WTC's overheating MN problem

[Maxiy]

I was told that under low range 4x4 conditions the engine will get hot [No...der!] and this is normal.

When pulling up the clyde, my MN sits around 92-95

When i was in the vic high country late last year, did a full day of driving in low range, up some very steep muddy climbs, generally hovering around 3000rpm, the truck comfortably sat between 88-92

I am no mechanic, and the following statement may be wrong (so someone please correct me), but i tend to find that the temps REALLY start to climb when i push it up hill in a gear that is too low, subsequently the revs drop. I assume this is because more fuel is being pumped into the engine by putting the foot down, but because the revs are down, the turbo is not being very efficient, so you get a hotter burn.

With that said, my MN has never got over 96.

[RHKTriton]

Just curious, how thick is the radiator core in your unit? I was surprised that my son's 09 mn auto had the thicker core whereas my manual ml only had the pissy 16mm unit.

Since fitting the 28mm core, I've not seen the temp gauge rise more than a needle width, even on the recent 40degree days.

Have you considered bypassing the auto cooler in the radiator and fitting a larger, second auto cooler?

This should take some of the heat load out of the radiator and up the auto cooling. Might have to revert in winter to help warm up auto.

One idea I've been playing with is venting the engine bay somehow ( bonnet or guard vents), mainly to get some of the turbo heat out.

[wildturkeycanoe]

Just curious, how thick is the radiator core in your unit? I was surprised that my son's 09 mn auto had the thicker core whereas my manual ml only had the pissy 16mm unit.

Since fitting the 28mm core, I've not seen the temp gauge rise more than a needle width, even on the recent 40degree days.

Have you considered bypassing the auto cooler in the radiator and fitting a larger, second auto cooler?

This should take some of the heat load out of the radiator and up the auto cooling. Might have to revert in winter to help warm up auto.

One idea I've been playing with is venting the engine bay somehow ( bonnet or guard vents), mainly to get some of the turbo heat out.

I like the bonnet vent idea. My bonnet paint is fading in the middle, I reckon bc of the heat in the engine bay. Popping the hood after driving, you can't even touch the airbox lid it's that toasty.
I agree about getting the trans fluid away from rad, but space is at a premium under there. Gonna try extra cooling fan first, then failing that, tackle larger trans cooler

[RHKTriton]

A common mod on the old Cherokees was fitting spacers to the bonnet hinges to allow air out of the engine bay.

The three issues I see with bonnet vents is meeting the ADRs for pedestrian impact and the possibility of oil getting on your windscreen, if something craps itself. Also the possible path for fumes finding their way to the cabin air intake.

Maybe you could relocate lights out of the bull bar to use the holes as inlets?

[wildturkeycanoe]

A common mod on the old Cherokees was fitting spacers to the bonnet hinges to allow air out of the engine bay.

The three issues I see with bonnet vents is meeting the ADRs for pedestrian impact and the possibility of oil getting on your windscreen, if something craps itself. Also the possible path for fumes finding their way to the cabin air intake.

Maybe you could relocate lights out of the bull bar to use the holes as inlets?

I had a look this afternoon, just a quick peek considering it is over 40 degrees today, Whew!
I am going to relocate the number plate and put some holes in the steel behind it to give the rad more flow through the centre section. In looking at the flow situation, almost half the radiator sits in below the bullbar anyway and is blocked from air by the factory bash plate. Maybe I'll remove that, re-install the bash plates for the bullbar and put a ton of holes in them.
In any case, I think it is not so much a question of surface area but the volume the fan sucks through. When at low revs [>2500rpm] the temperature seems to climb rapidly. Obviously the clutch fan doesn't suck as much at this speed so I am going to go for electric assistance.
Anyway, going off the original topic so I will leave it at that, unless the future proves me wrong and the engine is another dud.

[OffRoadDave]

WTC, I don't suppose you've ever replaced the fan clutch on your Triton? That would be my first thought if it's overheating in low range. I didn't see any mention of it in your posts.

[RHKTriton]

ORD has a good point.

While your engine bay is cooking, see how easy it is to turn the fan.

[thebaton]

my engine gets pretty hot on a 40c day going uphill, hits the redline and once while fully loaded going up a long hill it did the safety thing and (auto) went back to 2nd gear so i had to pull in.

