Typical time to get a 1993 SC 1KZ-TE blowing warm air?

I am a new Hiace owner.  I took the van for the first time up to the ski mountain the other night for some night skiing.  When we were done it was 20F (-7C) in the parking lot.  I started it about 20 minutes before leaving to get warmed up but it took forever (an additional 20 minutes driving) to start blowing warm air out of the heater.  I have no data points on this and wanted to get a typical time to heat up or do I have something I need to look at?  I appreciate any insight.  Cheers!

Ok, so the thermostat on the 1kz-te is somewhat inconveniently placed half way along on the RHS side of the block, and it a terrible (inlet sensing) design.

I have no idea what Toyota were thinking, but the same brain lock also affected BMW, Land-Rover/MG, Porsche etc, so I assume some whiz kid wrote a paper that convinced them to pursue the insanity.

I write in detail about this, and how to adapt the cooling system to the sane solution that LandRover adopted, and I also wrote about how to fix the temperature gauge to stop it lying. It has a large, deliberate, dead-spot in the crucial zone.

I'd also add that the heater matrixes can get clogged, so if you get the chance, empty the coolant, blow out the matrixes and use new Toyota long life coolant.

But for future, I'd look at doing my mod, as it works extremely well.

Incidentally the deadspot in the gauge is added because this coolant system is useless and fluctuates too much. It's more serious in cold weather. The thermostat measure both the (freezing) water from the radiator and the hot water from the head, via a bypass. The problem is that when it opens, it takes a long time to close, and in the meantime the freezing water enters the head. So the head gets subjected to alternate hot/cold/hot/cold.

The Landrover fix works on a large external bypass, and changes the entire coolant operation to mimic that of a thermostatic shower mixer, just directing water of the best temperature back into the engine.
So it takes in hot and cold, the hot from a big bypass straight from the head, and the cold from the radiator. A tee piece after the head allows the water to flow either way (into the bypass or radiator).
With this mod the old thermostat is mimicked with stainless washers and a bolt to allow the water into the engine all the time, and to allow water from the head bypass to also flow. This creates a nicer flow in the head, instead of continually swapping sides that the old system used.

Thanks GPW! I appreciate the insight.  Is this (https://hiace-super-custom.forumotion.com/t3430-cooling-the-1kz-te-in-the-hiace-super-custom) the most relevant thread to performing your mod?

There is a nearby shop in Portland, Oregon that offers a fan clutch mod (https://www.vanlifenorthwest.com/products/hiace-kzh106-kzh100-tuned-fan-clutch-30-1kz-te-engine).  Is it a mod to address the same issue or a different issue that can arise with the 1KZ-TE engine?  I appreciate your insight.

Hi!

Sorry, yes, that is the only thread on the modification.
My only additional comment, having done this now, is that it makes sense to do the timing belt and a new water pump at the same time, because the access is good when you are doing the job anyway, and the new bypass pipe obscures the front of the timing chain cover!

The fan clutch mod is just to lock the fan boss, I'm not sure how much difference it makes except using more fuel, if it's working well then I'd not do anything to it, unless you can accurately get the factory amount of fluid in there, just in case the years have caused some to be lost.

Hi,

I would say that the situation you describing is normal/expected and I have exactly the same “symptoms” when returning from skiing. Effectively you are driving down hill for 20-30 min with engine idling! About the only things you will find hot and toasty in that sort of driving would be brakes! Once I reach flat road or start climbing mountain passes, heat is back! From my experience, my gas engine Subaru "suffers" from same “symptoms” when returning from skiing.

I had a slow warmup issue one winter and it was because my thermostat was stuck open. It would take forever to warm up and the air would never get super hot.

If it warms up very slowly in normal city/highway driving then you most likely have thermostat issue. If the issue is related to downhill driving from ski resorts only, then I would not worry to much about it.

I appreciate all the feedback. I plan on doing some large part replacements before I start adventuring out into the national forests and a thermostat replacement is on the list.

Make sure you flush the system when you changing thermostat and if you have a rear heater, you probably would like to flush the rear heater core as well. For some reason in my van the rear heater core silts up every two or three years...