1995ish 3vze overheating...
 

Hi all, just bought my 1995 4runner 4x4 3vze a few weeks ago and have been lurking here ever since.

Here is my issue, what I’ve done so far, and what “was” done by a shop.
I do not believe I have a 95 3vze engine. It was swapped. I see a circle with the numbers 93 printed towards the passenger side right next to the timing belt black cover.
It’s definitely not a 95 motor. Spring tensioner.

My 95 3vze has an over heating problem, it had a head gasket rebuilt by a shop and they also replaced thermostat, water pump, timing belt. But she is still running hot after a few miles driving around town. She would start to heat up quickly at idle and cool off when I revved up. She did not heat up just idling in the driveway.
I replaced the radiator with a CSF 2056, and did a complete flush and put in Toyota red coolant (shop used green). I also burped her multiple times. That did not solve my issue, I pulled out the thermostat and she ran fine for my commute to work and then starter heating up close to red on my way home doing 70MPH. I pulled over and sat for 5 minutes, started her up and she was at 3/4 of the temp. I started driving and she cooled off to the 1/2 mark. I’ve checked my oil and it looks normal though it seem like it was steaming after I pulled the oil cap off when I got home. It is not milky. The exhaust isn’t smoking white. The coolant reservoir is at full and the radiator is full of coolant. My heater and AC both work extremely well. She does run longer before heating up close to red if my heater is at max. I also replaced the radiator cap with a Toyota cap.
Many ideas?
My fan clutch seems fine it speeds up when I give it throttle. It also does a 1/4 of a rotation if I try spinning by hand.
Coolant is visibly flowing in the radiator.
Top and bottom radiator hoses both get hot and I have to let go after a few seconds of holding them
Would a bad oil cooler cause overheating?
I have a fan shroud but not the lower portion, would that cause the issue even if I’m not running a thermostat?

She also has ported and polished heads. No cat, with a custom exhaust. And a surging idle. Yay me. But overheating is my primary concern.

having the complete fan shroud would help, you could also check your timing, it can make it run hot if it's off.
Also check your radiator for packed fins, bugs and stuff can collect in the front and stop air from passing through.
Even if you see coolant flow when looking into the radiator it could still be partially blocked.
You have replaced everything else, maybe it's time for a radiator.
It sounds like you have checked or replaced everything else that I would have, so if you aren't loosing coolant it would be one of the items above.

Thanks for the reply.

Gotcha. Timing could be an issue she does idle at 1100-1500 until she’s really warm.

The radiator is new, I put in a CSF 2056.

to check timing I pull off the black cover and rotate the entire belt x2?

would a water pump or timing belt from a newer/ older engine be different? Th parts seem the same for what I think I have. I think mines a 93 motor.

No, don't rotate the belt. I think you need to get someone to help you.
you need a timing light and the distributor needs to be turned to adjust timing, but only after the proper contacts are jumped in the diagnostic connector and the idle properly adjusted.
if you pull the black cover it will be to check the marks on the pulleys to see if they are properly aligned.
the timing belt and water pump are the same on all the 3vz engines.

The paperwork from the shop says that was checked and adjusted. I rather not have anymore shops look at her.

I’ll pull the cover and check the timing lines when I get back from celebrating America’s birthday. Haha.

Would a cracked block seem like a reasonable conclusion even though my oil and coolant seem fine? She does leak oil but I think it’s from the pan. Or am I possibly looking at barely functional aftermarket parks. I know the shop did not use OEM.

After further review of the forum when it comes to bad timing. It seems like I have a lot of similar symptoms. I will try to check the timing myself once I have the time. Unless anyone actually knows a good shop in my area that won’t take my arm.
I’m in Washington state. Tricities area.

thanks @akwheeler.

If you are determined to do it yourself here is some basic information for you.
The timing belt only handles VALVE timing, it keeps the crank shaft and the cam shafts in time to open and close the valves at the correct time in relation to the piston movement and fireing order.
The timing marks on the crank shaft and the cam shafts need to be lined up all at the same time and on the compression stroke for the #1 cylinder. if your crank shaft is at the TDC mark but your cam shaft marks are 180 degrees off you are not on the compression stroke and you need to turn the crank shaft one full turn and check all the marks again.
This should all have been done when the timing belt was replaced, so if it is off take it back and make them do it correctly.
They also should have set the SPARK timing which is controlled by the distributor adjustment.
Rotating the distributor will advance or retard the timing OF THE SPARK in relation to piston and valve postion.
This can only be adjusted CORRECTLY by putting a jumper across the diagnostic connector (check your manual I think it's the E and TE terminals but it has been decades since I adjusted timing on one) with the engine warmed up, idle properly adjusted and a timing light on the #1 spark plug wire pointed at the crank shaft timing marks. Then rotate the distributor (loosen the hold down bolt) until the correct setting is achieved (check your manual for how many degrees before top dead center) then tighten the hold down bolt and pull the jumper off.

