Novak Conversions Jeep Wrangler TJ radiator

Overheating problem

Personally I'd be doing all my own work because while you had that radiator out you could have checked and tested a lot of things and gotten a better sense of what's going on.

Might be the water pump. Can you see coolant circulating with the cap off the radiator?

Are you 100 per percent sure a Denso radiator was installed or is it possible the mechanic is flat out fucking with you? Trying not to be offensive here...I can tell you a long story about how I paid Jifffy Lube to check my transmission fluid and not only was the fill plug seized but there wasn't a drop of oil in there... wouldn't be the first time nor the last time a mechanic lied to someone.

-Mac
 
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MikeE024 said:
I'd probably change the water pump since they can fail intermitently...the impellar spins on the shaft only when things get hotter under load.
Click to expand...

the pump is essentially brand new. the whole cooling system is brand new with only 1-2,000 miles on it. the denso radiator is like 24 hours brand new now haha. i just dont see the water pump failing right away?
 
I posted back on one page 1 about sealing up the openings around the core support / grill, I was at the Junk yard the other day and took this picture of a 99 TJ with the factory deflectors still in place. maybe this explains what I was trying to describe.

IMG_1791.JPG
 
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macleanflood said:
Personally I'd be doing all my own work because while you had that radiator out you could have checked and tested a lot of things and gotten a better sense of what's going on.

Might be the water pump. Can you see coolant circulating with the cap off the radiator?

Are you 100 per percent sure a Denso radiator was installed or is it possible the mechanic is flat out fucking with you? Trying not to be offensive here...I can tell you a long story about how I paid Jifffy Lube to check my transmission fluid and not only was the fill plug seized but there wasn't a drop of oil in there... wouldn't be the first time nor the last time a mechanic lied to someone.

-Mac
Click to expand...

i trust this mechanic. worked with our family for 30 years. how long should i run the jeep with the cap off before getting fluid circulating? I'll test that again when i pick it up today. im at my wits end with this issue and honestly i will probably just replace the water pump either way since its only $40 bucks, but i really dont think the water pump is bad.
I had the mechanic doing the work since he didnt charge me for the denso.
 
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5TTTj said:
I posted back on one page 1 about sealing up the openings around the core support / grill, I was at the Junk yard the other day and took this picture of a 99 TJ with the factory deflectors still in place. maybe this explains what I was trying to describe.

View attachment 543005
Click to expand...

ill take a picture of that area when i get my jeep back tonight. that makes sense.
 
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Dvaniwaarden11 said:
the pump is essentially brand new. the whole cooling system is brand new with only 1-2,000 miles on it. the denso radiator is like 24 hours brand new now haha. i just dont see the water pump failing right away?
Click to expand...

Do you remember what the impeller on the water pump looked like? There are a lot of impeller designs and some of them are much better or worse than others.

I believe Chrysler switched from a cast impeller to a plastic high flow impeller at some point. The plastic one supposedly has a ~20 percent or better increase in flow over the cast one.

The AC Delco I bought came with the lower flow cast impeller, so I actually went with the FlowKooler pump instead. Like the late model OEM plastic impeller, it is a high flow impeller, but is made of billet aluminum rather than plastic.

Not sure if the billet aluminum one beats the stock plastic impeller in terms of flow rate (I suspect it does but cannot back that up with data), but it almost certainly beats out the cast impeller.

AC Delco on top and FlowKooler on bottom:
20200902_115752.jpg


20200902_115809.jpg


20200902_115804.jpg


20200902_115738.jpg
 
MikeE024 said:
You wouldn’t be having issues if new parts were always good.
Click to expand...

Exactly. I did my rear main three times before I switched from Felpro to Mopar. Several thermostats before I bought a Flowkooler. Ironically I went through a couple Bosch pumps (made in Brazil) before the cheapest fuel pump...Brute Power...worked.

It's the new normal and I just about expect to do a replacement 3-5 times before I get a working and functional part.

Truck is getting a 0152 code...one listed cause is a fuel leak through the vacuum reference line into the intake...and since that regulator is a year old guessing that's the cause and not any of the rest of the twenty year old parts.

-Mac
 
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Steel City 06 said:
Do you remember what the impeller on the water pump looked like? There are a lot of impeller designs and some of them are much better or worse than others.

I believe Chrysler switched from a cast impeller to a plastic high flow impeller at some point. The plastic one supposedly has a ~20 percent or better increase in flow over the cast one.

The AC Delco I bought came with the lower flow cast impeller, so I actually went with the FlowKooler pump instead. Like the late model OEM plastic impeller, it is a high flow impeller, but is made of billet aluminum rather than plastic.

Not sure if the billet aluminum one beats the stock plastic impeller in terms of flow rate (I suspect it does but cannot back that up with data), but it almost certainly beats out the cast impeller.

AC Delco on top and FlowKooler on bottom:View attachment 543007

View attachment 543008

View attachment 543009

View attachment 543010
Click to expand...

