Overheating is not solved

[themud]

before everyone gets to excited about the alumrad being al just remember its a drop in replacement it does have plastic tanks...Im not knocking it cause I have one in my heep right now and it does get a little warm but I think its just a bad airflow design FLAW from DC..I will also be going electric once I get a/c bracket from a tj(it takes the fan clutch completely out no studs to cut)...Plus youve got to get a fan worth crap I picked up a permacool 14 fan it moves about 3000 cfm it should do the trick after I put in a good shroud..
luck
themud
ps I do agree the tranny is the problem mine does the same thing..

 

[robs]

Buzzzzzzzzzzzttt!!!

themud was right.

Nice radiator, but plastic ends...

Pretty tough to judge since it's only like 75F outside right now... BUT... it might be a LITTLE better, but it ain't gonna fix it...

In the driveway... zipping the engine between 2-4000 rpm with the air on high, and it stayed right at 195F...

BUT... I tied off to a tree and put in low range and just spun for a little while... NOT LONG AT ALL... jumped right up to 230F... once at 230F, it took a LONG time to come back down...

So... guess it's time to do the head gasket. :rattle: :rattle: :rattle:

 

[robs]

In the woods today... 96°F outside... hitting 230-240F after a few hill blasts... No real change with the Aluminum (and plastic) radiator... in fact, it heated up quicker than the CSF...

However... driving home, anytime I got over 45 mph, it ran very cool... right at 195F... the CSF never did that... Like themud is doing, it might be an airflow issue with this radiator.

 

[old_man]

Here are a few stupid questions I'm going to ask. I ask these because I've never seen a 4.0L overheat if it was fine mechanically.

Did you replace the radiator cap when you did the radiator? (they get old and don't hold pressure) This is a very common thing. Ideally change the cap every year or so. 16lb.

Is the lower radiator hose the type with the spring inside? (When hot and high rpms, they can collapse without the spring)

If you replaced the water pump lately, are you sure they gave you the right one. There are right and left hand rotation pumps. (They look identical on the outside, and even on the inside unless you look at the direction of the vanes)

Have you checked for hydrocarbons in the radiator? (A leaky head gasket can cause all kinds of problems in this area) This is especially important with an aluminum radiator as the hydrocarbons and byproducts will turn the coolant into an acid and eat the radiator in short order.

Have you burped the engine block to get rid of trapped air? (A trapped air bubble can cause overheating) This is done by backing out the temp sender on the back of the head.

What color is the inside of the tail pipe? (Checking for lean burn condition)

Have you pulled the spark plugs and check them for running too lean? (Running white with buildup is a symptom of running lean)

Have you checked your vacuum pressure at an idle? ( A large vacuum leak will cause the lean run scenario, most likely will have a high idle)

If you have AC, have you checked that the AC condenser isn't blocked?

Have you checked your fan clutch? (I take a piece of safety wire and wire the clutch so it can't spin and see if that fixes it.)

I've even seen engines run hot due to a plugged exhaust. Normally associated with a drop in power and sluggish accelleration.

Lean run issues can be caused by a dozen or so things. If it is a lean burn, post back and we can cover the possibilities.

This is a general list. Sorry if I asked a question that you already answered.

Lots of luck.

 

[robs]

Here are a few stupid questions I'm going to ask. I ask these because I've never seen a 4.0L overheat if it was fine mechanically.

Did you replace the radiator cap when you did the radiator? (they get old and don't hold pressure) This is a very common thing. Ideally change the cap every year or so. 16lb..

Great questions. THank you!

Yes. I'm on my third radiator and 5th cap.

Is the lower radiator hose the type with the spring inside? (When hot and high rpms, they can collapse without the spring)

Yes

If you replaced the water pump lately, are you sure they gave you the right one. There are right and left hand rotation pumps. (They look identical on the outside, and even on the inside unless you look at the direction of the vanes)
.

I've got a high flow waterpump now... it's vanes were the same direction as the orginal removed.

Have you checked for hydrocarbons in the radiator? (A leaky head gasket can cause all kinds of problems in this area) This is especially important with an aluminum radiator as the hydrocarbons and byproducts will turn the coolant into an acid and eat the radiator in short order.
.

