Overheating/Random Problems

L

levi.watson

New member
Hey there guys! First off, I've got a 89 4Runner, rebuilt 2.4L engine from Oregon Engine Rebuilders, probably has 600 miles on the new engine, car has 232K. I've replaced:

Water Pump
T-Stat
Radiator/Hoses
Clutch
Battery
Fan clutch was out, replaced it with a electric fan, comes on around 160º
/other stuff that I'm forgetting.

Two weeks ago I was driving for probably about 10 min and the temp gauge spiked, pulled over quick and there was coolant all over. I let it cool off, put new fluid in there, no problems. Drove 120 miles round trip averaging between 65-80 MPH, absolutely fine.

Last night the charge light came on, along with the e-brake light. The e-brake light gets brighter when I actually have the brake on. The battery is new, I haven't left the lights on for long periods before, so it should be good.

This morning drove for about 7 min on the interstate (65MPH), saw the gauge going up, so I pulled over for 15, limped it to a stopping area, left it there for 2 hours, (it's like 40º here right now) got back in, driving home I noticed that there was a pulsing in the idle, very noticeable. It was running hot again, so I pulled over and had a buddy tow me home. It's sitting in the drive now, no idea what to do...

Any help would be appreciated. Thanks guys.
 
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Were you able to get hot air blowing from the heater? I'm wondering if you have air trapped in the system somewhere. There are a lot of little spots for air to get trapped. I'd park on an incline, let it idle, and take rad. cap off to let any air escape ....
 
Pulsing idle like it revs and drops? It might be a vacuum leak somewhere. You can also check your idle control screw, sometimes you can get a vacuum leak through there as well, some people put teflon tape around the screw for a better seal...
 
Charge and brake light on at the same time is a sign of a non-charging alternator. Check the belt first, and if its still on there, check the alternator wiring and see if you're getting a charge out of it.

Your fan is probably not picking up the temp from the radiator but the air coming through the fins, and if its 40º out, its not hot enough for it to trigger the fan. Although I too run an electric fan (flex-a-lite black magic made for the 22re trucks/4runners), and I've never had an overheat issue with my truck in the 15+ years I've had it in the truck, I'd suggest going back to the stock clutch fan.

It could be that you're putting a big load on the electrical system with your fan, which could be why your alternator isn't charging any more. I run a MeanGreen alternator at 140 amps, the stock alternator is only around 45 amps, and given everything else running (spark, interior fan, lights, ecu and other stuff), you probably don't have enough to keep up with an electric fan. I bet that the specs on that fan are around 20-30A for a draw, which will suck power away from the ecu and other stuff in the engine compartment.

On top of that, if the alternator is trying to keep up, there's a full load on it which can create a surge in the engine (its trying to supply enough hp to keep the alternator spinning at idle). Check to see if this surge is happening when the fan is on. And, check the battery's voltage when the fan is on too, see if there's enough voltage there and that the alternator's able to keep up with it.

Unfortunately, unless you upgrade all the components, you'll end up with other weak places in the drivetrain. Electric fans want power, so upgrade that, you need to upgrade alternator. Upgrade alternator, you need to upgrade wiring to alternator. Upgrade wiring, you'll need a better battery to maximize storing the power from the alternator.

Or, repair the clutch fan and throw it back in. Its really not hard to replace the fluid in the clutch fan, and its relatively cheap to do, unlike upgrading everything else to make the electric fan work properly.

One other thing about "burping" the radiator. This MUST be done, and done properly! I've popped a head gasket once because of air in the system and not catching it in time.

From cold start, pull radiator cap off, set aside. Get the front end up HIGH! If you have an incline in your driveway, use ramps and get it as high as possible, 15º incline at least, more if you can. Turn your heater control in the cab to full heat, then let the engine come up to temp, watching the movement of the water in the radiator. You'll know when your thermostat opens when you see antifreeze start rushing past the opening.

Let it run like that for several minutes, I like to rev the engine slightly (around 1200rpm) just to get good movement of the antifreeze through the engine and heater core in the cab. Top off radiator, close cap, take it for a drive with heater core on full cold.

Around 2500-3500rpm, turn heat on full, if you hear gurgling through the system, you have not gotten all the air out of the system and you'll need to do this all over again. If it just turns hot and you don't hear anything when you flip it from hot to cold, you're good to go.
 
You said there was coolant all over. That is not good. Now you dont see it. Is it leaking on a manifold and evaporating? If it leaked all over, it didn;t fix itself.
I agree with above on the electric fan loading your stock alternator. However, stock is 60A at rev. A lot lower at idle. I installed a 120A alternator from a Jaguar XJ, almost plug n play.
Is the thermostat stuck closed?
 
v_man said:
Pulsing idle like it revs and drops? It might be a vacuum leak somewhere. You can also check your idle control screw, sometimes you can get a vacuum leak through there as well, some people put teflon tape around the screw for a better seal...
Click to expand...

Yeah, it sounds like it idles normal and then goes to a lower RPM. Ok, I'll see if I can find any leaks there... Any tips on finding them? Not really sure what the vacuum system does, so I'm not sure how to check it...
 
Ok, thanks! That's a lot of good information. The fan is definitely on when it's hot, I have the fan's t-stat hooked into the radiator, and when it was hot I double checked to make sure it was running. I tried to repair the clutch fan, I put the silicon fluid in it and it still wouldn't engage... Tried to buy a new one, no one has one that fits mine. It was totaled like 20 years ago, and I'm assuming that the front end had some work done and they put a random fan clutch in there. So that's why I went electric.

That's good to know on the air, I'll have to get that out hah.
 
So the first time it overheated, it def passed by the cap and lost quite a bit. I filled it back up, and everything was normal. Then, yesterday, it was getting really hot, but it didn't spray everywhere, it just sorta oozed out and didn't spray everywhere...
 
The water pump is on the same belt as the alternator. If the belt is slipping or seizing, that would explain the intermittent overheating.
 
KidVermicious said:
The water pump is on the same belt as the alternator. If the belt is slipping or seizing, that would explain the intermittent overheating.
Click to expand...

Ok, I went to check that belt, and to my surprise I found it was gone... i guess that would be causing a couple problems haha. Thanks for all your help guys!
 
LOL!

Quite possibly the easiest fix to overheating and no charge issues!

:clap2:

Glad you didn't damage anything! No water pump action usually means blown head gasket pretty damned quick in Toyota engines! And I've definitely had my fair share of BHGs!

I'd still burp that radiator when you get that belt back on, and if you have a gauge layin' around somewhere, I'd test compression too, just to make sure nothing's damaged.
 
flyinhawaiian01 said:
Glad you didn't damage anything! No water pump action usually means blown head gasket pretty damned quick in Toyota engines!
Click to expand...

I lost the alternator belt on top of a mountain once. Spent the next four hours alternating 5 minutes of driving and 20 minutes of letting the truck cool off to get to the nearest pavement. I went through my whole ten gallons of water replacing what the rad blew off. I think that was the awesomest head gasket ever.
 
penbergm said:
You said there was coolant all over. That is not good. Now you dont see it. Is it leaking on a manifold and evaporating? If it leaked all over, it didn;t fix itself.
I agree with above on the electric fan loading your stock alternator. However, stock is 60A at rev. A lot lower at idle. I installed a 120A alternator from a Jaguar XJ, almost plug n play.
Is the thermostat stuck closed?
Click to expand...

What year Jag XJ? What mods did u have to make? It sounds like a more affordable option than a MeanGreen or other custom alt.
 
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