No thermostat question

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

beatdown83fj60

beatdown83fj60

10 Year 15 Year
Joined
Jul 30, 2006
Threads
57
Messages
615
Location
Evergreen, Colorado
Ok when I got this truck I knew it needed a radiator, and I'm getting one next week. I have been driving it just the short ride to work and back every day which is about 10 miles and all highway. The first few days it was getting pretty warm and wanting to overheat. I dinked around with it a little bit to see if it was anything besides the radiator. I had to pound down the ears on the rad. cap to get it to seal at all. Still driving kind of warm but did a little better. Then I took out the thermostat. Absolutely no overheating, in fact it won't even warm up. Is this normal? Could the tstat have been the only problem? I also noticed that the tstat can go in two ways, is it possible it was in upside down? I haven't done one of these in like 6 years so I cant remember which way it goes in. I'm getting a new tstat tomorrow to see what happens, it's kind of cold in that truck.
 
Yes it is normal for the truck to run cool with no thermostat. usually the spring side of the thermostat goes towards the cylinder head or engine block on most cars/trucks. yours is definitely this way. as for the radiator, why do you think you need a new one? is it because its leaking or because the truck is overheating? its very rare for radiators to get plugged up in this day and age. try a thermo first. as it warms up you should feel the lower rad hose get hot first. as the temp needle gets close to halfway you should feel the upper radiator hose start to get hot. if the upper hose gets hot and the lower hose cools down then you are getting good cooling from the radiator(usually). i have a feeling that the thermo will fix your problem. good luck.
 
Well I'm putting the radiator in for 3 good reasons.
1. I have an A/T and I've read too many horror stories about the radiator corroding and dumping coolant in the trans and killing it. I just bought the vehicle so I have no idea what the history is on it.

2. When you look under the cap you can see that the thing is literally clogging up like crazy, there are dime sized chunks of scale laying on the top fins (a couple of them or so whenever you look.

3. I found one that a guy ran for a few weeks before blowing a headgasket and parting out the truck that he will sell me for $50, and it's a performance radiator.

I'm sure I could get away with just a thermostat for a long time, but I'd feel better knowing the age and more of the history of my radiator given the 3 reasons I provided. I wanted to make sure that it was normal because someone told me that without a thermostat it should warm up quicker but it just didnt sound right. I thought the tstat held in warm coolant on purpose so that the engine could warm up then opened up at a certain temp to let the colder coolant from the radiator in. Wouldn't that mean if nothing limited the flow the engine could never really warm up?
 
exactly. for 22r's they seem to recommend a 180 deg. thrmo. For 22re's a 195 deg. I've heard of people putting in 180's in the 22re's Personally, I tried it, and another friend is running the 195. Appears to be no difference.

Why does the lower rad hose get warm first? conduction of the heat through the backed up coolant until the thermo opens?
 
Not sure why the lower hose get's warm first, mine wouldn't at all before I pulled the tstat, and now that I'm more awake than last night I read that first post better. The P.O. MUST have had the tstat in upside down lol, the spring wasn't pointed down towards the block at all.
 
Well brand new tstat and once again, it wants to overheat. I've got to say that out of a LOT of things that can go wrong with a vehicle, cooling system problems probably frustrate me and piss me off more than almost anything. I just want to rip my hair out right now. And to add to that, no heat while overheating. Blowing warm or cold. Losing hope in my abilities fast here.
 
Well the bottom end is in poor enough shape where I won't take the time to put a head gasket in it. I think I'm just going to drive my second vehicle for a month or so until I have the rest of the cash for a new motor. Unfortunately, that second vehicle is a Jeep lol :crybaby:

P.S. if it needed an HG wouldn't it overheat all the time? The reason I ask is because without the thermostat it runs nice and COLD, and I thought if the HG was bad it would run hot no matter what.
 
Last edited:
I'm not familiar with the specifics of your particular engine, but the coolant system can be a mire. You're best off starting at the basics and working upwards. Complete flush and refill of the system should be the starting point.

Radiator. If its condition is dubious, get it replaced.

The thermostat, you've already done. :) Btw, with regards to the thermostat, running without can cause either overheating or overcooling. Without the 'stat, the engine has no way of regulating coolant flow, so can lead to either condition occuring.

Rad cap. If the rad cap is not sealing properly, you may be loosing coolant and pressure from the coolant system. The pressure is required to heighten the boiling point of the coolant, so you would be best repalcing the cap if it's quality is debatable.

You mention the rad has the ATF cooler inbuilt? Another thing to check would also be the ATF, if so, as fluid that is past it's best can lead to the autobox generating excessive heat, which is then transferred to the coolant.

Final check would be the hoses themselves. If the rad is scaling, as you mention, some of the hoses could also be in a partially blocked condition.

If none of those cure the problem, then look at the head itself.
 
Also, since I'm assuming it's the 4Runner in your sig, don't forget to check the hoses going to the rear passenger heater core. They're a smaller diameter and might get clogged easier.
 
Mine doesn't actually have a rear heater, I was a little bummed about that actually lol. The P.O. also had one wrong bolt holding the upper tstat housing on and it finally gave up the ghost and stripped. I've got to drill and tap the hole today :rolleyes:. That doesn't look very fun, it's in kind of a crappy spot.
 
Well through further investigation the HG is toast. I've decided. I'm going to have to drive my #eep until I can afford a new motor unfortunately, if I can swing the cash I'll probably do the 5 speed swap at the same time. We'll see! This thing is too old and tired to justify doing an HG only.
 
No, but when I first got it back and drove it around for a day or so, and saw what looked like the beginning of milkshake. I wiped it out and drove it for a day or two and it was fine. Then it got a little warm twice (still not into the red, getting warmer faster each time). Today it kind of started running like s*** and I pulled the cap when I got home, milky goodness. Im going to get a new motor in it here soon. I kind of thought the HG was the problem in the back of my mind especially when I asked the P.O. if he thought it was the head gasket and he got kind of defensive lol. I didn't care, I was getting a beautiful 4Runner for $800. It has enough life left in it to get to my mechanic to swap the new motor in it so I'm happy. In the end I will be out about $2500 for a perfect rust free 4runner with a brand new engine. Breaking somewhat even but I'm stoked on the motor!
 
A stuck T-Stat Can Melt your Engine Fast

Word. Learned it the hard way one morning in Santa Fe on the way to Taos and used up a journal bearing in a 68 FJ 40. Have never bought another used car without first replacing the t-stat! Cheap, too. Before you replaced, did you have any coolant leaking or bulging around the hose fittings?
 
Well the truck had a barage of cooling problems. The tstat and radiator were toast and I think the HG was already on it's way. Oh well, I'm just going to throw a new motor in it and be happy for a long time!:D
 
Hm... maybe I should just buy a whole new engine like you're doing. Mine is already out.

With the parts I want, it will cost me about $1,000 to rebuild mine, and my block is far from perfect... it still has milkshake sitting in parts of it, I still can't get one of the f*cking head bolts out (sheared off, not to mention the threads on the other head bolts on the block side may be fuxd :mad:) so... interesting.

Anybody know of a place around Boise that I can get a Toyota engine? I'd rather not get one through the local Schucks/Autozone/etc..
 
You must log in or register to reply here.

Share this page

Back
Top Bottom