This I have NOT done. I loose no coolant over a very long period of time. I've been told this is my problem. I would like to exhaust other issues before yanking off the head... :yeck:

Have you burped the engine block to get rid of trapped air? (A trapped air bubble can cause overheating) This is done by backing out the temp sender on the back of the head.
.

Couple times.

What color is the inside of the tail pipe? (Checking for lean burn condition)
.

Sooty

Have you pulled the spark plugs and check them for running too lean? (Running white with buildup is a symptom of running lean)
.

I've fought this for years. I've replaced plugs a few times. No real signatures of lean burn.

Have you checked your vacuum pressure at an idle? ( A large vacuum leak will cause the lean run scenario, most likely will have a high idle)

.

Not yet. Will do tonight. However, I just found a hole in the vacuum cannister, and have plugged it. It ran fine even with this system leak.

If you have AC, have you checked that the AC condenser isn't blocked?
.

Clean

Have you checked your fan clutch? (I take a piece of safety wire and wire the clutch so it can't spin and see if that fixes it.)
.

I've replaced the clutch before. I've got a flex fan to install tonight.

I've even seen engines run hot due to a plugged exhaust. Normally associated with a drop in power and sluggish accelleration.
.

Agreed. However, today, it's close to 100F outside... I flogged it on the interstate, and it never got over 210F.

Lean run issues can be caused by a dozen or so things. If it is a lean burn, post back and we can cover the possibilities.
.

Agreed.. I've changed the oxygen sensor as well..

This is a general list. Sorry if I asked a question that you already answered.

Lots of luck.

Thanks Bro! It's driving me NUTS

 

[Fergie]

Here is something else...

Are you going by the temp gauge you have? If so, have you checked the actual engine temp with temp gun?

Your temp gauge may be inaccurate.

I am in the same boat as you. I just switched my CSF to a Modine, removed the trans from the radaitor cooling loop, and fixed a leaky lower rad hose, along with flushing the entire system.

So, get the gauge checked, and think about installing a seperate temp gauge.

Fergie

 

[themud]

Here is something else...

Are you going by the temp gauge you have? If so, have you checked the actual engine temp with temp gun?

Your temp gauge may be inaccurate.

I am in the same boat as you. I just switched my CSF to a Modine, removed the trans from the radaitor cooling loop, and fixed a leaky lower rad hose, along with flushing the entire system.

So, get the gauge checked, and think about installing a seperate temp gauge.

Fergie

Yes as a matter of fact I just did that today you dont wanna know what I found just plingin that gun all over the place...The results will shock the hell out you...thermo cover 210*, exhaust 335*+, intake 300*+, sending unit for gauge 215*220*, tranny pan 150*, tranny pan near the crossover pipe 206*(OUCH), oil pan185*(all over)...I did even more things too...AND THE DAMN FAN DOES COME ON AT 218* on the dot as setup by DC...
themud


Past 210 on the guage its accutate just not linear...

 

[robs]

I've found the same thing with the IR gun.

My new fan clutch was a little weak, so I popped another one in last night... a much larger and stiffer one than what was on it. Don't know yet if it helped, but it definately moves more air.

 

[langer1]

Much the same problem here previous owned did everything to fix the problem, gave up and sold it cheap to a friend of mine. The orignal owner was a slow driver and only had the problem when pulling his boat. My buddy is a hard driver and had the over heating problem all the time.

One day the rad. just blew luckely a local radator shop is also a Jeeper and sold us the Modine radator, a three year problem was solved.
Check out Dave Rupples on the net.

 

[robs]

I've found the same thing with the IR gun.

My new fan clutch was a little weak, so I popped another one in last night... a much larger and stiffer one than what was on it. Don't know yet if it helped, but it definately moves more air.

New fan clutch was a little bigger too... under load, it met my new radiator... made a nice 8" diameter hole in it.

 

[Fergie]

Well, just drove home in +100* weather in stop and go with the AC on.

NEVER WENT ABOVE 215*!! !! !!

