1hz overheating still!!

I would have said to try CEM. Even if it does not cure the heating problem the engine will run better and the oil will be clean. I used it and it made a bit difference to the oil condition. Let us know the results please. The 1HZ does not normally give overheating problems.
By the way, how many K's on the clock?
Good luck

I had a ford years ago that would overheat in stop start traffic . No matter what i did i couldnt fix it . My current troopy never overheats but i do take it to a radiator place every 12 months and get them to flush and change the coolant . Alloy and old coolant dont mix .

Have you replaced the thermostat, or even tried running it without one to see what happens.??
Do you have an EGT gauge and if so what are your max EGT temps.??Does the engine blow black smoke?, may be over fuelling.
I have turboed(and I/C) my 1HZ, temp gauge has never gone above just under half, before or after turbo was fitted.
Do you still have your cowling around the fan?
Is your I/C top mount including a bonnet scoop, this has been known to cause heating issues due to disturbed air flow.Saying that, this is the setup I have and no worries....yet.

Hi Chris,

I'm going to take a guess that you have replaced the thermostat?

Other than that, you don't indicate what boost the turbo is running at.
Was the fuel pump turned up prior to the turbo install and not retuned afterwards?
What type of coolant are you using?

Other than that, have you removed the head to see what condition it and the head gasket are in?

While it's pretty difficult to diagnose a problem with out seeing the vehicle up close, if you are wanting further assistance you could try asking the question on LCOOL you will need to join the group, or hereOffroad 80's

Cheers,
Wayne.

Chris,

when they replaced the radiator did they put new upper and lower hoses in?

Mine did exactly the same thing on long hills towing my CT.

I did everything you did and eventually changed the upper and particularly the lower hoses. Because they were old and soft, on these hills they were sucking themselves thin and restricting water flow. If I backed off the accelerator the needle dropped.

Check your hoses.

Mine also had a turbo and intercooler. The intercooler sat in front of half of the radiator. Didn't help.

The temp needle never moved unless I was towing and on a long slow hill. I think you'll find it's more common in 1HZs than people are prepared to admit.

Solved it by buying a 200 series. No, just joking, check your hoses.

cheers

Yes i have replaced the thermostat. twice actually because the second time we actually checked the thermostat in water with a gauge to make sure it worked right!
Secondly im running 14 pounds boost, but must admit have the fuel turned up almost fully, only time i get smoke is on hard accelaration and changing gears. but as for cruising no smoke! even up a hill foot flat to floor no smoke! i have a 3 inch mandrel exsaust running right through.

But saying all this, prior to installing a turbo and intercooler it was doing this overheating before hand.

It hasnt become worse since the install nor better.
only time i dont have heating prob is in winter, im gueesing the cooler temps. must play a big part in it.

my EGT runing on highway is about 240 -280
hottest i can get it possible is 470 deg c
but ihave noticed if i am towing a small trailer on a long hill, if the EGT temp is from 320 deg up wards is when it will start to creap up on my gauge as the start of the overheating.

My aircond stops to work by this time so i am cooking with the Ute.

Ohh sorry, about the coolant I use the toyota recomended redish coolant. 50/50 as recomended by toyota themselves.

Hi I had this problem done all the things you did,I was in Darwin and went to a radiator place and the chap there told me quite common, the way to fix it was too fit a dual core raditor .Cost $650 fitted it almost twice as big as the old radiator solved all the problem, left Darwin with 19 ft caravan ,a lot of hot weather never a problem..,run cooler then ever it did ,I have a turbo fitted.This is a company in Vic Called Aussie Desert Coolers whom make these radiator.Very common up north with turbo Toyota.

Does you radiator stay brim full of coolant or does it use about half the top tank & then stop using water?

Chris,

You have tried everything to no avail, so I feel you may have a number of cracked combustion chambers. Have seen similar problems to what you are having in a 2H, and it had a couple of cracked chambers. From memory it may have had a cracked head too.

Pretty frustating, eh? From my experience with Toyotas, they rarely overheat, unless the radiator cores are blocked with mud, grass seed or insects. Have never had to resort to re-charging the viscous hubs, and have only ever replaced one water pump, and a couple of cooling fans.

