2.8 diesel 4 runner overheating issues

[Oldhenry]

Hey guys. Old man had got an issue with his 2.8 turbo diesel 4 runner. It has a Denco turbo system on it and just had the head replaced but now when driving up hills it's heating up. When using the a/c it's worse again. Cooling system has been flushed and a new thermostat. My ideas were to check the boost being run and amount of fuel and replace the viscous fan and water pump but does anyone have any knowledge about and other issues to look for. Once he is over the hills and on a down hill run or on the highway it's fine just when he even looks at a hill he is back to second to keep the motor steady.
Cheers Daniel

[tweak'e]

why the new head?

most likely radiator, especially if they didn't cut the tanks off and clean it.
also check thermostat.

the other thing is timing. may have gotten cam or pump timing out.

[CRUZAAMAD]

my mechanic, rebuilt my 2h, had overheating issues, thought wounding the fuel screw right up will fix it.
got sick of it and left it, then natrad got onto the viscous coupling and fresh oil, fixed, had the pump serviced and the fuel screw was soo overfueled it was gutless, once redone it revved freely.
mechanic decided couple years ago to drink roundup to fix his troubles.
it done the job too, i later found out.
get onto it quick, do the cheap stuff first then do the big bucks when all else is checked over. not waste coin

[brad 93hilux]

I chased my over heating problems in my lux for years replacing whole cooling system (no good) then went to a 3.0L EFI diesel.. (Exactly same- motor had 70,000kms on clock and never overheated in donor car)
Even was told bonnet scoop was the problem (removed it, still
No good)
I can change my current 5Le motor from 7-7.5psi to 14 psi boost (doesn't leave 14 now) and its exactly the same..
The ONLY thing I didn't do was go a bigger radiator over standard..
I just have two temp gauges now and drive accordingly to temp ie- back off at 120 degrees and don't let it go over 125.

I know this doesn't help but I tried everything mechanics and guys on this forum suggested..
Good luck buddy, hope you do better then me

Brad

[Mr DJ]

Brad, I'm guessing your using the 5LE fan and have put new viscous fliud in the fan hub ?
You can also adjust the fan hub (while it's open) to start locking up earlier if you want it to.
Using higher CST grade fliud will make it lockup more too.

[brad 93hilux]

Yeh I used the 5le one as it was a lot newer, i also put 3 tubes of silicone grease in it, the fan does work really hard, I chased it for ages and just gave up spending more money.
It's only on the highway it gets hot or long sweeping hills when boost is on constantly for long periods.

[frodog]

Try replacing the fan hub oil, also are the rubber flaps still in the inner guards, attached to the chassis? These help isolate the radiator as the only way for air to get into theengine bay and then exits at the back of the bay, sort of drawn thru like a venturi idea. I had removed mine after a body lift and an old dude told me about the flaps and it helped mine heaps.

[brad 93hilux]

Check/ replace thermostat
Pressure test / clean radiator / new radiator
Check between radiator and shroud it is sealed (usually foam) so fan does not suck air that's not coming through radiator
As said pull off viscous fan hub and repack with tubes of silicone grease (buy from Toyota)
Ensure nothing is blocking radiator ie- lights badly dented a/c condensor in front of radiator
Can get dyno test done to ensure fueling is right as setup wrong it will make it overheat
I was told bonnet scoops without a intercooler disrupts air flow under bonnet and best to remove them as there is not as much draw through radiator
Can try to space up back of bonnet between hinges and mount which helps draw more air through radiator
Was told by a lot of guys (did alot of research) not to remove viscous fan and go thermo fan, apparently a repacked viscous fan is more efficient

This is what I tried
Good luck

[Mr DJ]

One thing I did try was running the coolant hoses from turbo through a trans cooler before going back into the main system.
Worked ok for temp spikes from hard working turbo, but keeping trans cool was a higher priority for me with limited space to put 2 coolers.

[Oldhenry]

They guy we bought it off threw a timing chain and destroyed the head. So it was replaced. Radiation has been flushed and the thermostat. The only problem is driving hills not when normal driving is done so my thought was maybe too much boost and fuel. He is getting the fan hub serviced this coming week. Fingers crossed. Cheers for the ideas

[brad 93hilux]

My truck is exactly same around town or 4wd'n it will never get hot just on highway or long hills.

My kit is a turbo glide kit with a garret T25 and these don't get setup with water coolant, I thought since they are only oil cooled and there is a factory oil cooler on the side of the block (cooled by water coolant) boost was heating oil more then the radiator could get rid of the heat. I even tried a top mount large oil cooler under bonnet scoop to try to cool the oil to help but didn't really help much.

But at least you have a few ideas to try.

Brad

[Oldhenry]

Yeah I think a cooler of some sort wouldn't go astray for the turbo itself and was thinking about an oil cooler to keep oil temps down but I didn't know if they were much chop.
On another note that truck of yours brad is a weapon. I'm hoping to do similar to mine within the next few years when the house is pretty much paid of. Just can't justify the coin ATM. Great build thread too. Cheers for the input here.

[old ed]

I'm having the same issues with my hzj75 troopy.I gave up on the fluid clutch and locked it up. It made it a little better, but I still have to be careful when towing my van or travelling fast. Around town or short trips, no problem. Hard work on cool days ( ambient less than 30 ) is usually ok too. My next step is to bypass the inbuilt oil cooler and dump the heat outside the engine bay. That should reduce the load on the radiator. I've got the filter sandwich plate fitted already. Once I get the plumbing organised I'll post the results, good or bad.

[howesy]

aussie desert cooler triple flow radiator,,, worth the dollars and 3 tubes silicon oil in the hub with sealed shroud, street and strip aluminum may be avail now too I got one for the cruiser and its choice