I was planning on an engine rebuild at around 300k (i`m 260k atm) so a couple of summers away if the vehicle is in good condition otherwise by then (taking all else into account then too like new models and price of MQ models with gear etc). Is the machining flaw something you could have an engine rebuilder fix ? Or is it always going to be luck of the draw with these 2.5 engines?

I`ve had my fan checked - ok
Replaced radiator with a higher capacity PWR radiator - gives me a longer run before temps redline
I have an engine oil temp gauge and it hits 120c in these conditions but the oil pressure is good. Engine runs very well otherwise.

[srb]

Surprise, surprise. They found nothing wrong and reckon the bullbar/winch is blocking airflow. I'd be surprised if a frw extra inches of vertical metal makes any difference at 20km/h in low range. Apparently no exhaust leakage into coolant, so it only overflowed due to temp n pressure. Now I have to figure out how to get more airflow into it, or the truck is going to blow up or end up for sale.

Yeah unfortunately that's the standard BS response that dealers go with.
I can definitely say from experience that bullbars and winches make no noticable difference to the efficiency of the cooling system on these Tritons.

I had similar issues to you in the first year of owning my Triton, my dealer fobbed me off and said everything was normal, I didn't have a bullbar at the time so they couldn't blame that... I then installed a bullbar and they then later blamed that.

I ended fixing the issue myself by just bleeding the cooling system properly when I changed the coolant.. That was 7years ago and I've never had the issue again.

Sent from my E5823 using Tapatalk

[wildturkeycanoe]

ORD has a good point.

While your engine bay is cooking, see how easy it is to turn the fan.

The fan works fine, because I can hear it roaring and feel the horsepower disappear whenever the temps get hot. It's when I'm going slow, low range and under load, that the engine boils. Not enough revs for clutch fan to do its job. That's why I'm adding electric to boost the airflow.

[OffRoadDave]

ORD has a good point.

While your engine bay is cooking, see how easy it is to turn the fan.

The fan works fine, because I can hear it roaring and feel the horsepower disappear whenever the temps get hot. It's when I'm going slow, low range and under load, that the engine boils. Not enough revs for clutch fan to do its job. That's why I'm adding electric to boost the airflow.

Define "I'm going slow, low range and under load", only place I can see this causing overheating problems is while rock crawling, climbing steep hills and like should always be enough revs to get the fan working.

If you reckon you don't have enough revs to spin the fan to get it working with an auto, it's rooted, the stall speed of the torque converter pretty much guarantees there will be enough revs for the engine fan to work.

You'll never push as much air with electric fans, that a properly working engine fan will do, if you are rock crawling though, go for it.

Just as an indication of what to expect from a working fan (at least based on my own Triton), turning the air con on, on a 25 degree day is enough to get it roaring at 2500rpm with my Triton, get the temp over 30 degrees and it's pretty much engaged all the time unless you are highway driving.

[wildturkeycanoe]

ORD has a good point.

While your engine bay is cooking, see how easy it is to turn the fan.

The fan works fine, because I can hear it roaring and feel the horsepower disappear whenever the temps get hot. It's when I'm going slow, low range and under load, that the engine boils. Not enough revs for clutch fan to do its job. That's why I'm adding electric to boost the airflow.

Define "I'm going slow, low range and under load", only place I can see this causing overheating problems is while rock crawling, climbing steep hills and like should always be enough revs to get the fan working.

If you reckon you don't have enough revs to spin the fan to get it working with an auto, it's rooted, the stall speed of the torque converter pretty much guarantees there will be enough revs for the engine fan to work.

You'll never push as much air with electric fans, that a properly working engine fan will do, if you are rock crawling though, go for it.

Just as an indication of what to expect from a working fan (at least based on my own Triton), turning the air con on, on a 25 degree day is enough to get it roaring at 2500rpm with my Triton, get the temp over 30 degrees and it's pretty much engaged all the time unless you are highway driving.

