Still overheating

[Don Logan]

Hi, back in january i left my truck outside my cousins house for about 5 weeks untouched while i went away. When i eventually picked it up, i drove it 70 miles home on the motorway and noticed about 50 miles into the trip that the temperature gauge was creeping up. I eased off for a while and stuck the heaters on full and it went back down a bit. Then i had to go up a long hill and the gauge went up to just before the red before i could find somewhere to pull over. I left it about half an hour and stuck some more water in and then carried on. The gauge still went right up to over three quarters when i put my foot down and went back down to halfway when i eased off for a bit. This had never happened before i left it outside my cousins.
A couple of days later I changed the thermostat and burped the cooling system as shown on here and took it for a drive, but the same thing happened after about 15 minutes of driving when i sped up to 50ish mph.

If it's not a cracked head or the head gasket gone, then does anyone know what else it could be or where i should go from here? I'll take it for a sniffer/pressure test, but it could pass that and still be buggered couldn't it?

I know the tests aren't 100% and that the only proper way to find out is to get the head off and to take a look. There's no white gunk under the oil filler cap and the oil level is fine. Could it be the water pump? I was told that's not so easy to get to and test?

Does anyone have any suggestions as to what to do from here? If i knew it was definitley the head then i'd probably get a new one fitted, money permitting, but i don't want to have to pay someone to strip the head off to check it, just to say that it's fine and that it must be something else. Also, if the head is gone, the truck's gonna have to sit around in someone's garage while i get a new one delivered.

Also, the truck has just sat there pretty much since march as the MOT and tax ran out and then i buggered off travelling for a few months. Is this likely to have caused any other problems? I took it for a drive for the first time in ages the other day and it started straight away and didn't stutter or chuck out any smoke or anything like that.

So, i'm wondering what to do now. I'll book it in for a sniffer/pressure test and if it fails that i'll think about getting a new head fitted. If it passes however, then what should i do? Anyone know how much Stevo charges for a KZN130 head?

Thanks.

[darkdezigns]

sounds like head to me,mine had no gunk either,but pushed all the water out,best bet is when cold refil rad,leave cap off,then let it tick over and warm,if after less than a couple of mins it pushing the coolant out,id say head,gwh had his head done at stevo's today £1050 fitted,i did my own over weekend with help from a mate,mine was 995 in parts,but i really went to town,all oem stuff,then a rad after that too,just took mine for its first run and WOW

[MattF]

Did you replace the rad cap too? Check the viscous hub is operating correctly.


'Use the search function' is the answer to the next question.

[biosurf]

Not being funny but is the rad clean? Get a hose pipe or something behind it and see if water runs straight through. Pay particular attention to the bottom of it as thats where the ATF cools

http://www.hiluxsurf.co.uk/forums/sh...t=idiots+guide


Talking of which have you checked the ATF?

[Smego2]

Mine does that cause the rad fins are a bit perished, will get a new rad at some point, used to be as bad as urs but after lots of cleaning it now only does it if I push past 80 on a hill.

[Bathafarn]

My mechanic changed all the fluids on my Hilux and told me that the radiator had been really dirty and that he had had to flush for 30 minutes before he was confident it was really clean. A couple of months later it presented with similar overheating issues as you have and the mechanic told me the head gasket had blown. I took the head off and had it pressure tested and skimmed - engineer said there was hardly any warpage at all and he doubted it had been the head at all - had I checked the radiator? Flushed the radiator - all clear. Then I decided to take it out and have a proper look. OMG, gloops of gunk the size of my fist came out and on inspection by a radiator specialist I was told that the core was shot due and had been for some time. The clean water flushes I had witnessed were just the input water taking the path of least resistance. New core, engine running fine - except I still haven't worked out why my turbo doesn't want to turn - it was before the rebuild.
So it may not be your head at all. Take the radiator our and have it properly checked first.

[Don Logan]

Cheers for all that. Yeah the rad is quite dirty on the outside due to off roading and not being able to get all the muck out, but was almost new when i bought the truck. I'll take it out and have it looked at i think. Thing is, it never overheated until i left it sitting still for about 5 weeks. This was back in february when it was really cold and chucked down snow for few days. Any chance something could have frozen and expanded then broke/burst something? There are no water leaks...

