Outer Limits 4x4 Board

G’day all

Recently I went up to Teewah Beach with my mates. I have a 2.8L 1993 Single cab Hilux.

During the trip I got some serious overheating problems. After about 30 minutes or so of driving, the temp would climb into the red. Especially with the engine under load (100+ speeds/hills/soft sand driving) aka high revs.

This made the trip home very difficult (had to stop every 20mins or so to let the temp cool down and refill the radiator. The engine was getting to hot that the boiling hot water in the radiator was pouring out through the overflow valve, and even coming through the top of the radiator when the cap was still on. I reckon after about 20mins or so of highway driving, I’d lost around 3-4L of water/coolant.

Today I flushed out the radiator and looked for cracks/leaks. Couldn’t find any visible problems.

The only visible thing I noticed was when I let the engine run with the radiator cap off. After about 15mins of idling + revving, the water in the radiator began to bubble/jump.

Thoughts?

P.S. I had the thermostat replaced about 2 months ago, so I’m guessing it aint the thermostat?

do 4 things

1. Clean the radiator outside and have it cleaned at a shop (take tanks off)
2. Replace viscous clutch. Add silicon fluid if you are feeling broke, toyota sells it.
3. Hope it's not a head gasket. I assume it's diesel. If petrol, check timing.
4. Make sure you run coolant, not water long term. Water works better, but not for long....

Paul

What are the tell tale signs of a cracked head?

put the radiator cap on and feel the top radiator hose before you start the car ... it should be nice and soft and squishy.

start the car and then squeeze the hose again .... if there is any difference in pressure on that top hose within 10 secs then its definitely a cracked head or a gasket. if its still nice and soft and squishy then its not a gasket or head problem. maybe a water pump prob or somethini guess.

i know this cos my 03 td hilux overheated once, the mechanic did what i just said above so i got it pulled apart and what do ya know a cracked head.

hope this helps

Ross

it sounds to me like you have a cracked head or the gasket is gone
the bubbling you are getting in your rad is your compression leaking into the cooling system you would be very lucky if you didnt crack the head

Thanks for the replies all.

peeko22, I just tested it. Didn't notice a change in pressure. The engine was a little warm when I started it, would this have an effect?

If I had cracked a head, would I hear a repetitive noise when the engine is running? Because the engine sounds perfect to me, starts perfectly every time as well.

Can anyone recommend a good mechanic on the north side, around Nundah?

Cheers all

well thats a good sign... but dont quote me ... try doin it when the car is cold say first thing in the morning and maybe wait 30 secs for it to build pressure.

my car sound great for about 10 mins the next day idleing then suddenly a white puff of smoke came out and it made a pucking noise. kinda like running on 3 cylinders. turned out a hole in my top radiator tank caused the whole thing ....:/

if there is still no pressure when the car is generally cool still, then thats a good sign . ...still get it checked out though, get the mechanic to do a compression test then you will know for sure . sorry i only no some southside mechanics

I'd say take it to a radiator shop/mechanic's and get it pressure tested that'll show up leaks. Once it's upto running temp feel top and bottom hoses they should be close in tempreture this means thremostat is opening ok if ones heaps colder than the other it needs replacing.

Take it to a good rad repairer, they can check for combustion gasses in the coolant there too.

As previously mentioned, take the rad out, and get it rodded, chances are that its 50% or more blocked.

Its very common to see cars on the side of hills with bonnets up when you get a warm day now.
Also when up at speed, just as you described, it sounds like a blocked up rad, either internal, or external.

the cooling system was just managing during the cooler months, and now its warm, your not getting effective heat exchange.

Possible causes are mixed coolants, sediment/ crud in the cooling system blocking the cores in the rad. External blockages, mud, seeds, plastic bag etc. Check the aircon condensor too, as air has to get thru this before getting to your rad.

Following this, make sure your shroud is properly sealed, get some 1/2" self adhesive foam for door sealing around the house, bunnigs has it.
And make sure your shroud is effectively sealed between the rad and itself.

From what you described it sounds like a rad just failing to keep up, you will get some air bubbles and stuff when you top up a cooling system.

Trains

Had similar issues with mine over the last two weeks.

Radiator sent out and checked/reco'd by the local radiator shop. Apparently 40% blocked. $71.50 later they fixed a small leak, flushed it and no more overheating.

Also did the water pump at the same time (225,000km old) and still looked like new.

viscous fan is my bet.
About $120ish for my cruiser at Bursons
fixed my overheating problem straight away

Taking it to a mechanic tomorrow. I'll keep ya updated.

Cheers fellas

Put a new sealed radiator cap on it

ALux wrote:What are the tell tale signs of a cracked head?

what u r describing been there had it
sand brings out the problem more

high n mighty wrote:Put a new sealed radiator cap on it

Actually craig, you have got a good point there. A cooling system needs to run under pressure to operate correctly. The properties of coolant (water mostly) make it expand under heat, and also by by presurising the fluid you can raise the boiling temperature. By having a leak (loss of pressure) even if it is small, this does not allow the cooling system to maintain pressure. Therefore the coolant can boil at a lower temperature, possibly causing an overheating situation.

The bubbles in your radiator neck after the motor warmed up could either be a air pocket caused by the initial overheat clearing itself, or a leak in the head gasket/head. Get a cooling system pressure test done and go from there. Start with teh basics then work from there. Unless a leak is pretty bad you will have trouble finding them till you apply pressure to the cooling system. The 2.8l do crack heads from time to time.

Layto....

So what is the verdict ????


Trains

Radiator was 'extremely blocked' according to the mechanic.

All fixed