I have transplanted a J23 motor from a 2005 Aerio into a 1998 Sidekick Sport w/Auto.   

I did a 'long block' swap, keeping everything Sport, (wiring intake, exhaust, and externals) to make the transverse mounted J23 fit. 

It runs very well.  I am pleased with the swap.  Much more power and a very good replacement for the 240,000 mile tired motor.

The problem I am having is that the engine runs about 30 degrees hotter than normal at idle and speeds up to 70MPH and I can't seem to
find out why. 

I've confirmed the temps of 230-240 with multiple scan tools, and resistance tests of the ECT according to the Service manual charts.

The motor has never overheated but the elevated temps are a real concern.

With the Swap I put in a V6 Grand Vitara Denso Radiator, 2 10 inch 800 CFM Fans (about 1600 CFM) with a shroud made out of an aluminum baking pan.   

During the Swap I also added a new thermostat (Car Quest Brand).  The water pump SHOULD be OK.  I have a cool rubber hose
running into the motor at the bottom ,  a hot radiator hose at the top so coolant is flowing.

I have parked the vehicle now until I can solve the problem.   

My calculations may have been wrong with planning the cooling capacity as I think the Aerio's radiator is about 20% larger
than a Grand Vitara but I would think that a radiator rated for a 2.5 V6, larger than the 2.3 would have been sufficient.

Thank you for your time.

I've confirmed the temps of 230-240 with multiple scan tools, and resistance tests of the ECT according to the Service manual charts.

Maybe it's time to confirm the ACTUAL temperatures with an IR gun or similar - all the multiple scan tools are doing is reporting the temperature sensed by the same sensor.

I missed the edit time limit ...

Which sensor are you running, the 2.0 & 2.3 Aerios use a different part number, and the 1.8 Sport sensor is also a different part - try using the sensor that matches the ECU you're using, assuming that it will physically fit.

I missed the edit time limit ...

Which sensor are you running, the 2.0 & 2.3 Aerios use a different part number, and the 1.8 Sport sensor is also a different part - try using the sensor that matches the ECU you're using, assuming that it will physically fit.

The J18 and J23 ECT part numbers are the same,  The measurements were tested in a water pan with a candy thermometer and compared against the charts in the Suzuki Manuals so I know the temp numbers are correct.

So the engine at idle climbs to 230.  So the problems are

Not enough cooling mass. This is a V6 Grand Vitara radiator  1" thick    This should be sufficient
Coolant Flow ,  The thermostat isn't operating properly or the coolant tube that runs from the back into the thermostat housing is somehow plugged,affecting thermostat opening
Lean fuel ratio making the overall running temp higher.

There are many others who have done this swap and I was hoping to have others share if they are having a lean condition or seeing elevated temps but so far nobody has responded with any details.

I keep searching for answers as to why things are so hot.

The following data was taken from Suzuki's WWEPC, specifically the US market vehicles.

J18 (SV418) coolant temp sensor - 13650-50G01
J20 (SQ420) coolant temp sensor - 13650-50G01
J20 (RH420) coolant temp sensor - 13650-54G00
J23 (RH423) coolant temp sensor - 13650-73H00

Now - regarding your candy thermometer experiment - the coolant temp sensor is not a precision measuring device - all I'm suggesting is that you use one to verify that a problem does exist.

The following data was taken from Suzuki's WWEPC, specifically the US market vehicles.

J18 (SV418) coolant temp sensor - 13650-50G01
J20 (SQ420) coolant temp sensor - 13650-50G01
J20 (RH420) coolant temp sensor - 13650-54G00
J23 (RH423) coolant temp sensor - 13650-73H00

Now - regarding your candy thermometer experiment - the coolant temp sensor is not a precision measuring device - all I'm suggesting is that you use one to verify that a problem does exist.

J23 temp sensor is 2 wire, J18 is 3 wire so using the J18 as it fits in the wiring harness. I understand the ECT is not precision but  there is a temp chart.



I got resistance readings within the ranges at temps for this sensor so I am fairly confident that the Coolant temp from the ODB2 scanner is correct.

I've figured out how to log data anow for the scanner nd need to log TPS, ECT, IAT, RPM , load, MAF readings , LTFT. all at once and log over time to see if I really have a lean condition or if the coolant system isn't up to the task
 
I'm all over the place on this and I've been instructed to gather the details to analyze from facts.

I haven't had real good luck with non-OEM thermostats. You might either try a new OEM thermostat or swap the old one back in, to see if that changes anything.

I haven't had real good luck with non-OEM thermostats. You might either try a new OEM thermostat or swap the old one back in, to see if that changes anything.

