mapple83

94 PU 4X4 22RE...OK so she runs at op temp when driving non stop above let's say 40mph. The more I stop, the hotter she gets. If I turn the engine off and start her up 5min later, almost in the red! At first, it sounds like a fan clutch issue but my fan seems to be blowing pretty decent at idle. The radiator was replaced 2yrs ago, new stat, and new water pump. Coolant level is good. The water pump wheel did seem rather stiff (easily turn with hand but no free spin, where as the old one free spun ) when I bought it which made me wonder. Let me know whatchoo guys think.

xxxtreme22r

Sounds like a sticking thermostat or fan clutch to me.

Team420

fan clutch.... just cuz it appears to spin fine at idle dont mean it working....

also could b a stuck tstat.... but my money is on the fan clutch

mapple83

If it were the fan clutch wouldn't the fan not blow? The thermostat is virtually new but hey, I've have new parts crap on me before.

xxxtreme22r

Even with a bad fan clutch the fan can still turn, just won't turn as fast as it should.

Helpful hint if when you start the truck say in the morning when it's colder and you can hear the fan start fast and then eventually slow down after maybe 15-20 seconds as it warms up, it's bad. When first started it will also provide a little drag on the motor so when the fan clutch releases when cold you will hear the fan slow down and engine rpm might jump a little.

mapple83

[QUOTE=Team420;51859963]fan clutch.... just cuz it appears to spin fine at idle dont mean it working....

I guess I don't really know the exact function of the fan clutch then. (scratching head)

Team420

This pretty much sums it up.... A good way to test it.... with engine cold, and off, spin the fan by hand... any resistance? if so, it needs to b replaced, it should spin freely

Also as mentioned above... if it sounds like a jet engine taking off, when u start it (cold) then slowly quiets down, it likely needs replaced

xxxtreme22r

Actually it should have a little resistance when it's cold. And it should sound like a plane when it first starts. If it doesn't there is no resistance in it enough once it reaches op temp that the clutch doesn't engage.

That's the funny thing with these clutches if it's bone cold it's enough to actually engage the clutch for a very short period of time.

mapple83

All very good info but the fact that it gets so much hotter after I turn it off for a few min, wouldn't that sound more like a stat issue? I should get a fail safe anyhoo. Might as well check this possibility off first since its a cheaper easier repair too.

xxxtreme22r

Never get a fail safe thermostat. If anything get the Toyota dual stage thermostat. Well worth the $35 for it at the dealer.

And that temp jump after tuning off is called heat soak.

rworegon

Belt tension ok? Any additives been dropped in the radiator the past 2 years potentially clogging it?

On the fan clutch:
https://www.yotatech.com/forums/f2/f...ild-22r-18900/

mapple83

[QUOTE=xxxtreme22r;51859982]Never get a fail safe thermostat. If anything get the Toyota dual stage thermostat. Well worth the $35 for it at the dealer.

Ok that really begs the question, why never get a fail safe? I mean, I trust your judgement, but you'd not expect the fail safe stat to be a detrimental mistake ( you said never and my brain interpreted NEVER!!!). BTW thanks for all your help. You've been a consistent source of much appreciated info in regards to the sputtering Toy that hates me.

[QUOTE=rworegon;51860012]Belt tension ok? Any additives been dropped in the radiator the past 2 years potentially clogging it?

Nope, no additives but I have drained and replaced the fluid about 4x thanks to worthless reman alternaters from clarks, and I think I read somewhere new coolant has a detergent affect that can sometimes dislodge grime only to lodge it somewhere else down river creating a clog. Aren't there pressure test kits or something for cooling systems? Oh and thanks for the fan clutch link

xxxtreme22r

Just google up "fail safe thermostat", you'll see why.

I don't know how expensive those bottles of fan clutch fluid is, but my fan clutch I got at Autozone was $40 with a lifetime warranty and has been flawless. (as long as I keep the mud off of the fan)

Your not using standard green coolant are you? Should be either using Toyota's red (kinda pricey) or using a long life universal. (I use the Peak universal)

I don't think this is what your problem is, but read this and make sure you don't have these same symptoms.

http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

Either way, the part number for the dual stage thermostat is 90916-03070.

rworegon

Your local auto part store may have one you can borrow or the local radiator shop can do the test for a small charge, about $25 around here.

The tubes of the fan clutch oil from Toyota is a bit spendy. With some research on other forums, I found that Diff-Lock Silicone Oil 7,000wtg that RC guys use in their toys was being used with success and much cheaper. The local hobby shop did not have any, so I tracked it down on the web. Viola, it has worked perfectly in my rebuilt AISIN fan clutch that a friend was sending the recycler.

mapple83

UPDATE; I ended up just replacing the fan clutch with a Hayes one for $50.00 . When I went to the stealership after I first wrote this I tried to go the easier cheaper route and bought the 2-stage thermo...or so I thought. The guy apparently thought me stating I needed a TWO-STAGE thermostat was insignificant and just sold me the reg one. Didn't notice till i got home and opened the box. Went back the next day and the next moron behind the counter tried to tell me they didn't exist and that he worked there for 20 years so he should know. Yeah buddy, you should know. Anyways I persisted and made him look it up and found out it was $57.00 . Decided it was more likely my fan clutch and I'd try that first. So new fan clutch in today...nothin. same symptoms. I guess I'll pull the t-stat and test it with hot and cold water. Which begs the question, how come nobody suggested that free diagnostic?

xxxtreme22r

Because f the thermostat is sticking then it may or may not get tripped with boiling water. And unless you got a way to know what temp the water is at, it's just a quick check.

This is a known issue with the thermostat. And has a TSB related to it. Surprised that dual stage part number nor the TSB # didn't come up related to that regular thermostat.

Yet another reason why I don't trust dealerships to give me the correct part when I don't supply the part number.

And unless you have those same symptoms in that article I provided, it's not going to solve your issues.

mapple83

Yeah I definitely do but I just don't touch the ac or heater as my solution. Not related to the issue at hand tho.

mapple83

Uh that last quote came out weird. My responses are in the quote. Sorry bout dat dare

xxxtreme22r

The temp overshoot only happens if you have your heater on. It's because of the way the piping is designed and how the return from the heater core is attached. Just in case you have a different perception on the actual issue.

If you have to turn the heater on to eliminate the problem, then the overshoot isn't what's causing it.

skypilot

iTrader: (1)

I have found over the years that there are a lot of bad thermostats. I have also found that getting a "good" one is a hit or miss affair. I used to replace them every year just before it got cold because they stuck open and I had no heat for winter. I knew they were bad because the engine never got warm in the summer. I think I went through a dozen 'stant' brand units before I found one that actually works like its supposed to. It stays closed a little on the long side so the engine gets hotter but then you can see the gauge drop and know it opened and I have not had a problem with it so far.

Thermostats are cheap, keep a spare & replace whenever.