OK guys, I'm back on the road again, head skimmed, cracked piston replaced. Ugly job, wouldn't wish it on anyone...
As some of you are aware, I've fitted a proper temperature gauge. And I've some interesting observations.
Aftermarket stats and original toyota stats are NOT THE SAME. Now, for any other application, the difference isn't relevant, but because of the heat involved in the townie...
Toyota stat 90916 03046 (82-95c) has an opening diameter of 30mm, lift of 10mm.
Pattern ones (Rob can you check your item, please) have an opening 25mm x 8mm.
In my car, and I'm not sure what difference viscous vs electric fan makes,
Aftermarket stat- temp is 95- 102c
toyota stat 95- 98c
Now that's a bit hot for my likings, especially as most cars show about 90 on the gauge. So...
Aftermarket stat, three 3mm holes drilled in it's periphery 82- 95.

John Davis is fitting a similar gauge to his, it's got the viscous fan. So that'll fill in some gaps in the results.

I'm not telling you all to go out and drill holes in your thermostats or replace them all with Official Toyota, but the figures tell me that there is a restriction in the cooling system, and that restriction is the stat.

I'm returning the toyota stat to the dealer today for a refund. If this is not forthcoming, then I'll drill a couple of holes in it too...

- (#5102) david miller, 15 Aug 02

This reminds me of a general comment made to me over the parts desk at my (helpful) local Toyota dealer. It went something like, "Townaces? great - but you must change the thermostat. The ones [originally?] fitted in Japan are not suitable [for UK]. A different part no. is recommended for UK/now".
So, is there something in this? Do I need to go back and enquire further? Is 90916 03046 what was fitted in Japan? or the one recommended for us?

- (#5103) Dave Mason, 15 Aug 02

that part number is the one listed on the cd. It's the same item as fitted to all other 2C cars, and most other toyotas too.

I'm convinced that this is an important issue. I'm wondering if it's something to do with the flow that is lost to the rear heater. Perhaps the pressure reduction caused by the rear heater being in line (note, no water valve) stops enough water from going through the rad...

Time for a chat with YOUR parts man, dave!!

- (#5152) david miller, 15 Aug 02

"My parts man" says:
90916 03046 is what he's recommending,
it's not what's originally fitted for Japan,
it is the "cold climate" version - and when I pressed him as to what that means he seemed certain that it opens sooner, at a lower temperature.

He re-iterated that cooling is our main problem and that his experience was:
1. check the viscous fan coupling - the fan is vital when driving fast,
2. change the coolant, rigorously flush out blockages and airlocks,
3. ensure thermostat is UK specification.

So perhaps Ace Answers needs detailed a "how to" page on (2) and (3) above.

- (#5153) Dave Mason, 15 Aug 02

Well, I can't find any reference to any other thermostat- not for older models, no substitutions. So I'm not convinced that your man is helping us...
Cold climate would mean a hotter stat anyway, methinks.
The restriction certainly seems to be at the stat. I can run my electric fan until the rad goes cold, and the engine can still be HOT! This tells me that the flow around the block and head is sluggish. 82c in the block, 96c in the head, no cooling actually happening.
I'm led to believe that no stat will cause overheating too, as the flow is too fast, and the coolant doesn't get a chance to pick up and give off heat...
- (#5154) david miller, 15 Aug 02

i agree with dave miller, i have an old peugeot 405 and have a summer thermostat fitted which opens at a lower temp to keep engine cool in summer. if coolant is not circulating around the block it could be that these vehicles suffer from some kind of blockage that aint to easy to shift,some kind of design fault with internal waterways which results in a build up somewhere,or a lazy waterpump? is there any way to check the flow rate of coolant around the engine?

- (#5155) paul chapman, 15 Aug 02

I too was a bit suspicious of what "my parts man" said, but reported it to add to the debate as suggested.
Yes, I disagreed with what he said and thought a "cold climate" stat would open later, at a hotter temperature, (which is why I pressed him and quoted his dubious answer) and a "summer" one opens at a lower temperature, which seems to be our shared view but I wasn't sure.
Likewise I've always felt the fan is needed more in traffic queues and slogging up long hills rather than in the fast cruise. Whenever, you still need it.

But I'm not convinced either about having "no stat will cause overheating too, as the flow is too fast, and the coolant doesn't get a chance to pick up and give off heat" - I can't see any cooling problem with fast flow. The stat is there to hold the engine and lubricant in their design temperature range for efficiency and to reduce wear, so in the end, yes, I do agree no stat is not a good idea.

