Another Overheating Thread

[Retroben]

Hey fellow Yotahomers

I've seen threads here and on the FB forums about overheating issues with the 3VZE, but they all seem to get left unresolved.

As others have reported, I can't drive my motorhome on any hilly or mountainous highways unless the ambient temp is under 80F, or it will overheat. The temp guage gets up to the red, I pull over and let it idle for 10 minutes or so, temp drops back down a bit, and so on.  This does not happen on flat terrain even at 90 degrees. 

Underpowered, yada yada.

 

My radiator looks to have been replaced with a nice new copper model. Timing belt, water pump and thermostat done less than 10k miles ago. Red toyota coolant still looks fresh and the level stays within the limits on the overflow bottle.

 

Meanwhile I've lived in cold climates where car/truck grills are blocked off (even with cardboard) to restrict air flow through the radiator, helping the engine reach and maintain temperature in extreme cold. Granted, these vehicles were older tech but the principle still applies. Radiators don't work well when you block them.

 

There is a transmission cooler and a/c condenser both in front of my radiator, blocking more than half its surface area, and right in the middle. I can't blow an air gun through those layers and out the other side. I can't imagine the radiator is dissipating heat at full capacity with those windshields in front of it.

 

My a/c doesn't work anyway, never converted from R-12. Maybe removing that big condenser would help? Ideas?

[thewanderlustking]

It's been a while since I have had a Toyota RV, but I currently have two 3VZE 4Runners.  Let's start off with I live in Florida.  It's hot here is an understatement and it's a humid hot that doesn't ttransfer heat as well as a dry hot (cooling system wise).  These trucks never run the slightest bit hot, EVER.  Even when I blew the hradgaskets on Thing 1, it didn't get hot...   My trucks aren't overloaded like an RV, but they aren't running light/empty either.   So lets go down the rubber hole.

 

1)  Somebody else needs to add input here as this is RV specific and I forget the direction that needs to be taken...  The heavily loaded RV's either need to be run with overdrive off, or on.  I want to say its OFF...  Especially in hills. One way adds a crazy amount of heat into the system.  It is enough of a concern I added transmission temp gauge into my old Mini Cruiser, and now monitor that in my 4Runners.  This descries the core of your issue perfectly, hills vs flats.  

 

2)  Sure if you are not going to get AC working, you could remove the AC condenser.  I never would, but as a mechanic with shop access, I can also reasonably fix any AC issues my trucks have.   AC removed will drop the resale value of the truck.  Broken/installed is better than removed.  The transmission cooler and AC condenser shouldn't drop the efficiency of your radiator to the point of poor efficiency.  Saying you can't blow through them though, is concerning.  If they are clogged up with dirt/debris then you do at least need to get them cleaned out to get flow through them.  

 

DO NOT remove the transmission cooler.  These really need the extra transmission cooling.  

 

3)  You can "recycle" your AC condenser electric fan, put it on a relay/switch for extra cooling...  But look at your primary fan clutch too.  These do eventually go bad.  

 

4)  Check head gaskets...  

 

You really need to do some diagnostics.  #1 is free, figure out which way to set the O/D switch.  #2, clean blocked condenser and transmission cooler.  Air should flow easily through them.  #3 check your fan clutch.  

 

#4 and further Diag will require minimal tools.  Get a blocktestor kit, watch videos on how to use it.  Simple and cheap.  The expensive/nice kits are $125.  The cheap kit is like $30=50.  You have a 3VZE, you need to own this and know how to use it.  It takes 2-3 minutes to test it.  Get yourself a laser thermometer.  Verify your engine temps.  Look at the hoses, see if the thermostat is working.  A new one, DOES NOT mean a working one...  A decent laser temp gun is under $100.  You can get it on Amazon for $30.  I use aVERY nice Snap-On laser temp gun.   It is well worth whatever I paid for it, but not for driveway now and then and I wouldn't throw it in my truck toolbag.  I have a cheap amazon laser gun in my truck that hopefully works if I ever need it...  

 

The IDEAL tool for diagnosing cooling systems would be a thermal camera.  The one I use, is NOT affordable.  They have some 😂that attach to phones and are WAY cheaper.   Not sure if they are in the affordable or reasonable range yet though.