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Radiator recommendation?

3K views 39 replies 13 participants last post by  Jeffncs 
#1 ·
I changed my water pump and installed a 195 thermostat into my 4.2l CJ7... she continued to run very hot. I pulled and flushed the radiator to find lots of large, flaky rust coming from the top of the radiator..... I thought about getting it flushed professionally, but am leaning towards a replacement.

Before dropping in a new rad, I’m going to install an inline radiator screen to capture more rust flakes before entering the rad. I’m also going to run one of those rad flushes for a few hours and then drain, flush, flush, flush.

I’m tired of messing with things and am planning on replacing the radiator after all that is done and the filter is in place. I’m leaning towards a $250 unit from O’reilly Auto Parts that’ll come with a lifetime warranty. Before I throw money at their rad, do you have a suggestion for an alternate that’s in the same price range or only slightly more? The O’reilly unit has plastics tanks and aluminum core...

Suggestions for an alternate rad?
Anything else I should check before throwing more money at the cooling system?

Thanks to all in advance!
 
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#3 ·
If you have a brass/copper radiator I suggest getting it recored at your local rad shop. Cheaper than a new one and you will keep a local business going. I have a 70 year old rad in my Willys.

Avoid aluminium/plastic radiators. I am sure they will work fine for some years but they are costly and tricky to repair. The brass ones are more expensive but maintainable.
 
#4 ·
I have and recommend the Summit center cap radiator. If my old one had been repairable I would have had it repaired. Take it to a shop and get it professionally cleaned and repaired. A reputable shop will tell you if it is better to replace than repair.

The rust flakes/scale you are seeing have clogged the tubes in the radiator. You need to get as much of the scale as possible out of the cooling system no matter whether you repair or replace your radiator.

Please give us more info about the inline filter.
 
#5 ·
I changed my water pump and installed a 195 thermostat into my 4.2l CJ7... she continued to run very hot. I pulled and flushed the radiator to find lots of large, flaky rust coming from the top of the radiator..... I thought about getting it flushed professionally, but am leaning towards a replacement.

Before dropping in a new rad, I'm going to install an inline radiator screen to capture more rust flakes before entering the rad. I'm also going to run one of those rad flushes for a few hours and then drain, flush, flush, flush.

I'm tired of messing with things and am planning on replacing the radiator after all that is done and the filter is in place. I'm leaning towards a $250 unit from O'reilly Auto Parts that'll come with a lifetime warranty. Before I throw money at their rad, do you have a suggestion for an alternate that's in the same price range or only slightly more? The O'reilly unit has plastics tanks and aluminum core...

Suggestions for an alternate rad?
Anything else I should check before throwing more money at the cooling system?

Thanks to all in advance!
I went with an aluminum radiator. Works good, but, if it fails, no repair on trail. So I will be going back to the original brass at some point. They are more expensive. But if you maintain your cooling system, they should last.

As far as your in stream screen to catch rust. I don't know how you have that designed, but wouldn't that be risking plugging the cooling system?
 
#8 ·
Here's that pic of the inline filter...
Interesting. Learn something new everyday.

Repairing the original is not a bad way to go. I still have my original, but most radiator shops around me have closed down. Mine will need a new core replacement. I can buy a core, but my soldering skills may not be up to par to install it. So I will have to find someone to do it for me.😁
 
#10 ·
Thanks to all for the advice...

I just arrived home from dropping my radiator off at a local shop for repair. They’re going to remove the top tank and clear out the tubes manually. They’ll also pressure test it going into the core for integrity. In fact, he said it would probably be tested three times while they have it!

Assuming no surprises, he said it would function as new when I get it back... thanks again to all for the advice and guidance!!
 
#12 ·
You can use one of these to back flush the engine (whole system) When I do it, I open the radiator drain too.

https://shop.advanceautoparts.com/p...kf0aa/7690003-P?searchTerm=radiator flush kit

Mix your antifreeze 50/50 BEFORE you pour it in---it will ALWAYS be correct!

I always add "water pump lubricant" to mine, looks like you can bundle the whole works cheaply at this link

https://www.amazon.com/Prestone-Super-Radiator-Anti-Rust-AS170Y/dp/B07GQ5XC8M

I never have rust--I think it gets started by using plain water (maybe improperly mixed coolant) in the cooling system.

I have an Advance Auto lifetime radiator from 2000 $183 all brass---I have a binder full of lifetime receipts (other info for "Mr. Jeep" too)---some are originals---some are copies of "fading/ thermal receipts---oldest is 1989 for my alternator.

Just for my '77, they include: 3 sets of drum brake shoes/ water pump/ ignition module/ 3 mechanical fuel pumps/ 258 headers/ radiator/ OEM type heater fan and core/ secondary heater core-fan-motor (backup heat) / distributor/ engine mounts/ master cylinder/ all 4 "U" joints/ all 4 shocks/ steering stabilizer/ harmonic balancer/ starter/ alternator----maybe I forgot something? And quite a few tools

All kept safe in my book. Whenever I have to swap out something, I insure I keep the receipt or they give me another one also stating "lifetime warranty".

