HJ80 Diesel Radiator

Submitted: Thursday, May 20, 2010 at 19:39
ThreadID: 78623 Views:3183 Replies:9 FollowUps:10
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My Non Turbo HJ80 runs hot (just over 3/4 on the gauge) when the engine is under load. Ambient temp under 22deg is ok. As soon as I back off the temp gauge will come back down to normal.
It has a almost new non genuine Radiator fitted and I have been told that I need a Genuine Radiator to fix the problem.

Can anyone offer some advice if they have experienced similar problems and how did they fix it.

Thanks

Wayne Bell

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Reply By: Member - Toyocrusa (NSW) - Thursday, May 20, 2010 at 19:44

Thursday, May 20, 2010 at 19:44
Hi Wayne. The fluid coupling for the fan drive deteriates over time. Possibly needs the silicon fluid replacing. regards,Bob.

AnswerID: 417421

Follow Up By: Member - Wayne B (NSW) - Thursday, May 20, 2010 at 20:02

Thursday, May 20, 2010 at 20:02
Have checked that and it appears ok. I can 4wd all day low speed driving and there is no problem with overheating. But under these conditions the engine is not under load for extended periods of time.
Only occurs on long pull up slight incline or when working the engine for an extended time say 10 minutes under full load fifth gear between 95 and 110kph
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FollowupID: 687540

Follow Up By: get outmore - Thursday, May 20, 2010 at 20:25

Thursday, May 20, 2010 at 20:25
no real way to easily check it. except when its running warm quickly pull over and pop the bonnet and turn it off - if it keeps spinning - thats your problem

after market radiators work just fine



just reaplace the silicone fluid - takes less than an hour and has always worked for me

heres the step by step procedure

How to replace Silicone in an 80 clutch fan
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FollowupID: 687544

Follow Up By: Member - Ian H (NSW) - Thursday, May 20, 2010 at 20:27

Thursday, May 20, 2010 at 20:27
Yep, what he said.
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FollowupID: 687545

Reply By: Hairs & Fysh - Thursday, May 20, 2010 at 20:29

Thursday, May 20, 2010 at 20:29
Hi Wayne,
I believe you wouldn't need a Genuine Radiator to fix the problem. someone is have a lend of you. I'm about to soon, replace my stock radiator with an after market 4 core, cause my 1hd-t's radiator is a little on the sad side and last summer she got a little to hot pulling the camper at just over a 115k's an hour. I believe they are worth about $680 to $720 depending on where you go. This is Repco and NatRad prices.
Just check to see if the fins aren't clogged to start with. Are you running the correct coolant mixture for your model? Do you have big spotties up front?
Maybe you have a stuff thermostat, they can cause dramas.
I put a piece of fly mesh behind the grill and it stop a lot of bugs and seeds from clogging the radiator.
Still could be the fan clutch fluid/silicone.
Process of elimination I guess.
Hmmm

AnswerID: 417435

Follow Up By: Member - Wayne B (NSW) - Thursday, May 20, 2010 at 20:47

Thursday, May 20, 2010 at 20:47
Ok I will do the Fluid in the fan clutch first.

I removed the spotties only made a slight difference. I guess you are right with process of elimination. I thought it may have been the water pump not circulating the coolant fast enough, I dont know what the impeller is made out of if it is tin then it may be worn away??. Also thermostat although I dont think so as it cools down very quickly when I back off the accelerator.

I also thought the aftermarket radiator should be ok. That was one of the reason I posted to see if anyone else had problems with these radiators.
Cheers
Wayne B
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FollowupID: 687548

Follow Up By: Hairs & Fysh - Thursday, May 20, 2010 at 20:57

Thursday, May 20, 2010 at 20:57
Hope you find the culprit,
Nothing worse than a vehicle that overheats.

Keep us updated, Cheers.

