Prado Thermostat

[Tallyman]

I'm looking to fit the Prado 82 C thermostat, as despite having fitted a new viscous fan unit, mine is still getting a bit too hot (read over 115c) when towing or close to 100C on fast M-way journeys (and before you suggest, it's already got a new radiator and an ATF oil cooler fitted). Just checked with our local Toyota main dealer and the part number usually quoted for this - 90916-03121 - comes up as a bottom radiator hose, not a thermostat.

Can anyone whose bought one shed any light on the part number or if there has been a change of part number since the original information was provided, or even if there is another source for them apart from the main dealer route? Main dealer can't do a search as their new all singing, all dancing computer system either needs the part number or a chassis number to search. Just trying something like "Prado thermostat" doesn't work. Isn't technology wonderfull!!!

Thanks

[TonyN]

All the 3.0 stats I've ever fitted are 82 deg ???

[Tallyman]

Hi Tony,

I'm sure mine is at least an 88 C (you fitted it a few years back when you did my major service) as my temp guage keeps climbing to just under the 90C mark on my guage before it steadies itself when it's not under load. Just checked with Roughtrax and they confirm that the 3.0 is set at 82C, so I'm going to get a new one from them.

Thanks for the info.

Regards

Mike

[Alamo]

Same scenario when I bought a Prado stat from Toyota myself a few weeks ago. I took the small box from the previous stat (with part number on it) but the guy on the parts counter was adamant that the part number shown on the box was actually a radiator hose. We almost got to a point where he was suggesting I'd stuck the label on the box myself to confuse him

One of the other guys in the parts dept eventually suggested that he should just order the part and see what turned up, which he did.......2 days later I get a call from them to say my Prado stat had arrived.

I think I've still got the box (with Toyota part number) in my garage so will dig it out when I get home from work tonight. I'm almost sure the invoice I received at the time stated that the part was actually a coolant hose, but doubt I'll find that now.

Alan

[Tallyman]

Thanks Alan. Sounds exactly what I was told. Looks like the main Toyota parts database has been updated with the wrong information then.

[Alamo]

Mike,

Just had a mooch around my garage and found a sealed, unopened, stat with Toyota part number 90916-03121 which is 71 deg Prado stat. The 82 deg is part number 90916-03118 and rubber sealing ring is 16346-67010.

Hope that helps.

Alan

[NiftyNev]

Toyota part number 90916-03121 which is 71 deg Prado stat.

Correct.

Nev

[Tallyman]

Mike,

Just had a mooch around my garage and found a sealed, unopened, stat with Toyota part number 90916-03121 which is 71 deg Prado stat. The 82 deg is part number 90916-03118 and rubber sealing ring is 16346-67010.

Hope that helps.

Alan

Thanks Alan. I've now got the 82 deg stat from Roughtrax and will fit that at the weekend. If that doesn't make much difference to the running temp then I'll look at ordering the 71 deg stat from our local dealer.

Regards

Mike

[Alamo]

Correct.

Nev

Thanks for the confirmation Nev.

Thanks Alan. I've now got the 82 deg stat from Roughtrax and will fit that at the weekend. If that doesn't make much difference to the running temp then I'll look at ordering the 71 deg stat from our local dealer.

Regards

Mike

No problem Mike. Glad to have helped! Hope the new stat sorts things out for you mate, but let us know either way.

Alan

[Sir Plug]

I'm looking to fit the Prado 82 C thermostat, as despite having fitted a new viscous fan unit, mine is still getting a bit too hot (read over 115c) when towing or close to 100C on fast M-way journeys (and before you suggest, it's already got a new radiator and an ATF oil cooler fitted). Just checked with our local Toyota main dealer and the part number usually quoted for this - 90916-03121 - comes up as a bottom radiator hose, not a thermostat.

Can anyone whose bought one shed any light on the part number or if there has been a change of part number since the original information was provided, or even if there is another source for them apart from the main dealer route? Main dealer can't do a search as their new all singing, all dancing computer system either needs the part number or a chassis number to search. Just trying something like "Prado thermostat" doesn't work. Isn't technology wonderfull!!!



Thanks

I have the Prado stat in mine....made all the difference and can handle all that a New Zealand summer and towing of the boat, throws at the truck. The part number you now have may be correct but I have one fitted that is 90916-03121 (I am in New Zealand) , get it fitted and notice the difference!

[Tallyman]

OK, update. Decided to start work on this when I got back from the office tonight. Getting at all the bolts that hold the thermostat cover pipe in place was a real bugger, espoecially as the 12mm one that holds the ATF pipes in place was rock solid on there and would not come out, making it a whole lot more difficult to get the pipe out. I had to cut off the lower hose in the end. Good job I have a new one. The ends of that pipe where the hose fits had a lot of red weeping around the outside, so looks like the seal wasn't that good.

Anyway, had a look at the thermostat and, as TonyN suggested, it is an 82C one, so that blows my first theory out of the water!! As I'd already bought a new 82C one from those nice chaps at Roughtrax, I think it going to stay in the box and I'll see if either the local main dealer or a local jap import parts supplier has the 71C Prado stat in stock and will fit that instead.

Can't see any problems with the radiator, so it's not that causing the problem. I suppose it could be the water pump, but I presume those either work or don't and I'm fairly sure it's working, and all the belts are tight.

The most annoying part is that last year the car towed the caravan with no overheating problems at all, but since the first outing this year when it went close to 115C on the guage towing up a long steep hill it's been acting up even when driving solo, and that's after fitting a brand new viscous fan unit, as the old one had lost most of its oil and wasn't sealing well even when refilled.

So, hopefully the 71C thermostat will help keep the temp down, as I really don't want any problems towing down to Cornwall later next month, otherwise I'll be looking for a new towcar.

[wishbone]

If your engines hitting 115 degrees why would fitting a lower temp thermostat help ? (When the engine hits 90 degrees they'll both be fully open so no difference)

[Tallyman]

If your engines hitting 115 degrees why would fitting a lower temp thermostat help ? (When the engine hits 90 degrees they'll both be fully open so no difference)

Basically to start the cooling process at a lower temperature.

[Tallyman]

OK, further update. I've now fitted all the bits, including the 71C thermostat and on a test drive last night I managed to get the temp up to a heady 86C on the local dual carriageway at an indicated 80 mph, so I'm quite happy with that. Just need to try it out towing the caravan now.

One small problem I did find when led under the front watching for leaks, before taking it for a drive, was that I hadn't checked the alternator drive belts for quite a while. One of them was so stretched I could almost pull it over the pully. The other wasn't much better. They were both bouncing around on the water pump pulley, which leads me to believe that part of my problem with overheating under load was the belts not providing enough drive to the water pump to circulate the coolant properly. Luckily I'd bought the belts off Roughtrax a while ago but hadn't got around to fitting them.

So, something worth checking for any other of you that have overheating problems on what should be otherwise sound cooling systems.