overheating:X

[mwollman]

All right, so over the winter I noticed at lower RPMS my 4runner was overheating. I checked the coolant levels and they were low so I filled it up. March comes around and it starts overheating in idle, so I check the coolant levels, they were low, so again I filled it up and filled up half of the overflow. It's now may and the other day I was in a drive-thru and once again, it started overheating. I replaced the oil two weeks ago and got about 5 quarts after 12k miles and it was completely black, no water at all. I've had a few suggestions to check my fans and thermostat, but I'd like to see if anyone else has had a similar problem. As for the coolant disappearing, I just hope it's not a head gasket:X

EDIT: Was just looking at the "strawberry milkshake" threads. What exactly happens in this situation, and what can I do to check it? Does the tranny fluid and coolant mix in the water lines or the transmission? Thank you for you input!

 

[empty403]

All right, so over the winter I noticed at lower RPMS my 4runner was overheating. I checked the coolant levels and they were low so I filled it up. March comes around and it starts overheating in idle, so I check the coolant levels, they were low, so again I filled it up and filled up half of the overflow. It's now may and the other day I was in a drive-thru and once again, it started overheating. I replaced the oil two weeks ago and got about 5 quarts after 12k miles and it was completely black, no water at all. I've had a few suggestions to check my fans and thermostat, but I'd like to see if anyone else has had a similar problem. As for the coolant disappearing, I just hope it's not a head gasket:X

EDIT: Was just looking at the "strawberry milkshake" threads. What exactly happens in this situation, and what can I do to check it? Does the tranny fluid and coolant mix in the water lines or the transmission? Thank you for you input!

Have you checked for any leaks? Try putting a white cardboard underneath to find out. If you do check to see if it's coming from the water pump - there is a small hole in the water pump that coolant will come out off when the seals start going bad inside within it. If your exhaust has a white plume of smoke coming out accelerating - Could be a damaged headgasket or worse a crack in the block, allowing coolant to get in the combustion chamber. The "strawberry milkshake" is when the coolant mixes with the transmission fluid turning the color to a milky pink color - it can cause rough shifting. Take a look at your tranny dipstick for this color and it may be overfilled from the coolant coming in. You can try bypassing the radiator (by coupling the 2 hoses that go into the radiator) and see if coolant leaks out of the transmission ports of the radiator.

 

[Singtoe]

The transmission is enough to check. Lock at the dipstick. If it is creamed up, your Radiator is leaking into the cooler.

If your truck is not leaking, you've got bad head gasket. Sorry for the bad news.

 

[brian2sun]

If your truck is not leaking, you've got bad head gasket. Sorry for the bad news.

Most likely, but I wouldn't say 100%. Now if it's also idling rough, missing, blowing smoke or water, etc.. then I it's a HG or cracked head. A compression test should tell you if it's one of those though. Otherwise, it could just be a bad water pump. If it's a slow leak somewhere, the drips don't always make it to the ground. I would look for coolant trails with an extendable mirror under the water pump and thermo, inspect the radiator, and I would do a cooling system pressure test to see if you can find a leak. If it drops pressure, but no leaks appear, that's another good way to diagnose a HG. A partially clogged radiator and/or coolant passage(s) could be another cause.

Given that you went 12K miles and then drained out pitch black oil, I'm guessing you're not big on maintenance OP. That's why I'm thinking it could just be a worn out water pump and a small leak somewhere. How many miles are on it? Ever do the timing belt/water pump? Original radiator?

 

[MAD 69]

..... I'm guessing you're not big on maintenance OP. That's why I'm thinking it could just be a worn out water pump and a small leak somewhere. How many miles are on it? Ever do the timing belt/water pump? Original radiator?

if he is lucky he will get away with just replacing the water pump, but most likely he also need the TB. You might also want to change the oil a bit more often, every 12,000 miles is hideous - even with Synth fluid.

 

[LittleCaesar]

I'd check the radiator cap, fan clutch, water pump.

12,000 miles, excluding possibily using Mobil 1 EP, is too long of an interval to be running oil in this engine.

 

[mwollman]

Okay, I will check that and see what I can find. I waited 12k just because my oil wasn't even low then, I used mobil 1 full synthetic, and it was the typical color of oil when it's changed, a dark brown I guess you could say if it's on white or a lighter color. I just checked my tranny fluid and it was far above the "hot" indicator. I don't know if this is because I was just driving or if it's because there is coolant in there. As far as the TB and radiator, the TB was replaced around 100k and the radiator is still the original. As of now I have around 135k on my engine. The people that owned it before me knew less than I did so everything that was done to it was all dealership/shop work. I haven't seen a leak but I will look around a little bit and see if I can find a leak. Sadly though I live in the valley of Oregon and it just went from sun to pouring down rain so this may be delayed :/

EDIT: Just checked I have 145k and had the previous oil replaced at 133k. Also, I haven't replaced the water pump yet, and I doubt it was replaced before hand either.

 

[mwollman]

One more thing to add if it was unclear before. This has been happening for months now. No white smoke from my exhaust, no loss of power, and no other problems at all. Every couple months or so I will start overheating when I am idling, or driving up the mountain and don't drop gears so it's running low RPM's. If I take off/drop gears or run my heater on HOT it will cool down.

 

[alp]

One more thing to add if it was unclear before. This has been happening for months now. No white smoke from my exhaust, no loss of power, and no other problems at all. Every couple months or so I will start overheating when I am idling, or driving up the mountain and don't drop gears so it's running low RPM's. If I take off/drop gears or run my heater on HOT it will cool down.

I would say it is a fan clutch. Do you hear a loud powerful sound from the fan when you start your truck in the morning and after about 30 seconds it goes away?

 

[mwollman]

Yep, as a matter of fact all you can hear for 30 seconds is a fan when I start it up, atleast until it warms up a little. I've heard this from other runners and tacomas even so didn't think anything of it.

 

[mwollman]

Wait, what does this have to do with losing coolant tho?

 

[mwollman]

Okay so I pulled my skid plate off and this is what I saw.

That is on the bottom passenger side of my radiator. The skid plate was dark in that area too, and only in that area. I checked my trans fluid and it came out dark on the stick and a similiar dark reddish brown I guess you could say. It was also reading above the HOT point if that says anything.

 

[empty403]

Okay so I pulled my skid plate off and this is what I saw.

That is on the bottom passenger side of my radiator. The skid plate was dark in that area too, and only in that area. I checked my trans fluid and it came out dark on the stick and a similiar dark reddish brown I guess you could say. It was also reading above the HOT point if that says anything.

Good find, it looks like it may just be a leaking radiator. Just in case you haven't been doing this, check the transmission oil level while the engine is warm and running at idle, drain or fill as needed. Also, bleed the radiator, right after you replace the radiator and fill it up (with the coolant mix ratio recommended for your region), try to park the vehicle at an incline so that the radiator hole is somewhat at the highest point. With the radiator cap off, let the vehicle idle until it warms up. While warming up you will see bubbles come out. Fill the radiator up, as needed. When the bubbles stop coming out (after about 10-15 min) your done and replace the radiator cap.

 

[BrianSD_42]

1) get a camera that can focus or use the closeup feature

sorry but....

2) 12k without changing the oil, you will lucky if that engine lasts another few years, even if you rebuild it. I am not a mechanic that is just my opinion.
If the head is cracked or gasket gone bad you will have to make choice to fix or sell.

I dont know if it is worth it to spend $1200-$2500 fixing an engine that went 12k without an oil change and then started missing.