5.2 engine cooling - JeepForum.com
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post #1 of 72 Old 05-30-2021, 02:18 AM Thread Starter
HassZJ1998
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5.2 engine cooling

hello Jeepers, hope you're all having good times.

i need some input from users who reside in rather hot climate areas, where ambient temperature can reach up to 120~130 easily, since i live in Kuwait and we do get this much often, so kindly forgive the lengthy post but am gonna try and explain the issue i am having to the smallest detail hoping it helps.

my 1998 ZJ is fitted with the 5.2 engine yet it has only an electrical fan which runs in 2 speeds, currently it is running only in the higher speed, the engine coolant temperature gauge goes slightly above the 212 on highway driving, no towing not even speeding, just cruising around 50 mph give or take, it stays around the 212, goes down a little so it looks normal keeping in mind that the electrical fan engages only at the higher speed, i kept the Jeep's engine idling when the gauge was above the 212 and after a while it went down to around the 190.

the engine cooling system uses the 2 coolant temperature switches fitted in the upper and the lower radiator hoses, i know the switches are corroded yet they seem to work, at least one speed is engaging, so these switches, i can't find them here in Kuwait, not even anything similar to them, i found some in the scrap yard from an XJ they seem to fit physically yet i am not sure if they will work in harmony with the rest of the cooling system reading the temperature properly and all that.

i am thinking the fan relay might not be working, but if it's faulty, does it still work in the higher speed only ?

summer is coming and it's already like 110 today, the A/C isn't working and i yet need to check it out and this is the main reason for this post.

what i am thinking about is: removing the whole electrical fan, removing the coolant temperature switches, installing a clutch driven mechanical fan with a shroud which i can easily find here in the scrap yards (like the one's on the WJs and the KJs since they work fine even without the assist of an electrical fan, yes the A/C cooling becomes less at prolonged traffic stops but then gets cool when i drive, or rev the engine up a little) and possibly a small electrical fan with a bypassed switch custom made which is something commonly done here especially to old cars (like for example my 1988 Chevy Caprice) to assist and engage when i switch on the A/C, since i am not sure i should be fixing the A/C before addressing the "possible" engine over heating coming ahead with the blazing summer we have here.

a whole radiator and thermostat job is on the way, please if any one has a similar situation let me know what do you think, is having a mechanical fan better ? or shall i keep the electrical fan and i try some of the coolant temperature switches and see how it goes ? also the fan relay, not really sure about it !!

ironically, the factory calls it a "Heavy Duty Engine Cooling" and then they add "Maximum Duty Engine Cooling" as it says in the build sheet, yet almost every one who used a V8 ZJ here complained of the engine over heating and loss of A/C cooling at traffic stops, and this started back in 1994 when some imported ZJs from the US (not equipped for the gulf region) and these ZJs started to show overheating and it took the reputation of the V8 ZJs rock bottom to the extent that back then we struggled to sell a V8 ZJ and it's sales numbers were very very low.

thank you for reading this much.


please take a look at my posts maybe you can help me, i always appreciate any feedback, thank you.
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post #2 of 72 Old 05-30-2021, 02:50 AM
wingless
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My 5.2L cooling is fine in 90F southern FL ambient temperatures.

When I had my engine apart I scraped the cooling passages in the block and heads to remove as much scale as possible.

Note that there should be rubber mats on both sides of the radiator so all cooling air goes through the radiator, instead of the easier path on the sides, bypassing the radiator.

The shroud and bottom of the shroud should also be in place.

Mine has the mechanical fan w/ clutch. Mine was special ordered / built w/ maximum cooling.


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post #3 of 72 Old 05-30-2021, 03:32 AM
PolkaPower
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Mech fan cools better over all and is more reliable but e fan cools better at lower temps. Depends on what you are using it for. Is it a commuter? Off road?
Living in Nevada the temps got to 110ish but not as high as you are seeing.


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post #4 of 72 Old 05-30-2021, 03:48 AM Thread Starter
HassZJ1998
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Quote:
Originally Posted by PolkaPower View Post
Mech fan cools better over all and is more reliable but e fan cools better at lower temps. Depends on what you are using it for. Is it a commuter? Off road?
Living in Nevada the temps got to 110ish but not as high as you are seeing.


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i worry about possible engine overheating when i am in a traffic jam like a mile long sometimes, cuz at the end of a highway there are traffic lights at an intersection for example, you know when you move like a couple hundred yards then stop again for like 5 minutes or so, not only the ambient temperature but also the heat from all the vehicles around, that's why i am worried about, possible overheating.

no off-roading, no towing at most some desert and definitely not in mid-summer, just a daily driver.

thank you.

please take a look at my posts maybe you can help me, i always appreciate any feedback, thank you.
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post #5 of 72 Old 05-30-2021, 04:02 AM
PolkaPower
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Quote:
Originally Posted by HassZJ1998 View Post
i worry about possible engine overheating when i am in a traffic jam like a mile long sometimes, cuz at the end of a highway there are traffic lights at an intersection for example, you know when you move like a couple hundred yards then stop again for like 5 minutes or so, not only the ambient temperature but also the heat from all the vehicles around, that's why i am worried about, possible overheating.

no off-roading, no towing at most some desert and definitely not in mid-summer, just a daily driver.

thank you.

E fans cool better at lower rpms. Also leave a good amount of space between you and the vehicle in front of you.


