OP
No need to get nervous at 220. But I am under the impression that anything above 235 is too hot. The 0331 casting cylinder head doesn't like heat.
Need advice from 110 degree plus climate TJ owners
- Thread starter iamloganjames
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- coolant radiator temperature
No need to get nervous at 220. But I am under the impression that anything above 235 is too hot. The 0331 casting cylinder head doesn't like heat.
Hood vents won't lower the engine temperature. If that was the case the factory would come up with vents that wouldn't leak in downpours and they could run a smaller less costly radiator.
I disagree with your logic.
Every company makes compromises.
An extreme example we all know, is race cars use vented hoods to keep coolant temps down.
Ok you know all the answers, I'll just back out of here.
Honestly surprised by your response here.
Before I replaced the entire cooling system, it would overheat on the highway. In order to travel to a crawling event 6 hrs away, I installed these vents. Only after the vents was I able to drive at normal highway speeds and keep the temps in check for the entire drive.
I could go on and on about my VW GTI and all the issues guys have at the track in GTIs keeping coolant temps down, until they install vents in the proper location.
Not sure what your deal is.
Edit: My point is, that the original radiator was clogged, but the added airflow through the radiator and out the hood vents made the radiator slightly more efficient. You said vents can't make the engine run cooler, which is false, in my case.
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IOwnCalculus
TJ Enthusiast
Power loss from heat should be expected regardless of how well your cooling system is doing, especially in the Phoenix area. High temperature at Sky Harbor is "only" 103 right now but density altitude is already nearly 4200'.
The power loss is the same day/conditions/time. Not as compared to different conditions.
I know how DA works.
TNHEADDUCK
TJ Enthusiast
If you are relying on an electrical temp gauge and sensor set up it is only a guess as to what the actual temp is, get a quality manual gauge and plumb it in before the thermostat for a more accurate reading. I don't see how hood vents would lower the actual water temperature in the cooling system if all of the components are working as they should, after the thermostat opens a few times and gets the cooling system saturated with heat it stays open for most if not all of the time. JMO.
Not the best angle but doesn't look to me like the vents should be a problem.
Does it work hard to cruise at 70 or do you have to give it a lot of gas? What RPM? instant MPG?
I've always run hotter crawling than on the highway.
Brianj5600
TJ Expert
Middle Tennessee doesn't seem to have as much humidity as it did 10 years ago. We had pop up thunderstorms 2-4 days a week. I used to mow twice a week and now I can go weeks.
I don't think the vents hurt either, but they are not the topic of discussion. I just mentioned them to be clear about my cooling system. They were added prior to completely replacing my cooling system, with all the parts as recommended by this site, which made a big difference in temps. I had to block them off in the Nebraska winters to keep the jeep coolant warm enough.
The motor is not working hard at 70 due to 3.73 regear. Instant MPG is unknown, but I don't get more than 13-15 avg mpg.
OP
I think I've fixed it. First I did a radiator flush. Found a bunch of what looks like sand in the radiator. Maybe vandalism. I don't have a hood lock and this doesn't look like it's from the water jacket.
Then I put the radiator back in and did a full cooling system flush (excluding heater core) with 1 bottle of prestone as105 and distilled water. Then I flushed all that out with distilled water again. Heater core only got flushed with distilled water. No chemicals. Then I filled with distilled water only and heater core still bypassed I did opt to reinstall the thermostat that the last mechanic put in, and it appears to be a 180. Wish I knew that. Couldn't tell that before because it never stopped climbing.
Now the temp dropped as far as 186 at about 45 mph with the AC on in 100° ambient. I'm going to test again at 115° this afternoon. 
Then I put the radiator back in and did a full cooling system flush (excluding heater core) with 1 bottle of prestone as105 and distilled water. Then I flushed all that out with distilled water again. Heater core only got flushed with distilled water. No chemicals. Then I filled with distilled water only and heater core still bypassed I did opt to reinstall the thermostat that the last mechanic put in, and it appears to be a 180. Wish I knew that. Couldn't tell that before because it never stopped climbing.
Now the temp dropped as far as 186 at about 45 mph with the AC on in 100° ambient. I'm going to test again at 115° this afternoon.
OP
OP
C.J. Roberts
TJ Addict
I think I've fixed it. First I did a radiator flush. Found a bunch of what looks like sand in the radiator. Maybe vandalism. I don't have a hood lock and this doesn't look like it's from the water jacket.
View attachment 343413
I did opt to reinstall the thermostat that the last mechanic put in, and it appears to be a 180. Wish I knew that. Couldn't tell that before because it never stopped climbing.
It sounds like you fixed the original problem. HOWEVER, the Jeep wants a 195° thermostat. It's supposed to run at 210°. Otherwise, the ECM is going to think that it's not fully warmed up, and will add more fuel causing the engine to run rich.
OP
I will be replacing in a few months with the right one. I'm just not interested in tearing it apart again in this weather. Should have just replaced it since I wasn't the one who purchased the part. Grr.
I agree. No reason to believe the factory gauge. I'm in Tucson. Have the original thermostat, mine per the gauge runs just under 210 and drifts about a needle width higher if I'm climbing a long hill with the AC on. It's never boiled over or overheated. Has yours?
OP
Problem is solved now. Temps now stay under 220 all the time. Even with AC on in direct sunlight at idle, 115 degrees ambient. Nobody's 4.0 should run hotter than mine unless they have an automatic as well as the Cali emissions cats that I have.
If you see numbers over 225 on your electrical guage (read via OBD2 port), there is definitely room for improvement. Keep in mind, the numbers I achieved are with a completely factory cooling system. No mods or trickery. But no winches or accessories blocking the grill either.
If you're relying on boiling over as your indicator of a problem, expect a cracked cylinder head in your future.