I've been getting some advice from a local hotrodder and he suggested i look at the increase in CCs of the engine as well as Radiator Volume between the 1.8 and the 2.3 motors to help formulate an approach.

 1.  The 2.3 engine is 24% larger than the 1.8
 2. The volume of the Aerio Radiator is roughly 28% larger than the Sidekick Sport Radiator (2 Row) .
 3.  I'm using a pair of 10" fans that are supposed to offer 1750CFM in pairs
  4. I have a fan shroud for these fans, I used an aluminum baking pan and it is drawing air well.

 So I need to increase the Radiator Size and air flow.    I put in a V6 Vitara radiator, 2 row when the original was a 1 row. essentially doubling the volume of the original radiator but the temps are still high.

  Even with the larger Radiator volume of the V6 Radiator it may not be enough to properly cool the J23 engine.     I also have a 2" body lift so that may be changing airflow and coverage.

   The next phase of my testing is to replace the 2 10" fans with a single 16" 3000 CFM fan to see what the temps give me.

    I have ordered a 3 row Aluminum Radiator which will take a few weeks to arrive.

   I've checked all the external pipe/tubes on this engine and put on a new water pump and Stant thermostat that I tested (pan of water) and the system is working as it should but
 the data is leading me to the fact that my cooling system as a whole is too small.

During the Swap I also added a new thermostat (Car Quest Brand).  The water pump SHOULD be OK.  I have a cool rubber hose
running into the motor at the bottom ,  a hot radiator hose at the top so coolant is flowing.

But you say the outlet radiator hose is cool. If it is cool (or substantially cooler than the inlet hose) then it sounds like the existing radiator is cooling fine.
I would have played around with the thermostat before I bought another radiator. I have seen a substantial difference in running temps between an auto parts store thermostat and an OEM one. Ironically, the auto parts store thermostat made the engine run too cool in the winter (couldn't get much heat out of the heater). But I also think the auto parts store one was a 180* one and OEM was 192* or something like that...been too many years ago. Also, sometimes you use a rubber oring on the thermostat, sometimes you don't and that can affect the coolant flow through/around the thermostat, which in turn affects cooling. Don't recall if it was a 1.6 8V vs. 16V thing or what...again been too many years ago since I messed with thermostats.

But you say the outlet radiator hose is cool. If it is cool (or substantially cooler than the inlet hose) then it sounds like the existing radiator is cooling fine.
I would have played around with the thermostat before I bought another radiator. I have seen a substantial difference in running temps between an auto parts store thermostat and an OEM one. Ironically, the auto parts store thermostat made the engine run too cool in the winter (couldn't get much heat out of the heater). But I also think the auto parts store one was a 180* one and OEM was 192* or something like that...been too many years ago. Also, sometimes you use a rubber oring on the thermostat, sometimes you don't and that can affect the coolant flow through/around the thermostat, which in turn affects cooling. Don't recall if it was a 1.6 8V vs. 16V thing or what...again been too many years ago since I messed with thermostats.

I have been using Stant thermostats for a very long time in all my vehicles and they are a reputable product.  I made sure I tested this one on the 'stove' before I installed it.    I have confidence that the Stant is working properly.

I do not have confidence in the fans that I have to deliver enough CFM to pull enough air through the radiator to lower the coolant temp properly or there is not enough cooling surface to get the temps down enough before entering the engine.
While the lower hose is cool, the temps may still not be reduced enough  to keep the temps in the engine down as a whole.

I have spent a lot of time on this working through the issues to make sure that the data is right.  The ECT temps showing from the computer are correct.  I have confirmed that all the external plumbing on this engine (way different than an 8v or 16v 1.6)
is not obstructed .  This engine is a reverse flow water pump so it pushes water into the engine.   I know the air has been removed from the system.

So my approach is to change the fans to a higher CFM unit and re check to see if it lowers the temps at the ECT.    More CFM may just reduce the temps to an acceptable range but I won't know until I try.

The 3 row radiator is the next step if the fan does not cut it.   
.

You might be right about the fan. I'm running a 16" electric fan on my 1.8 & it does well. I've long thought about a 2.3 upgrade.
One thing you mentioned in your last post 'might' be more relevant than you think. The odd way the J series engines open the thermostat & that it's a push rather than pull system. The thermostat actually opens from coolant that flows THROUGH the heater core, then through a tube below the exhaust manifold to hit the back side of the thermostat. Is your heater core clear? If it isn't, it might be restricting flow & causing the thermostat to open late?? Just a thought.

This engine is a reverse flow water pump so it pushes water into the engine.

More out of curiosity than anything else - what makes you think describe this as a "reverse flow"?  How many vehicles can you name where the pump pulls hot water out of the engine as against pushing cold (or cooler) water into it?  I can't think of any.

