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Since the fix is slow to arrive and not seaming to work... I am considering removing the top plastic panel covering the top of the radiator support and inserting a section of flat plastic sled to reduce some of the airflow through the radiator. I had a friend stuck in the middle of no where on the intestate in New Mexico last week for 6 hours idling in a blizzard as all traffic was stopped for miles the entire time overnight. They would have froze in a 5th Gen CR-V or at the least had to beg to get into another vehicle. These cars could be very dangerous if you live where it gets below zero and idling will result in no heat and you went off the road or were stuck on a closed road because of accident. It happens more than you think in northern states. I am going to test with this later this week. Will return with valid feedback assuming this thread does not turn all negative.

PS: if you are going to sermon about why this should not be tried, save it. We are into multiple winters on this issue, we have a valid temp gauge and the sled can come out in 10 seconds. Truckers, school buses and diesel pickups have run these for 40 - 60 years for this very reason.
 

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Since the fix is slow to arrive and not seaming to work... I am considering removing the top plastic panel covering the top of the radiator support and inserting a section of flat plastic sled to reduce some of the airflow through the radiator. I had a friend stuck in the middle of no where on the intestate in New Mexico last week for 6 hours idling in a blizzard as all traffic was stopped for miles the entire time overnight. They would have froze in a 5th Gen CR-V or at the least had to beg to get into another vehicle. These cars could be very dangerous if you live where it gets below zero and idling will result in no heat and you went off the road or were stuck on a closed road because of accident. It happens more than you think in northern states. I am going to test with this later this week. Will return with valid feedback assuming this thread does not turn all negative.

PS: if you are going to sermon about why this should not be tried, save it. We are into multiple winters on this issue, we have a valid temp gauge and the sled can come out in 10 seconds. Truckers, school buses and diesel pickups have run these for 40 - 60 years for this very reason.
There is a already grill with slats in front of the radiator but I can't speak to the conditions that open or close it. But whether slats are open or closed, or a piece of plastic inserted in front of the radiator, or even if the fan comes on when it shouldn't, wouldn't this only make a difference if the car is moving?

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Since the fix is slow to arrive and not seaming to work... I am considering removing the top plastic panel covering the top of the radiator support and inserting a section of flat plastic sled to reduce some of the airflow through the radiator. I had a friend stuck in the middle of no where on the intestate in New Mexico last week for 6 hours idling in a blizzard as all traffic was stopped for miles the entire time overnight. They would have froze in a 5th Gen CR-V or at the least had to beg to get into another vehicle. These cars could be very dangerous if you live where it gets below zero and idling will result in no heat and you went off the road or were stuck on a closed road because of accident. It happens more than you think in northern states. I am going to test with this later this week. Will return with valid feedback assuming this thread does not turn all negative.

PS: if you are going to sermon about why this should not be tried, save it. We are into multiple winters on this issue, we have a valid temp gauge and the sled can come out in 10 seconds. Truckers, school buses and diesel pickups have run these for 40 - 60 years for this very reason.
to be honest I tried it last year when we had a bad cold spell...looked like crap,but I sealed up everything I could......But it didnt do anything to help on mine....I still cant figure out why one CRV has no heat issue and if ya bought the one beside it....it has no problem with heat and yes I have tested this theory with 2 CRV's on the same cold morning doing the same route with both.....mine ended with 3 bars and very little warm air .the other one heated up way faster to full temp and super heat....its been into 2 dealers and both say its normal,but cant give you a answer as to why some have no heat and others are great.....and good point about someone getting stuck on a deserted road....good post
 

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There is a already grill with slats in front of the radiator but I can't speak to the conditions that open or close it. But whether slats are open or closed, or a piece of plastic inserted in front of the radiator, or even if the fan comes on when it shouldn't, wouldn't this only make a difference if the car is moving?

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From my quick test the shutters were open when it was 35F. Didn't seem to matter if I had the AC on or not
 

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As JBeachy stated it's not going to be simple but it certainly is doable.
You would have to remove the Slats in the front and use some extension wire to wire it up in the trunk area. The reason is that if the cable is disconnected or the Slats cannot move the dash gives up some kind of annoying error.

Once you have the hard part out of the way then just go ahead and block it up with something. I would love to see someone try this, it would be great if it worked.

Rob
 

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As JBeachy stated it's not going to be simple but it certainly is doable.
You would have to remove the Slats in the front and use some extension wire to wire it up in the trunk area. The reason is that if the cable is disconnected or the Slats cannot move the dash gives up some kind of annoying error.