Unfortunately I’m not sure since my mechanic installed the part when he put my new 4.0 in.
 
5TTTj said:
I posted back on one page 1 about sealing up the openings around the core support / grill, I was at the Junk yard the other day and took this picture of a 99 TJ with the factory deflectors still in place. maybe this explains what I was trying to describe.

View attachment 543005
Click to expand...
I still have the stock parts in those spaces you mentioned

IMG_6362.jpeg


IMG_6360.jpeg


IMG_6359.jpeg
 
Once again wanted to add more pictures of the winch blocking half of the grill. My mechanic swears this is the issue lol.

Also I know people on here hate the k and n air filters. Previous owner installed one on this Jeep. Could that be increasing the engine temperature to where my cooling system can’t catch up?

And it’s confirmed a denso radiator.

IMG_6364.jpeg


IMG_6365.jpeg


IMG_6367.jpeg
 
Im prepared to unwire the winch and remove it to at least test to see if I still overheat on the freeway tomorrow before I start pulling parts out to replace the water pump.
 
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A K&N air filter may cause a number of problems but overheating is not likely one of them.

Pulling hotter air in through the intake actually reduces the maximum temperature of combustion you can get since the air is less dense and can combust less fuel.

Is your heater working well? If not, it could indicate the line is plugged or otherwise not flowing correctly. The heater core line has to be free flowing as it is the bypass loop for any coolant that doesn't get forced through the thermostat. If it's blocked, and the thermostat closes, the coolant can get deadheaded long enough to boil in the engine block or cavitate in the pump, causing coolant flow to stay disrupted even if the thermostat does open again.
 
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Steel City 06 said:
A K&N air filter may cause a number of problems but overheating is not likely one of them.

Pulling hotter air in through the intake actually reduces the maximum temperature of combustion you can get since the air is less dense and can combust less fuel.

Is your heater working well? If not, it could indicate the line is plugged or otherwise not flowing correctly. The heater core line has to be free flowing as it is the bypass loop for any coolant that doesn't get forced through the thermostat. If it's blocked, and the thermostat closes, the coolant can get deadheaded long enough to boil in the engine block or cavitate in the pump, causing coolant flow to stay disrupted even if the thermostat does open again.
Click to expand...

Heater works completely fine. So I know I have no clogs in the heater core.
 
Dvaniwaarden11 said:
Heater works completely fine. So I know I have no clogs in the heater core.
Click to expand...

I had this same problem on a Camaro in high school,I even ran a second gauge on it,it turned out to be a cheap auto zone thermostat that I installed ,you need to get to the dealer and get a mopar thermostat with a hole in the top,install it with the hole at 12 o’clock and it should fix your problem.
 
Alright everyone, I figured it out.

I took my whole front bumper off since I couldn’t access the winch bolts without removing it. I drove it around all day pedal all the way down going 75 up hills. Noticeably more power and the hottest I could get the engine was 215-217. I was unable to get it to overheat again. I know a lot of people on here said it couldn’t possibly be the winch blocking the airflow but it was 100% the problem.
Thanks again for all the help with my jeep. Appreciate the generosity of people in this forum.

Now I have a great excuse to replace this bumper with something more low profile.
Thanks!!

IMG_6371.jpeg
 
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Oops, this didn’t fix it.
Just got back from a trip to the inyo national forest outside bishop CA.
great trip, some good technical off-roading but was a little hot out. Great time regardless.

Turned a 5 hour travel day into an 8 hour travel day because I would overheat up to 235-240 a few times on the freeway. Would always drop my speed down and the temp would drop. Happened mostly on long hill climbs where the motor had to work harder than normal. Generally on the flats it would be fine as long as I hovered around 55 mph. Was about 105-110 outside, so had the AC cranked until it would get hot and then turned the AC off.

I’m doing one last test before dropping $250 on a mopar water pump I found. If that doesn’t work, I’ll drop $550 on a mopar automatic radiator I found on eBay.

(I’ve heard you can use the automatic radiators for manuals as long as you plug the transmission ports on the bottom of the radiator)

On the trip I had the thought that maybe my condenser was clogged or dirty. I believe it would be the stock condenser from 1997 since I don’t think it would have been replaced with the engine swap.

So today I purchased some condenser cleaner at Home Depot and repeated the instructions multiple times to ensure any dirt that was inside was in fact flushed out. I used slow water pressure from a hose as to not damage the fins. I was hoping that perhaps that was blocking a bunch of the air before it could get to the radiator which would cause my cooling system to not function as effectively as it should.

Hoping that was the case but I’m not convinced because I didn’t see a ton of mud etc on the ground after I finished cleaning.

Will test it on the highway tomorrow to see if I see any improvement. Since taking the bumper and winch off, my Jeep doesn’t overheat as quickly as it did before so I feel like it’s an airflow problem but I’m not sure. Not sure stoked to spend $750+ on mopar parts, but I want to be rid of this overheating problem to not have constant anxiety staring at my gauges every 30 seconds.

