Overheating Troubleshooting - I pushed it over the edge

[JohnnyxRex]

A about 2 weeks ago I noticed an issue with my 2005 v6 - the heater did not work unless I was moving. Late last night I went on a food run, and while waiting in the cold parking lot I hopped on the forums. I found some thread that implied that the heater performance could be dependent on RPMs (so it would work over 2500 RPM, etc)

This is where I think I screwed up - I tested this theory by revving the motor. It worked! The heat started immediately. I held it at redline for a few seconds, then back down to idle, and the heat cut off. I headed home, and all was well until this morning.

On the way to work today (a short 3 mile trip) the coolant temperature suddenly goes to max. No lights came on or anything, but the motion of the needle caught my eye. I limp it back home and pop the hood to see that the coolant in the reservoir is bubbling/boiling. I haven't messed with it since then.

How should I troubleshoot this? After reading a few threads, I suspect the water pump was on its last legs and I killed it last night with my revving. I'm pretty strapped for cash and want to do this in a thoughtful way.

The coolant was changed last year, and I didn't notice anything weird then. The water pump has probably never been replaced, and the mileage is 195k (I bought at 125k).

Thanks!

 

[triethylborane]

Some items off the top of my head: Revving the engine to obtain heat from the HVAC is an indication of an air pocket in the heater core system.

As for the water pump, if the shaft connected to the pulley has axial play, that is you can move it to a degree that is out of spec, then it might be the water pump. I cannot find toyota's spec for water pump axial play, but here is a video that sort of shows the kind of excessive play you are looking for:

VW waterpump shaft wobble - YouTube

My guess is that it is not the waterpump, but perhaps the thermostat, fan clutch or a head gasket. 3 miles is a short distance, so something is not allowing the coolant to circulate to the radiator, or the coolant is reaching operating temps so as to trigger the thermal clutch for the fan . . . this is testable at idle or with engine off. There are tons of videos on youtube on how to diagnose a bad thermal fan clutch.

It could be a head gasket issue where combustion gasses are heating the coolant, but this one Id mark at a low probability.

 

[duffdog]

Overheating and bubbling generally indicates that you have broken something. Check the easy things first, fill with water and change the radiator cap. Make sure that there are no loose fittings on the heater lines that would let water escape. If the pressure is holding, you have no leaks and the water level keeps dropping, you most likely have blown the headgasket. The heater would fail to work because the coolant can leak into the cylinder and blow out the exhaust, causing it to slowly drop until there is no coolant in the heater core and only the radiator is full. Revving the engine could push water into the heater core temporarily until the leak in the headgasket takes so much water that there is none left for the engine and it warps the head.

 

[Captsolo]

Don't drive it far. Overheats can ruin an engine. I'd change the thermostat first. Call in an expert.

SR5 150,000 miles 2005. Never threw a "code" in 15 years. Runs and starts great. Never an overheat.

You must be losing coolant. Could be a failed or failing WP. Maybe a really bad clogged radiator.

Does a stuck thermostat need changing? It's rare that they stick.

BTW: THE Coolant level in my overflow tank is steady and at the same level for 6 months. I check it often.

4runner is 15 years old and never had a radiator or WP problem.

Check the coolant level often and correct the problem. If it starts with a miss and doesn't run right I'd look for that "head gasket" issue and start with Blue Devil.

If BD doesn't stop it from losing coolant for 6 months you got a HG job. Probably worth it.

My 2005 4runner runs like when it was new. Amazing Toyota products out there. I bought my daughter a new 2015 Camry when she graduated Florida State and she and the car are now out in Denver with a big Wall Street Broker (two years and lots of raises); and the Camry runs like new still, and looks like new. I have read of some 2015 Camrys with 300,000 miles. She's got 45,000 miles now!

My family will never own anything but Toyota products. Except picture with three F225 Yamaha 4 strokes.

 

[JohnnyxRex]

Ok, thanks for all the replies so far. The first thing I did this morning was top off the coolant level with water. I tested it for over 30 minutes and drove about 20 miles - no issues so far. It operated within the regular range and the heater works "instantly" again.

I've got my fingers crossed that that was this resolves it, but that still doesn't tell me why the coolant level was low in the first place.

I think I'm going limp the tires another month to save funds in case this issue reappears.

 

[JohnnyxRex]

Don't drive it far. Overheats can ruin an engine. I'd change the thermostat first. Call in an expert.

SR5 150,000 miles 2005. Never threw a "code" in 15 years. Runs and starts great. Never an overheat.

You must be losing coolant. Could be a failed or failing WP. Maybe a really bad clogged radiator.

Does a stuck thermostat need changing? It's rare that they stick.

I've got the same model. It's been great other than the cats going out about 2 years ago.

I know that there's coolant being lost somewhere, but I don't know yet if its a slow leak or a fast one. The heater acting up over the past few weeks makes me think it is slow. It's raining today, so maybe tomorrow I can inspect for leaks.

If it's a major job I may just sell it before I spend the money to replace these tires though ¯\_(ツ)_/¯

 

[newton22]

Do you want warped heads? That's how you get warped heads lol.

