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Unread 04-02-2014, 05:37 PM   #1
Punisher8738
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My LJ is now on the road. It drives great in the city but on the freeway if I maintain about 2300rpm/60 mph it wants to warm up to 230. I've gutted my winch case (Warn powerplant) to minimize obstruction. I've got a Dakota Digital fan controller that is set at 205 on/200 off. I've read the stock thermostat is around 195. Since I'm in Texas and it's not even close to being hot now and I don't have a/c yet, I'm considering a 160 thermostat. I have the gen3 motor/water pump with the older one piece water neck/thermostat. I've read on ls1tech these are actually around 170/175. I'm curious if anyone else has experienced similar issues and what they're doing for a thermostat/cooling.

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Unread 04-02-2014, 06:04 PM   #2
Toms87
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I had a similar issue with my 305 on the highway. I swapped radiators and installed hood louvers which helped but didn't cure the problem. The problem ended up being that my fan shroud wasn't good enough. I installed a late 90s V8 Thunderbird electric fan and everything has been fine for a couple years now. The fan is nearly as tall as the radiator and the shroud covers the entire cooling surface, so the fan pulls air in through all the available space in the radiator. With my old setup of a plain Autozone e-fan, air was only getting pulled through the circle area that the fan covered. I also took out the temperature on/off sensor that I had and installed a 3 way low/high/off switch in the dash instead.

Old fan vs. new fan/shroud


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Unread 04-02-2014, 06:26 PM   #3
Punisher8738
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Thanks for the reply. I'm running the Novak a radlok/Griffin with the SPAL 16" shrouded fan. I've also got louvers in the hood too...

I did the coolant system purge last night to check for air in the system but haven't driven it since.

Tonight I'm going to swap thermostats and lower the temp setting on my controller. I've got a manual switch I can turn on too.

If this doesn't resolve it I'll look into upgrading the fan.

Are you running a/c in your jeep?
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Unread 04-02-2014, 07:33 PM   #4
Toms87
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Quote:
Originally Posted by Punisher8738 View Post
Thanks for the reply. I'm running the Novak a radlok/Griffin with the SPAL 16" shrouded fan. I've also got louvers in the hood too...

I did the coolant system purge last night to check for air in the system but haven't driven it since.

Tonight I'm going to swap thermostats and lower the temp setting on my controller. I've got a manual switch I can turn on too.

If this doesn't resolve it I'll look into upgrading the fan.

Are you running a/c in your jeep?
I'm not running a/c.

One thing I was considering was header heat wrap to get some of the heat transferred out of the engine compartment, but since the fan & shroud fixed the problem I never got around to doing that.

Does your fan have a high and low? I'd drive it around on high and see what happens.

I got my fan from the junkyard, but here's the RockAuto page for reference. These look just like mine.
https://www.rockauto.com/catalog/x,c...,parttype,2181
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Unread 04-02-2014, 10:26 PM   #5
Punisher8738
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Thanks, No it's a single speed that's supposed to be rated around 2300cfm. Tomorrow I'm going to swap in a 160 thermostat and I just reprogrammed the fan on/off. If this doesn't work I'll start looking at the fan and I appreciate the info you linked.
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Unread 04-03-2014, 07:49 PM   #6
panaceabeachbum
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I am going thru similar, 5.3 in YJ, hood Poisin spyder hood louver. 3200cfm fan. Temps stays at 180 on the highway but rapidly hits 220 in traffic or slow driving in the woods
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Unread 04-06-2014, 03:32 PM   #7
Punisher8738
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Just swapped thermostats for a 160, did the "purge" I read about on an LS forum and also adjusted my fans to 195 on and 190 off... We shall see. Unfortunately the temp dropped 20 degrees over the weekend but we should be up to the 70s tomorrow. Hopefully I just had some air in the coolant lines.
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Unread 04-07-2014, 07:17 PM   #8
Toms87
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Quote:
Originally Posted by panaceabeachbum View Post
I am going thru similar, 5.3 in YJ, hood Poisin spyder hood louver. 3200cfm fan. Temps stays at 180 on the highway but rapidly hits 220 in traffic or slow driving in the woods
I could be wrong, but I have always been under the impression that hot on the highway will likely have a different cause than hot at slow speeds.

Quote:
Originally Posted by Punisher8738 View Post
Just swapped thermostats for a 160, did the "purge" I read about on an LS forum and also adjusted my fans to 195 on and 190 off... We shall see. Unfortunately the temp dropped 20 degrees over the weekend but we should be up to the 70s tomorrow. Hopefully I just had some air in the coolant lines.
Do you have a picture of your fan setup, for my curiosity?
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Unread 04-07-2014, 08:09 PM   #9
Punisher8738
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I'll take one tonight. So far so good, a lot of info on ls1tech about air in the coolant passages. I did the purge which was basically just letting it run until the thermostat opened with the radiator cap off. Saw quite a few air bubbles and added a bit of fluid.

