drewberglund

I just recently replaced my thermostat and have noticed my 87 4runner acting a little differently than before. When its cold and hasnt been driven for a few hours my engine heats up to just under the red on the guage and then suddenly plumets down to normal range. It always happens within the first 10 minutes of driving and Im guessing its the thermostat opening up atfer the engine heats up. Anyone familiar with this.

Jake94

Called Over Shoot

Jake.

leebee

you have an air pocket/bubble in the system. let the rig cool down over night, next morning, take off the cap, start the rig and let it run. put a catch basin under the front end and let it come up to temp, it will bubble over (catch basin) and the air pocket/bubble should work its way out. shut it down, let it cool and top off with proper mix coolant (rad and overflow reservoir), replace cap and you should be good to go.

lee

4Crawler

iTrader: (3)

Yep, sounds like the 22RE Temperature Overshoot problem, as noted on my page linked above. I had that problem and the specified thermostat in the TSB fixed it for good (and its a far superior t-stat to boot).

drewberglund

Thanks for the help 4crawler I will try that.

leebee

i stand corrected, after reading rogers post i agree with his solution to the prolem. has anyone has a similar problem with suceeding generations of runners and does the same solution correct the problem?

lee

4Crawler

iTrader: (3)

Not really my solution, just using Toyota's own Technical Service Bulletin and upgraded thermostat. The thermostat will fit all 22RE engines and while the TSB lists certain year engines, I think it any vintage 22RE with the overshoot problem would benefit from the thermostat. In fact, I would run that 2-valve t-stat in any 22RE engine, its just a superior design. The smaller valve can respond faster to coolant temp changes (the response time is propotional to the mass of the slug in the t-stat) and the smaller valve has a much smaller mass slug so much faster response time. Also, with 2 valves, you have some redundancy in case one fails.

Erich_870

Not to Highjack, but I'm concerned that I have an air bubble in my system. During warm days if I stop the engine really quick, I get this knocking sound like a pipe and water hammer and then my coolant system barfs coolant out of my over-flow bottle. I don't get it.

When I replaced my fluid this summer (It had been doing the same thing before I replaced it so I just left the level low so it wouldn't puke in the parking lots) I thought I had fixed it. I ran my heater on high for a long time, thinking the air was in the heater core, and when ever I open my radiator cap, its full. How do I get this barfing to stop?

Erich

mikedog

Another way to eliminate the coolant temp overshoot problem is to just buy a regular single pellet slug style thermostat and drill (2) 9/64" or 5/32" holes in the flange around the housing.

This will ensure that some coolant will always be flowing through the system even when the main pellet valve is closed. In addition, the drilled holes provide an escape for any air bubbles that may get trapped in the system.

The main advantage of drilling the holes as opposed to getting the Toyota 2-stage thermostat is that you can buy a lower temperature stat if you want to. You're not stuck with the stock 195* temp range of the Toyota 2-stage thermostat. You can run a 180* in the summer and a 195* for the winter. In my 22R, I run a 160* in the summer and a 180* in the winter here in So.Cal.

Bigblock

V6's are bad about that ,u gotta remove a heater hose to let the air lock escape!

PirateFins

I tried that with a stock 195* t-stat. Drilling 2 9/64" holes 120* apart. Worked fine for the overshoot because the truck never warmed up. I never got up to 1/8th scale warm. Doesn't work well when it's 10* outside. I changed to the 2 stage t-stat and the overshoot is gone and the truck runs at 1/4-1/2 scale when warm and feels nice during the winter. IMHO Sometimes the cheap trick does not pay off.

PirateFins

Here's a good question for y'all. On a 6 cyl the jiggel valve gets put in the 12 o'clock (top of t-stat housing when vertical) position to allow air bubbles to escape. Where do you place the jiggel valve on a 22RE that has a horizontal t stat housing??

I can never figure out the best location for it.

4runnerx4

Don't want this to be whats happening but both of those problems can indicate a bad head gasket. Also on the 22r/re engines when the timing chain guides wear out and the factory ones will on an old engine the chain rubs on the timing cover. I learned this the hard way it wore a pin hole between the chain cover and the water jacket in the chain cover. Keep an eye on your oil & water for the dreaded milkshake. Head gasket problem usually has the quick rise in temp untill enough pressure builds up to open the thermostat and if it's a tiny area in the gasket you wont notice the loss of water for a while. The boil over problem usually indicates air entering the system and could be from a bad radiator cap. Either way if it's not due to the thermstate i would keep a close eye on things! I hope this is not the case!!!

jimbo74

from what i have heard on the 22r engines also the re it doesnt matter where you put the jiggle valve