Coolant Loss - Engine Overheating

[Sol]

Hello All

I've written up my recent saga regarding inlet manifolds here (https://www.aulro.com/afvb/aulro-s-o-s-and-breakdown-only-/280048-p1247-restricted-performance.html) and no sooner were they replaced but the coolant crossover assembly under the throttle body split while towing a 2 tonne camper into Springsure, Central QLD today. Warnings were 'low coolant' and then 'engine overheating' (the latter briefly at least). With the use of some bailing wire and zip ties I managed to hold the assembly together enough to fill and hold some water and limp into town (albeit the water leaking quickly out again).

Will now source a new assembly from MR Auto tomorrow and get it shipped, fitted and filled with coolant ASAP. I don't plan to start the car again unless I absolutely have to (the campsite we are on can only accomodate us for 2 nights!)

Engine sounded OK with no further dash warnings other than 'low coolant' on the limp into town but after reading some horror stories on here I'm worried about any damage yet to be identified. Does anyone know what I should be checking for on pre or post repair? I've got an IID but haven't pulled any codes as yet.

[Tombie]

There won’t be anything to check.
It will all depend on how much “engine overheating” took place, how hot it actually got etc.

Don’t drive it until you can fit the part. It’s an easy job.

[BradC]

It’s an easy job.

Which is not something often heard in relation to a D3/4.

[DiscoJeffster]

Which is not something often heard in relation to a D3/4.

Often....ever.

[Ferret]

I carry one of these fittings as a spare as people have reported them failing before. But I'm wondering whether I should just fit as a precaution now based on time / ks travelled.

What are people's thoughts - when's it time to change it out as preventative maintenance?

[DiscoJeffster]

I carry one of these fittings as a spare as people have reported them failing before. But I'm wondering whether I should just fit as a precaution now based on time / ks travelled.

What are people's thoughts - when's it time to change it out as preventative maintenance?

Just fit it. If you change it every timing belt then you’ll be all ok.

[PerthDisco]

Just fit it. If you change it every timing belt then you’ll be all ok.

Agree, 7 years or less. There is also a plastic fitting where the hose connects to the engine block. I’ve also got this for next belt time but it’s a single piece whereas the top unit is joined / glued and splits there. The block fitting a real bugger to access.

For my second timing belt change (half life of car) I’m thinking to go the whole hog on new radiator, condenser, thermostat, water pump, top and bottom hose, oil cooler and these plastic fittings since you are pulling things apart once and once only.

[coopers1969]

i had the exact thing happen to mine the only code that came up was coolant overheated. i has able to put it on a flat bed and take it my my local indy, they did a pressure test on the system, i guess to make sure no other damage to the cooling system, but all good refilled replaced the damaged part and no issues for the last 25000 km.

[Sol]

Yep, seems like a common issue but of course I didn’t know that until it happened and read the numerous posts. Preventative seems to be the way to go if you’re on a long trip, especially towing.

MR Auto are sending one today and hopefully fitted and fixed in a day or two.

Praying there’s no further issues or over-cooked motor.

[PerthDisco]

Yep, seems like a common issue but of course I didn’t know that until it happened and read the numerous posts. Preventative seems to be the way to go if you’re on a long trip, especially towing.

MR Auto are sending one today and hopefully fitted and fixed in a day or two.

Praying there’s no further issues or over-cooked motor.

Fortunately it seems to emerge as a small split, slow leak therefore slow manageable loss of coolant before letting go big time. Ignore any coolant loss at your peril

[Sol]

Fortunately it seems to emerge as a small split, slow leak therefore slow loss of coolant before letting go big time. Ignore any coolant loss at your peril

This was me exactly. Small split that then let go big time.

And hindsight is 20/20 vision

[gavinwibrow]

Yep, seems like a common issue but of course I didn’t know that until it happened and read the numerous posts. Preventative seems to be the way to go if you’re on a long trip, especially towing.

MR Auto are sending one today and hopefully fitted and fixed in a day or two.

Praying there’s no further issues or over-cooked motor.



Which leads to the question/s I've been meaning to ask

1 - is it worth fitting a low coolant alarm as per recommended for D2, or does the D4 already have a similar feature built in along with a coolant temperature gauge that actually works :MileStone:(unlike the D2)?

2 - I usually don't connect up my GAP tool around town, and haven't actually worked out if it provides an equivalent warning?

