Hood louver thread to end all hood louver threads

[Fishtaco]

26 degrees this morning and my Jeep isn't running hot.

C or F ? I know your Canadian roots so you must be converting naturally? lol
Quick Q is US temp taken in the shade year round like it is in OZ?
Today was 29c in the shade but outside it was 35c+

I hate Black cars

 

[Viking Jeeper]

The OP never said his Jeep overheats.

 

[Steel City 06]

A few notes:

What brand of water pump did you use? I've noticed some of the aftermarket brands have a less aggressive impeller design than the later model TJ factory water pumps (the ones that have the plastic impeller). The only aftermarket (excluding OEM) pump that I've seen that has an equally or more aggressive impeller style is the Flowkooler, which uses a bullet aluminum impeller in lieu of the OEM plastic one. I'd be concerned that some of the aftermarket cast ones are not designed to be as high flow as the OEM ones, or at least the later model ones.

What thermostat brand are you using? Some brands are better than others. While thermostats are only explicitly rated in opening temperature, there are quite a few other factors that come into play. There are more aggressive thermostats that have a narrower band (I suspect the Stant is among them), and ones that have a wider band. More aggressive thermostats generally maintain a more consistent temperature, but if a certain point is exceeded, there becomes a risk of oscillation in the thermostat opening state, resulting in an oscillating engine temperature.

Increasing airflow does make a noticeable difference, but at a cost. The 11-blade Explorer fan and HD fan clutch would absolutely reduce underwood temperatures. But you will likely see a small but noticeable loss in city MPG. Generally, it's better to fix the underlying issue, but the Explorer fan can be a quick fix for a few different things. (It doesn't ever solve the root issue, unless that issue is solely airflow.)

 

[TurboTJ]

I was wondering the same thing.

I have been toying with the idea of making a fan speed sensor using an Arduino or something. At high enough road speed I suspect that the hurricane blowing through the radiator is sufficient to cause the fan to windmill. In other words, the airflow is powering the fan rather than the fan powering the airflow. I’ve got no real reason for doing this. I am just curious.

 

[mrblaine]

I have been toying with the idea of making a fan speed sensor using an Arduino or something. At high enough road speed I suspect that the hurricane blowing through the radiator is sufficient to cause the fan to windmill. In other words, the airflow is powering the fan rather than the fan powering the airflow. I’ve got no real reason for doing this. I am just curious.

I'd be curious about that. My reason is when we get a sub par radiator in these, the air flow on the highway is still not enough to make them work so on hot days you have to run with the AC off.

 

[Steel City 06]

I have been toying with the idea of making a fan speed sensor using an Arduino or something. At high enough road speed I suspect that the hurricane blowing through the radiator is sufficient to cause the fan to windmill. In other words, the airflow is powering the fan rather than the fan powering the airflow. I’ve got no real reason for doing this. I am just curious.

I've actually been looking at this too. You can get a OBDII to Arduino interface so you can sample as many PIDs as you want. Coolant temperature, A/C pressure, intake air temperature, ambient air temperature, road speed, throttle position, ASD status, etc. Using all of that you can easily create a program to control the fan and fine tune it well beyond the OEM PCM software.

If you have a SPAL brushless fan, they have about 80 different speeds and and can be controlled by PWM signal. The Arduino is capable of PWM output. Brushless SPAL fans only need a PWM signal, and have their own internal relays and processors, so if you can just amplify the Arduino PWM to about 7 volts or so (peak to peak) using a transistor or MOSFET at up to 10mA, then you need absolutely zero extra controllers or relays other than the fan itself and the Arduino.

In addition, you could easily wire a three-position rocker switch to give the arduino a signal to manually maximize or manually shut off the fan.


One thing I would note is that the standard Arduino isn't all that temperature insensitive. However, there is a company based in the US that makes a bulletproofed Arduino called the Ruggeduino. You can get a version of the standard or the MEGA with either much higher voltage tolerance or much higher temperature tolerance. Both boast improved voltage/temperature profiles, but they each do one even better than the other.
https://www.rugged-circuits.com/
If I ever get around to this, I'll probably 3D print a case and bracket for it. I may just use PETG for simplicity, but I'm eventually going to print some carbon fiber impregnated polycarbonate, so I may just go with that instead.

I've even been toying with the idea of adding Auto Stop/Start and EHPS.

 

[TurboTJ]

Well, you’re way ahead of me there. I just want to kluge together something to take some data and answer some questions.

 

[Paulstanfill85]

My 100% stock Mopar cooling system with the OE hood never overheats even when towing my trailer up long grades in the summer. You have a fixable problem and you don't need hood vents or non-OE parts to do it.

You have a bad thermostat. Fix it and before you do, use a drive around flush to clean out the block.

I would be inclined to agree with you both after this morning. I suppose it just took a cool day for me to really notice. It still did not climb to operating temperature. It must be stuck open a bit. I purchased a mopar thermostat which was quite expensive, but I'd like my problems to leave me. I also picked up a radiator flush as well. I will see what the thermostat looks like here in a few hours or tonight after the flush has done its job inside the block.


I will say that the hood no longer flutters on the highway at all with the venting.

 

[Jerry Bransford]

Running too cool in the mornings usually points to either a bad thermostat or one with a 165 or 180 degree rating where it should have a 195 degree rating. Running too hot on hot days, towing, etc. usually points to either a clogged radiator or an aftermarket radiator. Very few aftermarket radiators, and none that are inexpensive, cool our TJs as well as the Mopar radiator does.

 

[Paulstanfill85]

Running too cool in the mornings usually points to either a bad thermostat or one with a 165 or 180 degree rating where it should have a 195 degree rating. Running too hot on hot days, towing, etc. usually points to either a clogged radiator or an aftermarket radiator. Very few aftermarket radiators, and none that are inexpensive, cool our TJs as well as the Mopar radiator does.