Ok. Going up steep rough hills 2nd low range revs between 2000 n 3000rpm. Yes, fan is working as you can hear it. But it still overheats.
Anyway that's beside the point now after this morning's episode. Decided to try n put the electric fan in. Ripped out the intercooler in the process to give it a cleanout - ooooh, yuck. Full o black grime. Couldn't fit in the fan I have, so decided to give the A/C condenser a clean with the hose. Put the intercooler back in and while under the truck putting the bolt on the end of the intercooler, got drips of coolant coming off the bash plate. Figured it was just from wetting any dried up green from the overflow spillage but it didn't stop. Went for a drive after putting it all back together n found more coolant escaping. Can't see exactly where but looks like from front left side in the fins somewhere. Great! Only 2 months out of the 12 month warranty. There is no way I damaged it, I have the A/C condenser in front protecting it. Also noticed today coolant dried up around the 127kPa pressure cap. That wasn't there before. I have only been city driving and now it still gets so hot it's blowing the coolant past the cap, even though gauge hasn't been over 3/4. I'm suspecting it's another head problem but Mitsi lied about it. Not happy at all. Can't afford another radiator, even if I install myself. Maybe I should've sold it last week......what did I do to deserve such a problematic car?

[wildturkeycanoe]

BTW. If the engine boils and loses coolant, how does it suck more coolant back in when the cap is pushing down tighter on the rubber? Need to be pretty good vacuum to top the system up. What are chances it sucks air instead of coolant too?
EDIT - I just checked the coolant. Started engine at warm, took cap off easily, no pressure. Coolant level started to rise gradually and after idling for a minute it was overflowing the sides where the cap sits. Obviously liquid expands as it gets hot, so that explains that, but I also noticed the rubber that sits on the pressure section [new cap]has pitting about 50% of the way around. This was installed when the engine was changed out 9 months ago[I know it had standard radiator cap when the rad got replaced]. How can a rubber seal that has only been removed once or twice by the dealer have pitting in such a short time? I reckon they've given me a second hand cap when they put the new engine in, but in any case, this probably explains the loss of coolant when hot...at least a little. Shouldn't be that bad after less than a year. What do you think?

[RHKTriton]

You're not having any fun!

Radiator caps can bug out early - the one that came with my replacement radiator started letting coolant boil out after about six months. New cap and no more probs.

Operation of the cap ( I hate this pissy little units) works by the main pressure spring working against the coolant pressure. When relieving pressure, coolant passes under the main seal and out the overflow hose.

This hose is connected at the bottom of o/f bottle and normally has about 30% of coolant in the bottle.

For minor overflow events, such as shutting down on a hot day, some fluid may perculate into the bottle.

As the engine and radiator cools down, a vacuum develops and fluid is returned to the system via that little dangly valve in the cap.

I've always wondered how that little valve is 'encouraged to seal, as it has not spring or built in tension to close.

Re the ongoing problem, I and likely the others are assuming that you have checked that there is nothing obstructing air flow through the radiator core. Checked area between the core and shroud, gap between rad and condenser (common spot for grass, etc build up). Is the ac core clean?

[wildturkeycanoe]

You're not having any fun!

Radiator caps can bug out early - the one that came with my replacement radiator started letting coolant boil out after about six months. New cap and no more probs.

Operation of the cap ( I hate this pissy little units) works by the main pressure spring working against the coolant pressure. When relieving pressure, coolant passes under the main seal and out the overflow hose.

This hose is connected at the bottom of o/f bottle and normally has about 30% of coolant in the bottle.

For minor overflow events, such as shutting down on a hot day, some fluid may perculate into the bottle.

As the engine and radiator cools down, a vacuum develops and fluid is returned to the system via that little dangly valve in the cap.

I've always wondered how that little valve is 'encouraged to seal, as it has not spring or built in tension to close.

Re the ongoing problem, I and likely the others are assuming that you have checked that there is nothing obstructing air flow through the radiator core. Checked area between the core and shroud, gap between rad and condenser (common spot for grass, etc build up). Is the ac core clean?

Al clear between AC condensor and rad plus why I hosed it out to make sure. Checked again this arvo, had a tiny bit dripping. Opened th he bonnet, looked around. Nothing to see. Closed bonnet and the drips started flowing faster. Looks buggered already, couple hundred mm in few hours. Prob gonna go dry tomorrow going to work. Just can't understand how hosing the radiator caused it to leak n why slamming the bonnet made it worse. Prob a crack getting larger. Damn these cheap aluminium cores....bring back the brass!