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post #6 of 72 Old 05-30-2021, 04:51 PM
TonyStadnichuk
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I am kind of going through the same thing right now. I would suggest not doing anything until you get the rad changed and thermostat. I took mine out. Pretty much half the fins are missing and if you touch the rest they turn into powder. Upon removing the rad, I find that the external transmission cooler is plugged from old oil and also the a/c condensor. If you come across the same issue, you will have a lot of cleaning to do! If the condensor is plugge, a/c will suffer. Oil cooler plugged, it will raise engine temp. In my opinion the electric fans are the way to go. They have the ability to move a lot more air than a mechanical is an idle/traffic stop situation. I will get some pics to share of my rad, condensor and external oil cooler.
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post #7 of 72 Old 05-30-2021, 05:09 PM
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I'm running a 5.9 efan with a dcc.controller http://www.dccontrol.com/constant_te...ontrollers.htm
I have my transmission cooler bypassed from the radiator. This brought engine temp down a few degrees. I have a large transmission cooler and a power steering cooler. Be careful not to block too much of the radiator with placement.img_20180604_150833.jpg
img_20200522_105417-copy.jpg


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post #8 of 72 Old 05-30-2021, 06:32 PM
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My set up is a Omix-Ada 17105.09 Fan Clutch and Liberty fan blade and cools the crap out of everything. It's a touch loud though.. In the 80s the air is consistently 40+ deg at most times in the middle a.c. vent.
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post #9 of 72 Old 05-31-2021, 02:04 AM Thread Starter
HassZJ1998
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Quote:
Originally Posted by TonyStadnichuk View Post
I am kind of going through the same thing right now. I would suggest not doing anything until you get the rad changed and thermostat. I took mine out. Pretty much half the fins are missing and if you touch the rest they turn into powder. Upon removing the rad, I find that the external transmission cooler is plugged from old oil and also the a/c condensor. If you come across the same issue, you will have a lot of cleaning to do! If the condensor is plugge, a/c will suffer. Oil cooler plugged, it will raise engine temp. In my opinion the electric fans are the way to go. They have the ability to move a lot more air than a mechanical is an idle/traffic stop situation. I will get some pics to share of my rad, condensor and external oil cooler.
true, i was thinking the same, i need to get the whole cooling system done first.


thank you and i'll be waiting for the photos.

please take a look at my posts maybe you can help me, i always appreciate any feedback, thank you.
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post #10 of 72 Old 05-31-2021, 02:15 AM Thread Starter
HassZJ1998
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Quote:
Originally Posted by StPaul59 View Post
My set up is a Omix-Ada 17105.09 Fan Clutch and Liberty fan blade and cools the crap out of everything. It's a touch loud though.. In the 80s the air is consistently 40+ deg at most times in the middle a.c. vent.
thanks buddy, definitely gonna consider this setup, much appreciated

i am just curious about the clearance, is there enough room for them both fans ?

please take a look at my posts maybe you can help me, i always appreciate any feedback, thank you.
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post #11 of 72 Old 05-31-2021, 02:26 AM Thread Starter
HassZJ1998
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Quote:
Originally Posted by PolkaPower View Post
I'm running a 5.9 efan with a dcc.controller http://www.dccontrol.com/constant_te...ontrollers.htm
I have my transmission cooler bypassed from the radiator. This brought engine temp down a few degrees. I have a large transmission cooler and a power steering cooler. Be careful not to block too much of the radiator with placement.Attachment 3989765
Attachment 3989767


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talking about blocking the radiator, yes actually, there is a massive trans oil cooler covering like one third of the radiator surface, square in shape, was fitted when i had the trans rebuilt back in 2007 (i'll try to send photos) and i will replace it with another one.

and thanks for the link as well, very interesting, variable speed control ? means i can control the fan speed ?

please take a look at my posts maybe you can help me, i always appreciate any feedback, thank you.
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post #12 of 72 Old 05-31-2021, 05:27 AM
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Quote:
Originally Posted by HassZJ1998 View Post
talking about blocking the radiator, yes actually, there is a massive trans oil cooler covering like one third of the radiator surface, square in shape, was fitted when i had the trans rebuilt back in 2007 (i'll try to send photos) and i will replace it with another one.

and thanks for the link as well, very interesting, variable speed control ? means i can control the fan speed ?

It automatically ramps up fan speed as needed. There is an on off switch for water and it ramps to full speed when the ac is on. You can set it to different temperature as well.
The liberty fan blade is bolt on and seems to move more air than the stock ZJ fan. I have one but never installed it because I was still tinkering with various electric Gan set ups.


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post #13 of 72 Old 05-31-2021, 06:34 AM Thread Starter
HassZJ1998
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Quote:
Originally Posted by PolkaPower View Post
It automatically ramps up fan speed as needed. There is an on off switch for water and it ramps to full speed when the ac is on. You can set it to different temperature as well.
The liberty fan blade is bolt on and seems to move more air than the stock ZJ fan. I have one but never installed it because I was still tinkering with various electric Gan set ups.


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so about the trans oil cooler, better to remove it yes ? or at least replace it with one that goes long and narrow placed at the bottom side so it won't block the radiator ?

i am sorting out the cost of each option, either mechanical fan + electrical or keeping the electric fan as is and repair whatever needed to be sure it works.

thank you

please take a look at my posts maybe you can help me, i always appreciate any feedback, thank you.
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post #14 of 72 Old 05-31-2021, 06:55 AM
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Quote:
Originally Posted by HassZJ1998 View Post
thanks buddy, definitely gonna consider this setup, much appreciated

i am just curious about the clearance, is there enough room for them both fans ?
No. I ditched my efan for now to try this. My efan wasn't cutting it, but it's going back in when I get some things fixed.
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post #15 of 72 Old 05-31-2021, 08:08 AM
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I've not read up on them much, but some guys on IFSJ (Wagoneer Forum) would swear by the heat sink style trans coolers. They would mount them to the frame rail right by the transmission, which should get a lot of air flow but gets hit directly by rocks/road spray.

https://derale.com/product-footer/fl...sion/heat-sink

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