I pretty much always have no problem.

Only on one occasion was I "tested" by an employee. I simply called the manager over and a few customers, I asked the feller to check my pulse!

About a year ago, I had a heart attack---I darn near voided my warranties!

Below is a few pages in my book

-----JEEPFELLER
 

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#13 ·
A couple of late questions:
Have you verified the overheating issue with an IR gun?
Shroud?
Proper fan and in working condition?
Just a couple of additional questions on traditional overheating causes.
 
#14 ·
Great questions....

I should have verified the temps with an IR fun, but didn’t. However, I’m all but positive that my rad is clogged. I’ll add a pic of the first flush through it upon buying the Jeep. It’s nasty...better now, but I’m still pulling rust chunks out of the rad.

If nothing else, I’ll k ow my rad is clean and fully functional.
 

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#15 ·
That is nasty soup, could be it had no fresh coolant for a long time. The core/freeze plugs, thermostat housing and water pump impeller are all at risk from rust. Maybe you could get a look under the manifolds for any rust staining or dribbling from the plugs. Photo is with the manifolds removed on one that started having a mystery coolant leak.
 

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#18 ·
I agree completely. I think someone before me added straight water to the system and failed to use coolant. Once my rad come back from the shop (hopefully today!) I'm going to reinstall and start the full flush process.

I will say that the freeze plugs aren't showing any obvious signs of leaking at this point and I replaced the water pump already. I'm hopeful that I caught it early enough that it's recoverable.... time will tell!
 
#16 ·
IF you have to get a new core, my 1st choice would be to see if they can get or make a copper/brass with horizontal tubes rather than the traditional vertical.
 
#20 ·
As an update, the radiator shop called me yesterday afternoon with an update... said he’s not getting the flow he expects after the flush and recommended pulling the tank and rodding the core tubes to clear the debris. I gave him the green light as it’s still cheaper than a low quality replacement and an all-copper/brass radiator.

I should have it back early to mid of this week.
 
#21 ·
One thing about rodding out the radiator tubes, IF any tubes are thin on account of corrosion the rodding will puncture the tubs and you'll need a new core. This has been my experience innumerable times.
 
#25 ·
As follow up for those of you that are interested...

I installed my freshly riffed and pressure tested radiator along with the inline radiator filter. I wanted to share a pic of it installed and what the screen caught after 20 mins of driving with distilled water and flush in the system. Note the rust scale at the left side of the glass tube...

It’s running a little cooler now and will hopefully run even cooler with actual coolant in the system not water.
 

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#26 ·
I like your inline filter. It will probably run a little hotter when you run coolant. Water has more cooling ability than coolant. We run coolant to prevent the radiator fluid from freezing and to keep corrosion down. Pure water transfers the heat better.

As follow up for those of you that are interested...

I installed my freshly riffed and pressure tested radiator along with the inline radiator filter. I wanted to share a pic of it installed and what the screen caught after 20 mins of driving with distilled water and flush in the system. Note the rust scale at the left side of the glass tube...

It's running a little cooler now and will hopefully run even cooler with actual coolant in the system not water.
 
#28 ·
I'm big on trusting the science and the science says properly mixed antifreeze/coolant raises the boiling point and lowers the freeze point. A thermostat does nothing to prevent overheating. Simply put 180* thermostat opens at approximately 180* and a 195* opens at approximately 195*. Thermostats get the engine to and keep it to the low end operating points. In colder weather you will appreciate this when you are waiting for the heater do its job. No matter which thermostat you use if you have a problem with overheating changing a properly functioning thermostat won't help you.

If your water pump isn't leaking leave it alone. They last for years not months.

A lot of the scale you see will wash out when you drain the water. You won't know how it will work until you put it back together and try it. Remember coolant raises the boiling point so temperatures in the 210-220* are okay in city traffic or slow speeds. When I only had an electric fan I had it set to come on at 210*.

You still haven't filled out your profile. Please do it.
 
#29 ·
The above was spoken by a true South Carolina boy!

Just to add to that,

For every (1) lbs. that you raise the water pressure in the radiator (or even your pressure cooker) -----At sea level

You "give" the water 3 additional degrees of temperature before it boils .

So

A 16 lbs. radiator cap will build 16 lbs of pressure before it "vents" additional pressure (can't hold anymore)

16 X 3 =48 (48 being the additional temperature that can be achieved above open air boiling point)

Boiling point is 212 Degrees

Boiling point under 16 Lbs. of pressure is 212+48 = 260 Degrees.

