2007 hilux 1kd over heating under load

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Madaz7
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2007 hilux 1kd over heating under load

Unread post by Madaz7 » December 28th, 2017, 2:51 pm

Hey there, thanks for the add team.

I own a 2007 turbo diesel hilux, recently whislt on my way up the freeway heading to wombat state Forrest noticed my trucks air con went warm all of a sudden and about ten mins later whilst travelling up a decent grade hill ( pentlands ) my truck started to over heat temp guage reached 3/4, let the truck get back to normal temp roadside then kept going, didn't think to much of it being a 38 degree day. Kept going and no problems even all the way home ( Melbourne). I changed the thermostat to a 30% more flow one and swapped out the old fan hub. Took her for another trip back up the pentlands and she's done the same thing again!!! Had anyone had this before? Where do I start?

Madaz7
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Re: 2007 hilux 1kd over heating under load

Unread post by Madaz7 » December 28th, 2017, 2:53 pm

Also blows no smoke, even on start up no rattles at all, gets 600kms to a tank. I do have a bullbar whinch and spotlights tho,

Peter Aawen
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Re: 2007 hilux 1kd over heating under load

Unread post by Peter Aawen » December 28th, 2017, 4:02 pm

Were you in top gear or even worse, an overdrive gear & trying to maintain freeway speeds when the temp went up?? Maybe even doing that as you climbed a loooong hill under load?? Did you check to see if there was any smoke while it was under load & getting hot??

Still, the temp going up to 3/4 on a diesel generally IS NOT A BAD THING BY ITSELF!! It's only if there are other signs of over-heating that it becomes a problem! In fact, if you've got a diesel with a temp gauge that DOESN'T go up when the engine is working hard on hot days, or go down & drop below mid range when you engine brake/coast down the other side of that same hill or drop similarly on cold days when the engine is hardly working as you toddle around the flat roads of the 'burbs, then you probably need to get the gauge &/or sender fixed!! If it's behaving like that, then it's most likely been 'damped' to stop upsetting the incompetents who want to see it hit mid position & then never move, cos they just don't realise that an engine cooling system's temp MUST vary up and down as the engine load changes or something is drastically wrong with it!! :whyme: But ANY TEMP on the gauge which remains between the 'just off the stop/Low' mark & the High mark that's about 3/4's of the way up the dial but not yet into the red is actually NORMAL; and the coolant temp in a properly running diesel WILL & MUST vary in between those low & high marks (but should not go into the red) or your engine & cooling system is not going to be working properly!! Put simply and bluntly, engine & coolant temps WILL vary with load & speed, & your gauge should reflect that or it's dodgy, and that means you may not ever know the engine is really over-heating until it's waaay too late to save it!! Temp gauges on diesels, especially old school diesels, that never move are just WRONG, & have likely been doctored or set up specifically to do just that, possibly even at or by the factory, but it's most likely been done simply to stop worrying those poor people who have no idea of how their engine actually works & that the coolant temp does and MUST vary with changing loads! :petrified:

So your temps increasing like that could just be that you were pushing your foot down harder while trying to maintain speed up the climb & the engine just couldn't push the vehicle any faster but your heavy right boot caused over-fuelling & thereby over-heating followed..... you will generally find that if everything else is fine, simply lifting your foot a little & possibly changing down a gear so you are running a bit slower albeit at higher revs generally solves the 'getting warm' problem.... if it doesn't, then you'll need to look at flushing the rad, cleaning the core of all the mud &/or bugs that you've jammed in there over the years which is now blocking the essential cooling air flow; &/or possibly even back-flushing the rad & block as well as replacing the coolant with fresh stuff; also check that the fan hub is working properly, the fan blades haven't gone flexy over time, &/or that the fan shroud & all the other shielding that forces air to go thru the radiator is in place & functioning..... But generally, if your diesel only gets warm at highway speeds while you are pushing to maintain hwy speeds up a long hill, it's either over-fuelling cos someone's wound the fuel up too much searching for too much power out of an engine designed for relatively low rev lugging torque; or as outlined above, you are expecting it to drive like a petrol engined vehicle & diesel powered engines quite simply don't quite do that!! Back off at tad, change down a gear, drive to keep the revs in their sweet spot/range & not just to maintain freeway speeds, & remember that you hafta stir & use that gearbox selector lever to do that properly..... when you hit a hill in 5th & start to slow, then you should change down rather than just pressing harder with your right boot... drive properly based on keeping the revs in the right range, not just on using your right boot to maintain road speed in the highest gear possible. ;)

Good Luck!

