Overheating Troopy

Submitted: Sunday, May 19, 2013 at 14:49
ThreadID: 102295 Views:4575 Replies:9 FollowUps:5
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Hello all, I have recently upgraded my 94 diesel troopy 1HZ to a 1HZ upgraded to 1HD with an after market Denco turbo not intercooled. New radiator same size as original, fan checked by Toyota and new 3 inch exhaust, clutch. In short we bought a caravan and GVM is 3 tonne but more likely 2.5 when we go away. The troopy has heaps of power but when we hit a hill or a long slow rise the turbo heats up to 500+ deg and the radiator comes up to the boil. Things get touchy if the hill is to long and the troopy just wont cool down until im rolling down the other side and it comes back to norm pretty quick, drives normal with no overheating all-day when not towing. Have had the timing checked and now scratching with nearly $20,000 spent on motor and turbo with all the other bits and pieces. Should I put a intercooler on turbo or just put a huge radiator in it. have been quoted $1000 for this radiator that is one extra core but smaller tubes. Any other suggestions to keep it cool would be appreciated. Tows at 90klms/hr alright till you hit a rise, but wont tow at 100klms/hr the temp starts to creep up.
Thanks in advance
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Reply By: Dust-Devil - Sunday, May 19, 2013 at 15:31

Sunday, May 19, 2013 at 15:31

Install a EGT guage and drive to that. Expect a minor cardiac arrest when you first fire it up and see what the EGT guage is telling you.


AnswerID: 511383

Follow Up By: Ross M - Sunday, May 19, 2013 at 18:25

Sunday, May 19, 2013 at 18:25
Dust Devi
As Coogs already knows his EGT's go to 500 then it would follow that he already has an EGT gauge and won't have to fit another one.

Not unless he wants to know PRE and POST.
FollowupID: 789616

Follow Up By: Dust-Devil - Monday, May 20, 2013 at 01:34

Monday, May 20, 2013 at 01:34
Re - read it and see what you mean.

Seeing as how he stipulates 500Deg+, it is anticipared that his EGT thermocouple is post turbo and someone has mentioned something to him about 500C for post turbo's EGT sensors.

If that is the case Coogs should be driving to the EGT gauge and doing his level best to keep at or under 500Deg.

It's amazing what a gear change or two will cause the EGT to do.

Very similar exercise to the dudes on this forum who instal Scan Gauges so they can monitor transmission temps whilst towing. This alerts them when the temp gets near or reaches a critical point and they manually shift down a gear or two so that it runs cooler

FollowupID: 789662

Follow Up By: Coogs - Monday, May 20, 2013 at 07:45

Monday, May 20, 2013 at 07:45
Dust Devil,

Yes I had a EGT gauge fitted with the Denco Turbo and was told that 700 deg is melt motor temp and that it should be kept under 600 if possible, the prob is that if the turbo is worked hard for to long as in a hill, the temp rises and the longer it takes to climb the hill it affects the motor temp.
FollowupID: 789665

Follow Up By: pop2jocem - Monday, May 20, 2013 at 11:20

Monday, May 20, 2013 at 11:20
Hi Coogs,

What gear do you tow in?
What RPM do you downshift at?
Do you have a boost pressure gauge and if so what max boost pressure do you get?
Does it make any difference with air con on or off?
For what my humble opinion is worth you have two separate but possibly related problems.
I replaced the 1HZ engine in my old 75 series with a 1HD-FT, standard fuel settings and standard turbo and had the standard radiator rodded and cleaned. I removed the air con condenser from in front of the radiator and had a different unit installed on a roof bar. I did all this to tow a caravan. I noticed that the coolant temperature hardly went above 87 degrees C even in 40+ ambients. The turbo waste gate kept the boost pressure at 10.5 psi but the exhaust temp would climb to 550 C and would probably have kept climbing if I had not downshifted even though the RPM was above 2000. I bypassed the waste gate sensing hose via a control tap so that I now get around 12 psi max boost and the exhaust temp has dropped around 50 degrees C in most situations and never gets above the 550C mark no matter how long the hill. I did not increase the fuel settings as I consider the power adequate for my needs and I was after keeping the exhaust temp down.
Hope I didn't bore you too much with all that (;-))

FollowupID: 789682

Follow Up By: Coogs - Monday, May 20, 2013 at 16:02

Monday, May 20, 2013 at 16:02

I usually tow in 5th if its easy goin, but I quickly learnt that gear selection is most important with this turbo. I change down pretty quick if I see a rise looming or hear the engine noise change and try and get some speed up. I don't have a boost gauge fitted but the dyno tune set the boost at 9 psi as I only wanted it for towing the van not hooning and engine life is more important to me than speed. I will think about moving the air con condenser but im not sure about roof bar. Can you send a pic of your setup for my ref? I have removed spoties and even belly plates to create air flow while towing but still heated up on way home from Tallebudgera recently. The thermostat is 83 deg according to engine installer which is same as 1HD motors with turbos. Im not sure about the waste gate sensing bypass but will go back to dyno and ask. I think I will start with moving the air con condenser and fitting an intercooler before putting a bigger radiator in. Thanks for the advice and stats, it gives me something to start with. I just want to be able to tow our van at 100 if possible without any hassles or overheating.
Email: dirtydeedsdingohire@bigpond.com
FollowupID: 789710

Reply By: Rockape - Sunday, May 19, 2013 at 15:41

Sunday, May 19, 2013 at 15:41
in the later tojos, Toyota put in a radiator that was about 50mm longer. That was fitted to the 78 series and did give much more cooling to the narrow fronted vehicle. This is the Toyota Part No. 1640017360. I think these were fitted to the vehicles around 2001. I know this radiator made a big difference to mine and she never ran hot.