Once you have the hard part out of the way then just go ahead and block it up with something. I would love to see someone try this, it would be great if it worked.

Rob
if it wasn,t for warranty..i would jump all over that idea....I am old and would like even a little heat with a remote start....the block heater plan doesn't seem to be any help
 

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if it wasn,t for warranty..i would jump all over that idea....I am old and would like even a little heat with a remote start....the block heater plan doesn't seem to be any help
I wish there was a simple DIY solution but I cannot think of anything.
It seems to me that Honda could fix this issue with software changes but for some reason they have not done what IMHO at least seems like the easiest ways to do it.

We know the computer has all the temperature readings and other data that it needs so why not just adjust the code to do something like the following and change the TStat to one that works better for cold climates.

Outside temp is below X (it's cold out)
Inside Temp of Car is Y (it's freezing inside)
First Close the Slats via the computer.
Once the engine gets hot due to no water flowing through it, direct the water through the HVAC only. Keep the Fan at a Minimum and raise fan speed as Y reaches above minimum comfortable temp. Then open Tstat and allow water to flow through the radiator. repeat the cycle if the temp drops at a stop light etc.

And yes for the person that is about to chime in and say the point is the engine is not getting hot. The engine getting hot versus the cabin getting hot are two different things. With no water flowing through the engine it will get hot fairly fast.

I am not an expert on how car heating systems work but it seems like this could be done. The only problem is that it makes the vehicle more susceptible to single point failure that could wreck the engine.

Rob
 

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I wish there was a simple DIY solution but I cannot think of anything.
It seems to me that Honda could fix this issue with software changes but for some reason they have not done what IMHO at least seems like the easiest ways to do it.

We know the computer has all the temperature readings and other data that it needs so why not just adjust the code to do something like the following and change the TStat to one that works better for cold climates.

Outside temp is below X (it's cold out)
Inside Temp of Car is Y (it's freezing inside)
First Close the Slats via the computer.
Once the engine gets hot due to no water flowing through it, direct the water through the HVAC only. Keep the Fan at a Minimum and raise fan speed as Y reaches above minimum comfortable temp. Then open Tstat and allow water to flow through the radiator. repeat the cycle if the temp drops at a stop light etc.

And yes for the person that is about to chime in and say the point is the engine is not getting hot. The engine getting hot versus the cabin getting hot are two different things. With no water flowing through the engine it will get hot fairly fast.

I am not an expert on how car heating systems work but it seems like this could be done. The only problem is that it makes the vehicle more susceptible to single point failure that could wreck the engine.

Rob
This makes a lot of sense, but the US EPA may not approve, as this could potentially significantly change the emissions...and fuel mileage ratings as well. I'm not an expert on this, I just suspect that the EPA is likely taking a close look at any changes Honda wants to implement.

And, as others have said, how is it that some CRVs wont heat up the cabin, yet others will? Still seems like a manufacturing variance to me.
 

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neat video on how shutters open every time you stop...explains why at a stop sign or just idling you lose bars and heat

https://www.youtube.com/watch?v=n1fgcNF9OsY
My experience: In Texas also (N. Houston) last week, 38 F constant temp outside, I drove about 10 miles. I was also trying to see how the shutters and AC compressor work and my experience was different than that displayed on the video. I got out of my car 3 times during my drive and looked at the shutters - they were always closed even after the engine got fully warm. I got out in parking lot at about the 7 mile mark and left my car running, looked at both set of shutters and they were closed. HVAC was set to manual, AC to OFF. I then set the HVAC to Auto and shutters opened and compressor turned on (I opened the hood to see). I then set AC to OFF again and shutters closed (all this while stopped at the same parking lot). I then drove home and stopped by the mailbox, engine left running (AC was set to OFF but HVAC blowing warm at slow speed) and the shutters were closed. I drove home, shutters still closed on my driveway. I then pulled into the garage and turned the engine off, shutters opened up (they are supposed to - as I understand it to keep them from icing closed).

Don't know why the video shows the shutters opening when he stopped, suspect the 54 F outside temp may have had something to do with it compared to my 38 F.

My test would be very easy to replicate. I would be curious if you or others drive a few miles on a cold day (with AC to OFF but HVAC on) and then stop at a safe spot and look at your shutters while engine still running.
 

