Hi guys
Bought myslef a 4runner a few weeks ago in australia.
Its got 270K KM on the clock and seems very clean, took it for a RWC test (similar to MOT in U.K) and passed first time with no issue.
I did about 300KM around the city with no problems, then the day i left Melboune i noticed it was overheating slightly so i pulled straight over and checked everything and noticed that the oil was very low and the rad was pretty much empty.
I filled up the oil and coolant and when i started it i noticed alot of water coming out of the exhaust (it's winter here in australia but im from england im used to white smoke and water drops coming out of the exhaust in the winter) but this was alot of water!! the rad was empty again....... which got me thinking, head gasket.
I let it cool back down and filled up the coolant again and after doing so, when i ran it again there was nothing coming out of the exhaust.
I dont understand how coolant could have got into the combustion chamber and then ater being refilled, stop itself.???
2 days later with no problems and no coolant loss i began my 200KM trip into the country to start a new job ona farm. Pretty much half way at about 80KM out of the city i noticed the temp guage near the red so i pulled straight over, let it cool down and then checked it again, oil was fine but rad had emptied again.
I really cant get my head around this as it seems to just empty the rad only whenit feels like it, if its a head gasket it should burn coolant all the time (when tstat is open)
The only thing i can think (and what im hoping for) is that its not a head gasket, it is another issue causing an overheat and the rad appears emtpy because of the amount of steam and water going into the overflow bottle when the engine overheats.
I have owner a few renault 5 turbos in the past which are renound for blowing head gaskets, i had 3 go on me so i kind of know what im looking for.
Please give me your thoughts, if enough water could leave the rad via the overflow when it overheats and anything else you can think of.
Thanks alot guys!!

I had an overheating issue with mine as well. It still runs hot occasionally, but as far as water loss fill it and run it while looking at the engine to see if its leaking anywhere. I ended up having to replace the water pump. The water in the exhaust might be a coincidence not a symptom. Don't quote me on that though. Check around the radiator as well for any leaks. I have also hear that the 2nd gens are real picky about having fan shrouds.

Welcome to the board! First, what motor? Second, if you're thinking head gasket, go straight to a block test. Do not pass go, do not collect $200. There's a couple different brands, plug "head gasket block test" into your search engine and pick one.

Water in the exhaust could have been due to stopping the motor before it was completely warmed up. I don't know if that was your situation, but it's one possibility. Do the block test, find out of your head gasket is good or not, then go from there.

When was the timing chain done? Possible the drivers side guide has failed and the chain has worn through the housing? Pull the valve cover and with a flash light look down on the drivers side timing chain guide and see whats up.

Sorry I forgot that part... It's the 3l v6.
I've contacted the previous owner and he said he had the water pump changed recently. I would ask more info but I've lost his contact number now! Perfect.
I've been running it to work and back for the past week (only about 5km each way) but still no problems....
There are 3 hairline cracks in the top of the radiator so I've got it booked in to a radiator repair shop to replace the top on the weekend, am I right in thinking this could cause an over heat sure to lack of pressure ?
I will get a pressure test done soon, but I'm not seeing any creaminess in my oil. Is there any thing else that could cause coolant loss other than head gasket?
Thanks !! !!

A coolant pressure test is pretty simple and would rule out external issues that are easier to fix than internal. ANY compromise in the system like 3 tiny cracks can really cause the problems you are having.

Damn it! Giving it another check over this morning and I've got cream under the oil cap.
Pretty sure it's a head gasket now......
So just how bad is a head gasket on one of these ,I've heard alot that it's easier and cheaper to put a new engine in. Surly not!!

Drain the oil and see what that looks like. If the truck was sitting for a while, it's not uncommon to get condensation in the motor and cause what you saw.
If you have the same situation coming out of the oil pan, then you have a real problem. When you bleed the air out of the cooling system, you need to be sure you don't have any high spots in the hoses being above the filler. Air rises. You need to have the heater turned on to be sure to push any air out of there. Sometimes you have to heat cycle several times.

Agreed on moisture under oil cap. Certainly not a definitive example of head gasket leak. A coolant pressure tester pump set up is pretty cheap and is very easy to rule out obvious external leaks. Be sure to check it ice cold with pressure, as well as warm it up and CAREFULLY remove radiator cap and check it somewhat warm with pressure. Ive seen MANY times where things leak cold, or leak hot depending on how the various materials mate up with one another.
I would be replacing thermostat simply because it's simple and could cause the problem: for example thermostat stuck closed, overheated and then boiled out a bunch of coolant. You therefore added coolant, still had an air pocket and then had to add more. Make sure also your passenger side floor is dry and you don't have any condensation buildup on the windshield once it warms up. That would be heater core which is a relatively large pain in the wallet. Requires ENTIRE dash removal as apparently the engineers saw it fit to install heater core first when building the entire vehicle.
Also, some of the 4Runners have an additional heater core located under the center console for rear heat, and there are lines and hoses under your drivers side floor board. Many places to leak potentially.

Sorry I forgot you're in Australia. By driver side I mean the left hand side of the vehicle as viewed from where you normally sit

Thanks for your reply mate.
Pretty sure it's not heater matrix as all is dry inside the truck.
First thing I'll do is get the rad repaired and rule that out then pressure test the system.
That was my initial thought, air pocket or stuck stat causing overheat and boiling my coolant away..... But I'm just not sure how much coolant you could loose by this, one time I had to top it up with about 4L!
And as for the creamy cap, what else could cause that if it's not a head gasket?
Thanks

It would only take a very small amount of condensation to cause the carmel colored oil under the cap. I'd change the oil and see if it comes back. I assume the oil on the dipstick looks OK?

Yeah oil on dipstick looks fine....
I've had the radiator repaired now so I'll be keeping an eye on things the next few days and update you
Going to test the head gasket sooner rather than later though. Not sure how yet though.

Hate to bring it up, but any luck?