Draining Coolant

I took off the rad cap, loosened the drain cock on the rad, and took out the drain bolt on the block, but only managed to get about 7 US qts to drain. Per the service manual the LH series (3L engine) with front and rear heater should hold 11.6 US qts. I had all the heater valves open and the van nose-down an incline. Anyone have a similar experience?

Hey hows it going? How did you get to the engine block drain bolt? Can’t even see mine (if it has one?)

On the 3L, the bolt is accessed from underneath the van, so if you have 4wd you have to take the bash plates off to gain access to the underside of the engine. It's just aft of the injection pump in the photo below, with the white stuff (thread locker) around the bolt. Mine is a two-piece bolt, but the outer bolt (brass color) is cross threaded so I have to remove the whole thing.

My advice is once the bolt is "hand loose" turn it by hand until you get a trickle of coolant coming out, which will find a path down the side of the block and you can get your catch pan under, then loosen it a touch more to increase the flow. If you remove the bolt completely, the coolant shoots out and splashes all over everything and is harder to catch in your pan.

Ahhh found it. Unfortunately it seems very seized. Am taking the van to Poplar in Chesterfield tomorrow as I’ve had to cède defeat in the question of heater cores. I’ve done a flush as best I can and will turn it over to them for the full monty. Thanks though. Everything about this can raises the thought ‘why? Toyota? WHY?!’

milkman wrote:

Everything about this can raises the thought ‘why? Toyota? WHY?!’

LOL, the Japanese have a habit of seeking component quality perfection but of not seeking the simplest way of doing something. It's fine if they are serviced rigorously but they are sometimes not tolerant of neglect.

Like the 1kz-te cooling system, it was hardly rocket science to put the thermostat on the engine coolant outlet but no, they had to follow the fad on the time of sticking it on the inlet - doh!! That little trick destroyed so many engines it was embarrassing, and Toyota got off relatively lightly, many Porsches are on their second engine due to that, eventually it was Landrover that solved it after being surrounded by blown head gaskets and chaos.

It always amuses me that in a van there's no space in the engine bay (but heaps under the floor just sitting about...).

BTW on my van there is a tap on the bottom of each radiator (the 1kz-te has two) - check yours..

@GPW, the 1KZ-TE's thermostat is on the engine coolant inlet?? That's making my brain hurt. So the thermostat spring actuator would be inside the block, and when the coolant in the block got hot enough it would open, only to be met with cooler coolant from the rad? That would make it want to close back up until the rad got heated up up to the block temp, thereby causing a delay from fully closed to fully opened? Meanwhile the block is like "getting a bit hot in here!"

Is the opening temperature on the 1KZ-TE's thermostat lower temp than the 3L's? I would expect the coolant temp after the rad to be much cooler than what's coming out of the engine coolant outlet, seems like it would to lead to premature full/partial closing of the thermostat valve...

Edit: I had to do some googling on the subject and I came across this image from Nissan which helped me understand how an inlet-side tstat would function:

Yes that's pretty much the diagram that Porsche, Toyota, MG/Rover etc all used at about the same time. I didn't realise that Nissan were dumb enough to try it too. I'm sure some professor came up with the idea and it was 'flavor-of-the-month' for a while in engine design centres, it's legacy is thousands of dead engines and $millions spent in warranty claims and repairs.

Note there is a bypass from the head of hot water that flows into the business side of the thermostat to make it open or close, so the thermostat gets another disc to blank that off when fully open and another drilling in the head is needed - usually on one side only. It's a stupid idea - I think your engine is free of this particular design disaster but it's interesting nevertheless!

The major problems with this system are lag in cold weather and heat soak in hot weather. Also the thermostat moved to the side of the block which is often inaccessible - the BMW engine in the MG is so difficult to get to people don't bother. BMW made the engine so efficient however that it never breaks, people merely add a new slip-in Renault thermostat into the top hose to get the heater blowing warm again.

The lag issue is what kills the engine heads via rapid heat cycling, worse in cold weather. Normal thermostats keep a very stable temperature because they are inches away from the hottest water in the engine, straight off the head. These dumb designs however can allow a huge amount of freezing cold coolant into an engine before they realise it is cold and close again. This then repeats as the temperature in the engine fluctuates wildly between hot-cold-hot-cold. This made the MG car in the UK famous for blowing head gaskets and cracked a few weaker heads too (like Toyotas).

Then in hot weather after using the engine and coming to traffic lights the engine can get way too hot because the water from the radiator is making the thermostat happy as the engine turns into cheese, then on setting off the bores get scored. This killed thousands of the Porsche engines using this system as they'd race up to the lights, their cyclinder walls turned into the consistency of mature cheddar, then they'd race away.

Because the temperature swings are so wild in this system the makers helpfully add a dead spot in the temperature gauge as to not alarm the driver, known as a 'damped' gauge. This hilarious, stranger than fiction addition gets added to the 1Kz-te Hiace as well as all those 996/997 Porsches that ate their engines.

Read my threads about how to remove the damping and re-plumb the 1kz for more info!
I used the Landrover fix in mine which must be said works remarkably well, there is no damping on the meter now and it moves around 1mm between going up a hill and coasting down hill.

For continuity.

https://hiace-super-custom.forumotion.com/t3430-cooling-the-1kz-te-in-the-hiace-super-custom

Great write up!

Hello. Was going to start a new post with my experiences here but this is a good place to start.

