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Cooling Question (yes I searched)

Karlm

NAXJA Forum User
Location
Antioch, CA
Ok, so I went through and replaced every single part of my cooling system except for my heater core aout 3 years ago. I put in the 3-core GDI radiator whiched worked OK for a while. This summer it started overhearing in traffic again and overheating while climbing grades at speed. At regular highway speeds it is fine. Water pump and fan clutch are good to go, so I'm leaning toward the radiator (especially after searching and reading some less than stellar reports n the GDI) Does it seem like I'm on the right track here? It seems to me like my setup is just not dissipating heat unless air is being forced through the radiator from driving at speed. Also, opinions seem to be fairly mixed on the Modine and the CSF radiators depending on which thread you read. Any advice on which way to go? I know this topic has been beat to death (as evidenced by the 10+ page of threads that came up when I searched) but after 2 hours of reading, I still had a few questions. Thanks for any help.

Karlm
 
GDI tend to leak and have quality control problems, your's must be OK because it worked three years ago. I would not suppect the radiator, sounds like a clutch fan problem. If it's not pulling air when your going slow, the best radiator in the world won't work. When is the last time you did a good job of washing the bugs out of the A/C and radiator?
 
langer1 said:
GDI tend to leak and have quality control problems, your's must be OK because it worked three years ago. I would not suppect the radiator, sounds like a clutch fan problem. If it's not pulling air when your going slow, the best radiator in the world won't work. When is the last time you did a good job of washing the bugs out of the A/C and radiator?

He said its also overheating pulling grades at speed.
 
I wouldn't say it worked fine for 3 years. It just worked. It never worked perfectly. I could still get it to overheat in 90+ weather if I really pushed it. It just has gotten worse over the last 3-4 months. I'll check the fan clutch again when I get it home from the shop this afternoon (time for regular trans. service - 160,000 miles and still tight and right :) ) Last time I checked the clutch it was ok, but that was in the spring. If it was just low speed then I would lean toward the clutch or the fans, but at freway speeds the fans don't really help as much and it was still overheating pulling grades.
 
how many miles have you driven in the last three years? You may just have a ton of bugs and gunk built up in the radiator. Use a degreaser and soak the radiator real good and then hose it out.

-Brent
 
If you did a search on the subject you would find the recommendation to replace the fan clutch every 5 years. In addition, you can't really test it. That is why the recommendation is to replace after 5 years. It is worth it. If the problem persists, then I would suspect the pump. Having said that, the only failure I have experience with on the pump is a blown seal. I believe all the posts on this site would support that statement.
 
When you say overheat, what temps do you reach and for how long?
 
Do a plug reading. You may be running too lean. If that is fine then you have other issues. A common problem is the lower radiator hose collapsing when it gets hot.

I run a GDI 3 row with a 4.7L stroker. It sometimes runs on the high side when crawling on the trail, unless I turn on the AUX fan, but even pulling the high mountain passes here in Colorado, I have never had it get above the 195 thermostat, even on the hottest days with the A/C, so a GDI is definately capable of cooling a stock 4.0L.
 
Funny, sad funny, I upgraded to the GDI three years ago and this summer had to have it rodded - was partially blocked with corrosion. Which rekindled the debate over distilled water and tap water, which I was using.

The rod job has returned me to 210, give or take a few, and I'm happy. Flushed again and returned with mostly distilled water and coolant and some tap water that I know remained in the system.

Depending on your tap water, an annual flush is probably warranted. But for sure, if your fan clutch is more than 5 years old, like the man said, change it.
 
I have seen a ton of post about overheating?
I guess I am lucky I have an 89 MJ and when bought it the guy had just installed a new 2core closed system replacement unit (don’t know brand)
I removed the mechanical fan and installed a 1996 XJ electric fan on the driver side and placed the 89 electric fan on the pass side
I have yet to over heat any time on a daily drive and that is with the fans off 90% of the time
I run one fan in stop and go traffic with steady temps of 200
Now when off road (and I do that allot) I do have to run both fans to keep it at 200 or below one fan will get up to 210
So what is my point? It is I agree with other posts here that you must have a BAD FAN CLUTCH or some obstruction of airflow
I recommend dump the mechanical fan and run electric it gets you as much as 15+ more HP and maybe a mile or two per gallon? Also make sure all your cooling fins are clean clear and straight!
 
Sounds obvious but "Condenser Fan"??? I spent 3 weeks replacing everything and finally realized it was the $50 condenser fan
 
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