[PerthDisco]

It has a low coolant warning for the bottle level and if for any reason you need to top up coolant that’s the warning to find out what’s leaking ASAP. It is easy also to see the main culprit part in the valley and see if any coolant residue is around.

Lifting the bonnet during road trips for a look and smell is the go. The bottle is well placed to eyeball the level in an instant.

[Tombie]

No automotive coolant temperature probe works once out of coolant. So D2 vs D4 comparison is moot.

D2 gauge works fine - IF - coolant isn’t lost (and engine is just overheating)

D4 has a low coolant sensor, warning on dash etc. and works very well.

[Sol]

I got a ‘low coolant’ message on the dash and then ‘engine overheating’, at which point I pulled over promptly! As others have said, the leak is very obvious once you remove the engine cover, looking under the throttle body from the passenger side. You can smell it too.

[gavinwibrow]

No automotive coolant temperature probe works once out of coolant. So D2 vs D4 comparison is moot.

D2 gauge works fine - IF - coolant isn’t lost (and engine is just overheating)

D4 has a low coolant sensor, warning on dash etc. and works very well.


Mike, we will have to agree to disagree.
In my D2a, I routinely had my Evo set on instrument mode with the coolant alarm set at 105 C for normal driving, and occassionally 110 C when I knew it could get a bit warmish, but I would be keeping an eye on it.
The LR gauge wouldn't move until over 115 C, and even though I know from Blknight that the TD5 is designed to operate at up to 120 C, only a 5 degree differential is too close to expensive for my liking.

[gavinwibrow]

No automotive coolant temperature probe works once out of coolant. So D2 vs D4 comparison is moot.

D2 gauge works fine - IF - coolant isn’t lost (and engine is just overheating)

D4 has a low coolant sensor, warning on dash etc. and works very well.


Mike, we will have to agree to disagree.
In my D2a, I routinely had my Evo set on instrument mode with the coolant alarm set at 105 C for normal driving, and occasionally 110 C when I knew it could get a bit warmish, but I would be keeping an eye on it.
The LR gauge wouldn't move until over 115 C, and even though I know from Blknight that the TD5 is designed to operate at up to 120 C, only a 5 degree differential is too close to potentially expensive for my liking.

[Tombie]

Mike, we will have to agree to disagree.
In my D2a, I routinely had my Evo set on instrument mode with the coolant alarm set at 105 C for normal driving, and occassionally 110 C when I knew it could get a bit warmish, but I would be keeping an eye on it.
The LR gauge wouldn't move until over 115 C, and even though I know from Blknight that the TD5 is designed to operate at up to 120 C, only a 5 degree differential is too close to expensive for my liking.

And it doesn’t have to. Normalised gauges are in almost everything now.
5c is a lot in an engine. Remember a pin hole that drops pressure reduces BPt back towards 100c.

Seperate the 2 situations and this is what you have.

1) Overheating.
2) Sudden loss of coolant

1) can be fan failure, hard work under load in excessive heat etc.
the ECU and engine can easily deal with this. Fuel cut occurs in alternating cylinders and the engine protects itself.
Running at 115c won’t hurt it. For comparison in summer I’ve had EL falcon 6s running at 118c without a problem. It was in the workshop manual this was a normal range temp.

2) Sudden loss of coolant.
No immersion based sensor can read temperature once not immersed. Guess what else can’t happen - engine protection strategy can’t work because it doesn’t know it’s hot.
The D4 has a slightly better factory set up, it looks for coolant level drop. First warning. What it won’t sense is complete fluid loss as a temperature increase - submerged probes only work submerged remember.

Low coolant warning SHOULD mean “Cut load and Pull over as soon as safe.” Not keep driving watching temperature gauge.

[BobD]

Mike, we will have to agree to disagree.
In my D2a, I routinely had my Evo set on instrument mode with the coolant alarm set at 105 C for normal driving, and occasionally 110 C when I knew it could get a bit warmish, but I would be keeping an eye on it.
The LR gauge wouldn't move until over 115 C, and even though I know from Blknight that the TD5 is designed to operate at up to 120 C, only a 5 degree differential is too close to potentially expensive for my liking.