Another thing is now you have more power you maybe leaving it in to tall a gear and it is over fuelling. Just try easing up a bit and coming down one or two gears, that will also allow more air through the radiator from the fan. I never let my old girl get below about 2200 revs on a climb.

If that fan is working ok you will differently hear engage when the temp rises.

I am sure you would have checked the normal things like the thermostat.
AnswerID: 511384

Reply By: Cravenhaven - Sunday, May 19, 2013 at 15:59

Sunday, May 19, 2013 at 15:59
I'm surprised that you didnt put in an intercooler when you upgraded to the turbo. It might well be worth considering as a solution to your overheating. The turbo works by compressing the air thats going into the inlet manifold so that more oxygen is gulped in on each inlet cycle, the trouble is that when air is compressed it gets hot. You are probably increasing the inlet air temperature by 80 degrees when under load so its no wonder the radiator is struggling to cool it down.
A well designed intercooler can get the temperature of the inlet air back down to a few degrees above ambient and the boost in power from the intercooler would be significant and noticeable.

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AnswerID: 511385

Reply By: Member - john y - Sunday, May 19, 2013 at 17:01

Sunday, May 19, 2013 at 17:01
G'day Coogs, for what its worth had an identical problem .After many $$$.s New head pump reco the problem was that the rubber elbow on the turbo inlet had deteriorated and had expanded to 2-3 times it's normal size. Under hard acceleration {hills} the elbow would collapse and restrict the airflow to the turbo causing power loss and. immediate temperature spike .Backing off and everything reverted back to normal.On the flat @2400 rpm no problems. The elbow should be 2 1/2 " Dia. hope this may help. Regards john y.
I will go anywhere as long as it's forward

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AnswerID: 511389

Reply By: BAD4B - Sunday, May 19, 2013 at 23:12

Sunday, May 19, 2013 at 23:12
First i would Upgrade the radiator.it will make huge difference, but dont buy the cheap chinesee ones.PWR radiators recommended, its not cheap but worth it.it did solve my overheat problem . Also think about oil cooler and intercooler as well.
AnswerID: 511422

Reply By: howesy - Sunday, May 19, 2013 at 23:29

Sunday, May 19, 2013 at 23:29
aussie desert cooler street and strip full alum. one works a treat
AnswerID: 511423

Reply By: mountainman - Monday, May 20, 2013 at 21:06

Monday, May 20, 2013 at 21:06
stick with the factory brass setup, fit a bigger radiator, either up the core or a larger radiator agian.

the ally ones are not the go.
not many shops can weld ally, and they fatigue crack soo much easier than a brass radiator.
your better off with a natrad radiator.
australia wide backup, quality brass radiators.
and friggen cheap when they clean them out.
charged me a 120.
they pulled the radiator out, cleaned it, and new coolant.
i couldnt even do it for that.. soo CHEAP.

ally radiators have no place in 4wds that go offroad.
corrigations, spoon drains and washouts would kill a ally radiator.
then theirs the cost.
way too dear !!

other option is fit a oil cooler to the engine to assist engine temps.
to help it out some.
they make some pretty cheap ones now. well priced.
AnswerID: 511471

Reply By: Tim HJ61 (WA) - Saturday, Jun 01, 2013 at 23:25

Saturday, Jun 01, 2013 at 23:25

So, you have your EGT pickup pre turbo?
Assuming so, then your numbers are all good re the turbo. If you are reading 500°C POST turbo, that's too much!

Seems like you're fuelling is set about right with 9psi on a turboed 1hz, and the EGT you are getting.

Installing an intercooler would reduce your EGT by possibly 100°C. Whilst the EGT are not a problem at the moment, EGT are also an indication of load on the engine. If you can reduce the load on the engine, and increase it's efficiency, it may very well help keep the coolant under control. An intercooler would help achieve this. It would also block airflow to the radiator - unless you got a water to air unit. Even then the WTA radiator needs to dissipate a lot of heat and will block air to your radiator.

Is your fan clutch working correctly? Do you hear it roar when the temps rise? Of course the fan coming on adds load to the engine whilst it is trying to give more airflow, increasing pressure on the cooling system.

There is always a pay off with power, and getting rid of the heat. Reducing your load, changing down, slowing down, will be the cheapest option for what otherwise seems like a reasonable setup. You might have simply found the limit to a happy setup.

When I added a 600mm FMIC to my HJ61, it covered the entire radiator. But because it aided engine efficiency, I didn't notice any decrease in cooling system effectiveness. I also have a high performance GTurbo and 3" exhaust, run 19psi and maximum fuel supply from the IP in my 12h-t. It tows well with 470nm of torque, but has it's limits.

If you had installed a full 1HD-T with it's direct injection, factory turbo, oil squirters to keep the pistons cool etc etc, you may have had a better outcome, or a 1HD FTE, or a V8 etc etc - but that's not what you've got. Maybe your expectations to tow a 3T van at 100kmh with ease are unrealistic. How much you're prepared to spend on an intermittent problem that can be controlled by your right foot is only a question you can answer.


AnswerID: 512350

Reply By: Coogs - Thursday, Jun 13, 2013 at 14:00

Thursday, Jun 13, 2013 at 14:00
Thanks for all the great advice, I have decided to get an intercooler Air to Air and it gets mounted under the bonnet with a bonnet scoop fitted to direct air straight into the intercooler. The bonnet scoop is a patrol type scoop with a rubber seal to join bonnet to intercooler when bonnet is closed. Has anyone got one of these fitted on a troopy or Toyota landcruiser and how efficient is it in dropping the EGT's down? What price is it fitted roughly and where or who did it. I am in Brisbane. If someone has a pic of one could you email it to me please.

AnswerID: 513050

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