Engine overheating, ideas?

[mike_nofx]

Its a tb42 petrol patrol, carby auto.

On short trips (<20 mins) there is no problem, it wont run hot, but on any decent trip, like 45mins plus the temp gauge will begin to rise. Its not just up hills the temps will rise, its strange really sometimes it will get hotter uphill then cool down when going down hill... then the exact opposite will happen, it heats up travelling downhill then going uphill it cools down. Whenever i come to a stop, or travel slow during the trip (20-30kmh) it will heat up.

The overflow bottle fills with coolant then begins spitting it out of the overflow hose. There doesnt appear to be any leaks in the system. Its NOT the thermostat as i tried removing it and i still had the same problem. Its also not the radiator cap, as i tried 3 different ones (all used ones).

My only other guess is the fluid coupling in the fan. The fan doesnt have much resistance when turned by hand, spins easily.
BUT on the trip i was just on, i was sitting over 80km/h basically the whole way and it still ran hot. I would think that anything over 80kmh would be enough air flow, that a fan wouldnt be needed anyway?

Any other ideas?

Thanks
Mike

[mike_nofx]

Oh, forgot to mention, i have owned the patrol a few months. When i first purchased it i flushed the radiator and block, fitted a new factory thermostat and quality coolant.

I have been on a few long trips with no problems at all. Its only the last two trips i have been on that its been a problem.

Mike

[BadMav]

Silly question, are the radiator fins full of mud or silt?
Give it a good blast with a hose all over to be sure.

[Eddy]

First I'd do is take out the radiator and take it to a radiator bloke for a proper clean out!
Chances are most of the flutes in the core are full of crap, and the Rad dude will take off the tanks, and poke a little cleaning rod thingy through each of the flutes in the core.


The old "flush the radiator and engine block" thing does SFA

[nerida67]

As said take the radiator to a radiator shop and get the thing rodded
About $100-$120
Dont EVER totally removed the thermostate it will run hotter
If the guage is goin up and down then the therostate is working
The temp should drop goin down hills (more air flowing thru radiator)

Im betting the radiator is full of crud
Get it sorted ASAP before summer time hits or youll cook it

[mike_nofx]

How much resistance should a good fluid coupling have?

[bad_religion_au]

my money is on head/head gasket cracked

[chimpboy]

my money is on head/head gasket cracked

Not impossible. Short of that I would be looking a lot harder at the rad than at the fan. With a dodgy fan you expect symptoms at idle not when travelling at any speed as you suspected.

Flushing the radiator and block could be what filled the rad up with crud in the first place

[mike_nofx]

Cracked head or head gasket is also topping my list now.

Didnt suspect it at first as there was no water in the oil, and exhaust doesnt seem to be blowing any steam (though i could probably check that again) but with the cap off and engine running, there are air bubbles.

If i was looking for temporary solutions is that chem (weld?) stuff any good?

Mike

[BadMav]

Yeah it works but only lasts a month at best.

[Goatse.AJ]

my money is on head/head gasket cracked

X2 Especially that it seems to be doing random shit..

Assuming you've checked that it's not just a dodgy temp guage or sender issue.

[bad_religion_au]

Cracked head or head gasket is also topping my list now.

Didnt suspect it at first as there was no water in the oil, and exhaust doesnt seem to be blowing any steam (though i could probably check that again) but with the cap off and engine running, there are air bubbles.

If i was looking for temporary solutions is that chem (weld?) stuff any good?

Mike

my first ever cracked head didn't have any of those symptoms... apart from the pressurising the overflow bottle (which yours is doing). that's what made me think it.

mate of mine got over 6 months out of his chemi-welded 1fz-fe (was still running when it was pulled). just make sure the heater core is getting water flow when you do the chemi-weld

[DamTriton]

my money is on head/head gasket cracked

The overflow bottle fills with coolant then begins spitting it out of the overflow hose.

Cardinal sign - water displacement by gas.

[nerida67]

My GQ was overflowing into overflow bottle,
Got real bad towing 2.5t up steep hills
Everything else was working guage goin up and down ,all good

Talked to ALOT of different people regarding this and got alot of different answers
Young bloke said ,blocked radiator seemed it
Dropped the rad out , got it rodded and totally blocked
Would have lasted 2 months and cooked it
(This was winter time also,would have lasted half a day in summer)
Got rad rodded,new hoses ,new cap
All Good

[mike_nofx]

Thanks for the tips people.

While the radiator may very well not be 100% clean I just don't think it's the main cause. Only because it was running fine one day then overheating the next. It didn't slowly over time run hotter and hotter.

Also there are more bubbles with the cap off and it gets hot now after 15mins of driving.

Thanks again.

[nerida67]

You got bubbles
You got troubles

[mike_nofx]

Will using that chemi weld for now stuff me up later on when I decide to fix it properly?
Does it leave a mess or anything in the cooling system?

Thanks

[bad_religion_au]

Will using that chemi weld for now stuff me up later on when I decide to fix it properly?
Does it leave a mess or anything in the cooling system?

Thanks

yep, you can end up with water passages blocked, the heater core blocked etc.

[Goatse.AJ]

my money is on head/head gasket cracked

The overflow bottle fills with coolant then begins spitting it out of the overflow hose.

Cardinal sign - water displacement by gas.

That could also be something as simple as a farked radiator cap too though.

[DamTriton]

my money is on head/head gasket cracked

The overflow bottle fills with coolant then begins spitting it out of the overflow hose.

Cardinal sign - water displacement by gas.

That could also be something as simple as a farked radiator cap too though.

...but with the cap off and engine running, there are air bubbles....

[Stu - r - dee]

Mate I have just been through all the same dramas, mine did the same thing, spewed coolant into the overflow bottle, bubbles int he radiator, took the head off, was blown from the water jacket into cyl 6, the block had eroded away so head gasket was working hard to try and seal, $890 and head reco'd with new vrs kit and head bolts, runs great now. I put up with this problem for like 5 months adding addatives to the colling system to patch it up, do it soon as you cant trust them when you neex to rely on it.

All the best Pal

Stu

[charged88]

Probably the head gasket but here's another possiblity,
Is your auto fluid cooled through your radiator or do you run tranny cooler?
I had a an old commodore that would overheat with plenty of airflow, and it had new rad water pump and so on.
Turned out that the tranny was running way to hot and transferring the heat through the radiator therefore overheating the motor.
I put a tranny cooler on and problem solved. Even if this is not the problem its good practice to have a tranny cooler especially if towing.
Cheers
Lewis

[OL GQ UTE]

Head gasket...no way around it. Dont bother with chemiweld or anything like it....pull it off and get it fixed properly!

[MyGQ]

Bubbles in the coolant is the head gasket dead and/or cracked head.

[garth]

Head gasket...no way around it. Dont bother with chemiweld or anything like it....pull it off and get it fixed properly!

X 2, do it right first time.....when you have compression going into the water jacket/radiator - where is the coolant going to go when you shut the engine down?.... sooner or later you'll get coolant into the bore and when the engine is started you have a good possibility of bending a rod.

good luck

[Jake GQ..]

my money is on cracked head. get a presure test done and is there any steam coming out of the exhaust