Get an OBD bluetooth scanner and making sure coolant temps don't go much over 200 degrees F.

 

[JohnnyxRex]

Do you want warped heads? That's how you get warped heads lol.

Get an OBD bluetooth scanner and making sure coolant temps don't go much over 200 degrees F.

What do you mean? It appeared to operate in the range with no visual evidence of it overheating like it did before.

Did basically the same test with BlueDriver logging today. Temps climbed from 130s to 192 degrees F. There was one erroneous reading that was like -9F, but it was only one. I watched it closely while it got up to temp (while idling). No visible problems.

 

[Teamoatmealpie]

you can buy a cheap kit to test for exhaust gasses getting into the coolant.

You gotta laugh at the Scotty videos !!!

<iframe width="560" height="315" src="https://www.youtube.com/embed/v0U8Iyf0kk4" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

 

[Drcoffee]

Scotty is a riot to watch. Some of his tip and tricks are so redneck I would never do it to my cars. But he is entertaining.

 

[JohnnyxRex]

you can buy a cheap kit to test for exhaust gasses getting into the coolant.

You gotta laugh at the Scotty videos !!!

<iframe width="560" height="315" src="https://www.youtube.com/embed/v0U8Iyf0kk4" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Ok, so I bought this kit and ended up trying this - no head gasket leak. That's good, thanks for the recc.

What's not good is that the coolant level has dropped again. I've been keeping it topped off with water, but now I've got to figure out where the leak is so I can switch back to the Toyota Long-Life Coolant. It's been raining a lot here, so I haven't been able to track it down.

Any ideas? I'm debating getting quotes for a serpentine belt/water pump replacement.

 

[duffdog]

Ok, so I bought this kit and ended up trying this - no head gasket leak. That's good, thanks for the recc.

What's not good is that the coolant level has dropped again. I've been keeping it topped off with water, but now I've got to figure out where the leak is so I can switch back to the Toyota Long-Life Coolant. It's been raining a lot here, so I haven't been able to track it down.

Any ideas? I'm debating getting quotes for a serpentine belt/water pump replacement.

definitely look at the water pump to see if its spitting coolant out the bottom weep hole. Oh...and the radiator cap. My cap just self destructed and would let water right by it. A new one is cheap enough.

 

[The G-Man]

definitely look at the water pump to see if its spitting coolant out the bottom weep hole. Oh...and the radiator cap. My cap just self destructed and would let water right by it. A new one is cheap enough.

Absolutely look at those things, but your symptoms don’t sound unlike my own symptoms. Take a look at my thread. My block test somehow came back negative but I still had HG leak.


Sent from my iPhone using Tapatalk

 

[Teamoatmealpie]

It really can only go a few places, leaking water pump, leaking head gasket into engine or your radiator or a hose is leaking.

another option is to add the ultra violet dye to your rad- then you black light the water pump/ hoses/rad, etc to see if its leaking.

You can get the UV/dye kit from any auto parts store comes with dye/ UV flash light and some tinted glasses to help spot the leak.


And as mentioned above a failing rad cap might let coolant out there too. Rad caps are cheap.

 

[importman]

I also recommend checking the radiator cap. My runner was losing a small amount of coolant and you could smell it anytime you walked by it after driving. I pressure tested the system and found nothing leaking. As an afterthought I checked the cap and it was deteriorated terribly. New cap, no more leak.

 

[newton22]

you can buy a cheap kit to test for exhaust gasses getting into the coolant.

You gotta laugh at the Scotty videos !!!

<iframe width="560" height="315" src="https://www.youtube.com/embed/v0U8Iyf0kk4" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

These don't work. My fluid stayed blue even with a slow HG leak.

 

[The G-Man]

These don't work. My fluid stayed blue even with a slow HG leak.

Yep. I had same experience.

 

[Captsolo]

YOU WROTE: On the way to work today (a short 3 mile trip) the coolant temperature suddenly goes to max. No lights came on or anything, but the motion of the needle caught my eye. I limp it back home and pop the hood to see that the coolant in the reservoir is bubbling/boiling. I haven't messed with it since then.



Thanks![/QUOTE]



Whatever you do, don't drive it with that "overheat"/boiling coolant - or you'll ruin the engine.

After reading all these HG leak posts I lift the hood on my 2005 4runner/150,000 miles (once a week) and check the overflow canister for and "loss" of coolant. For the last 6 months the level has maintained itself at the same height, so I can't have a HG issue.

 

[JohnnyxRex]

These don't work. My fluid stayed blue even with a slow HG leak.

This is what makes me think I should get out from under it. I went and looked at a 2014 today.

I just need the thing to last another month before I change jobs and move. I am truly considering replacing the tires and bringing it to a mechanic to do the water pump/belt/pulleys, but a head gasket leak sounds expensive and not worth it. How long did yours last?

 

[JohnnyxRex]

On second thought, it is not clear to me that there is "for sure" any kind of head gasket leak. It may just be the water pump.

How did you guys eventually know that it was the head gasket? Did it just suddenly get worse?