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FollowupID: 687550

Reply By: Michael ( Moss Vale NSW) - Thursday, May 20, 2010 at 20:43

Thursday, May 20, 2010 at 20:43
Wayne, have a look at your thermostat, some have a smaller centre disc that opens in the middle and could cause low flow, worth a check..Michael
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AnswerID: 417441

Reply By: nowimnumberone - Thursday, May 20, 2010 at 21:12

Thursday, May 20, 2010 at 21:12
i wouldnt say your cruiser is over heating just getting hotter from the load
if you look at most temp gauges normal is anywhere on the temp guage alll the way up till the red bit right at the top.unless its going into the red i wouldnt worry about is because if the engines under load of course it will be hotter. non turbo 80s arnt a power house ive driver hour after hour in the sand with the guage way higher(but still under the red bit)than normal and no probs.also as a mechanic in the 4wd trade ive saved people heaps of money for unneccesary repairs/extras for something thats just normal. i think people panick when the guage isnt sitting in its normal spot id start getting woried if it was running in the red.
cheers
AnswerID: 417446

Follow Up By: Michael ( Moss Vale NSW) - Thursday, May 20, 2010 at 21:26

Thursday, May 20, 2010 at 21:26
Its a common problem with 4.2TDI GU's from new, sustained load, towing will do it everytime.. Michael
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FollowupID: 687559

Follow Up By: get outmore - Thursday, May 20, 2010 at 21:48

Thursday, May 20, 2010 at 21:48
thats just not true

Tojo gauges are desighned to sit level over quite a wide temp range. The minute they deveate up it means there getting pretty darn hot. its at this stage the aircon will shot off and if you pull up to quick they will start to boil

by the time they get anywhere near the red your starting to run some pretty high temps and you have to idle them down for quite a while to prevent boiling on switch off

we run tojos flat stick in low range and any movement in the gauge indicates a cooling problem which shouldnt be occuring
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FollowupID: 687562

Follow Up By: Member - Amy G (QLD) - Friday, May 21, 2010 at 07:58

Friday, May 21, 2010 at 07:58
Don't agree on this one- the factory gauge on an 80 only rises above half when the temp is going up rapidly (checked against digital gauge). If things are ok in cooling system land then it generally doesn't get above around 92 degrees before the thermostat opens fully and the temp reduces, and this is within the dead spot on the factory gauge.
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FollowupID: 687586

Reply By: Member - Phil G (SA) - Thursday, May 20, 2010 at 21:43

Thursday, May 20, 2010 at 21:43
My daughter has a 1997 HZJ80 and had the same overheating problem when she bought it last year. There are many things that contribute, so we went through them all and found the following:

#1 Radiator core was 60% blocked (top tank removed and core rodded).
#2 Lower 1/3rd of air cond condensor was full of mud and grass
#3 Lower 1/3rd of radiator fins were full of mud and garbage
#4 Thermostat removed and tested - found to be opening 5 degrees higher than specs - replaced with new Toyota thermostsat (only $30) that tested fine.
#5 Fan clutch removed, and disassembled - found to be OK, just added a few mls of Toyota silicone fluid.
#6 Threw away the useless driving lights.
#7 While we were there, replaced water pump, belts and hoses incl timing belt. New Toyota coolant.

She runs a temp alarm (TM2) and now the temperature never rises.

I doubt the aftermarket radiator would be an issue with a standard 1Hz. If you had an aftermarket turbo, it might.
AnswerID: 417451

Reply By: Muntoo - Thursday, May 20, 2010 at 21:56

Thursday, May 20, 2010 at 21:56
Mate, i had the same problem with a 75 series. Run for days at 100km/h and temp wouldnt move, but as soon as you hit 105km up she went.

Got radiator cleaned and flushed, new hoses, new belts, new water pump, new radiator cap, radiator was fine so left it alone, fan was fine, had me stuffed for 2 years. Sold vehicle to a mate, had him stuffed for 6 months, he fitted extractors and it run a tad cooler. Wow, problem solved we thought, but it wasnt to be. Next day he just happened to try a newer radiator cap of another 75 series and BINGO. The other radiator cap was new but must have been faulty to begin with. Now has a brand new radiator cap and he can run at 120km/h without a drama in 40 degrees with air con on. Process of elimintaion mate, start from the smaller things like the cap and hoses, then work your way up.
AnswerID: 417453

Reply By: PeterInSa - Friday, May 21, 2010 at 11:29

Friday, May 21, 2010 at 11:29
Wayne,
You do not say whether your vehicle is a manual or an auto, had a similar problem with a auto statesmen and connected up another auto trans cooler in series with the original and also installed a larger radiator.