[wildturkeycanoe]

The mystery deepens. By Monday morning I'd lost about 2 litres of coolant. I poured it all back in before going to work and crossed my fingers. Got there okay and put the container under to catch future drips. Checked at smoko and there was barely a drop of coolant leaking. What?? Pondered this until lunch and then came out to find it'd started again. By knock off time I had about half a litre so in it went and I cruised home without air con to be safe. Stopped at shops, no leaking. Got home, no leaking. Thought maybe it only leaks when it cools down, so put the bucket under again for overnight. Perhaps the seal on the plastic reservoir is expanding and sealing it up when hot, but it doesn't look like it's coming from there, but from the fins.
Then today, all day, it hasn't even spilled a drop. Miracle? I can't imagine it would just heal itself like that. Now I can't trust it at all, not knowing when it'll leak again.
To put this back into perspective of the engine exchange topic however, I wonder if Mitsubishi are dosing the coolant mix with some anti-leak additive to try and prolong the engines that have the inherent machining problem? If they start to leak in the head, the additive blocks it up and the problem is stopped or at least delayed. In my case, maybe that's how the rad fixed itself. I wonder if anyone at Mitsubishi would answer this honestly if they were doing it? Perhaps there is a chemical test one can perform to find coagulating additives?
I might do some research, because right now I am totally perplexed.
On the bright side, I think the intercooler clean has given me slightly better grunt and economy, but time will tell. Got down to 12L/100km this morning, best economy since the new engine went in.

[GLX58]

Are you absolutely sure there is not a leak/crack somewhere in the cooling system vs problems this thread is about. It is sounding more like a bit more like cooling system failure (cracked core, loose/cracked piping) now? I'd say it seems very doubtful a 'stop leak' type product is in play here - they range from utter snake oil to barely work in my experience. With a 2l leak your car is literally pissing coolant - I'd say a stop leak would not have any chance of stemming that (?). Does not seem like a good idea for mistu to go that way either

[thebaton]

I have to do some hill driving today in mid 40c here in South Australia, should be a test eh, i`ll bring lots of water (for myself, have coolant in the tray) in case it cracks the *****. Coolant level is topped up, i fully expect the engine to hit red line uphills. I`ll check coolant levels when its cooler another day haha. Have to say i wouldnt fancy running around somewhere like the Kimberley if you cant trust your unit.

Would it be normal to expect the air conditioning (which is perfectly cold when its not 42c) to run like a hair dryer in stop start driving when the temperatures hit the low to mid 40c??

[RHKTriton]

The possibilities for warm air out of the ac are likely; low gas, compressor clutch intermittent or not engaging, or the cores are flagged. The biggie is also having an AC condenser fan.

These issues should probably go in the relevant thread.

[NowForThe5th]

Agreed and split the thread.

[wildturkeycanoe]

Are you absolutely sure there is not a leak/crack somewhere in the cooling system vs problems this thread is about. It is sounding more like a bit more like cooling system failure (cracked core, loose/cracked piping) now? I'd say it seems very doubtful a 'stop leak' type product is in play here - they range from utter snake oil to barely work in my experience. With a 2l leak your car is literally pissing coolant - I'd say a stop leak would not have any chance of stemming that (?). Does not seem like a good idea for mistu to go that way either

Definitely no crack. Been driving all week, stop start traffic, A/C running, 39 degrees and not a drop of coolant leaking. No idea what happened on Sunday. If the cooling system had a problem, you'd think driving around in near forty degrees would show some kind of symptoms. The worst thin GB is that clutch fan stealing all my get up n go. Accelerates to 60km/h sluggishly, then it's like the throttle sticks and it takes forever to gain more speed, while the fan whines away joyfully.
Going for a highway run on Saturday so we'll see if I need to use my backup water container.

[Joel]

Could you have over filed with coolant and caused the leak?

[wildturkeycanoe]

Could you have over filed with coolant and caused the leak?

I hadn't touched the cooling system, it just started leaking out of the blue. Crazy eh? Even crazier it fixed itself 24hrs later.

[thump60]

My old mans 2012 triton had a warranty job done (short motor) and after he had overheating problems according to the instrument gauge. so i took it to local mitsi agent and they fixed it easy as. When dad drove ute he diddn't seem to have any probs but when i drove it with the headlights on it pushed temp gauge to the red zone (80kph 30deg day). Seems the problem is when a roobar is fitted to the tritons they need to shift a earth point because of the roo bar, so got the earth point reconnected in a different spot and hey presto no more problems. The mitsi mechanic new his shit

[NowForThe5th]

Let me get this right. You're saying that it only overheated when driven with the headlights on and the cause was a an earth that needed relocating because a bullbar had been fitted?

What earth point?