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I removed that top panel, it was a fail. No way you can get to the radiator to slide something in. I then looked from below, no way there without major bottom of the bumper cover removal. I must admit I had no idea about the shudders, so that really performs the same goal. Great link CRV-Owner. on the shudders operation. Wish they just stayed closed period until 85% warmed up. Jbeachy you have a great point, the benefit of blocking it is assuming airflow through the radiator is causing the cool down. I am thinking it may have to do with the overall aluminum block and heads dumping off the heat so well. (I know, a ton of cars for 15-20 years have had all aluminum engines but I am grasping) I had a old ford Diesel 25 years ago that would cool down at idle. An old timer diesel guy told me the huge case iron block at extreme cold temps was like a heat sponge and shed engine heat via the engine block.

I do know the CVT is heated via the cooling system in the winter. Our HR-V has the exact same exchanger system. it has zero warm up or engine heat issues. It also HAS NO shudders in front of the radiator. It is wide open.
 

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The CRV has a belt driven water pump. The moment the motor starts, coolant is rapidly flowing in a loop.....block to head, head to block, over and over again, very rapidly. The heater core is always part of this coolant flow loop when the motor is running. When the t-stat is closed, zero coolant flows thru the radiator.....that is if the t-stat is functioning as designed.

We have several folks on the forum that monitor both Coolant Temp 1 (internal engine coolant temp) and Coolant Temp 2 (cold bottom tank of the radiator) via a ScanGauge II. If the t-stat is closed, CT 2 basically remains the same temp as ambient temp because no hot coolant is flowing thru the radiator, thus the radiator is not part of the cooling system loop UNTIL the t-stat ever so slightly begins to open.

The only way I can think of to not have coolant flowing (engine running) is to have an ECU controlled electric water pump. Doubt that will ever happen.

I monitor engine coolant temp using a ScanGauge II and have noticed actual coolant temp will drop 10-12 degrees when the HVAC fan is on speed 6 or 7 but have never seen the factory temp gauge drop below the mid-point once the needle has reached the mid-point. I also monitor vent temp with a probe type thermometer and have never noticed a drop in vent temp, even though actual engine coolant temp has dropped 10-12 degrees when fan speed is on HI.

With regard to the "so called" CVT warmer, now there's a joke. I monitor tranny fluid temp and it takes a long time for tranny fluid temp to equal engine coolant temp. In my situation, 45-60 minutes of in-town driving before the tranny fluid temp equals engine coolant temp. In an hours worth of driving around town, the engine has been at operating temp for >50 minutes. Once tranny fluid temp equals engine coolant temp, tranny temp continues to rise and can easily be 40-50 degrees above engine coolant temp, depending on time driven.

Oh those crazy grill shutters......I think their opening/closing has something to do with being in PARK vs DRIVE, vehicle speed, ambient temp, engine coolant temp and who knows what else. Most of my driving is in-town.......why would those shutters need to be CLOSED when driving <40mph, or when engine coolant temp is showing 210F sitting at a stop light in 45 degree ambient? That's just crazy.

I feel for those folks that have heat problems.......a really nice (expensive) car to have problems like that.
 

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The only way I can think of to not have coolant flowing (engine running) is to have an ECU controlled electric water pump. Doubt that will ever happen.
Snap!!
I thought that they had a separate Electronic controlled valve for the HVAC water bypass.
Yes you could put two T-Joints in the lines and hook up an electronic valve but then comes a lot of further complication with finding a method to control the valve.


Rob
 

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The CRV has a belt driven water pump. The moment the motor starts, coolant is rapidly flowing in a loop.....block to head, head to block, over and over again, very rapidly. The heater core is always part of this coolant flow loop when the motor is running. When the t-stat is closed, zero coolant flows thru the radiator.....that is if the t-stat is functioning as designed.

We have several folks on the forum that monitor both Coolant Temp 1 (internal engine coolant temp) and Coolant Temp 2 (cold bottom tank of the radiator) via a ScanGauge II. If the t-stat is closed, CT 2 basically remains the same temp as ambient temp because no hot coolant is flowing thru the radiator, thus the radiator is not part of the cooling system loop UNTIL the t-stat ever so slightly begins to open.

The only way I can think of to not have coolant flowing (engine running) is to have an ECU controlled electric water pump. Doubt that will ever happen.

I monitor engine coolant temp using a ScanGauge II and have noticed actual coolant temp will drop 10-12 degrees when the HVAC fan is on speed 6 or 7 but have never seen the factory temp gauge drop below the mid-point once the needle has reached the mid-point. I also monitor vent temp with a probe type thermometer and have never noticed a drop in vent temp, even though actual engine coolant temp has dropped 10-12 degrees when fan speed is on HI.