Thoughts?
 
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Dvaniwaarden11 said:
Oops, this didn’t fix it.
Just got back from a trip to the inyo national forest outside bishop CA.
great trip, some good technical off-roading but was a little hot out. Great time regardless.

Turned a 5 hour travel day into an 8 hour travel day because I would overheat up to 235-240 a few times on the freeway. Would always drop my speed down and the temp would drop. Happened mostly on long hill climbs where the motor had to work harder than normal. Generally on the flats it would be fine as long as I hovered around 55 mph. Was about 105-110 outside, so had the AC cranked until it would get hot and then turned the AC off.

I’m doing one last test before dropping $250 on a mopar water pump I found. If that doesn’t work, I’ll drop $550 on a mopar automatic radiator I found on eBay.

(I’ve heard you can use the automatic radiators for manuals as long as you plug the transmission ports on the bottom of the radiator)

On the trip I had the thought that maybe my condenser was clogged or dirty. I believe it would be the stock condenser from 1997 since I don’t think it would have been replaced with the engine swap.

So today I purchased some condenser cleaner at Home Depot and repeated the instructions multiple times to ensure any dirt that was inside was in fact flushed out. I used slow water pressure from a hose as to not damage the fins. I was hoping that perhaps that was blocking a bunch of the air before it could get to the radiator which would cause my cooling system to not function as effectively as it should.

Hoping that was the case but I’m not convinced because I didn’t see a ton of mud etc on the ground after I finished cleaning.

Will test it on the highway tomorrow to see if I see any improvement. Since taking the bumper and winch off, my Jeep doesn’t overheat as quickly as it did before so I feel like it’s an airflow problem but I’m not sure. Not sure stoked to spend $750+ on mopar parts, but I want to be rid of this overheating problem to not have constant anxiety staring at my gauges every 30 seconds.

Thoughts?
Click to expand...

I overheated on the highway recently while trying to drive to CA.

I replaced the water pump with a Gates this time and installed a different thermostat since mine was stuck closed due to heat damage. I usually would have replaced the radiator for this symptom but I was confident the Mopar unit was working and it wasn’t plugged up.

I just drove from Tucson to Riverside in 113* ambient temps for 7 hours. I was good to go with an average speed of 80 mph that included up hill climbs especially around Palm Springs. The rig was loaded down, so there was a good amount of resistance on the engine as I pushed through the winds.

Edit: I didn’t install the new Mopar WP that I also purchased on Amazon because I didn’t like how the bearing felt when spinning the impeller.
 
Last edited:
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Dvaniwaarden11 said:
Oops, this didn’t fix it.
Just got back from a trip to the inyo national forest outside bishop CA.
great trip, some good technical off-roading but was a little hot out. Great time regardless.

Turned a 5 hour travel day into an 8 hour travel day because I would overheat up to 235-240 a few times on the freeway. Would always drop my speed down and the temp would drop. Happened mostly on long hill climbs where the motor had to work harder than normal. Generally on the flats it would be fine as long as I hovered around 55 mph. Was about 105-110 outside, so had the AC cranked until it would get hot and then turned the AC off.

I’m doing one last test before dropping $250 on a mopar water pump I found. If that doesn’t work, I’ll drop $550 on a mopar automatic radiator I found on eBay.

(I’ve heard you can use the automatic radiators for manuals as long as you plug the transmission ports on the bottom of the radiator)

On the trip I had the thought that maybe my condenser was clogged or dirty. I believe it would be the stock condenser from 1997 since I don’t think it would have been replaced with the engine swap.

So today I purchased some condenser cleaner at Home Depot and repeated the instructions multiple times to ensure any dirt that was inside was in fact flushed out. I used slow water pressure from a hose as to not damage the fins. I was hoping that perhaps that was blocking a bunch of the air before it could get to the radiator which would cause my cooling system to not function as effectively as it should.

Hoping that was the case but I’m not convinced because I didn’t see a ton of mud etc on the ground after I finished cleaning.

Will test it on the highway tomorrow to see if I see any improvement. Since taking the bumper and winch off, my Jeep doesn’t overheat as quickly as it did before so I feel like it’s an airflow problem but I’m not sure. Not sure stoked to spend $750+ on mopar parts, but I want to be rid of this overheating problem to not have constant anxiety staring at my gauges every 30 seconds.

Thoughts?
Click to expand...

Did you buy a thermostat from the dealer yet?
 
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Moglocker said:
Did you buy a thermostat from the dealer yet?
Click to expand...

OP this is a great question and should not be overlooked. Your thermostat may have been compromised by the previous overheating problems even if it wasn’t the root cause.

This could be an easy fix. I’d install a new thermostat.

In the very least, you can pull yours and boil test it and/or drive around without a thermostat to see if the issue goes away.
 
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