3L Upper Radiator Hose Diameter

If I recall correctly, I wiped some coolant on the adapter before inserting it into the hose. I don't recall it being a struggle.

djathens what kind of temps are you seeing in summertime? I have the sensor in the upper radiator hose and today, after replacing the thermostat, I saw 207 with the AC on sitting in traffic. Before my thermostat was stuck open and I rarely saw over 190.

207 in that situation seems reasonable to me. I think I've seen 212 as the max, and that was going over a mountain pass in the summer with my wife, dog, and camping gear inside and on the roof. Around town I rarely see it go over 200. If it did, it would be in a similar situation as you described.

Keep in mind you are pulling around a lot more weight and cooling a larger volume than I, with the same engine and AC capacity, so you're bound to generate higher temps in the same driving scenarios. Unless you have the 1KZ engine, then you have 30% more power on tap, but then you have other cooling issues to be concerned about.

I guess that's the only downside of the belt-driven fan boss vs an electric radiator fan. It doesn't help much if you aren't making good RPM. It really is key that it functions correctly, I could see our vans overheating very easily if it didn't engage when needed. If you were somehow approaching 220 in stop-and-go traffic, in a pinch I suppose you could put it in neutral and hold it at 2500rpm while dumping heat into the HVAC. Or just pull over and shut it off

Yeah I’ve considered either locking up the viscous fan or adding an electric one. It’s probably not a huge deal. I just switched off the AC and it immediately started dropping down to 200. Anytime I’m moving it drops consistently.

Out here, my mechanic has a Super GL that he has built into a camper, and he installed an auxiliary radiator with an electric fan that he can switch on when needed. He said it gives him that little extra headroom and peace of mind in the summer on long climbs.

harmonep wrote:

Yeah I’ve considered either locking up the viscous fan or adding an electric one. It’s probably not a huge deal. I just switched off the AC and it immediately started dropping down to 200. Anytime I’m moving it drops consistently.

The Hilux lads seem to add viscous silicon fluid to their fans which can lock them 'on' if you overdose. It's probably the easiest and safest way if you want to get that route, or just add a bit.

An electric fan may help for traffic tickover, but I don't think would be powerful enough to make much difference when the engine is working, that viscous fan coupling transmits a lot of power to the fan which is tricky to match with electricity IMO.

Well it wouldn’t be to try and match the viscous fan. It would just be on the front pushing air through the rad in addition to the viscous fan.

The A/C has a big fan on it, on a Peugeot I have it helps cool the radiator (as the Peugeot's fans are a bit slow to kick in).

But I note you said it helps if the A/C is off, which is interesting. I wonder what is going on with the airflow there.

You may also find it worth taking the rad out and having it reconditioned, it could be a bit bunged up and the van could probably use a coolant refresh anyway. Try to get Toyota Extra Long Life pink stuff in there when you refill, it's good stuff.

I’ve just flushed my system. I’m not really that worried about it. 207F (97C) sitting in traffic with little airflow on a 97F (32C) day doesn’t seem unreasonably hot to me.

As far as the AC goes, the AC condenser is positioned horizontally in front of the radiator so the AC fan probably doesn’t affect the radiator air flow. I think heating up with the AC on is a function of the increased engine strain to run the AC compressor.

Ah Ok, on my 1Kz it's in the same place but there's also a 2nd engine rad there too!
On my Peugeot the radiators and one after the other in a sandwich.
I did think it was radiator city, but some cars have 8 I'm told

personally i am looking at fitting a CHT (cylinder head temperature ) gauge

https://en.wikipedia.org/wiki/Cylinder_Head_Temperature_gauge

Apparently they respond faster than a coolant temp sender..Carting and air cooled engines , like Vdubs and aircraft engines use them..i have 1kzt engine so cannot use a sparkplug temp sensor, so will get my IR temp gun and will try and find the hottest spot on the cylinder head and hopefully find a mounting point for the temp sensor....Just an idea ive been thinking about.
Anyone else done this?? would like to hear about it..thnx

I know a number of people that have used them and attached the sensor to a rocker cover bolt. I can’t imagine that’s more accurate than measuring the water as it leaves the engine. To get to a better location for the sensor you might be dismantling more than I’d be comfortable with. I’m satisfied that I’m getting a good measurement with the sensor in the upper radiator hose.

well a rocker cover bolt would be of no use atall!! ...its far too exterior..im hoping to find a point alot closer than that....may try finding a deep thread or make my own copper heat sink to fit j or k type sensor..i need to do more research..i dismissed the sensor thing in the top hose as trying to get more accurate temp rather than water temp...just my theory wrong or not

One thing to bear in mind is that not all thermostats are equal in flow rate.

i recently changed out a thermostat on my wife's car (just because I changed a coolant pipe and the coolant, there was nothing wrong with it), and popped a new one in.

I noticed that the new one had a much bigger hole to let the coolant through, probably 50% greater flow. Both were quality after-market ones made for that engine/car, but it was interesting to see the difference.
So in the marginally coole Hiace it may be worth researching for the best flowing thermostat.

Also look at the coolant, water is the best heat conductor, coolant less so. So perhaps choosing an extra long life coolant (the pink stuff, Toyota do it), buy it in concentrate than use it diluted to 30 - 40% instead of the usual 50%.
This may also help carry the heat away better.