It's easy for me to talk because I haven't hit this problem in my 14 months/15,000km - I trust Toyota too much to think there's a design fault but the only thing I know about the water system is that it's complicated and unconventional. Is it possible that having the hot/cold box option (I don't), with extra plumbing, makes you more susceptible to over-heating?

Otherwise, once you're keeping the system full and the water pump is pumping I'd pursue the theory of uncleared sludge blockages or airlocks. I've noticed a number of overheating reports are following work on the system - that points to airlocks. For what it's worth I've found that filling very slowly (taking at least 5 minutes) there is no drop in level on subsequent checks.

- (#5156) Dave Mason, 16 Aug 02

Just to bring this TTT-
It seems that Toyota's racing division, TRD offers a 160f thermostat for "tuned" cars. That's 71c in real money. Fensport are the UK's TRD distributor, so I've dropped them a line to get a price. I'm going to guess £45- 50, though...

- (#5157) david miller, 18 Aug 02

just fitted a new durite temp gauge - tests showed that the temp is around 98 on tickover after 30 mins
- this is with the viscous fan fitted - and i can tell you that viscous fan sure shifts some air @ 17 inches its a powerful item - i must admit im not sure electric ones are for me at this moment in time - maybe after i open up the stat periphery (3 x 3mm holes)the temp will settle to a figure in the low to middle 90,s then the electric fan might be ok
hope this helps
jim
- (#5158) J Adgo, 18 Aug 02

Another thought, for anyone that wants to fiddle.
Most stats seem to have some freeplay between the actuating rod that sticks out of the capsule, and the bridge that it acts on. Putting the stat in a vice and pressing the bridge down until the valve is just barely beginning to open (need a piece of 2" tube or similar to support the flange), decreases the opening temp slightly, but increases the lift at all points after that.
I've tried that on my spare stat, and the results are 80-95c running, with a fast warmup.
Jim, before you play with the stat, can you give me sone temperatures on climbing and decending hills? Also, any chance of clamping or blocking one of the rear heater hoses and note any changes.

- (#5159) david miller, 19 Aug 02

I,too, have now fitted the Durite gauge and, how refreshing it is to see the temperature gauge actually doing something. Here are the details of my mods, and results, after only a day's testing but, after a long motorway and London traffic trip, this coming weekend, I might have some different figures.
My vehicle is a Masterace TD with 4WD and, of course, the extra radiator. Also, I have retained the viscous fan. I have fitted the genuine Toyota thermostat, part No 90916-03046 (30mm opening diameter) which I have modified with three, 3mm holes in the valve plate, giving a fairly effective by-pass at all temperatures. From cold, to completion of a 15min stationary tickover, the gauge did not register above 65c. On my generaly sedate motoring, ie, 60/65mph on A roads, the gauge registers 82/85c. When pulling, fairly hard, sometimes in 3rd gear (auto),up a long hill, the gauge registered approx 92/95c. It is so refreshing, also, to see this accurate gauge registering a fall in temperature (as it should) when descending, at light throttle openings, the same long hill. The old gauge never moved from the middle postion, giving rise to thoughts, on occasions, that it had failed.
It may be that my three, 3 mm holes, in the stat, are a bit too much for effective winter heating but, I don't think that I am too far out. I tend to agree with David , and am of the opinion that a "standard" stat, does give too much restriction to effective water flow and a slightly less effective heater, in winter, is a small price to pay to avoid the "bananna head" syndrome.
I will post any other observations but, if anyone wants more information on this gauge/stat setup, do feel free to contact me., I am, of course, concious that David has been MOST helpful with his postings and direct emails, and my modifications are just copying what he has been doing. (No original thoughts here I'm afraid)
Incidentally, if anyone wants the Durite gauge, and has difficulty in locating a supplier, Vehicle Wiring Products, at Ilkeston, in the Midlands, can supply the range, together with all the ancilliaries, ie, adaptors (needed on our engine) etc.
Try sales@vehicleproducts.co.uk

- (#5180) John Davis, 21 Aug 02

After fitting my new durite gauge ( see previous ) i found the temp to be well in the upper 90,s after 15 mins tickover - fitted an after market stat and did the 3x 3mm holes mod to find a new temp of 83 degrees, althought i have to say the stats very inaccessable its been a worthwhile mod - next step is fitting a electric fan from a mark 2 astra diesel ( its a big fan ) with the Kenlowe variable sensor - ps tip here ..fit the adjuster near the glow plug fuses - spare fuse available too - there are some handy pre tapped holes and the flap opens for easy adjustment -
due to my self employed status - dave - i didnt have the opertunity to check the temps with the old stat and the heater circuit clamped off - sorry dave .. i would now say very strongly to all owners to fit the durite gauge - u might well be in for a surprise as i was - looks like dave,s conclusion has a lot of milleage in it i.e. its flow the townies need not extra fans . the electric fan justs frees up some more power, makes the belts easier to access and gives a few more mpg,s