[darkdezigns]

Cheers for all that. Yeah the rad is quite dirty on the outside due to off roading and not being able to get all the muck out, but was almost new when i bought the truck. I'll take it out and have it looked at i think. Thing is, it never overheated until i left it sitting still for about 5 weeks. This was back in february when it was really cold and chucked down snow for few days. Any chance something could have frozen and expanded then broke/burst something? There are no water leaks...

thermostat may have got stuck

[Don Logan]

Right, today i had the truck looked at. The bloke checked the head with the dye test and pressure tests, both of which he said were fine. He ran it for 45 minutes on idle up and the temp gauge didn't go above halfway. He said that the all the pipes were hot and that there's a good amount of heat coming through the blowers. The coolant looks clean and the radiator looked clean enough. There's no white gunk under the filler cap. It hasn't lost any coolant. I've already changed the stat. He said that the overheating problem it's having seemed strange and that if there was a problem with it, then it should have overheated sitting the on fast idle for 45 mins, which it didn't. So then i took the truck back home and on the way stuck my foot down, which made the temp needle go up after a while. Then i eased off and it went back down. Then i left it on idle up outside my house for half hour and the temp was fine.

So next is to flush and burp the rad and give it an extensive clean as per this:

http://www.hiluxsurf.co.uk/forums/sh...t=idiots+guide

I know those tests can't confirm 100% that the head's buggered, but if it was, then wouldn't it at least get a bit hot after a long drive and being left on idle up for half an hour?

How would the ATF affect cooling?

Anyone know anything else i could try?

Thanks.

[Sancho]

How would the ATF affect cooling?


Thanks.

The radiator also cools the ATF so it tends to get hot when the ATF's gone off. If it's been off the road for a bit, just flush the system out, check the stat's OK, refill it properly, check for leaks (again) and check the fan's OK.

The heads do go eventually, but there's a lot of other stuff it could be too. If you're not losing any coolant then it's probably something up with the cooling system rather than the head.

[MattF]

List of things which should be done. Just cross off the ones you've already done.

1) Drain the coolant.
2) Flush and backflush the coolant system with all heater controls on maximum.
3) Flush through with de-ionised or distilled water.
4) Thoroughly clean and flush the radiator.
5) Replace thermostat and rad cap.
6) Refill the coolant system with a distilled/de-ionised water & antifreeze mix.
7) Drain the ATF and refill with new.
8) Check the viscous fan is operating correctly.
9) Replace the engine oil and filter.

[Don Logan]

List of things which should be done. Just cross off the ones you've already done.

1) Drain the coolant.
2) Flush and backflush the coolant system with all heater controls on maximum.
3) Flush through with de-ionised or distilled water.
4) Thoroughly clean and flush the radiator.
5) Replace thermostat and rad cap.
6) Refill the coolant system with a distilled/de-ionised water & antifreeze mix.
7) Drain the ATF and refill with new.
8) Check the viscous fan is operating correctly.
9) Replace the engine oil and filter.

Ok, to flush the rad do i just take off the bottom pipe and stick a hosepipe in the top? Is there a write up on this anywhere?

I imagine it's best to remove the rad to clean it? Is it easy enough to reconnect or shall i leave it in and clean it as per the earlier mentioned post (blocked hosepipe with holes drilled in the side)?

To flush with de-ionised or distilled water: Funnel attached to a hosepipe? How much water?

Drain ATF: Where's the filler and drain plug?

Viscous fan: How do i check that it's working ok?

Engine oil/filter: Will do.

Thanks for the advice (and patience), i don't have much experience with cars yet...

[Growler]

Haven't read all of this thread but have you checked the Viscous fan ?

I had similar temp issues on my 3.0L, steady 60 temp was fine all the way push it to 70-75 and temp gauge would red line

Swapped viscous fan, coolant flush and rad clean and all now working as it should be.

ATF on an auto runs through bottom section of rad and will transfer extra heat into the system. This is why people recommend adding a separate ATF cooler to the system before the rad.

[MattF]

I imagine it's best to remove the rad to clean it? Is it easy enough to reconnect or shall i leave it in and clean it as per the earlier mentioned post (blocked hosepipe with holes drilled in the side)?

http://www.hiluxsurf.co.uk/forums/sh...ad.php?t=58485

To flush with de-ionised or distilled water: Funnel attached to a hosepipe? How much water?

Either just pour a few litres through from the thermostat housing or reconnect the rad, refill the system with distilled water, go for a quick run and then drain and refill with coolant.

Drain ATF: Where's the filler and drain plug?

http://forums.bauchan.org/portal/articles.php?rid=5

Viscous fan: How do i check that it's working ok?

It should have little resistance when cold and a lot of resistance when the radiator is hot. Check with the engine off, obviously.

[Don Logan]

Ok nice one, one more though: Is there a write up on doing a full coolant flush?

Ihave looked on the search thing but the links i found are all broken.

Thanks!