Bob.

Hi Chris,

It seems you have tried just about everything but...

You say you have checked your gauges. What did this entail? Have you actually swapped the gauge sender unit with, say, the one from your friend's vehicle? Or tried a new one? Wouldn't be the first time a faulty/oversensitive sender has said an otherwise OK vehicle was overheating.

Even better would be to fit an accurate, calibrated coolant temp gauge to see exactly how hot the coolant is getting. Many standard vehicle gauges move to their 'normal' position (often just under half-scale) at the thermostat opening setting (typically 85-90 C), then don't move upwards again until the coolant temp is well over 100 C.

If I may be permitted a small 'plug': as well as reputable analogue gauges like VDO, etc. it is possible to display coolant (or any other temp you wish) on a Thermoguard EGT gauge by adding a second (or even a third) thermocouple in the appropriate place (such as the thermostat housing) and suitable switching circuitry.

Of course, it is only possible to display one temp at a time and the driver has to manually switch between the multiple inputs, but it gives you a very accurate coolant temp if you want it.

It's a while back now, but I'm pretty sure Roachie from this august Forum had his Thermoguard EGT set-up to switch between pre-turbo and post-turbo EGT.

Hope this helps.
Ian

Always amazes me.

The problems more widesread than you probably realize.

If I were you, and you don't already have it, I would add a large aftermarket oil cooler radiator out front, along with a supplemetal oil byass filter.

What this does apart from cooling the sump oil and stopping it becomming a heat sink for the excessive combustion temps buildup, is that it also increases sump oil volume a few liters - which also aids in the cooling of the oil and hence engine.

Not so hard really - your oil can help cool your engine just like your coolant if only you'll let it!

Cheers

Id be checking the head and possibly a crack in the bore some where ??? Have you had it pressure tested at all ?? This doesnt always work but its a starting point. Just because you are not getting any visible water in the oil doesnt mean it isnt leaking. It could be slighty blown but is burning it off. Head gasket can go either way, either water in oil, or oil showing in radiator, also bubblin up i your overflow radiator overflow bottle, but you would have obviously seen this yourself so my guess is as above, slightly blown but burning it off out the exhaust ??? WHG

Iccy
We had the same prob with ours, turned out to be the aircon condencer (?) in front of the radiator blocked with bugs.
Cheers Mac

I agree with the bloke from Thermoguard. I had a 2H with aftermarket Turbo with so called overheating problems. After spending a fortune as you have done, it turned out to be the Temp Sender, the bl--dy thing had corroded & you could see the internals. Replaced it & never had a problem again. A $10 part had cost me a small fortune.

Hi, well had the head off last year.
Had it checked and shaved.
put it all back together and still same.
the radiator is 2 weeks old PWR 2 core radiator. did make a small difference but not enough.
here is the image of the front of my cruiser, the bull bar is huge with lights.
ok i cant give you a photo, as i am not a financial registered user on here. but its a big arse aluminium bar. has aloy type of grill infront of the lights, maybe this is restricting air flow?
if you would like to see the photo, then Email me at pinpoint2@bigpond.com
And ill send you a photo.
Thanks again
Chris

Chris. My 1hz is 4.2 turboed and I carry a slide on camper giving me an all up weight of nearly 4 tonne fully loaded. I have done most of the desert treks and around the paddock with out any overheating probs, what I'm getting to is the fact that there IS definitely something wrong and your only solution is to keep looking. You would've changed your hoses when you changed your radiator, yes ? They can suck flat and restrict flow, other than this I have no suggestions.
Good luck. Rob.

I had a 92 75series a few years back. Much the same problem, ran fine until you hit a hill or really loaded it up. Ended up being a fractured head. It was not a big enough crack to effect under normal conditions but once it got past a point the temp went up. We found this to be the case by runnung it up in the workshop and sliding a sheet of cardboard in front of the radiator, after a period of time bubbles came through.
I currently have an 80 series with a similar problem, desert cooler radiator, toyota coolant, replaced thermostat, viscous hub etc, next step will be a proper water pump. They are not a standard, the fins are twice the size and the pumps are around $450.00. It is the only thing that has not been done to combat the temp going up.

