Coolant Temps

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Mar 30, 2003
Just wondering before I hookup an OBD-II scanner- what's considered a "normal" range of coolant temps? At what point should I *start* being concerned?
The A/C compressor has a cut-out at 226 F. That and above is clearly hot. I would be un-comfortable above 220 for sure.
Even that could be too warm.

This is a subject that became near and dear to my heart. While I agree with Cdan's reply, I've tried to "get inside" the Toyota engineers' heads a little.

My temp guage needle doesn't move from its normal position until coolant temp hits 222. From 185 to 221 the position is the same.

The needle doesn't touch the red zone until 233.

So temps up to 232 are not in the red zone. If not in the red, does that mean they are safe? It would seem that in the litigeous (read law suit crazy) society we live in, an auto manufacturer would be careful to not show a temp reading in the safe zone if it wasn't, in fact, safe for the engine. remember, most people driving a Landcruiser have no idea what the coolant temp is - only whether it is below the red or in the red. Below the red should be OK, right?

I ran most of 2000 miles in the upper limits of the temp zone - doing whatever necessary to stay below 232. Had the oil changed twice and the transmission fluid changed when I got home.

Would I do it again? Not without some cooling system mods. It just doesn't seem right to run at those temps. I'm thinking of Emailing Toyota's tech center for a clarification.

As a comparison, I have Detroit diesels in a boat. V6 485 hp, twin turbos, aftercooled.
Great big hunks of metal. The temp alarm sender goes off at 205 degrees. I don't know if it's a good comparison, but it makes 220+ sound high in a gas auto engine.


Did you notice how well your fan clutch behaved on the trip? I just replaced mine and have noticed quite a difference in the ammount of air it moves.

[quote author=landandsea link=board=2;threadid=1586;start=0#msg26888 date=1058291070]

It would seem that in the litigeous (read law suit crazy) society we live in, an auto manufacturer would be careful to not show a temp reading in the safe zone if it wasn't, in fact, safe for the engine.


Hey, we all gotta' feed our dogs! 8)

Dan....As the forum suggested, I tried to get the fan clutch replaced on the way home. Unfortunately it was the 3 day 4th of july holiday. While calling dealers in the Tuscon area, I came across John Hocker. He told me about the silicone replacement for the clutch and told me how to test the clutch by trying to stop it with my wife's nose. Actually, by wrapping a towel around my hand and trying to stop the fan. It wasn't easy to stop the fan, but it could be stopped. I haven't had achance to have it replaced yet, but it will get done. John indicated that if it could be stopped at all (idle speed, operating temp) it needs to be replaced.

I was talking to a aerospace engineer this weekend. He's hip on coolant temps and towing boats. He has a much modified, supercharged Suburban for towing. I told him of the 2 types of radiators that are available. He said that if the capacities are the same, the 2 row alum will do a better job than the 3 row brass. Do you agree?

-H- , I hear you. Just trying to make the point that a mfg would be careful. Without lawsuits, everything we buy would be junk and probably dangerous.

Ed (just don't sue me)
[quote author=landandsea l Actually, by wrapping a towel around my hand and trying to stop the fan. It wasn't easy to stop the fan, but it could be stopped. I haven't had achance to have it replaced yet"

Have what replaced? Your hand?
Someone told you to put your hand into a running engine with a towel wrapped around it so it was nice and close to the fan and the belts? I don't think THAT'S in the FSM ;)

Cheers, Hugh
My wife and son kept asking me if I really was going to do it. They said "how well do you know this guy"
Sorta brings new meaning to "Throw in the towel" don't it :eek:

Have you met John Hocker in person? Did you ask around to find out why his nickname is lefty?

I wonder if he wears a tie? ::)
Ed (or of course, CruiserDan)-
Tell us more about the "silicone replacement" fan clutch - I take it this is an upgraded part that replaces the original? I hope it isn't a prosthetic hand that makes the fan clutch a two part set ;). Thanks, BigMac
ED,i notice your 80 is a 1996(same as mine)and since we were experiencing similar temp issues while towing and now you are gonna replace your fan clutch,i would like to know how many miles you have on your cruiser(would rather compare mileage than stick my hand in the fan!!)



I think Ed was refering to putting new silicone oil in the existing clutch as opposed to replacing the clutch. In the 70's Toyota's clutches had filler holes in them to add oil. Toyoya still lists 3 different part numbers for the replacement oil. They do not mention re-filling procedures for the newer clutches that do not have fillers nor do they say what to use where. Based on what I just went through to change my clutch I would not like to do that job again for a long time. I would not be inclined to experiment. I can tell you that the 1FZ fan clutch has changed numbers and the new one I put on was different than the one that came off. The old gal really sucks wind now.

Thanks Dan -
Would you think I could expect to see a significant airflow difference between the new-style fan clutch and my 97's (which I can only presume to be the original)? I'm planning to finally install the new fan with the big ring around the blade tips (hard to stick a toweled hand into that baby) this weekend, so I can see where this is headed..... Thanks again, BigMac

I assume you mean the 16361-65010 3.0V6 truck fan? Are you installing that for grins or did you get a blower? I would not use that fan unless you are putting it on in conjunction with a blower. BTW IF you are installing a blower, it didn't come from me :'( . Oh well, I digress. Any way, what color is the base of your fan clutch?(the 4 bolt flange area that bolts to the water pump). If it is black you have the old-style clutch, if it's "Navy" blue(cool huh?), you have the new style clutch. I would put a new one on IF the old one is black, particularly if you are installing a blower. The part number is 16210-66020.

Cheers, Dan.
Dan -
I'll call you in the morning.... see, I knew where this was going.
Thanks, BigMac

Big Mac....The way I understand it - and someone please correct me if I'm wrong - the silicone in the fan clutch expands with heat and is the engaging factor in the clutch. I didn't know silicone reacted that way, but it explains why an old girlfriend looked so much better on hot days.

I think the FSM had a replacement procedure until 93 or 94. As CDan said, the job is removing the fan clutch. The new one is around 100 bucks. Can't save too much trying silicone implants on the old one. And there are other things that can wear out.

Ed (typing noticeably slower with one hand)
I learn something every day. I had never heard of a servicable fan clutch - only sealed units. IIRC, a bimetallic spring is also part of the clutch engagement mechanism. Since I will have things apart this weekend, will go ahead and swap the clutch for the new number, per Dan's suggestion. Since I need both hands to turn wrenches, and Dan knows well of what he speaks, I will forgo the "manual fan stop" verification step. Hope your hand heals well, BigMac

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