With regard to the "so called" CVT warmer, now there's a joke. I monitor tranny fluid temp and it takes a long time for tranny fluid temp to equal engine coolant temp. In my situation, 45-60 minutes of in-town driving before the tranny fluid temp equals engine coolant temp. In an hours worth of driving around town, the engine has been at operating temp for >50 minutes. Once tranny fluid temp equals engine coolant temp, tranny temp continues to rise and can easily be 40-50 degrees above engine coolant temp, depending on time driven.

Oh those crazy grill shutters......I think their opening/closing has something to do with being in PARK vs DRIVE, vehicle speed, ambient temp, engine coolant temp and who knows what else. Most of my driving is in-town.......why would those shutters need to be CLOSED when driving <40mph, or when engine coolant temp is showing 210F sitting at a stop light in 45 degree ambient? That's just crazy.

I feel for those folks that have heat problems.......a really nice (expensive) car to have problems like that.
The shutter controls software logic seems irrational if you ask me. It should be determined more by engine temperature and less by other inputs.
One scheme car makers use to warm up transmissions and engines in cold weather is to delay the torque converter lock up until the transmission reaches a minimum temperature. This causes the engine to rev higher and it creates fluid friction heat. Maybe Honda could do something outside their thinking box too.
 

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A lot of good ideas on how to do a fix because of a design problem....but how do you explain that many people are not having heat problems ???
How do you build a car one-day that's great heat and the next one doesn't. ????? I don't think it's a design problem it's a part problem.
I think the gas in oil is also a defect problem and maybe an additional problem because of improper heat. My CRV in summer the oil does not increase as much......but in cold weather the increase in oil is BAD. The Honda fix does not work
 

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Mine is going back to the dealer again for lack of heat. I'm dropping it off Thursday night and will get a ride over Friday morning. The service manager will be driving it (with me) and he can see for himself just how long it takes to warm up. Luckily it should be about 20F here then. I'm working on the list of excuses he will have
 

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Since the fix is slow to arrive and not seaming to work... I am considering removing the top plastic panel covering the top of the radiator support and inserting a section of flat plastic sled to reduce some of the airflow through the radiator. I had a friend stuck in the middle of no where on the intestate in New Mexico last week for 6 hours idling in a blizzard as all traffic was stopped for miles the entire time overnight. They would have froze in a 5th Gen CR-V or at the least had to beg to get into another vehicle. These cars could be very dangerous if you live where it gets below zero and idling will result in no heat and you went off the road or were stuck on a closed road because of accident. It happens more than you think in northern states. I am going to test with this later this week. Will return with valid feedback assuming this thread does not turn all negative.

PS: if you are going to sermon about why this should not be tried, save it. We are into multiple winters on this issue, we have a valid temp gauge and the sled can come out in 10 seconds. Truckers, school buses and diesel pickups have run these for 40 - 60 years for this very reason.
Maybe Honda should try this to help with the lack of heat issue:

https://www.rav4world.com/forums/124-4-4-interior/102673-heater-improvement.html

If above does not open, copy and paste it into your browser. Very interesting possible solution.
 

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In big trucks, we use what is called a winterfront for this purpose. Of course, diesels are different, and truck radiators are huge compared to car radiators. But, trucks run in all environments, from super cold to hot. So cooling systems are designed for high capacity cooling for hot environments, and winterfronts are provided for the cold. These are generally canvas and attach with snaps. If you google winterfront, and look at images, you will see that they are also available for many pickups and cars (Europeans use them extensively). You could also easily enough make one out of cardboard (you can see these around here on Mexican big trucks) and attach it on the outside of your grill with zip ties. A little experimentation in the cold to determine how much coverage is right, whether 100% or with some holes to allow some degree of airflow would be in order. This could be a good temporary fix until Honda solves it. It's what I would do if I had this issue with my '07. Luckily, I don't.
 

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Snap!!
I thought that they had a separate Electronic controlled valve for the HVAC water bypass.
Yes you could put two T-Joints in the lines and hook up an electronic valve but then comes a lot of further complication with finding a method to control the valve.


Rob

Some cars have a electronic or vacuum controlled "Heater Control Calve"......most do not have the HCV. It allows/disallows engine coolant to flow to/thru the heater core, when the motor is running. The Gen 5 CRV does not have a HCV. Engine coolant constantly flows to/thru the heater core when the motor is running.

In my opinion, HCVs are a PITA......causing even more problems. I've removed and NOT replaced a number of them in various vehicles. The main purpose of a HCV is slightly better A/C cooling by not allowing hot coolant to flow thru the heater core, which is part of the vehicle's HVAC system. The mechanicals of a HCV can freeze up/fail when coolant sits stagnant (not flowing) and corrosion can form in the heater core when coolant flow ceases/becomes stagnant.
 
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