I installed a Modine from Napa on Sunday, and have 50/50 mix and a bottle of water wetter in it.

Also, make sure you always get a dealer fanclutch as the aftermarket ones are thicker....20/20 ehh.

Fergie

 

[red91]

Well, just drove home in +100* weather in stop and go with the AC on.

NEVER WENT ABOVE 215*!! !! !!

I installed a Modine from Napa on Sunday, and have 50/50 mix and a bottle of water wetter in it.

Also, make sure you always get a dealer fanclutch as the aftermarket ones are thicker....20/20 ehh.

Fergie

Very Cool. No pun intended.

 

[FUNKYTEE5]

Well, just drove home in +100* weather in stop and go with the AC on.

NEVER WENT ABOVE 215*!! !! !!

I installed a Modine from Napa on Sunday, and have 50/50 mix and a bottle of water wetter in it.

Also, make sure you always get a dealer fanclutch as the aftermarket ones are thicker....20/20 ehh.

Fergie

2 Row? I'm looking to purchase one myself.

 

[Fergie]

Yes, it is a 2-row.

And the shop guy at the rad repair place told me that the Modines were better units in general, as he was handing me a patched CSF.

Fergie

 

[robs]

Also, make sure you always get a dealer fanclutch as the aftermarket ones are thicker....20/20 ehh.

Fergie

Yeah... 20/20 for sure... *sigh*...

 

[Fergie]

A small update:

Driving home with the AC on, it runs between 210-220. It only hits the 220 when I stop at a light or in traffic, but it cools back down quickly to 210.

Today, I decided to run without the AC on, and the gauge actually went below 210! Amazing to me. the only time it went above the 210 mark was when I stopped in traffic, and the the fan came on and cooled the vehicle off again.

Tomorrow I go in to have the rad sniffed, just to make sure.

Fergie

PS- Anyone have any advice on a seperate coolant gauge, one that is accurate?

 

[BIGWOODY]

I have an 89 that has had the cooling demons for quite a while now. With the differences in cooling systems it really seems that these problems should not cross over from one system to the other (open or closed). I think from my experiences that the blocks might actually decompose over time and produce sedement that flows through the cooling system clogging up passages, the smaller they are the easier they clog. The stock radiators and many aftermarket radiators have very small passages, adding more rows actually means smaller passages, not larger. I haven't really found a solution but have kept my demons at bay by doing a open system conversion and routine system backflushing.

You sir, have nailed it. I've taken apart many of these with unresolved cooling issues and found exactly what your speaking of. Why this rings soooo true is, IF your STOCK cooling sytem is in good working order and your gear ratio is anywhere near close for your tire size, it works flawlessly with a fresh motor. There isn't a need for bigass aluminum radiators and lower thermostats these may hide the problem or help it out a little, but it still isn't RIGHT! Yes, a tranny cooler is a good idea regaurdless of the condition of the motor. I've seen unreal differences in the temp in mine, it never hits 210 even with whaling on an obstacle for 10 minutes or so matting the gas. Before,about 3 minutes worth of hard "beating on it" it had to sit and cool down or I had to take it easy on it. I still stare at my temp gauge like a freak cause I'm so used to doing it.

 

[Fergie]

Took the Jeep to have it sniffed today, and the HG is good.

Everything seems to work just fine now.

All I have to do is figure out a way to get an accurate engine temp reading....maybe an aux gauge or something of the sort.

Fergie

 

[ryurabbit]

Have you checked the cat converter? I have had the overhating issues and both times its been the cat converter. I keep breaking them inside and they restrict the exhaust. Funny thing is that I only lost performance on the first one but the second one never even gave me a clue IT JUST GOT HOT!!!

 

[JEONLYEP]

I still stare at my temp gauge like a freak cause I'm so used to doing it.

Okay now that made me laugh out load. I know what you mean. Before I owned an XJ I never paid any mind to gauges. Now I can't go a tenth of a mile without looking there. :laugh3:

Going to check mine today to see if it's a head gasket leak or not. If it's not a leaky HG. then I'm going modine or CFS. But something got to change, because my 3 row GDI has been very disapointing.

Daryl