I installed a Mopar thermostat, drilled it, and flushed it beforehand.

It runs at just under 210 on the dummy gauge solidly. I will let you all know if anyone is interested how it runs on the trails in Hot Springs this weekend and pulling the trailer that far as well.

 

[Jerry Bransford]

I installed a Mopar thermostat, drilled it, and flushed it beforehand.

It runs at just under 210 on the dummy gauge solidly. I will let you all know if anyone is interested how it runs on the trails in Hot Springs this weekend and pulling the trailer that far as well.

Good work, just know that unlike the dummy oil pressure gauge the coolant gauge is giving an accurate temperature where its sender is. It's not a "dummy" gauge.

And even the oil pressure gauge as it is now started as a "real" oil pressure indicator during the early years of the TJ. The factory only converted/reprogrammed it to only show a mid-scale reading (if the true oil pressure is ok) because too many new TJ owners were complaining about the oil pressure going up and down. Dealers couldn't convince most of them that it was normal so they talked the factory into reprogramming it so it did not reflect the true oil pressure's normal ups and downs.

 

[mrblaine]

I installed a Mopar thermostat, drilled it, and flushed it beforehand.

It runs at just under 210 on the dummy gauge solidly. I will let you all know if anyone is interested how it runs on the trails in Hot Springs this weekend and pulling the trailer that far as well.

This post hasn't been up long enough for you to do a proper flush. The inside of the block has to look like this or better when it is clean.

 

[Jezza]

If it is overheating there is an issue in the system that is fixable without cutting holes. I run up and down the tollway everyday at 80 mph with th AC cranked and a turbo pushing boost the entire way. Never gets hot, never an issue.

 

[Brianj5600]

I've actually been looking at this too. You can get a OBDII to Arduino interface so you can sample as many PIDs as you want. Coolant temperature, A/C pressure, intake air temperature, ambient air temperature, road speed, throttle position, ASD status, etc. Using all of that you can easily create a program to control the fan and fine tune it well beyond the OEM PCM software.

If you have a SPAL brushless fan, they have about 80 different speeds and and can be controlled by PWM signal. The Arduino is capable of PWM output. Brushless SPAL fans only need a PWM signal, and have their own internal relays and processors, so if you can just amplify the Arduino PWM to about 7 volts or so (peak to peak) using a transistor or MOSFET at up to 10mA, then you need absolutely zero extra controllers or relays other than the fan itself and the Arduino.

In addition, you could easily wire a three-position rocker switch to give the arduino a signal to manually maximize or manually shut off the fan.


One thing I would note is that the standard Arduino isn't all that temperature insensitive. However, there is a company based in the US that makes a bulletproofed Arduino called the Ruggeduino. You can get a version of the standard or the MEGA with either much higher voltage tolerance or much higher temperature tolerance. Both boast improved voltage/temperature profiles, but they each do one even better than the other.
https://www.rugged-circuits.com/
If I ever get around to this, I'll probably 3D print a case and bracket for it. I may just use PETG for simplicity, but I'm eventually going to print some carbon fiber impregnated polycarbonate, so I may just go with that instead.

I've even been toying with the idea of adding Auto Stop/Start and EHPS.

GM fans now have 3 wires, +, - and 5v. That would make things much easier.

 

[Steel City 06]

GM fans now have 3 wires, +, - and 5v. That would make things much easier.

Any idea how the control system works? PWM? Analog? That is interesting though. Might actually be an OEM SPAL fan.

 

[SSTJ]

Good work, just know that unlike the dummy oil pressure gauge the coolant gauge is giving an accurate temperature where its sender is. It's not a "dummy" gauge.

And even the oil pressure gauge as it is now started as a "real" oil pressure indicator during the early years of the TJ. The factory only converted/reprogrammed it to only show a mid-scale reading (if the true oil pressure is ok) because too many new TJ owners were complaining about the oil pressure going up and down. Dealers couldn't convince most of them that it was normal so they talked the factory into reprogramming it so it did not reflect the true oil pressure's normal ups and downs.

Ha, I did not know this. I assume that the OEM gauge on my 97 is still "real". And yes, it worried me once.

 

[Jerry Bransford]

Ha, I did not know this. I assume that the OEM gauge on my 97 is still "real". And yes, it worried me once.

If it goes up & down in step with the engine rpms it's still working as designed.

 

[Paulstanfill85]

This post hasn't been up long enough for you to do a proper flush. The inside of the block has to look like this or better when it is clean.
View attachment 291603

I ran the flush agent for an hour as it asked for after filling with water and dumping. Mine definitely didn't look like that. Wow that is clean! What product do you recommend? I could put the old thermostat back in and flush with something else next week. I'm definitely interested. I wasn't attempting a half measure here, just following bottle directions.

Also, if my problems persist towing what radiator would you recommend? Oem or something else?

 

[mrblaine]

I ran the flush agent for an hour as it asked for after filling with water and dumping. Mine definitely didn't look like that. Wow that is clean! What product do you recommend?

There are two issues to deal with inside the block. One is scale and the other is rust. The Prestone 3 day drive around flush works great for scale, not so great for rust. We try that first and if that doesn't get it done, we use the Thermocure product.

I could put the old thermostat back in and flush with something else next week. I'm definitely interested. I wasn't attempting a half measure here, just following bottle directions.

Also, if my problems persist towing what radiator would you recommend? Oem or something else?

Before you swap anything, do the flush, then make sure the AC condenser and radiator do not have any blocked fins.

 

[Jerry Bransford]

Also, if my problems persist towing what radiator would you recommend? Oem or something else?

Mopar. Not "OEM replacement", Mopar.