As you can tell this gets complicated and you NEED a service manual and you NEED to study up on how this all works before you start tinkering.

I forgot to comment on your question about a cracked block.
First and foremost, if you are not losing coolant you don't have a cracked block or cracked head (unless you're a crackhead... sorry I just had to).:lof:

3VZE Overheating
 

The number in the circle on the plastic wire loom is some kind of sequence number, or part #, or date code.
I have two 95 4 Runners, One was built in October of 94, and it has the # 93 in that spot.
The other was built in October of 95, and it has the # 97 in the same spot.
So who knows.

Art.

Sorry for the double post.
I was trying to quote the O/P, and somehow it got posted as if I had made that statement.
Full moon.

Other than the stock gauge have you verified its over heating? You seem to be over heating in a lot of different scenario's. It is all so possible to put the head gaskets on the incorrect sides on this engine. Which causes the coolant ports to be blocked by the gasket.

Thanks for all the replies.

I’m having a hard time getting ahold of a timing light in my area, I’ll borrow one from a buddy this weekend.

After tinkering with my truck I have a question about the clutch fan. Will giving a warm engine throttle automatically increase fan speed? Mine only increases speed for the first few minutes of running if I give her throttle. When she runs at mid temp giving additional throttle does not increase fan speed. Does that seems normal? I would assume giving throttle would always increase fan speed. And if throttle increases fan speed and makes the water pump spin faster it would make sense why I’m cooling off with throttle. If the fan is failing and not actually working right the water pump would be doing most of the cooling. And this is why I overheat at high speed.

Does my thought process make sense?

+1 on chevking the ignition timing. It makes a bigger difference than you'd think. What you describe with the fan sounds pretty normal The fan should be hard to turn when completely cool. It should free up once the truck runs for a minute or two. Once the engine gets hot, the fan should engage. By hot I mean once the thermostat opens up and hot air starts getting pulled through the radiator. When the truck starts getting hot, shut it off and move the fan by hand. It should be difficult to turn. If its free then it needs a fan clutch. By the sounds of it, you have some kind of restriction of airflow. Most of these Toyotas, I've found I can usually hang onto the lower radiator hose with a properly functioning fan and radiator. If the lower hose is almost as hot as the upper, it isn't doing its job. Either a bad fan clutch or dirty radiator and/or condenser.

Kolton is right about the fan clutch, when cold with the engine shut off you should be able to spin the fan but it should stop quickly when you give it a quick spin IE: not even make one full turn before it coast to a stop.
your thinking about higher speeds and the water pump and fan operation is a little off, at 70 mph your fan isn't really doing much, there is already a lot of air moving through the radiator.
A bad fan clutch will always cause overheating at an idle unless it is just locked up solid which can cause hard starting or low idle when you start it up because of the extra drag.
Don't overthink it or try too many things at once, you are more likely to cause new problems that way, make sure the timing is right so we can check that off the list.

The fan does a quarter rotation when hot, warm, or cold I don’t see a noticeable difference. It has about 150k on it.

Im currently running without a thermostat and it’s runs at mid temp and starts overheating after about 10/20 minutes driving around. My radiator is brand new. And the lower hose is slightly less hot then the top.

No thermostat? My thot on that subject is my own. If the thermostat is removed there is nothing to stop the water temp from overheating/boiling. The T-stat by design holds water in the radiator to cool down when closed, then opens to circulate the cooler water thru the block then the cycle starts again. Yes there are engines that don't use T-stats but use other means to cool the water down.

No, this is not correct. The thermostat stops the water from flowing until the engine gets up to temperature then opens to allow cool water to flow through the engine and by cycling it regulates that temperature.
with no thermostat it should be running pretty cool all the time and never get up to proper efficient operating temperature.

So, your possibilities now are:
#1 the water pump is not working correctly
#2 there is a vapor lock in the cooling system (air bubble blocking flow or keeping the T-stat from opening)
#3 there is rust/scale/sediment in the block stopping water from flowing properly
#4 the timing is off
#5 the head gaskets are on upside down and backwards blocking some of the cooling passages.
I would start with the timing because it is the cheapest, easiest and so very important and you said you burped the heck out of the coolling system.

How do you clean rust/scale/sediment out of the engine besides the coolant flush/cleaner fluids? I did a 10 gallons of distilled water before I put in Toyota red.

And since I’m running without a thermostat it is strange that I’m running so hot? My motor heats up to mid after about 3-5 minutes idling without a thermostat. Wouldn’t a water pump be a easily noticeable failure? I can see coolant circulating inside my radiator.

yes, coolant flushing with cleaners is your only choice other than stripping down the engine to poke and prod and ream out all of the passages.
yes, it is very strange that your engine is running hot, with or without the thermostat.
you said that it has a new water pump, so it would be very strange for it to not move the coolant properly, if it is the right pump and not spinning backwards.