- (#5181) J Adgo, 21 Aug 02

Which of the Durite temp gauges are you all using ? Capillary or electric.
What specific adaptor(s) are needed.
Is connection to the original sender location or into a "T" piece. Thankyou

- (#5182) Ray Ambler, 21 Aug 02

Ray, it's the electric one 52323. You need an M16x1.5 to 1/8"NPT adaptor. It's in the original location- trying to use both on a "T" might result in an airlock or deadend, water not flowing past the sensors.
You could always put it in one of the water outlet locations (near rad cap). It'll read a few degrees hotter, but response might be a tiny bit quicker.
You might find the TIM gauge034 as well. very similar, comes with the necessary adaptor.

You self- employed too, Jim?

- (#5183) david miller, 22 Aug 02

Dave i decided to go for the durite gauge pod - costs about 3 quid. fits under the dash to the right of the cooler box lid (just misses it) - fitted a wickes hot water tank adjustable thermostat today to bring in the fan on low speed (through a resistor) - the stats designed to switch a hot water element so no relay is required - yes Dave i am self employed - 2 jobs .. college lecturer on motor vehicle and i am back on repairing fork trucks in the holidays - funny thing ..i am starting to get to hear of overheating problems on toyota fork trucks from my chums in the trade - no escape eh -

- (#5216) J Adgo, 22 Aug 02

My gauge is mounted on a cigarette lighter plug at the moment. I'll be replacing the gubbins of the original gauge with it's internals when I get a chance...

I'm in the lab & garage eqpt. trade, Jim- paint mixing scales amongst other things.

- (#5217) david miller, 22 Aug 02

Jim, what's the max. temp you've seen so far?

- (#5218) david miller, 22 Aug 02

Chaps, bought spacecruiser yesterday. 80 mile journey home. Watched temp. gauge carefully. Only slight rise on long uphill and well short of boiling.
You've guessed that when I parked in drive ready to show excited family I heard horrible bubbling noises and she sat there spurting coolant passed an overflow reservoir. Stopped eventually. No leaks obvious.
Where do I start?
She hasn't been used (apparently since April - old tax disc) but was serviced by toyota throughout 12 years - mileage is 125000

- (#5219) Richard, 24 Aug 02

Richard,
"Where do I start"
I am not familiar with the Spacecruiser but, it's layout and cooling system are, I am sure, similar to the Town/Masterace range. I would start by completely draining the cooling system because, at that mileage, you don't know when it was done last. Disconnect the bottom and top rad hoses and,gently, with a garden hose, back flush the radiator. Clean the expansion tank out and make sure that all the hoses which connect this tank to the rad/filler neck, are sound. This tank accepts the excess water, as the coolant increases in temperature and expands in the main cooling system. Some of this excess water is syphoned back into the main system as it cools, therebye maintaining the correct coolant level. Thoroughly check the rad/filler cap or, better still, replace it. It performs a very important function regarding the correct operation of the cooling sytem and is more than just a filler cap. Also, look in the Ace Answers lists for much information on cooling problems and their rectification. The "bubbling noises" if not too excessive, are quite normal as the hot coolant is still being pushed into the expansion tank, especially when the engine is stopped after a fairly long run. At this point, the coolant is still expanding and the hot engine, with no air passing through the radiator, will continue to heat up the coolant. It's usually good practice to let the engine (and fan) run for a short while before switching off and this will help the cooling system to function correctly. When the system is re-filled, do it slowly to avoid air locks. Also, open the heater controls so that the heater matrix is flushed also.

"spurting coolant passed an overflow reservoir"

Was the expansion tank (overflow reservoir)full when this was happening ? If it was, then the overflow was operating correctly but, you should check carefully that, in future, the overflow tank is only topped up to the "Max" level and, when the engine is cold, the coolant level is just up to the neck of the rad/filler cap. During average motoring trips, if the main coolant level continues to go down, and the expansion tank level continues to rise, you should check further, ie. to see if there is much activity, bubbles etc, when the engine is running and the rad/filler cap is off. Only do this when the engine is cold and, only at fairly low throttle openings. Excess pressure in the cooling system which allows coolant to be pushed out into the expansion tank,, might indicate head gasket problems.

- (#5924) John Davis, 24 Oct 02