Just to clarify, the 75 series was NON TURBO, my 80 series has an aftermarket DTS TURBO

Also have 1990 HZJ75 Trayback with 1HZ with 300,000kms. Never overheated before in its life. Put some Lightforce 240s on it and now when i go over 110km/h the temp goes up to nearly 3/4, it always sits at half or just under. Back off the throttle (110) and it drops back to normal. This is in day time, yet at night i can sit on 120km/h and no problem not a rise in temp. Same if its raining, no rise. I just put it down to the dry Kimberley heat and the big lights restricting air flow.. Have just this week flushed engine with the CEM stuff and had radiator flushed and am very happy with the CEM stuff. Oil is still clean somehow after 5 days.

I am not sure what your problem could be, but it sounds pretty bad if its overheating at idle, mine never rises at idle with air con on. My old SS used to overheat at idle but never when travelling even when giving it a bit of grief it never rose. But at idle and especially with air con on it would hit the red. I never figured it out as i never had to idle more then 20 seconds anyway.

Am going on a 2000km trip in couple of days so will report any changes i have found since flushing motor and engine. Will also be adding the CEM Fuel additive so will be monitoring my fule economy and performance also to see if there is any gain whatsoever.

Iccey, a couple of posts have suggested checking the top and bottom radiator hoses. You probably have done this but you haven't mentioned this in any of your lists of things done. A "soft" radiator hose (usually the top one) will give exactly the symptoms you describe.

Ok, one thing i havent done yet is replaced the hoses, now you have me thinking!
But mechanic said the hoses looked fine.
Then what explains the slight temp rise when on idle with aircond on? but if i idle with no aircond on then temp stays normal.

Ii didnt see any suction of hoses. actually the hoses were hard with a bit of pressure in them.

But no bubbling or water escaping anywhere.
i check my water level every morning and level is normal.

I figured if it is the head, cracked or something i would have lost water from pressure and gas inside radiator.
i will be getting the cem cleaner by tuesday and keep u all posted if it makes any difference, i dont believe in god but maybe i should start praying and hope something out of all this will fix what problem i am having.
Thanx
Chris

Been suggested a couple of times, check its not over fuelling.Fit an EGT gauge and see what temps you get.And Id try an after market temp gauge.We had a falcon that went into the red at every hill.Fitted a VDO gauge and it went to half and never went over it.Cycled nicely with the thermostat.

if you want horse power .dont try and make it , buy it..........

Sounds like you have change just about everything but didn't see that you had changed your temp sender, might be the problem.

I had overheating probs like you describe.

Went through most of your fixes. Things improved but....

Finally realized that basically I had a good guage. The temperature did go up on hills and under load on warm days. But came down whenever I backed off or on cooler days.

Did a few hundred k's. Motor just died... but don't think the overheating was a such an issue once I accepted the range the guage showed.

1HZ WILL run warm
i didnt think so but we had a hot spell and every 1hz work vehicle got warm enough to shut off the aircon
including the one with the clutch fan being replaced with a fixed fan and a new radiator

I got the 30,000km work 1hz boiling when i pulled up the other day and that has a brand spanker 3 or 4 core radiator (Dunno which it is much bigger than standard)

I don't know if this will help it does with 2H troopies.
Put some washers between the bonnet and the hinge bracket, this will lift the rear of the bonnet up a couple of mm allowing the fan to blow the hot air out of the engine bay at the windscreen.
Cheers
Dave

I, got the engine oil cleaner and fuel adative.(CEM) As one of the advertised products in the magazine.

Information given with product said to make sure i had more then 10 ltrs for the waist oil, actually they said 30% more capasity for all this sludje to come out of motor.I ran engine for 30 min!
well, no sludge and just the amount that went into the unit came out.
So i guess my engine is clean.
went for a drive and still hasnt fixed the overheating.

now ill try the bonnet lift. as i have nothing else to try.

Hi,

I know this may sound to simple, but a radiator cap of the wrong pressure will cause over heating.

Cheers