Overheating

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cjf202

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I have a 94 4Runner 3VZE that has been giving some overheating issues lately. It started a few months ago with me noticing a small coolant puddle under my truck. I tried several times to pinpoint the leak but every time I would run the truck and watch I didn't see any leaks. The puddle was near my drivers side front tire. After awhile of trying to figure it out I decided to use stop leak which I majorly regret now. The stop leak plugged up my thermostat so I replaced it with a toyota one. The leak issue seems to be intermittent now. I can go a week or more without seeing a drop in coolant or a puddle and then all of the sudden it leaks again. One time after moving the truck about 50 feet with the engine cold I saw coolant leaking and it appeared to be coming from above my thermostat near the water pump.

The last few weeks it's been trying to overheat on me when driving on the highway. Normally turning the heat on full blast brings the temp back down enough. I know I have some air in my system that I have been struggling to get out. I've parked on a hill 5 or 6 times and tried to burp it while squeezing all the upper hoses and can't dislodge the air. I can hear it when I first start driving and it sounds like its directly behind my gauges.

My 4Runner has been fine driving on one highway for 20 or 30 minutes at 70 mph but once i go through this one interchange and slow down to 40 or so and then speed up to 75 my temp gauge starts rising. I'm only on this road for about a mile and when I get off the temp continues to go up a little. Once I pull out at the stop sign the temp goes back down to normal. I think my water pump is on the way out but I'm not sure.

Any help is appreciated and I'm pretty desperate to get this figured out as its my DD.

Thank you!
 
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A new radiator fixed the overheating issue. I'm still losing a fair amount of coolant though. My only guess is the water pump. My timing belt has almost 50k on it, how much would it cost to get both replaced?
 
I too had an overheating problem that a rad recore took care of. The puddle by the front left tire is most likely coming from the overflow recovery tank. Check the hose that runs to it for cracks or splits. My tank had a pinhole in it. Got one online for about $12. As for how much to replace ur t-belt and WP, call around n see. I always call at least 5 places and am amazed at the price variance. Good luck!
 
Check for exhaust gas in the coolant before you waste anymore time or spend anymore money. You can buy a test kit at any auto parts store.
If there turns out to be exhaust gas in the engine coolant, you are then looking at doing the head gaskets. All the timing components have to come off then anyways so it's not much more labor. Good luck.
 
Tested for exhaust gas and it was negative. Checked my hoses and the overflow The only time I actually saw a leak was after I started the truck cold and moved it about 100 yards and parked again. From what I could see it looked to be coming from around the thermostat.
 
cjf202 said:
Tested for exhaust gas and it was negative. Checked my hoses and the overflow The only time I actually saw a leak was after I started the truck cold and moved it about 100 yards and parked again. From what I could see it looked to be coming from around the thermostat.
Click to expand...

That's going to be an easy one then, if it's anything like the tstat on the 22re. Tighten it. :)

If it's already tightened to torque, try pulling it and applying some fresh sealer and reinstalling it.
 
There is a hose that comes off the side of the water pump near the thermostat, that may be leaking. Is there a weep hole on these water pumps?
 
cjf202 said:
Tested for exhaust gas and it was negative. Checked my hoses and the overflow The only time I actually saw a leak was after I started the truck cold and moved it about 100 yards and parked again. From what I could see it looked to be coming from around the thermostat.
Click to expand...

That's good news!
I would pull the housing, install a new good quality 180 thermostat and put it back together with a new o-ring.
Be sure to check your thermostat housing for cracks or distortion.
 
I installed a new OEM thermostat in early February and all bolts are still tight. Today on my way to work which is only a 10 minutes drive, my 4Runner started to overheat. I assumed I was just low on coolant but when i tried to add water before leaving work but it only took about a half liter. I was sitting at a light for a few minutes before I noticed the overheat, so I don't know if the water pump is working at idle.
 
I wonder if you may have a plugged up radiator?.. If your radiator is more than 10 years old then you may need to take it into a radiator shop or get a new one.
Also - make sure there is no debris or anything stuck to the front of the radiator and blocking air flow.
 
Might be time to replace the water pump. At least you can rule it out as the culprit. You can buy a timing belt and water pump kit. Rockauto has them; they range from $109 to $225 for the kit.
 
Sounds excactly what I had goin on. Same year and engine. I had craploads of air in the system and I could hear it bubbling around in there. i knew it wasn't a HG cuz Its brand new. I got one of those no-spill funnels and put it on the radiator. Filled it up a plenty and ran the truck until the thermostat kicked in and started to watch the fluid running through. After a few minutes, bubbles started comin up like there was no tomorrow. I pretty much let it burp itself. After about 15 minutes, no more air. No more overheats since then.
I had the same leaking out of the underneath. I couldn't find the source. I found out though, that there was so much pressure, that the hoses were leaking at the joints. You shoulda seen all the coolant spilling ferociously in the grocery store car park. Crazy and Annoying. I checked all my hoses and replaced a few in case they were damged from the pressure.

Hope it helped :)
 
I think I'm gonna replace the lower radiator hose first and then try to burp it with the funnel I have. Last time I got a ton of air out but I've never been able to get it all. I replaced the radiator about a month ago.
 
Engine Pressurizing Radiator because of Bad HG?

Isn't that the 3VZE notorious for head gasket issues?
Are you having hard-start issue? If so, maybe compression is pressurizing your radiator and that makes your coolant reservoir overflow while driving. When you stop you would not see it but some overflow would drip on floor.When engine cools, some coolant may seep into cylinders causing hard start. On our Honda Civic, this problem blew the radiator cap off. When head gasket was replaced, mech said one of the cylinders looked like it was steam cleaned.
If you started engine cold with radiator cap off, you might see coolant splashing if HG bad enough.
Good luck.
 
Haven't had a chance to replace the lower radiator hose yet. I haven't had any issues since when I was going to work last week. I'll probably do the hose this weekend.
 
Intake?

do you have an intake leak? i recently had head gaskets done and heads machined, i have a warped intake, and it is causeing mine to over heat. waiting for new intake to come in.
 
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