You can watch the temp on a GAP11D if you really want to be sure. The fan doesn't even start to partially lock until 107 and the gauge only moves at 117 on the D4, at which point it jumps to just below the top. The fan is fully locked at about 115. Low coolant is a completely different kettle of fish to over heating, as Tombie said. Easy to reduce load and increase engine speed by dropping down a gear or two if it gets hot but loss of coolant destroys the engine very quickly, which is why you need to the low coolant alarm, which the D4 has.

Unfortunately at the moment my low coolant warning works too well and is intermittently activating with full coolant level. I will have to try to find out what is wrong I guess, so that if it does lose coolant I will know about it.

Re the plastic housing, I replaced mine with an alloy version when they did the two manifolds. I think it should be replaced at least with the timing belts, if not at lower mileage and 7 years of age perhaps.

[PerthDisco]

The sinking float in the coolant bottle is a common fault needing replacement of the bottle.

[DiscoJeffster]

The sinking float in the coolant bottle is a common fault needing replacement of the bottle.

I also found my sensor faulty. Replaced it from an old bottle.

[Discodicky]

Yep, seems like a common issue but of course I didn’t know that until it happened and read the numerous posts. Preventative seems to be the way to go if you’re on a long trip, especially towing.

MR Auto are sending one today and hopefully fitted and fixed in a day or two.

Praying there’s no further issues or over-cooked motor.

You'll be ok.
My son's 2008 2.7 D3 split his housing bigtime down on the Tasman Peninsula (Tassy) going up a steep hill towing his c/van and he drove around 6 klms before realising it.
Engine didn't seize but got pretty hot.
Had the local Indie fix it and the engine suffered no ill effects at all.
Still didn't use a drop of oil between 10k services and no horrible new noises @ 164,000 klms.
Mind you, we run (swear by) Wynns oil additives in our compartments and I am convinced that helped reduce potential seizure or pistons picking up.

Some engines, by design I guess, seem to get away with massive overheats more than others.
For example, I've seen V12 Jaguar (all alloy) engines get sooo hot due to one of the many hoses failing, yet they don't seem to suffer with any ill effects. Preferably get the water in slowly (as its cold and could cause metal cracking) but soon as possible, so as to allow the block and head/s to cool uniformly, particularly if they are different metals.
Some of the Jap stuff will blow a head gasket as soon as looking at it!!

[Milton477]

You can watch the temp on a GAP11D if you really want to be sure. The fan doesn't even start to partially lock until 107 and the gauge only moves at 117 on the D4, at which point it jumps to just below the top. The fan is fully locked at about 115. Low coolant is a completely different kettle of fish to over heating, as Tombie said. Easy to reduce load and increase engine speed by dropping down a gear or two if it gets hot but loss of coolant destroys the engine very quickly, which is why you need to the low coolant alarm, which the D4 has.

Unfortunately at the moment my low coolant warning works too well and is intermittently activating with full coolant level. I will have to try to find out what is wrong I guess, so that if it does lose coolant I will know about it.

Re the plastic housing, I replaced mine with an alloy version when they did the two manifolds. I think it should be replaced at least with the timing belts, if not at lower mileage and 7 years of age perhaps.



MR Automotive changed my plastic housing at 100k as a precaution. I carry the old one as a spare now.

On GAP you can watch 'Viscous Fan Pulse Width Modulation Pulse' which is the bottom right parameter in the screenshot below. The fan starts to be controlled when the temperature hits 100 deg. Depending on the gear, torque, angle, outside temperature etc the Modulation Pulse acts accordingly. This is shown on the two pics below where a drop in torque required causes the PWM of the fan to ease off a bit. There is obviously some pretty smart control happening to keep these vehicles cool. I have never seen 100% but at 50% the sound of the fan is unmistakable.

163539 163540

[Discodicky]

MR Automotive changed my plastic housing at 100k as a precaution. I carry the old one as a spare now.

On GAP you can watch 'Viscous Fan Pulse Width Modulation Pulse' which is the bottom right parameter in the screenshot below. The fan starts to be controlled when the temperature hits 100 deg. Depending on the gear, torque, angle, outside temperature etc the Modulation Pulse acts accordingly. This is shown on the two pics below where a drop in torque required causes the PWM of the fan to ease off a bit. There is obviously some pretty smart control happening to keep these vehicles cool. I have never seen 100% but at 50% the sound of the fan is unmistakable.

