Is it really overheating or is it blowing out hot coolant? Some types of head/gasket failures lead to air pockets from combustion gases that collect in the waterjacket that lead to overheating and blowing out coolant.

Check for a loose frost plug that lets out pressure after the vehicle is hot. Usually associated with coolant loss.

Some coolant loss situations, head/gasket failures will lead to vapour coming from the exhaust. BUT some catalytic converters will get hot enough that you will not see the vapours.

I don't see a rad cap on your list.

Use a Toyota factory water pump. There may be a problem with the ones you're getting.

Any blockage in front of the rad?

Any type gasket material inside the water passages or water jacket that's blocking anything?

How about other things like restrictions in the exhaust?

 

[UpsideDown]

Here's another thought - some water pumps are designed to work in reverse rotation (used with serpentine belts). Make sure that you get a proper factory pump and check the pump vane direction vs the actual direction of rotation.

There could be something wrong with the rebuilt units, or there is some chance that they are not right for your application.

 

[matt.mcinnes]

I had a friend who had a few issues with over heating he fitted a new radiator, water pump and themostat only to find it was still over heating every time and he could not work out why.

It turned out that he had not put the belt back on the water pump

With everything you have done there is not much I can think of, were the Rad's new? Have you tried without the thermostat in?

Does the heater actuall work well?

 

[BlueBoxFJ60]

All suggestions made have been done/checked. Nothing solved it. IR gun, pressure check, new cap,etc... all done. No mud recently, just highway

Idles smooth and runs great, Heaters blow very very hot

 

[matt.mcinnes]

All suggestions made have been done/checked. Nothing solved it. IR gun, pressure check, new cap,etc... all done. No mud recently, just highway

Idles smooth and runs great, Heaters blow very very hot

Can you confirm you actuall have good flow around the system?

Take the thermostat out fill the system with water disconect the top hose from the radiator, with the thermostat out and a couple of buckets of water at hand start the engine with the heater set to cold taking it out of the loop.

If the water pumps working it should empty the system out of the top hose, just add the water so you dont run the system empty while trying or you can stick a hose in there.

Just dont run dry.

 

[nikos8]

If you replaced the water pump, thermostat, radiator, hoses, fan clutch, head gasket and checked to make sure the head was not cracked then you should not be overheating. Like NocalFJ60 said, try an after market gauge. It might be your gauge, the temperature "sensor" or the wire connecting the two.

 

[Elbert]

If you have replaced all those components then one would assume its blown head gasket or cracked head / block. I can tell you is real pain in the @ss to get the coolant system bled of air. So if you have a good radiator, water pump, fan and fan clutch, good thermostat , radiator shroud, and assuming all parts are installed correct then. I would have to say the cracked block or cracked head is possble. Any coolant in the oil or vice versa?

Years ago I installed a thermostat upside down on my old z/28....did not take long before temp went "hot".... I felt kind of stupid when I discoverd my mistake. Worth making sure that the thermostat is right. You have no restriction blocking air flow across the radiator?

If all the cooling components are known good.....seems to me you need to look at the engine. I would also make sure your guage is right. I installed an aftermarket temp guage because the OEM one just does not work very well.

You running OEM setup for all the cooling components to include the fan and fan shroud?

 

[60wag]

I too am thinking a possibly cracked block but that could be eliminated with the hydrocarbon test.

 

[Live to Ski]

So, what makes you think you are overheating other than guage reading?

There is a known problem with the fuel guage grounds that affects both the fuel guage and temp reading. This might be your culprit.

 

[Rigger]

Bluebox: what exactly is it that tells you the truck is overheating?

Is it just the in-dash gage?

Or has it actually blown water and coolant?

I'm kinda with the others here that think it may be a gage or sender issue, or something similar.

 

[NocalFJ60]

All suggestions made have been done/checked. Nothing solved it. IR gun, pressure check, new cap,etc... all done. No mud recently, just highway

Idles smooth and runs great, Heaters blow very very hot

So how hot is it getting then? At this point you need to still consider all ideas. Just because you checked it doesn't mean it was done right.You could of got a bad part. Bottom line is if it is really overheating. You either don't have enough flow through the block to remove enough heat to keep the temperature down or something in the block is causing more heat than the cooling system can handle. Sounds like the cooling system has been through and is up to par so I would concentrate on the block.

So you drained the system and got it pressure tested?

 

[John McVicker]

I think it would help if you could list the temp # at various locations taken with your IR thermometer. ie: fins at the top & bottom, top of radiator, t-stat housing, hoses etc.

Seem st be some doubt that it is, or is not actually overheating. This will help clarify.

John

 

[BlueBoxFJ60]

yes i have good flow i did what mattmiccins said. It was one of the first things i did to make sure the water pump was pumping. Thes send ing unit has been replaces and the gauge has been tested against another . I dont have the numbers. The mechanic is the one that did the IR gun readings. And yes iit is overheating, if i let it i will puke water/coolant out the resivour and steam. Head gasket has been replaced and head machineded. No oil in coolant before or after the head work. hydrocarbon test came out good.

 

[NocalFJ60]

yes i have good flow i did what mattmiccins said. It was one of the first things i did to make sure the water pump was pumping. Thes send ing unit has been replaces and the gauge has been tested against another . I dont have the numbers. The mechanic is the one that did the IR gun readings. And yes iit is overheating, if i let it i will puke water/coolant out the resivour and steam. Head gasket has been replaced and head machineded. No oil in coolant before or after the head work. hydrocarbon test came out good.

Ok.. my next best guess is you solved the problem replacing everything with the cooling system but the head gasket was installed wrong or not the right gasket and is blocking coolant flow in the engine. It would not be fun to pull the head again to check plus you would just end up replacing it again if you pulled the head.