Theoretically, at 259 Degrees, the water is not boiling inside the pressurized vessel

CARELESSLY Snatch the cap off at this temperature and the water instantly turns to steam as it now can boil at 212 Degrees. If I'm not mistaken, you get 1600 more times steam than the water volume generating it.

Basically, the steam will overwhelm/ grab/ Burn you instantly as it will expand so quickly.

I strongly suggest using this kind of cap, you can bleed off pressure by raising the lever up before you take the cap off!

https://shop.advanceautoparts.com/p...ap-10330/17110037-P?searchTerm=radiators caps

It is "usually normal" to remain 195 degrees or less on a CJ, unless you've done some modifying..... we really don't want to get into the boiling thing!

-----JEEPFELLER
 
#35 ·
Was just looking at my 83 CJ7 owners manual for fluid capacities and noticed on the tech spec page they indicate a radiator cap of 14 psi. I have a 16 psi on now and it's running a bit warm. Could that be (one of the reasons) why?

JEEPFELLER, the link pulls up an 18 psi cap. But I will look for one with a vent lever since I've had to clean up coolant all over my engine and garage.
 
#30 ·
What JEEPFELLER said X2. I don't know why I forgot to mention the cap other than it could be a mental block. When I was 16 I worked in a filling station and a guy drove in and while I filled his tank up with Firechief he asked me to check his water. He neglected to tell me it was running hot. I had a 2nd degree burn from my wrist almost to my arm pit. I now check coolant levels only when the engine is cold.

It is called a cooling system. All the components work together and any weak link can cause problems. I have a cap test kit but I can go to town and buy a $7.00 cap before I can find it. It is probably on the shelf beside the dwell meter and SWR meter.
 
#31 ·
Dwell meter... wow.

Now the SWR meter, mine happens to be setting right in front of me so I can monitor the base setup....

I want to add something on the whole burn/scald thing. I was driving a 2.3L Ranger years ago, and the water pump went out. As you know, the temp gauge reads COOLANT temp. Well, when there isn't any coolant, it reads low temps. My father and I stopped to check why the engine was acting odd, I felt the radiator, and it was cold. I popped the cap, and that steam cam out so fast it blew the cap from my hand and burnt my arm wrist to elbow! There was still water in the block, but none in the radiator, as the water pump leaked it all out. But when I released the pressure... Moral of the story? DON'T always trust the "it's cold, there's nothing in it!" thought!
 
#33 ·
I know where my Dwell meter and timing light are (all both sets of 'em!) Here's my favorite in pic 1!

Mr. Bob gave me a cool "Willy Jeep" magnet a few weeks back.

I really like it, even though it won't stick to the body or dash. it will stick onto the storage box center-line, but mostly under the passenger seat, one of the few things I salvaged from the original body. It's now almost between the seats, just away from where people step to get to the back seat (last pic is some of them back seat people!)

It just looks at home in "Willy" (until someone likes it better than me),

I (and George) appreciate the hospitality that you and the rest of the Jeep bunch provide up there in your hometown!

---JEEPFELLER
 

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#36 ·
I clicked on the closest link (above) That you quoted me on.

It brings up a "16 lb" cap at Advance Auto Parts----2 other online stores show the same cap for an '83 CJ7 w/ 258

I doubt 2 more lbs on the cap would make it run any warmer.

Did you look at the other tests/ recommendations given to Jeffncs?

If your cooling system is still OEM, If applicable maybe the fan clutch is defective or your possible older radiator has internal mineral build up, "build up" being what I see as the most common evil to the system. Professional take apart and flushing or a new radiator usually fixes the issue.

----JEEPFELLER
 
#37 ·
Just ordered the 14-18 psi Stant safety cap on AZ, so we'll see. New 3 row radiator from Summit, so not a clog problem.

I now have two fan clutches on my desk that are too long and will trash my radiator. Returning both on Monday. US motor Works J22126 and J22149. The 149 has a shorter shaft than the 126 but still longer than the original by at least half an inch. Will be calling them on Monday to see if they have a solution.

Will also check the new Stant Superstat 195 degree thermostat I installed to see if it's opening correctly. Reviews haven't been very kind.

I've spent five and a half years restoring this 83 and the cooling system is giving me the most problems.

Not trying to hijack, but will follow up on this post to report any updates.

Thanks to everyone for the info.
 
#38 ·
Had issues with mine, however not as Fouled as yours, but it was my Sender. Replaced Sender and went with a Manual Gauge in the Block and no more issues, I did go Aluminum on the Rad and noticed it Cools a lot Faster when the Thermostat cycles.
 
#39 ·
So it seems that all my issues may be coming down to a bad sending unit. Using an IR thermometer, I pulled reading of just shy of 195* at the head going into the rad. Coming out of the rad, I’m getting a temp reading of 10-15* less.

I’ll throw a new temp sensor in to see if that helps in any way.
 
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