163539 163540


They are interesting numbers and prompt me to ask where in the engine/trans "circuits" are the temps taken?

I have a Scanguage 11 and amongst other features , can monitor the engine coolant and trans temps.

Generally speaking, the trans oil is always around 15 to 20 deg less than the engine (common is 75-80 v 90 Celcius) and they both fluctuate remarkably (in my opinion).
For example, today I went to my shack and returned on the Tasman Peninsula, Tassy.
Ambient temp 4 deg and trying to snow.
Going uphill the engine would go to 88 deg and trans to around 70, but downhill with trailing throttle, I could watch the engine drop to 82 and trans to very early 60's.

Earlier this year on a warmish day (from memory middle 20's ambient temp) whilst towing my 3.0 T c/van I'd see up to 102 deg engine and early/middle 90's with trans.

Do others experience similar temps and fluctuations?

[gavinwibrow]

Unfortunately at the moment my low coolant warning works too well and is intermittently activating with full coolant level. I will have to try to find out what is wrong I guess, so that if it does lose coolant I will know about it.

Re the plastic housing, I replaced mine with an alloy version when they did the two manifolds. I think it should be replaced at least with the timing belts, if not at lower mileage and 7 years of age perhaps.

Hi Bob. Is your float suspect?

Re alloy housing, which I think Tombie also has, I would logically think that was a once only purchase/fit, but seem to recall some even had troubles with the metal replacement/s?

[Narangga]

Hi Bob. Is your float suspect?

Re alloy housing, which I think Tombie also has, I would logically think that was a once only purchase/fit, but seem to recall some even had troubles with the metal replacement/s?

Said Tombie did post once that a couple of the early units did split. I have an alloy unit as the engine compartment in my vehicle rarely cools down due to the higher ambient temperatures up here. A 10km round trip to Woolies keeps it warm for hours. I therefore decided I wasn't going to be changing the plastic unit every couple of years as a precaution.

[gavinwibrow]

Said Tombie did post once that a couple of the early units did split. I have an alloy unit as the engine compartment in my vehicle rarely cools down due to the higher ambient temperatures up here. A 10km round trip to Woolies keeps it warm for hours. I therefore decided I wasn't going to be changing the plastic unit every couple of years as a precaution.


Thanks for that. Without having to look anything up, anyone have an idea what is the ballpark cost for the alloy version and from where?

[Tombie]

Thanks for that. Without having to look anything up, anyone have an idea what is the ballpark cost for the alloy version and from where?

Only made by TRS.

You can replace 4 standard units for the price.

But it is such nice billet.

[Tombie]

https://uploads.tapatalk-cdn.com/20200805/90fd6a2d6fcda9dfba316e427fce4010.jpg

[Sol]

Latest update, part arrived today in Springsure and hopefully fitted today. Big shout out to Frank Emhofer owner of Bluesky Mechanical. This guy knows his stuff across a wide range of vehicles and a thoroughly nice bloke too. Pics of the blown crossover assembly and work in progress.

163587

[101RRS]

I just replace the plastic unit each time the timing belt is changed and keep the old one in my spares. The metal one looks the goods but at about $600 regular replacement of the plastic one is my preferred option.

Garry

[scarry]

MR auto replace the plastic piece every coolant flush,which is every 5 yrs,from memory.
They also advise to replace float assembly in coolant bottle at same time as well.

[Sol]

They also advise to replace float assembly in coolant bottle at same time as well.

This - I wonder if this my issue. Got the car back, coolant level all good. Running as normal. Cleared all fault codes with IID but still says ‘coolant level low’. I know it’s not so what gives?

[DiscoJeffster]

This - I wonder if this my issue. Got the car back, coolant level all good. Running as normal. Cleared all fault codes with IID but still says ‘coolant level low’. I know it’s not so what gives?

Sensor or float issue. Simplest fix is a new coolant bottle.

[PerthDisco]

When i recently changed coolant I struck this problem and thought it was new bottle time. I gave the bottle a few sharp taps with a big screwdriver handle and all came well again like the float can stick at the bottom of the travel.

[Sol]

... a few sharp taps with a big screwdriver handle...

Haha - must be the simplest LR fix ever.

BTW, to replace the crossover pipe cost $150 for the part from MR Auto inc. delivery and $320 for labour and coolant. Happy with that but if you can DIY them that makes the billet version cost effective I reckon.