As said earlier would also check the Thermostat, the pump and the radiator cap, which I did also but for piece of mind a bigger radiator for touring (coming home) on 40deg days/nights especially if your coming home to NSW from SA.

Peter
AnswerID: 417526

Follow Up By: Wherehegon - Friday, May 21, 2010 at 14:15

Friday, May 21, 2010 at 14:15
Would be a manual, only made auto in the petrol and turbo diesels, only the 100 series non turbo diesel come in auto or manual.
Wayne, If you havent been playing in the mud and you havent filled the fins with seeds/grass/mud etc then my guess would be either the thermostat isnt opening all the way so is ok at lower revs allowing enough cooling but not at higher speeds. Id go the fluid clutch coupling first, either pull apart and replace the fluid (this is also not a definate as the spring on the front of the coupling could be stuffed due to age, or Id but a new one. Personally I would go genuine, yes they are alot dearer but have heard of people buying after market ones and having the same problem, I was even told this by the spare parts shop I was going to get myn from and he could have easily have made some $$ from me but said go genuine. This is an extremely common problem on all the 80 series. Some people say the clutch fan doesnt lock in when at highway speeds, that is crap, They will lock in whenever they need to, some vehicles you can even hear them cut in, some sound like a jet winding up and the same when they unlock, its all detected by the metal bi spring that runs across the centre of the clutch coupling at the front detects the temp of the air flowing through the radiator onto it, when the air is hotter then the setting on the spring it does its job unlocking and locking when ever needed. Normally toyota temp guages only move 2 to 3mill either way once they hit there normal runnning temp on the guage, for them to move more then a couple of mill indicates possible problems. Check also if the bottom radiator hose isnt sucking itself together, possible if hoses are old or are cheap crap non genuine replacements, they are generally very thin where as genuine are very think, I wouldnt touch one if it has the metal spring inside as they break up with age and guess where they end up ??.........Regards Steve
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FollowupID: 687625

Reply By: Member - Wayne B (NSW) - Saturday, May 22, 2010 at 08:36

Saturday, May 22, 2010 at 08:36
Thanks for all your input.
I will start with the Fan Clutch and Thermostat.
Then water Pump.

Agree with one comment re temp gauge reading. If the temp rises and you stop quickly without letting the engine return to normal temp then the radiator will boil
Temp gauges should not go up and down like a lift like my one dose. I am confident the engine is overheating not just a dud gauge reading.

Went to Auto Pro today asked for fan clutch oil. Bloke came back with Genuine Toyota 10000 Silicon fluid. I Did not believe they would carry the stuff saved me a 1/2 hr drive to the Toyota Dealer.

I will have to wait till the ambient temp gets over 23Deg to test the vehicle after I have done the Fan Clutch. Too cold here at the moment.

Cheers
Wayne
AnswerID: 417630

Reply By: Member - Wayne B (NSW) - Saturday, May 22, 2010 at 12:08

Saturday, May 22, 2010 at 12:08
Did the Fan Clutch today. Added additional oil.

Noticed that it is very stiff when cold but has very little resistance when engine at normal operating temperature.

The ambient temp is too cold to test the overheating

Cheers
Wayne
AnswerID: 417648

Follow Up By: 2517. - Monday, May 24, 2010 at 17:51

Monday, May 24, 2010 at 17:51
Dual Core Radiator is the way to go,I tried all the other things.Had the job done in Darwin ,owner told me common problem up there,after fitting new radiator towed 21 ft caravan 40,000km all good,did not matter how hot it got in the west.
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FollowupID: 688013

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