Ps: did you fit a 'High FLOW' thermostat, or a colder temp thermostat? High Flow thermostats often make diesel cooling systems somewhat LESS tolerant & capable of properly shedding any excess heat load, because they may actually reduce the time the flowing coolant gets to remain in the radiator, thereby it ends up spending less time losing heat!! Once you've made sure that all the other things are working as they should, you are generally better off to just make sure that the stock thermostat starts to open at the correct temp & hits fully open at the correct temp than you are to start playing with different or a/mkt thermostats!! If that is already done & you know everything else is good but it still gets hot despite driving properly, then maybe you could try drilling just ONE extra 1/8th" dia hole in the flange to help help increase coolant flow juuuussttt a touch without letting the flow get too fast/volume of coolant moved too high/too quick... Colder temp thermostats that are too cold can mean the diesel runs less efficiently than it should & you might end up using more fuel & blowing black oily smoke cos the engine isn't getting hot enough to properly ignite the fuel when it gets compressed, which can lead to you pushing harder with your right foot, making it blow more smoke & dumping more cold fuel into the cylinders, thereby washing the necessary oil splash off the cyl walls & making things worse as they wear quicker too...... running hot enough diesel temps without overheating is fairly critical, & running slightly hot is arguably safer for a diesel than running slightly cold.... :purplex:
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Madaz7
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Re: 2007 hilux 1kd over heating under load

Unread post by Madaz7 » January 19th, 2018, 6:06 pm

Hey mate thanks for taking the time to post a reply!! Much appreciated, as a matter of fact it actually started to over heat the other day whilst on a flat and level road, I was doing the speed limit 100kph truck was driving fine no smoke at all never has done so, slowed down had the heater on, my temp pulled down and I drove another 90kms home with out a drama. Also I have blown my radiator out with compressed air and garden hose ( appreared to be debre free?) I have a new radiator which I will fit tommorw.

And yes I fitted a new thermostat, a tridon one which has 30% more flow? And also flueshed the system out and fitted genuine coolant to the vehicle and still overheated.

I can drive around town all day air con on and everythng is good. But when I put it under load in top gear it seems to do it but only sometimes. And also when it does the air con will stop working? Go warm.

Once again thanks heaps mate for your reply. If u do no anyone in Melbourne that could help me in anyway in the way of information would be much appreciated

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Re: 2007 hilux 1kd over heating under load

Unread post by Peter Aawen » January 19th, 2018, 7:44 pm

The Air con stopping/going warm when the coolant gets hot/overheats is normal & to be expected. It's the system trying to stop you from destroying the engine; once the coolant temp gets high enough it triggers a safety cut-out that shuts the air con down so the cooling system doesn't hafta contend with also trying to get rid of all the heat generated in the cab as well running under hot conditions. So keep that in mind & be grateful that at least that is working properly!!

When you say 'put it under load in top gear' do you mean 5th or 4th?? FOURTH GEAR is actually the TOP or direct drive gear (1:1 ratio) in most manuals, and Fifth gear is an overdrive.... so pushing your foot down harder to maintain Hwy speeds or climb hills in FIFTH in a diesel/turbo diesel is quite likely to cause over-fuelling and therefore high Exhaust Gas Temps (EGT's) which will do EXACTLY what you describe & potentially destroy the motor if you let your EGT's get too high! Especially if you've had the fuel wound up to get a little more power - go a FRACTION over what's ideal and you can cook things pretty damn quick!! Have you got an EGT gauge & a turbo boost gauge? Well worth getting a good set & learning how to drive properly off those & what they can tell you - unlike a petrol engine, diesels often run best travelling slower at higher revs in a lower gear just to keep the EGT's low - anything over 500 deg C from a thermo-couple about 150mm on the exhaust side of the turbo outlet flange means your in-turbo & probably in-cylinder temps are getting dangerously close to melting metals!! And your cooling system simply CAN NOT handle those sorts of temps!! If your diesel hasn't had the fuel & injector system checked & tuned lately, then it's a good idea to get it done - and if you or anyone else has wound the fuel up to get more power, then that's probably the cause of your problems & you need to wind the fuel back a bit!!