The only thing unusual about the cooling system on a J series motor is the location of the thermostat - unlike the cars I grew up around, which typically had the thermostat sitting between cylinder head outlet and the radiator top hose, the J series engines have it between the lower hose and the water pump (the "cold leg" of the coolant circuit), something which is becoming more & more common.

Something to think about - because the thermostat is in the cold leg of the circuit, it is dependent on circulation of hot water through the heater core to warm it enough to open, at which point cooler water from the radiator will flow, mixing with the hot water from the heater,  reducing the temperature, and causing the thermostat to close, impeding the flow from the radiator - question - if you cool this water further (more cooling surface/more air flow) how does it impact the operation of the thermostat?

If you want a diagram of the J18/J20 cooling system as the vehicle left the factory, let me know...

More out of curiosity than anything else - what makes you think describe this as a "reverse flow"?  How many vehicles can you name where the pump pulls hot water out of the engine as against pushing cold (or cooler) water into it?  I can't think of any.

The only thing unusual about the cooling system on a J series motor is the location of the thermostat - unlike the cars I grew up around, which typically had the thermostat sitting between cylinder head outlet and the radiator top hose, the J series engines have it between the lower hose and the water pump (the "cold leg" of the coolant circuit), something which is becoming more & more common.

Something to think about - because the thermostat is in the cold leg of the circuit, it is dependent on circulation of hot water through the heater core to warm it enough to open, at which point cooler water from the radiator will flow, mixing with the hot water from the heater,  reducing the temperature, and causing the thermostat to close, impeding the flow from the radiator - question - if you cool this water further (more cooling surface/more air flow) how does it impact the operation of the thermostat?

If you want a diagram of the J18/J20 cooling system as the vehicle left the factory, let me know...

I have diagrams of the J18/J20/J23

Having been driving since '78 and 'handing wrenches since I was 3...'  I could identify fractions on the side of wrenches  before I know what they meant and could count so I've been around engines almost all my life.   
Most of the engines I have dealt with over the years the coolant is pulled out of the block to the radiator (Americal iron) and this engine pulls coolant in, so to me it is 'reverse flow'.

The coolant temp leaving the block on this motor is around 230  measured at the ECT and then makes its trip trough the heater core and then to a pipe wrapped around to the water pump to the thermostat.  and through to the water pump where it's mingled
with the lower radiator hose.  That temp from the pipe  It isn't going to drop  in that distance to under 180 to affect the  thermostat.   Its tough to get decent IR thermometer readings.

230+ engine temps measured at the ECT leaving the motor is way too high so to drop overall engine temps I have to ensure proper airflow or a larger radiator.

While many have done the J23 engine swap in Sports.  I've asked many of them for their input and many won't respond to share their data or if they are having the same engine temps I am having and they choose to bury their heads in the sand.

I believe overall temps on this engine operation are too high at overall 220 and higher. I have ODB2 app logging showing the temps running from 210 to as high as 250 at times.

 

You might be right about the fan. I'm running a 16" electric fan on my 1.8 & it does well. I've long thought about a 2.3 upgrade.
One thing you mentioned in your last post 'might' be more relevant than you think. The odd way the J series engines open the thermostat & that it's a push rather than pull system. The thermostat actually opens from coolant that flows THROUGH the heater core, then through a tube below the exhaust manifold to hit the back side of the thermostat. Is your heater core clear? If it isn't, it might be restricting flow & causing the thermostat to open late?? Just a thought.

Heater core has been back flushed  and is clear,   Along with the path leaving the motor to the thermostat.  I am sure of this.

With the J23 being 24% larger I would expect the additional generated by this motor to be about 24%  more too  . 

The 2 10" fans I am running now are supposed to be 1750CFM  the 16" I am replacing them with is 3000 CFM     I'll see where this leads me with temps after its install.

Most of the engines I have dealt with over the years the coolant is pulled out of the block to the radiator (Americal iron) and this engine pulls coolant in, so to me it is 'reverse flow'.

Are you suggesting that "American iron" has the pump in the hot leg of the coolant circuit?



The image above is a Ford Windsor - shows the water pump in the cold leg - yes - it does pull the coolant out of the block (actually the head), but it pulls it through the radiator, and pushes it into the block - exactly the same way the J18/J20/J23 does.  I can go find you a diagram for an SBC V8, or even a G13 from a Samurai - it's all the same - hot from the head to the radiator, cold from the radiator back to the block, and the J series is no different in that regard.

Take a closer look at the J18/J20/J23 diagrams you have - do they have flow direction arrows - out the back of the head, through the outlet pipe over the exhaust, through the top hose in to the radiator down through the radiator tubes, out through the bottom hose to the thermostat, through the pump back to the block.