Right now I'm still on the stock TJ fuel pump and 23lb injectors. In a couple weeks I'm going in for a set of PRC Stage 2.5 LS6 heads, bigger pump and injectors. I'm going to have the tuner run it a little rich or atleast check the AF ratios for any lean areas. That was another possible cause I read about that another jeep ls swap had. Basically same symptoms and a new tune corrected his heat issues.
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Unread 04-08-2014, 03:52 PM   #10
Punisher8738
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Here are pics of the fan/shroud and the PAC-2750 controller. Also gutted the case of my Warn Powerplant. May be able to trim some more fat off of it if needed this summer.

Sorry guys didn't mean to upload the same pics and can't figure out how to remove the doubles.
image-2651953926.jpg

image-3210809347.jpg

image-4143925849.jpg

image-3842783577.jpg

image-218028686.jpg

image-1048071624.jpg

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Unread 04-09-2014, 06:58 PM   #11
Toms87
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The picture is a little blurry but the shroud looks OK to me. I might be concerned about that winch blocking the grill in standard form, but it looks like there should be plenty of airflow with the way it sits in the picture.

Any updates after you got some air out of the system?
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Unread 04-09-2014, 08:31 PM   #12
AGTORG
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I have the same issue as you, 2001 TJ, 5.3 and Novak radiator and fan. Here in AZ during the summer going down the highway it does jump up to around 225-230, but never goes past that, been running it that way for two years. Changing the thermostat wont help. If you reprogram the PCM to turn the fan on at a lower temp, it will more than likely be on all the time when you reach normal operating temp. The issue is the fan itself, when going down the highway we are pushing 2000-2500 rpm and the fan being on actually blocks the airflow going through the radiator at the higher speeds, if that makes sense. Just an FYI I was told that this wouldn't have any ill effects at those temps.
But if you do happen to find a solution that would be good also. Keep us informed!
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Unread 04-09-2014, 10:41 PM   #13
Punisher8738
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Well today's drive went well. I never saw above temps above 195 which is where my fan kicks on.

I'm using a dakota digital sender with the upper radiator hose adapter. The temp reading from the dakota digital pac-2750 never got above 195 and the fan only ran once I came off the highway and idled a while. Once the fan kicked off they didn't come on.

I also have an autometer sport comp 2 full sweep gauge with the sender in the rear pass side head. Gauge never even hit 200. Once it warmed up it also stayed around 195.

The temp here is slowly getting warmer into the 80s this week.

At this point I've done the following and it's worked so far;

1. Swapped to a 160 degree thermostat. My water pump is the 3rd gen version where the thermostat/water neck are 1 piece. According to the LS motor gurus these actually run about 180 which is when I noted it opening and air bubbling out.
2. Purged the air from the coolant system
3. Trimmed some fat off the winch case
4. Adjusted my fan controller to 195 on/190 off.
Factory settings from Dakota are 205 on/200 off. Not a big difference but these temps were what were recommended on the LS forum.

I'll post any updates or changes if needed as the temp increases.
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Unread 04-10-2014, 08:44 AM   #14
Punisher8738
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Here's a better pic of the fan shroud just an FYI.

image-3082448464.jpg
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Unread 04-11-2014, 12:25 PM   #15
Punisher8738
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Ok so driving on the freeway around 60/65 I'm at 2300 rpm and temps run around 195. We've had some very strong winds here and going on an incline for about a mile I was at 3000rpm and temps raised to about 220 then later cooled down.

I'm looking at keeping the motor at or around 190/200 for my goal.

I've got the older ls1 style pump with the 1 piece thermostat/water neck that didn't appear to open until around 185/190 which apparently is common.

I'm thinking about trying to upgrade to an LS2 pump with the separate neck/thermostat which would more accurately start to open at the 160 mark.

Im also looking at a higher flowing Edelbrock or Evans Cooling water pump. Both use the newer thermostat and both are supposed to flow better and popular with the big power guys on ls1tech.

I'll keep the thread updated as I go. I'm also going to check my radiator hoses tomorrow night for collapsing under load. I know the lower radiator hose doesn't have a spring inside that some people have mentioned on the other forums.

Another point people have brought up is ensuring the heater core is flowing enough coolant by putting a "U" at the hose ends as a check.
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