Anyhow, see what the new radiator does, only make absolutely sure that you purge all the air pockets out of the cooling system before expecting it to withstand hwy speeds &/or loads. To do that, once you've changed the rad, then sloooowly fill it with coolant, and once you are up to about 1/2 volume capacity, do it with the engine running. Then, with the front of the car raised so the rad cap is the highest bit of the cooling system, let the engine fast idle FOR ABOUT 30 MINS or at least a couple of open/shut cycles of the thermostat and the viscous coupled fan. And keep the radiator filled the whole time - watch it fairly closely & add coolant as soon as the level in the rad cap/filler neck drops (you can leave the overflow tank disconnected while you are doing this! It is designed to accept the excess coolant as it expands when things warm up, and the sealed system allows all the excess to be sucked back as things begin to cool after you shut down!) Still, fill the rad slowly with the proper coolant & then run the engine at fast idle for long enough to purge any air pockets trapped in the block, which means at least 30 mins or so or those two or more cycles of the fan hub/thermostat - and while you're doing it, big bubbles in the system are generally good news (just add coolant as needed to keep the coolant level up above the radiator fins after every one that drops the level) they are the air pockets purging, but if you have lots of little foamy style tiny bubbles, then you've probably got a cracked head or gasket! Do the purge PROPERLY - taking too long than necessary is MUCH BETTER than doing it too quick & leaving an air pocket trapped in the system - that can do what you describe pretty quickly & not cooling things down soon enough may mean a dead engine!!

Now, if you've done all that & it still overheats, pull the new thermostat & replace it with a NEW OE spec Toyota part. Many a/mkt parts in the cooling system just aren't up to doing the job exactly like the OE Kit, so sometimes you just gotta stick with genuine, especially with thermostats & fan hubs! Sorry!! You might want to try adding a single 1/8 in dia hole in the skirt of the thermostat, just to improve closed coolant flow; but testing the thermostat on the oven top for accurate starting opening & fully opening temps is often the only way you'll realise that the a/mkt bits just might not be doing things properly or at the right times to match the viscous hub &/or thermostat starting/fully opened!! You might need to check that the water pump still has fins so that it can actually move water too...

And if you've done all that and it still overheats as you describe, then either just slow down, or start looking for things like bends or blockages in the exhaust system, they can push EGT's to dangerous levels - even just a slug of mud in the tail pipe, or maybe a loose baffle in the muffler that's restricting exhaust flow can cause things to overheat dangerously!! So, for that matter, can a restrictive turbo outlet/dump pipe - so if you got a free flowing after market exhaust fitted, maybe put on if you ever increased the turbo boost & wound the fuel up chasing more power (or got a chip fitted or whatever), just check the EGT's or the pipe temp on the dump pipe immediately after the turbo whenever things get hot - 550 deg C is the absolute limit post turbo, 500 deg C is generally considered the 'safe operational limit' - you can usually use one of those infra-red or remote sensing thermometers to check - but a turbo diesel REALLY SHOULD have both an EGT gauge AND a boost gauge, or you risk cooking things just by not operating the loud pedal appropriately in response to what your EGT's & boost are doing!!

Good Luck!
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thedjs
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Re: 2007 hilux 1kd over heating under load

Unread post by thedjs » January 25th, 2018, 11:15 pm

I had the same thing recently with my 2002 turbo diesel, uphill towing the camper trailer, it turned out to be a simple fix. The viscous fan had stopped working how it should be working to cool the engine. You could spin the fan backwards while the motor is running at 1000rpm. That was my car not saying yours will be the same.
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