In metric, I got ~2L of gunky mess out of the radiator.

This was the worst of it.

Some of the manuals have the drain valve seemingly on the LH side of the rad, but mine was on the RH side. It's accessible from below but I found it easier to access from the front (with the bumper and grill removed). With a manual gearbox the valve won't screw out fully (nor be fitable) if in gear as the linkages will obstruct.


I think this is the position for the front heater matrix in the hot position (if the controls are in place then so much the better)


In the centre of this picture is the main engine block drain.


It's close to where the dipstick tube meets the engine block and just forwards of the starter motor. On my van the drain was VERY tight but I found it could be removed with a 14mm socket, a short extension bar and a ratchet which was supported at the end of the starter motor.  Once loose I got no flow even with the radiator cap off and both it and the radiator drain valve needed prodding with stout wire. Eventually I got a torrent of gunky water.

This is the engine block valve


This was the inside of the thrermostat housing


That's been through the untrasonic cleaner after being cleaned with various sandpapers etc, paying particular attention to the sealing lip (ridge) for the rad valve.

I've also tackled the expansion bottle, which was a complete mess with the float valve and hoses totally gunked. This took a lot of effort but alterating between the untrasonic cleaner and the chuck-in-gravel-and-skake-madly technique, it's nearly as good as new and the float valve is working again and correctly electrically.

I'm currently on my second flush with Wynn's coolant flush but am only able to add ~6L of water / fluid from 'empty'. My manuals suggest the enpty and re-fill with front and rear heaters capcity is either 11L or 9.3L so either there is some blockage somewhere (but the heaters run warm) or the rad and engine draining doesn't get enerything out.

Any experiences to share here would be very welcome...

Prob going to fill with Toyota Red Concentrate and make up to assuming ~11L concentration. Next post prob on rad cooling... That might include a vote!

Cheers.

Sounds good! It will fill itself via the expansion bottle, so a few short trips and top-ups will soon have it taking as much as it needs, also see if there is any air bleed valves, sometimes manufacturers add them.

The bolt on the engine block requires blue loctite when reinstalling.

Also, if you have rear heat, you should consider disconnecting the hoses by the rear heater valve actuator/hardline and backflush the rear matrix, as it can get clogged up with debris and cause low/no heat in the rear.

Thanks for both the suggestion.

I can only find one of my bottles of locktite at the moment. When the others turn up i'll ask which you think I should use.

The comment about rear heat flush was genius, too. I've not really explored how this is set up and hoses are routed. Also, while I do get heat out of the floor ducts (and the fan and other controls work) I've no idea how this is performing compared to as expected. Further, when gently flexed the flexible hoses make the characteristic crack sound that indicates there are deposits lining the walls.

The next thing I noticed is, once tranversed from the left side, this piping sits considerably lower than the engine block drain so probably accounts for some of the 'missing' volume. A drain should have been fitted here!

While in reasonable shape for a 30y van, it's all 30y old so as I explore further I think I will replace the antique clamps as necessary (some will never close again if disturbed and I have a box of Amazon's finest SS types that'll do for starters). I'm thinking that any failure here will lead to total coolant loss so worth being throrough.

I also turned my attention to the front matrix and will try to back flush this, too. It's also on a convuled loop forwards and then up. There are 'sumps' too so I've no idea is this is emptied with either the rad (suspect not) or engine drain (more likely I think).

Does anyone have a decent schematic or can link to another model that has both front and rear heating to show how the system is configured and the flow is routed, please if that's possible?

As a camper, mine is not best described by the online links to the LH118V-RRNES that it is.

Will be getting some snaps and will add to this post.

I'm tackling the cooling, but I have to decide whether to delve deeper here and sort or, whether to tackle some of the deeper bits of the body that this all fixes to, too. Hmmm.

Also, wish I'd got everything steam cleaned before this much disassembly. Further hmmm.

Cheers

Definitely do the back heater as djathens suggested, if you can: I removed mine (To replace with a diesel heater), and although it was very efficient and worked fine - it still had lots of sediment inside!!

Hello.

There are various posts here regarding diesel heaters and was wondering if you have you made a post of yours, please?

I'd like to keep my rear coolant heater for use while driving (doesn't seem to be any sig probs with it) and eventually add a diesel heater (prob an Ebersp D2 if I can afford it) for use while stationary. I'm hoping that it's be possible to incorperate it into the rear ducting. Did you do this?

Thanks

LH119V wrote:

Hello.

There are various posts here regarding diesel heaters and was wondering if you have you made a post of yours, please?

I'd like to keep my rear coolant heater for use while driving (doesn't seem to be any sig probs with it) and eventually add a diesel heater (prob an Ebersp D2 if I can afford it) for use while stationary. I'm hoping that it's be possible to incorperate it into the rear ducting. Did you do this?

Thanks

Check out this:
https://hiace-super-custom.forumotion.com/t3479p25-camping-conversions

I modified the exhaust later, to put the outlet much further away, as the Chinese ones - or at least mine - had a slight leaky rubber gasket that allowed the inlet air to seep into the cabin.
The inlet was slightly dirty (being so close to the exhaust) so I made up a tight fitting gasket and positioned the exhaust much further towards the back of the van.

Also where I added it, I could access it well, which is worth bearing in mind!
I ran mine off the main tank, but a separate paraffin system for occasional use is probably better.